Image: Jorge Gonzalez This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
A newly discovered plant-eating dinosaur may have been a species’ “last gasp” during a period when Earth’s warming climate forced massive changes to global dinosaur populations.
The specimen, named Iani smithi after Janus, the two-faced Roman god of change, was an early ornithopod, a group of dinosaurs that ultimately gave rise to the more commonly known duckbill dinosaurs such as Parasaurolophus and Edmontosaurus. Researchers recovered most of the juvenile dinosaur’s skeleton — including skull, vertebrae and limbs — from Utah’s Cedar Mountain Formation.
Iani smithi lived in what is now Utah during the mid-Cretaceous, approximately 99 million years ago. The dinosaur’s most striking feature is its powerful jaw, with teeth designed for chewing through tough plant material.
The mid-Cretaceous was a time of big changes, which had big effects on dinosaur populations. Increased atmospheric carbon dioxide during this time caused the Earth to warm and sea levels to rise, corralling dinosaurs on smaller and smaller landmasses. It was so warm that rainforests thrived at the poles. Flowering plant life took over coastal areas and supplanted normal food sources for herbivores.
In North America, giant plant-eating sauropods — once titans of the landscape — were disappearing, along with their allosaurian predators. At the same time, smaller plant eaters, like early duckbills and horned dinosaurs, and feathered theropods like tyrannosaurs and enormous oviraptorosaurs, were arriving from Asia.
Enter Iani smithi, unique not only because it’s newly discovered, but also because of its rarity in the North American fossil record and its position in dinosaur history.
“Finding Iani was a streak of luck. We knew something like it lived in this ecosystem because isolated teeth had been collected here and there, but we weren’t expecting to stumble upon such a beautiful skeleton, especially from this time in Earth’s history. Having a nearly complete skull was invaluable for piecing the story together,” says Lindsay Zanno, associate research professor at North Carolina State University, head of paleontology at the North Carolina Museum of Natural Sciences, and corresponding author of the work.
Zanno and her team used the well-preserved skeleton to analyze the evolutionary relationships of Iani and were surprised — and a bit skeptical — of the results.
“We recovered Iani as an early rhabdodontomorph, a lineage of ornithopods known almost exclusively from Europe,” Zanno says. “Recently, paleontologists proposed that another North American dinosaur, Tenontosaurus — which was as common as cattle in the Early Cretaceous — belongs to this group, as well as some Australian critters. If Iani holds up as a rhabdodontomorph, it raises a lot of cool questions.”
Key among these is, could Iani be a last gasp, a witness to the end of a once successful lineage? Zanno thinks that studying this fossil in the context of environmental and biodiversity changes during the mid-Cretaceous will give us more insight into the history of our planet.
Iani smithi is named for Janus, the two-faced god who symbolized transitions — an apt name, given its position in history.
“Iani may be the last surviving member of a lineage of dinosaurs that once thrived here in North America but were eventually supplanted by duckbill dinosaurs,” Zanno says. “Iani was alive during this transition — so this dinosaur really does symbolize a changing planet.
“This dinosaur stood on the precipice,” she says, “able to look back at the way North American ecosystems were in the past, but close enough to see the future coming like a bullet train. I think we can all relate to that.”
The work appears in PLOS ONE and was supported by the National Science Foundation. Zanno is lead author as well as corresponding. Terry Gates and Haviv Avrahami, both of NC State and the North Carolina Museum of Natural Sciences, along with Ryan Tucker of Stellenbosch University and Peter Makovicky of the University of Minnesota, also contributed to the work.
Reference:
Lindsay E. Zanno, Terry A. Gates, Haviv M. Avrahami, Ryan T. Tucker, Peter J. Makovicky. An early-diverging iguanodontian (Dinosauria: Rhabdodontomorpha) from the Late Cretaceous of North America. PLOS ONE, 2023; 18 (6): e0286042 DOI: 10.1371/journal.pone.0286042
Spinosaur tooth from the Wealden seen from two different angles.
Palaeontologists at the University of Southampton (UK) studying a British dinosaur tooth have concluded that several distinct groups of spinosaurs — dinosaurs with fearsome crocodile-like skulls — inhabited southern England over 100 million years ago.
The team, from the University’s EvoPalaeoLab, carried out a series of tests on the 140 million year old tooth, discovered in the early 20th century, in a thick, complicated rock structure named the Wealden Supergroup. The Wealden lies across south-eastern England and was formed around 140-125 million years ago.
The scientists conducted statistical analysis on the tooth, which is stored at the Hastings Museum and Art Gallery in East Sussex. They meticulously compared its characteristics with other species in the spinosaur ‘family’ of dinosaurs to which it belongs. Their findings, published in the journal PeerJ, confirm the tooth doesn’t match that of any identified spinosaur species.
Project supervisor, Dr Neil Gostling explains: “While we can’t formally identify a new species from one tooth, we can say this spinosaur tooth doesn’t match any of the existing species we know about. Given how many individual teeth exist in collections, this could be just the tip of the iceberg and it’s quite possible that Britain may have once teemed with a diverse range of these semi-aquatic, fish-eating dinosaurs.”
The Wealden is famous for its spinosaur fossils. Baryonyx — discovered in Surrey in 1983 — is one of the world’s most significant spinosaur specimens, since it was the first to reveal the true appearance of this crocodile-headed group. Less impressive spinosaur remains — isolated teeth — are common throughout the Wealden, and have often been identified as belonging to Baryonyx. However, some experts have long suspected that this is incorrect.
“We used a variety of techniques to identify this specimen, in order to test whether isolated spinosaur teeth could be referred to Baryonyx,” said lead author Chris Barker, whose PhD focuses on the spinosaurs of southern Britain. “The tooth did not group with Baryonyx in any of our data runs. It must belong to a different type of spinosaur.”
The results show that distinct and distantly related spinosaur types lived in the region during Early Cretaceous times. This backs up research by the EvoPalaeoLab team, who argued in previous studies that the spinosaurs of southern England are more diverse than previously thought.
In 2021, they named the ‘Hell Heron’ Ceratosuchops from the Isle of Wight, and in 2022 announced the discovery of what might be Europe’s largest ever land predator, a giant known only as the ‘White Rock’ spinosaur. These several spinosaurs did not all live at the same time, but inhabited the region over the course of more than 15 million years.
“Museums themselves are places to make exciting discoveries as our understanding of specimens changes from the time they were deposited,” said Dr Neil Gostling. “What this work highlights is the importance of keeping collections alive, and developing our understanding of them. Curators are essential to help us navigate the cupboards and displays, helping us to unpick the often-incomplete records — either never fully recorded, or lost to time. The diversity of palaeoenvironments is not always hidden in rocks, it is often waiting in a museum, its importance waiting to be rediscovered!”
Co-author Darren Naish said “Dinosaur teeth preserve numerous anatomical details, and we can use various analytical techniques to see how similar, or different, they are to other teeth. Our new study shows that previously unrecognised spinosaur species exist in poorly known sections of the Wealden’s history, and we hope that better remains will be discovered that improves our knowledge. Here’s another reminder that even well-studied places like southern England have the potential to yield new dinosaur species.”
Reference:
Chris T. Barker, Darren Naish, Neil J. Gostling. Isolated tooth reveals hidden spinosaurid dinosaur diversity in the British Wealden Supergroup (Lower Cretaceous). PeerJ, 2023; 11: e15453 DOI: 10.7717/peerj.15453
Aotearoa New Zealand’s largest fault, the Hikurangi Subduction Zone (HSZ), is where the Pacific tectonic plate dives west beneath the Australian plate and underneath the east coast of the North Island.
In some parts of the subduction zone, GPS instruments are showing the plates slowly move by a few millimeters a year. This behavior is called a “slow slip” and occurs over periods of weeks or months. However, in other parts the plates are stuck, locked together, and building up pressure.
By understanding the structural factors that create the smoother slipping and stuck zones, scientists are seeking to better diagnose what areas could generate potential future earthquakes and tsunami. As Aotearoa’s largest source of potential earthquakes and tsunami, its critical to be able understand the HSZ in high-resolution detail.
In 2018 a collaboration of researchers from U.S., Japan, UK, and GNS Science used the RV Marcus Langseth to record numerous overlapping race-track “seismic reflection data” lines. The data were gathered together alongside deployments of ocean bottom seismographs and onshore seismometer in a effort called the “NZ3D” survey.
In an international collaborative effort spanning three recent high-profile publications, the first ever spectacular 3D seismic images of the northern part of Hikurangi margin have now documented new insights for understanding the structural, stratigraphic and hydrogeologic characteristics of the HSZ.
Understanding these qualities, specifically how they transport fluids, are key to knowing the conditions that lead to generation of subduction earthquakes.
How the 3D images were created
Seismic reflection data are typically how geophysicists visualize the crust. To capture this data a specialist vessel, in this case the R/V Marcus Langseth, tows an array of individual sound sources that are tuned and combined to radiate a sound wave downward to the seafloor. The echoes that bounce back from layers in the earth are recorded on a streamer towed behind the vessel and on sensitive seismographs located onshore and on the seabed.
While a grid of 2D profiles is good enough to identify major plate boundary structures, this high-resolution 3D data are needed to visualize details within subduction zones to improve understanding of fault geometry and slip behavior. The 3D data are combined in a CAT scan image of the subduction zone that shows the architecture and properties of the boundary between tectonic plates can contribute to variability in the location of strong and seismogenic versus weak slipping segments.
The 3D data provides new constraints on the physical conditions and rock properties to inform computer simulations and forecasts of earthquake ground shaking and tsunami inundation that greatly help improved hazard preparedness and response.
How fluids and underwater volcanoes influence how New Zealand’s largest fault moves
In June 2023 a Nature Geoscience paper reports how the NZ3D data capture a seamount (underwater volcano) caught in the act of subducting beneath the shallow part of the Hikurangi margin and forms sediment lenses in its wake that appear to enhance slow slip.
Further, in a Geology paper the NZ3D data reveal a detailed map of the deeper parts plate interface that shows that it has kilometer-high hill and valleys.
The new NZ3D data show that the plate interface may strongly govern the nature of how the margin deforms, including the localization of both slow slip and hazardous fast-slip earthquakes.
Most recently, a Science Advances paper revealed a previously hidden water reservoir within the layers of the Pacific plate being swallowed up in the subduction process.
The new finding suggests that subducting plate of volcanic rocks act as amplified source of water that influences the slip behavior of the margin. The trapped water is under pressure and results in the plate boundary being weak and prone to unlocking and sliding in slow slip. The study highlights the presence of significant water delivery to slow slip source from the incoming Pacific, that were previously unknown.
“Importantly, we are able to pinpoint the location of water rich layers, that allow smooth slipping, versus other water-poor segments that are stuck and will likely rupture in fast earthquakes,” says Dr. Stuart Henrys, project lead and principal scientist, GNS Science.
Revealing the mysteries of the subduction process in ways never possible before
The hope is that these new generation 3D images will be able to identify areas of the plate boundary where water rich layers enable smooth slip and other areas that are locked and stuck.
By understanding how the slip behavior varies along the subduction zone, it allows scientists to better diagnose and pinpoint areas that are more prone to generate large earthquakes.
Our 3D data also provides new constraints on the physical conditions and rock properties to inform simulations of earthquake ground shaking and tsunami inundation that greatly help improved hazard preparedness and response.
Henrys says, “Our unique 3D seismic data, acquired offshore Gisborne along the northern Hikurangi subduction zone, is providing breakthroughs in understanding of the physical processes that control earthquakes. Globally subduction zones are where one plate dives beneath another and can rupture in devastating earthquakes and tsunami like those in Sumatra (2004) and Japan (2011).”
“These zones are also subjected to benign slow slip behavior that lasts weeks or months. Diagnosing whether slip is fast or slow along the Hikurangi subduction zone, our largest fault, will provide more reliable forecasts and assessments of the risks to vulnerable people and buildings.
“The 3D data we acquired is combined in a medical CAT scan like image providing super cool visualization of a small part of the subduction zone. For the first time we are able to map in detail the architecture and determine properties of the boundary between tectonic plates. Importantly we are able to pinpoint the location of water rich layers, that allow smooth slipping, versus other segments that are water poor, stuck and will likely rupture in fast earthquakes.
“The results represent another piece in the subduction puzzle that we can start using in large-scale earthquake cycle simulations that greatly help improved hazard preparedness and response.”
Reference:
Andrew C. Gase et al, Subducting volcaniclastic-rich upper crust supplies fluids for shallow megathrust and slow slip, Science Advances (2023). DOI: 10.1126/sciadv.adh0150
New Mexico is renowned for its rich geological heritage and is home to a variety of rare gems and minerals. The state’s diverse landscape, including its deserts, mountains, and volcanic regions, has given rise to unique geological formations that have produced some spectacular and sought-after gemstones and minerals. In this article, we will explore a few of the rare gems and minerals found in New Mexico.
New Mexico is famous for its turquoise, which has been revered by Native American cultures for centuries. The state is known to have some of the finest turquoise deposits in the world. The most significant turquoise mines in New Mexico include the Cerrillos, Tyrone, and Burro Mountains mines. New Mexico turquoise is highly valued for its vibrant blue and green colors and is often used in Native American jewelry and artwork.
2- Rhodochrosite
Rhodochrosite is a beautiful pink to red mineral that is relatively rare and highly prized by collectors. In New Mexico, the Sweet Home Mine near the town of Alma in the southern part of the state has produced some exceptional rhodochrosite specimens. These crystals are renowned for their deep pink color and distinct crystal formations. The Sweet Home Mine is considered one of the premier rhodochrosite localities in the world.
3- Apache Tears
Apache Tears are a unique type of obsidian, a volcanic glass formed from rapidly cooled lava. Found in various locations across New Mexico, including the Black Rock and Zuni Mountains, Apache Tears are small, dark, and translucent stones. They are highly valued for their smooth, black appearance and are often used in jewelry and lapidary work.
4- Amethyst
Amethyst, a purple variety of quartz, can be found in several areas of New Mexico. The most notable amethyst locality is the Arturo Mine in the Organ Mountains near Las Cruces. The amethyst crystals from this mine exhibit a rich purple color and can range in size from small druzy clusters to larger individual crystals.
5- Flourite
Fluorite is a colorful mineral that forms in a variety of hues, including purple, green, blue, and yellow. Notable fluorite deposits in New Mexico can be found in the Hansonburg Mining District near the town of Bingham. The fluorite crystals from this area are highly coveted for their vibrant colors and exceptional clarity.
6- Geodes
New Mexico is known for its abundant geode deposits. Geodes are spherical or oblong rocks that contain hollow cavities lined with crystals. The Rio Grande Rift Valley, in particular, is a prominent geode-producing area. The geodes found in this region often contain quartz, amethyst, calcite, and other minerals. The famous Black Hills Geode Beds near Deming and the Otero Mesa are popular collecting sites for geode enthusiasts.
7- Fire Agate
Fire agate is a unique and mesmerizing gemstone known for its iridescent play of colors. It is formed from chalcedony with a thin layer of iridescent limonite or goethite on its surface. Fire agate can be found in various locations across New Mexico, including the Deer Creek and Round Mountain mines. The gemstone exhibits a range of colors, including fiery reds, oranges, and greens, and is highly prized by collectors and jewelry designers.
8- Smithsonite
Smithsonite, also known as zinc spar, is a zinc carbonate mineral that occurs in a variety of colors, including blue, green, pink, and yellow. It is a secondary mineral that forms in the oxidized zones of zinc ore deposits. Notable smithsonite localities in New Mexico include the Kelly Mine near Magdalena and the San Pedro Mine near San Pedro.
9- Petrified Wood
New Mexico is famous for its petrified wood, which is the result of ancient trees being preserved and transformed into stone over millions of years. Petrified wood specimens found in the state exhibit a wide range of colors, including red, yellow, and brown. The Petrified Forest National Park in northeastern Arizona, near the New Mexico border, is a popular destination for observing and collecting petrified wood.
10- Agate
Agate is a banded form of chalcedony, a microcrystalline variety of quartz. It is known for its beautiful patterns and vibrant colors. New Mexico has several locations where agate can be found, including the Datil-Mogollon area and the Rio Puerco Valley. The agates from these regions display a variety of banding patterns and colors, making them highly prized by lapidaries and collectors.
11- Variscite
Variscite is a rare phosphate mineral that is typically green in color. It is valued for its attractive hue and can be used as a gemstone or in ornamental carvings. The Little Green Monster Variscite Mine in Utah, near the New Mexico border, has produced some exceptional variscite specimens. The mine’s name originates from the vibrant green color of the variscite nodules found there.
12- Wulfenite
Wulfenite is a lead molybdate mineral known for its striking orange to red color. It typically forms as thin tabular crystals and is highly sought after by mineral collectors. New Mexico is home to several wulfenite localities, including the Glove Mine near Lordsburg and the Kelly Mine near Magdalena. The wulfenite crystals from these mines are renowned for their exceptional transparency and vibrant color.
13- Barite
Barite, also known as baryte, is a mineral composed of barium sulfate. It commonly occurs in a variety of colors, including white, yellow, and blue. Notable barite deposits in New Mexico include those found in the Harding Mine near Dixon and the Elk Creek locality in the Magdalena Mountains. The barite crystals from these localities can exhibit exceptional transparency and form intricate formations.
14- Apache Gold
Apache Gold, also known as Chalcopyrite, is a striking mineral that displays a brassy yellow color. It is a copper iron sulfide mineral that forms in hydrothermal veins. Apache Gold is often found in association with copper mineralization in various parts of New Mexico, including the southwestern region. The mineral’s metallic luster and unique color make it a sought-after collector’s item.
15- Topaz
New Mexico is known for its topaz deposits, particularly in the region around the Capitan Mountains and the Organ Mountains. Topaz can occur in various colors, but the most prized variety is the golden to sherry-colored Imperial Topaz. While topaz crystals from New Mexico are often small, they are highly valued for their exceptional clarity and rich colors.
16- Jasper
New Mexico is rich in jasper, a variety of chalcedony often characterized by its vibrant colors and unique patterns. Jasper can be found in various locations across the state, including the Jemez Mountains and the Rio Puerco Valley. The jasper varieties in New Mexico can display hues of red, yellow, brown, and green, and their beautiful patterns make them highly valued by lapidaries and jewelry designers.
17- Uvarovite Garnet
Uvarovite is a rare green variety of garnet known for its vibrant emerald-green color. It typically occurs as small, bright-green crystals that are rich in chromium. The northern part of New Mexico, particularly the area around the Grants District, is known for its uvarovite garnet deposits. While uvarovite crystals from this region are generally small, they are highly prized by collectors for their intense green color.
18- Apatite
Apatite is a phosphate mineral that can occur in a variety of colors, including green, blue, yellow, and purple. In New Mexico, the Harding Mine near Dixon is renowned for its exceptional blue and green apatite crystals. The crystals from this locality are highly transparent and can display vibrant colors, making them highly sought after by mineral collectors.
19- Chalcedony Roses
Chalcedony roses, also known as “desert roses,” are unique mineral formations that resemble rose blossoms. They are composed of chalcedony, a variety of quartz, and are typically formed in arid environments with abundant silica-rich sediments. New Mexico’s White Sands National Park is a notable location to find chalcedony roses. These delicate formations are a popular collectible due to their intricate beauty and resemblance to actual flowers.
20- Copper Minerals
New Mexico has significant copper deposits, and various copper minerals can be found throughout the state. These include chalcopyrite, bornite, and malachite, among others. Copper minerals often occur in association with other minerals, such as quartz, calcite, and azurite. Copper specimens from New Mexico can exhibit vibrant colors and intricate crystal formations, making them prized by collectors and mineral enthusiasts.
21- Eudialyte
Eudialyte is a rare and visually striking mineral that is highly sought after by collectors. It typically occurs in shades of pink, red, and brown and often exhibits intricate patterns and zoning. New Mexico’s Harding Pegmatite Mine near Dixon is known for producing exceptional eudialyte specimens. These specimens are prized for their intense colors and unique crystal formations.
22- Chalcedony Nodules
Chalcedony nodules are rounded formations composed of microcrystalline quartz. They often display a variety of colors, including shades of white, gray, brown, and red. New Mexico is known for its extensive deposits of chalcedony nodules, particularly in the southwestern part of the state. The nodules can be found in various sizes and shapes and are popular among lapidaries and rock collectors.
23- Selenite
Selenite is a translucent variety of gypsum that forms in delicate, elongated crystals. In New Mexico, the White Sands National Park is a notable location for finding selenite crystals. The gypsum dunes of White Sands create a unique environment for the formation of these crystals. Selenite crystals from this region can range in size from small, needle-like formations to larger, intricate specimens.
24- Vanadinite
Vanadinite is a vibrant red to orange mineral that consists of lead vanadate. It often forms hexagonal crystals and is prized for its rich color and high luster. New Mexico’s famous San Carlos Mine near the town of San Carlos is renowned for its exceptional vanadinite specimens. Crystals from this mine can exhibit intense color saturation and are highly sought after by collectors.
25- Hematite Roses
Hematite roses, also known as “iron roses” or “iron flowers,” are unique formations of hematite mineral that resemble roses. They are composed of radiating bladed crystals of hematite and can exhibit a metallic luster. Hematite roses can be found in various locations across New Mexico, including the Jemez Mountains and the Rio Grande Valley. These formations are popular among collectors and are prized for their aesthetic appeal.
26- Staurolite
Staurolite is a brown to black mineral that forms characteristic cross-shaped twins, known as “fairy crosses.” It is often found in metamorphic rocks and is associated with regions of high-grade metamorphism. Staurolite can be found in parts of northern New Mexico, particularly in the Taos area. The fairy crosses are treasured by collectors for their unique twinned crystal structure and folklore associations.
27- Zircon
Zircon is a gemstone known for its brilliance and wide range of colors, including colorless, yellow, brown, and red. It is a common accessory mineral in many granitic rocks. In New Mexico, zircon can be found in various locations, including the Harding Pegmatite Mine near Dixon and the Pala District. Zircon crystals from these localities can exhibit excellent transparency and are highly valued by gem enthusiasts.
28- Covellite
Covellite is a rare copper sulfide mineral that is known for its vibrant indigo-blue to black color. It often forms as thin coatings or crystal aggregates. Covellite can be found in limited quantities in certain copper mining districts of New Mexico, including the Tyrone and Burro Mountains. Its striking color and rarity make covellite specimens a prized find for mineral collectors.
29- Amazonite
Amazonite is a variety of microcline feldspar known for its vibrant blue-green color. It often occurs in granitic rocks and is valued for its beauty and ornamental use in jewelry and carvings. New Mexico’s Custer County is known for its amazonite deposits, particularly in the Mount Mica and Stoneham areas. Amazonite crystals from these localities can display intense blue-green hues and are highly sought after by collectors.
30- Azurite
Azurite is a striking blue copper mineral that often forms in granular or prismatic crystals. It is known for its intense color and is often associated with malachite, another copper mineral. New Mexico’s famous Copper Flat Mine near Hillsboro is known for its azurite-rich deposits. Azurite specimens from this mine can exhibit deep blue hues and are highly prized by mineral collectors.
31- Marcasite
Marcasite is a pale yellow to metallic gray mineral that belongs to the pyrite group. It often forms in crystal clusters or as stalactitic masses. Marcasite can be found in various locations across New Mexico, including the Magdalena District. Marcasite specimens from this region can display intricate crystal formations and a metallic luster, making them popular among collectors.
32- Turquoise
Turquoise is a prized gemstone known for its vibrant blue to green-blue color. It is a hydrated phosphate mineral that often forms in veins and nodules. New Mexico has a rich history of turquoise mining, with notable deposits in the Cerrillos Mining District and the Tyrone Mine. New Mexico turquoise is highly regarded for its intense color and is widely used in Native American jewelry and art.
33- Pyrolusite
Pyrolusite is a manganese oxide mineral known for its metallic luster and black color. It often occurs as botryoidal, stalactitic, or earthy masses. New Mexico’s famous Manganese District, located near the town of Lake Valley, is known for its pyrolusite deposits. Pyrolusite specimens from this area can exhibit a velvety black appearance and are sought after by collectors.
34- Rhodochrosite
Rhodochrosite is a beautiful manganese carbonate mineral that is highly valued for its pink to red color. It often forms as botryoidal or banded masses and can exhibit translucent to semi-transparent properties. New Mexico’s famous Sweet Home Mine near Alma is renowned for producing exceptional rhodochrosite specimens. The crystals from this mine are prized for their vibrant color and gem-quality transparency.
Conclusion
In conclusion, New Mexico is a treasure trove for rare gems and minerals, offering a diverse range of geological wonders. The state’s rich mining history and unique geological formations have contributed to the discovery of numerous rare and sought-after specimens. From the vibrant blue-green amazonite of Custer County to the intense red rhodochrosite of the Sweet Home Mine, New Mexico showcases a remarkable variety of gemstones and minerals.
Collectors and enthusiasts can find an array of fascinating specimens, including the golden Imperial Topaz, the intricate chalcedony roses, and the striking covellite. The state is also known for its deposits of smithsonite, fluorite, azurite, and turquoise, which have captivated the attention of gem and mineral enthusiasts worldwide.
New Mexico’s mining districts, such as the Harding Pegmatite Mine and the Copper Flat Mine, have yielded exceptional specimens that showcase the state’s geological diversity. Additionally, natural areas like White Sands National Park provide unique formations like selenite crystals and chalcedony roses.
Exploring New Mexico’s landscapes and mineral-rich regions offers a captivating journey into the Earth’s geological history. Whether it’s uncovering rare minerals in the mountains or searching for gemstones in the desert, New Mexico continues to be a haven for those fascinated by the beauty and rarity of these geological treasures.
Venetia Diamond Mine, South Africa. Photo by Dr Tom Gernon, University of Southampton
An international team of scientists led by the University of Southampton has discovered that the breakup of tectonic plates is the main driving force behind the generation and eruption of diamond-rich magmas from deep inside the Earth.
Their findings could shape the future of the diamond exploration industry, informing where diamonds are most likely to be found.
Diamonds, which form under great pressures at depth, are hundreds of millions, or even billions, of years old. They are typically found in a type of volcanic rock known as kimberlite. Kimberlites are found in the oldest, thickest, strongest parts of continents — most notably in South Africa, home to the diamond rush of the late 19th century. But how and why they got to Earth’s surface has, until now, remained a mystery.
The new research examined the effects of global tectonic forces on these volcanic eruptions spanning the last billion years. The findings have been published in the journal Nature.
Southampton researchers collaborated with colleagues from the University of Birmingham, the University of Potsdam, the GFZ German Research Centre for Geosciences, Portland State University, Macquarie University, the University of Leeds, the University of Florence, and Queen’s University, Ontario.
Tom Gernon, Professor of Earth Science and Principal Research Fellow at the University of Southampton, and lead author of the study, said: “The pattern of diamond eruptions is cyclical, mimicking the rhythm of the supercontinents, which assemble and break up in a repeated pattern over time. But previously we didn’t know what process causes diamonds to suddenly erupt, having spent millions — or billions — of years stashed away 150 kilometres beneath the Earth’s surface.”
To address this question, the team used statistical analysis, including machine learning, to forensically examine the link between continental breakup and kimberlite volcanism. The results showed the eruptions of most kimberlite volcanoes occurred 20 to 30 million years after the tectonic breakup of Earth’s continents.
Dr Thea Hincks, Senior Research Fellow at the University of Southampton, said: “Using geospatial analysis, we found that kimberlite eruptions tend to gradually migrate from the continental edges to the interiors over time at rates that are consistent across the continents.”
Geological processes
This discovery prompted the scientists to explore what geological process could drive this pattern. They found that the Earth’s mantle — the convecting layer between the crust and core — is disrupted by rifting (or stretching) of the crust, even thousands of kilometres away.
Dr Stephen Jones, Associate Professor in Earth Systems at the University of Birmingham, and study co-author said: “We found that a domino effect can explain how continental breakup leads to formation of kimberlite magma. During rifting, a small patch of the continental root is disrupted and sinks into the mantle below, triggering a chain of similar flow patterns beneath the nearby continent.”
Dr Sascha Brune, Head of the Geodynamic Modelling Section at GFZ Potsdam, and a co-author on the study, ran simulations to investigate how this process unfolds. He said: “While sweeping along the continental root, these disruptive flows remove a substantial amount of rock, tens of kilometres thick, from the base of the continental plate.”
The typical migration rates estimated in models matched what the scientists observed from kimberlite records.
“Remarkably, this process brings together the necessary ingredients in the right amounts to trigger just enough melting to generate kimberlites,” added Dr Gernon.
The team’s research could be used to identify the possible locations and timings of past volcanic eruptions tied to this process, offering valuable insights that could enable the discovery of diamond deposits in the future.
Professor Gernon, who was recently awarded a major philanthropic grant from the WoodNext Foundation to study the factors contributing to global cooling over time, said the study also sheds light on how processes deep within the Earth control those at the surface: “Breakup not only reorganises the mantle, but may also profoundly impact Earth’s surface environment and climate, so diamonds might be just a part of the story.”
Reference:
Thomas M. Gernon, Stephen M. Jones, Sascha Brune, Thea K. Hincks, Martin R. Palmer, John C. Schumacher, Rebecca M. Primiceri, Matthew Field, William L. Griffin, Suzanne Y. O’Reilly, Derek Keir, Christopher J. Spencer, Andrew S. Merdith, Anne Glerum. Rift-induced disruption of cratonic keels drives kimberlite volcanism. Nature, 2023; DOI: 10.1038/s41586-023-06193-3
Explosive lava spews from the latest eruption of the Fogo volcano located on the Cape Verde islands in November 2014. Science now knows that carbon dioxide – instead of water – triggered it. Credit: Ricardo Ramalho/Cardiff University
Geoscientists have long thought that water — along with shallow magma stored in Earth’s crust — drives volcanoes to erupt. Now, thanks to newly developed research tools at Cornell, scientists have learned that gaseous carbon dioxide can trigger explosive eruptions.
A new model suggests that basaltic volcanoes, typically located on the interior of tectonic plates, are fed by a deep magma within the mantle, stored about 20 to 30 kilometers below Earth’s surface.
The research, which offers a clearer picture of our planet’s deep internal dynamics and composition, with implications for improving volcanic-hazards planning, will publish August 7, 2023 at 3:00pm ET in the Proceedings of the National Academy of Sciences.
“We used to think all the action happened in the crust,” said senior author Esteban Gazel, the Charles N. Mellowes Professor in Engineering in the Department of Earth and Atmospheric Sciences, in Cornell Engineering. “Our data implies the magma comes directly from the mantle — passing fast through the crust – driven by the exsolution (the process phase of separating gas from liquid) of carbon dioxide.
“This completely changes the paradigm of how these eruptions happen,” Gazel said. “All volcanic models had been dominated by water as the main eruption driver, but water has little to do with these volcanoes. It’s carbon dioxide that brings this magma from the deep Earth.”
About four years ago, Gazel and Charlotte DeVitre, Ph.D. ’22, now a postdoctoral researcher at University of California, Berkeley, developed a high-precision carbon dioxide densimeter (which measures density in a tiny vessel) for Raman spectroscopy (a device that examines scattered photons through a microscope).
The natural samples — microscopic-sized carbon dioxide rich bubbles trapped in crystals emanating from the volcanic eruption — are then measured via Raman and quantified applying the newly developed densimeter. Essentially, the scientists are examining a microscopic time capsule to provide a history of the magma. This new technique is critical for near real-time precise estimations of magma storage, tested during the 2021 eruption in Las Palmas, in the Canary Islands by Gazel’s group.
Further, the scientists developed methods to assess the effect of laser heating on carbon-dioxide rich inclusions (found swathed in the crystals), and to accurately assess melt inclusion and bubble volumes. They also developed an experimental reheating method to increase accuracy and properly account for carbon dioxide trapped as carbonate crystals inside the bubbles.
“The method of development and instrument design were challenging, especially during the height of the pandemic,” Gazel said.
Using these new tools, the scientists scrutinized volcanic deposits from the Fogo volcano in Cabo Verde, west of Senegal in the Atlantic Ocean. They found a high concentration of volatiles in the micro-sized melt inclusions encased within the magnesium-iron silicate crystals. The higher amount of carbon dioxide enclosed in the crystals suggested that the magma was stored tens of kilometers below the surface — within the Earth’s mantle.
The group also discovered that this process is connected to the deep mantle source that supply these volcanoes.
This implies that eruptions such as Fogo’s volcanic flareups start and are fed from the mantle, effectively bypassing storage in the Earth’s crust and driven by deep carbon dioxide, according to the paper.
“These magmas have extremely low viscosities and come directly from the mantle,” DeVitre said. “So here, viscosity and water cannot play the common roles that they do in shallower and/or more silicic (rich in silica) volcanic systems. Rather at Fogo volcano the magma must be driven up fast by the carbon dioxide and this likely plays a significant role in its explosive behavior. This is a major step in our understanding of the controls on basaltic explosivity.”
Comprehending magma storage helps best prepare society for future eruptions, said Gazel, who is also a faculty fellow at the Cornell Atkinson Center for Sustainability.
“As deep magma storage will not be detected by ground deformation until the melt is close to surface,” he said, “this has important repercussions to our understanding of volcanic hazards. We need to understand the drivers of these eruptions. The only way to see these processes now is by observing earthquakes, but earthquakes don’t tell you exactly what’s happening.”
Said Gazel: “With precise measurements that tell us where eruptions start, where magmas melt and where they are stored — and what triggers the eruption — we can develop a much better plan for future eruptions.”
In addition to Gazel and DeVitre, the other authors of “Oceanic Intraplate Explosive Eruptions Fed Directly from the Mantle” are Ricardo S. Ramalho, Cardiff University, Wales, U.K.; Swetha Venugopal, Lunar and Planetary Institute, Universities Space Research Association, Houston; Matthew Steele-MacInnis, University of Alberta, Edmonton, Alberta; Junlin Hua, University of Texas, Austin; Chelsea M. Allison, Baylor University, Waco, Texas; Lowell R. Moore, Virginia Tech, Blacksburg, Virginia; Juan Carlos Carracedo, Universidad de Las Palmas de Gran Canaria, Spain; and Brian Monteleone, Woods Hole Oceanographic Institution, Massachusetts.
Reference:
Charlotte L. DeVitre, Esteban Gazel, Ricardo S. Ramalho, Swetha Venugopal, Matthew Steele-MacInnis, Junlin Hua, Chelsea M. Allison, Lowell R. Moore, Juan Carlos Carracedo, Brian Monteleone. Oceanic intraplate explosive eruptions fed directly from the mantle. Proceedings of the National Academy of Sciences, 2023; 120 (33) DOI: 10.1073/pnas.2302093120
Note: The above post is reprinted from materials provided by Cornell University. Original written by Blaine Friedlander, courtesy of the Cornell Chronicle.
Close up image on one wall showing numerous depressions of hadrosaur footprints. The ice ax in the lower left of the frame is approximately 3 feet long, for scale. Photo by Patrick Druckenmiller
University of Alaska Fairbanks scientists have discovered and documented the largest known single dinosaur track site in Alaska. The site, located in Denali National Park and Preserve, has been dubbed “The Coliseum” by researchers.
The Coliseum is the size of one-and-a-half football fields and contains layer upon layer of prints preserved in rock. The site is a record of multiple species of dinosaurs over many generations that thrived in what is now Interior Alaska nearly 70 million years ago. The scientists describe the site in a paper recently published in the journal Historical Biology.
“It’s not just one level of rock with tracks on it,” said Dustin Stewart, the paper’s lead author and a former UAF graduate student who published the paper as part of his master’s thesis. “It is a sequence through time. Up until now, Denali had other track sites that are known, but nothing of this magnitude.”
At first glance, the site is unremarkable in the context of the park’s vast landscape: just a layered, rocky outcrop rising 20-some stories from its base.
“When our colleagues first visited the site, they saw a dinosaur trackway at the base of this massive cliff,” said Pat Druckenmiller, senior author of the paper and director of the University of Alaska Museum of the North. “When we first went out there, we didn’t see much either.”
Stewart recalled being initially underwhelmed when he approached the site at the end of a seven-hour hike. Then dusk approached, and the team took another look.
“When the sun angles itself perfectly with those beds, they just blow up,” he said. “Immediately all of us were just flabbergasted, and then Pat said, ‘Get your camera.’ We were freaking out.”
In the Late Cretaceous Period, the cliffs that make up The Coliseum were sediment on flat ground near what was likely a watering hole on a large flood plain. As Earth’s tectonic plates collided and buckled to form the Alaska Range, the formerly flat ground folded and tilted vertically, exposing the cliffs covered with tracks.
The tracks are a mix of hardened impressions in the ancient mud and casts of tracks created when sediment filled the tracks and then hardened.
“They are beautiful,” Druckenmiller said. “You can see the shape of the toes and the texture of the skin.”
In addition to the dinosaur tracks, the research team found fossilized plants, pollen grains, and evidence of freshwater shellfish and invertebrates.
“All these little clues put together what the environment looked like as a whole,” Stewart said.
The area was part of a large river system, he said, with ponds and lakes nearby. The climate in the area was warmer than today, more like the Pacific Northwest. There were coniferous and deciduous trees and an understory of ferns and horsetails.
Based on the tracks, a variety of juvenile to adult dinosaurs frequented the area over thousands of years. Most common were large plant-eating duck-billed and horned dinosaurs. The team also documented rarer carnivores, including raptors and tyrannosaurs, as well as small wading birds.
Every year, thousands of people visit Denali National Park and Preserve to experience the stunning natural landscape and environment, Druckenmiller said. “It’s amazing to know that around 70 million years ago, Denali was equally impressive for its flora and fauna.
“It was forested and it was teeming with dinosaurs,” he said. “There was a tyrannosaur running around Denali that was many times the size of the biggest brown bear there today. There were raptors. There were flying reptiles. There were birds. It was an amazing ecosystem.”
Preserving fossil sites like The Coliseum is an important part of the National Park Service’s mission, said Denny Capps, the park’s geologist.
“On one hand, we must protect world-class fossil sites like The Coliseum from disturbance and theft,” he said. “On the other hand, we encourage visitors to explore for fossils in their geologic context to better grasp the evolution of landscapes and ecosystems through time, while leaving them undisturbed for others to appreciate.”
Druckenmiller plans to continue collaborating with the National Park Service to study The Coliseum and other track sites.
“Our track research in the park complements our work on dinosaur bones we collect in northern Alaska, along the Colville River,” Druckenmiller said. “Denali National Park and Preserve is a world-class area for dinosaur tracks. There is a lifetime of exploring left to do, and I can only wonder what other surprises await.”
Reference:
Dustin G. Stewart, Patrick S. Druckenmiller, Gregory M. Erickson, Jeff A. Benowitz, Denny M. Capps, Cassandra L. Knight, Kevin C. May, Paul J. McCarthy. Vertebrate ichnology and palaeoenvironmental associations of Alaska’s largest known dinosaur tracksite in the Cretaceous Cantwell Formation (Maastrichtian) of Denali National Park and Preserve. Historical Biology, 2023; 1 DOI: 10.1080/08912963.2023.2221267
Fossilized poop, called coprolites, collected in Nong Yakong village, Chaiyaphum Province, Thailand. Coprolites are an important source for studying ancient parasites. Nonsrirach et al. under CC-BY 4.0
Fossilized feces preserve evidence of ancient parasites that infected an aquatic predator over 200 million years ago, according to a study published August 9, 2023 in the open-access journal PLOS ONE by Thanit Nonsrirach of Mahasarakham University, Thailand and colleagues.
Parasites are a common and important component of ecosystems, but ancient parasites are difficult to study due to a poor fossil record. Parasites often inhabit the soft tissues of their host, which rarely preserve as fossils. There are, however, cases where traces of parasites can be identified within fossilized feces (coprolites). In this study, Nonsrirach and colleagues describe evidence of parasites in a Late Triassic coprolite from the Huai Hin Lat Formation of Thailand, which is over 200 million years old.
The coprolite is cylindrical in shape and over 7cm long. Based on its shape and contents, the researchers suggest it was likely produced by some species of phytosaur, crocodile-like predators which are also known from this fossil locality. Microscopic analysis of thin sections of the coprolite revealed six small, round, organic structures between 50-150 micrometers long. One of these, an oval-shaped structure with a thick shell, is identified as the egg of a parasitic nematode worm, while the others appear to represent additional worm eggs or protozoan cysts of unclear identity.
This is the first record of parasites in a terrestrial vertebrate host from the Late Triassic of Asia, and a rare glimpse into the life of an ancient animal that was apparently infected by multiple parasitic species. This discovery also adds to the few known examples of nematode eggs preserved within the coprolites of Mesozoic animals. These findings are therefore a significant contribution to scientific understanding of the distribution and ecology of parasites of the distant past.
The authors add: “Coprolite is a significant paleontological treasure trove, containing several undiscovered fossils and expanding our understanding of ancient ecosystems and food chains.”
Reference:
Thanit Nonsrirach, Serge Morand, Alexis Ribas, Sita Manitkoon, Komsorn Lauprasert, Julien Claude. First discovery of parasite eggs in a vertebrate coprolite of the Late Triassic in Thailand. PLOS ONE, 2023; 18 (8): e0287891 DOI: 10.1371/journal.pone.0287891
Note: The above post is reprinted from materials provided by PLOS.
A remarkable new fossil from China reveals for the first time that a group of reptiles were already using whale-like filter feeding 250 million years ago.
New research by a team from China and the UK has shown details of the skull of an early marine reptile called Hupehsuchus that indicate it had soft structures such as an expanding throat region to allow it to engulf great masses of water containing shrimp-like prey, and baleen whale-like structures to filter food items as it swam forward.
The team also found that the Hupehsuchus skulls show the same grooves and notches along the edges of its jaws similar to baleen whales, which have keratin strips instead of teeth.
“We were amazed to discover these adaptations in such an early marine reptile,” said Zichen Fang of the Wuhan Center of China Geological Survey, who led the research. “The hupehsuchians were a unique group in China, close relatives of the ichthyosaurs, and known for 50 years, but their mode of life was not fully understood.”
“The hupesuchians lived in the Early Triassic, about 248 million years ago, in China and they were part of a huge and rapid re-population of the oceans,” said Professor Michael Benton, a collaborator at the University of Bristol’s School of Earth Sciences. “This was a time of turmoil, only three million years after the huge end-Permian mass extinction which had wiped out most of life. It’s been amazing to discover how fast these large marine reptiles came on the scene and entirely changed marine ecosystems of the time.”
“We discovered two new hupehsuchian skulls,” said Professor Long Cheng, also of the Wuhan Center of China Geological Survey, who directed the project. “These were more complete than earlier finds and showed that the long snout was composed of unfused, straplike bones, with a long space between them running the length of the snout. This construction is only seen otherwise in modern baleen whales where the loose structure of the snout and lower jaws allows them to support a huge throat region that balloons out enormously as they swim forward, engulfing small prey.”
Li Tian, a collaborator from the University of Geosciences Wuhan, added: “The other clue came in the teeth… or the absence of teeth,” says Li Tian, a collaborator from the University of Geosciences Wuhan. “Modern baleen whales have no teeth, unlike the toothed whales such as dolphins and orcas. Baleen whales have grooves along the jaws to support curtains of baleen, long thin strips of keratin, the protein that makes hair, feathers and fingernails. Hupehsuchus had just the same grooves and notches along the edges of its jaws, and we suggest it had independently evolved into some form of baleen.”
Reference:
Zi-Chen Fang, Jiang-Li Li, Chun-Bo Yan, Ya-Rui Zou, Li Tian, Bi Zhao, Michael J. Benton, Long Cheng, Xu-Long Lai. First filter feeding in the Early Triassic: cranial morphological convergence between Hupehsuchus and baleen whales. BMC Ecology and Evolution, 2023; 23 (1) DOI: 10.1186/s12862-023-02143-9
Researchers have described a new species of armored reptile that lived near the time of the first appearance of dinosaurs. With bony plates on its backbone, this archosaur fossil reveals that armor was a boomerang trait in the story of dinosaur and pterosaur evolution: the group’s ancestors were armored, but this characteristic was lost and then independently re-evolved multiple times later among specialized dinosaurs like ankylosaurs, stegosaurs, and others. The study is published today in the Zoological Journal of the Linnean Society.
“We are just starting to understand that there were many dinosaur-like creatures across the planet well before dinosaurs evolved,” said the study’s lead author Sterling Nesbitt, associate professor of geosciences at Virginia Tech and a research associate in the American Museum of Natural History’s Division of Paleontology. “Dinosaurs were latecomers to the Triassic reptile party. They showed up well after many dinosaur-looking reptiles were established across our planet.”
Archosaurs are reptiles that are divided into two major branches: the bird-line, which includes pterosaurs and dinosaurs, including living dinosaurs (birds); and the crocodilian line, including crocodiles, alligators, caimans, and gharials. The newly described archosaur species, named Mambachiton fiandohana, is the earliest diverging member of the bird line of archosaur evolution. The fossil, which is about 235 million years old, was found in 1997 in Madagascar by a team of researchers led by the Museum’s Frick Curator of Fossil Mammals John Flynn, who worked at the Field Museum at the time, in close collaboration with scientists and students at the University of Antananarivo in Madagascar.
“This discovery documents the importance of the southern hemisphere fossil record in understanding this important period of the Triassic, when dinosaurs were first appearing,” Flynn said. “This time interval is really poorly known elsewhere in the world, showing the tremendous value of our quarter-century-long Madagascar-U.S. research and education partnership to advancing scientific knowledge.”
A four-legged, long-tailed precursor to dinosaurs and pterosaurs, Mambachiton is estimated to have been 4-6 feet (1.5-2 meters) long, weighing between 25-45 pounds (10-20 kilograms). Unexpectedly, the species had an extensive series of bony plates called osteoderms covering its backbone. Although osteoderms are common in crocodilians and their relatives, they are rare in bird-line archosaurs, with the exception of dinosaurs like stegosaurs, ankylosaurs, titanosaur sauropods, and at least one theropod.
Mambachiton shows definitively that the bird-line archosaur group was ancestrally armored. This armor was lost in the evolution of dinosaurs and pterosaurs but then re-appeared later several times, independently, in the dinosaur lineage.
“The loss and re-evolution of armor is an important aspect of the story of dinosaur evolution — freeing them from some of the biomechanical body constraints of the ancestral archosaurs and potentially contributing to some of the locomotor shifts as dinosaurs diversified into a dizzying array of different ecology and body forms,” said co-author Christian Kammerer, a former Gerstner Scholar at the Museum and a research curator in paleontology at the North Carolina Museum of Natural Sciences.
“Mambachiton demonstrates that retention of ancestral features or acquisition of new traits depend on interactions within the ecosystem,” said project co-leader Lovasoa Ranivoharimanana of the University of Antananarivo. “When a character is essential, it is retained, but when it is no longer useful, it disappears.”
Other authors on the study include Emily Patellos from the University of Southern California and Virginia Tech, and André Wyss from the University of California, Santa Barbara.
Funding or other support was provided in part by the National Geographic Society (grant #s 5957-97, 6271-98, and 7052-01); World Wide Fund for Nature/World Wildlife Fund, Madagascar; the Division of Paleontology at the American Museum of Natural History; and the Field Museum of Natural History Meeker Family Fellowship. The joint Madagascar-U.S. paleontological exploration, research, and education program was supported by the Université d’Antananarivo, Ministère de L’Enérgie et des Mines, and ICTE/MICET (Madagascar), and the American Museum of Natural History, Field Museum of Natural History, and University of California-Santa Barbara (U.S.).
Reference:
Sterling J Nesbitt, Emily Patellos, Christian F Kammerer, Lovasoa Ranivoharimanana, Andre´ R Wyss, John J Flynn. The earliest-diverging avemetatarsalian: a new osteoderm-bearing taxon from the Triassic (Earliest Late Triassic) of Madagascar and the composition of avemetatarsalian assemblages prior to the radiation of dinosaurs. Zoological Journal of the Linnean Society, 2023; DOI: 10.1093/zoolinnean/zlad038
Impact craters and their broader structures can be visible in a geologic map, like a bullseye. But what geophysical traces remain at the structure’s outermost edges? Credit: Huber et al. (2023), JGR Planets
Earth’s oldest craters could give scientists critical information about the structure of the early Earth and the composition of bodies in the solar system as well as help to interpret crater records on other planets. But geologists can’t find them, and they might never be able to, according to a new study. The study was published in the Journal of Geophysical Research Planets, AGU’s journal for research on the formation and evolution of the planets, moons and objects of our Solar System and beyond.
Geologists have found evidence of impacts, such as ejecta (material flung far away from the impact), melted rocks, and high-pressure minerals from more than 3.5 billion years ago. But the actual craters from so long ago have remained elusive. The planet’s oldest known impact structures, which is what scientists call these massive craters, are only about 2 billion years old. We’re missing two and a half billion years of mega-craters.
The steady tick of time and the relentless process of erosion are responsible for the gap, according to Matthew S. Huber, a planetary scientist at the University of the Western Cape in South Africa who studies impact structures and led the new study.
“It’s almost a fluke that the old structures we do have are preserved at all,” Huber said. “There are a lot of questions we’d be able to answer if we had those older craters. But that’s the normal story in geology. We have to make a story out of what’s available.”
Geologists can sometimes spot hidden, buried craters using geophysical tools, such as seismic imaging or gravity mapping. Once they’ve identified potential impact structures, they can search for physical remnants of the impact process to confirm its existence, such as ejecta and impact minerals.
The big question for Huber and his team was how much of a crater can be swept away by erosion before the last lingering geophysical traces disappear. Geophysicists have suggested that 10 kilometers (6.2 miles) of vertical erosion would erase even the biggest impact structures, but that threshold had never been tested in the field.
To find out, the researchers dug into one of the planet’s oldest known impact structures: the Vredefort crater in South Africa. The structure is about 300 kilometers (186 miles) across and was formed about 2 billion years ago when an impactor about 20 kilometers (12.4 miles) across slammed into the planet.
The impactor hit with such energy that the crust and mantle rose up where the impact occurred, leaving a long-term dome. Farther from the center, ridges of rock jutted up, minerals transformed and rock melted. And then time took its course, eroding about 10 kilometers (6.2 miles) down from the surface in two billion years.
Today, all that remains at the surface is a semicircle of low hills southwest of Johannesburg, which marks the center of the structure, and some smaller, telltale signs of impact. The bullseye, caused by the uplift of the mantle, appears in gravity maps, but beyond the center, geophysical evidence of the impact is lacking.
“That pattern is one of the last geophysical signatures that is still detectable, and that only happens for the largest-scale impact structures,” Huber said. Because only the deepest layers of the structure remain, the other geophysical traces have disappeared.
But that’s okay, because Huber wanted to know just how reliable those deep layers are for recording ancient impacts from both a mineralogical and geophysical perspective.
“Erosion makes these structures disappear from the top down,” Huber said. “So we went from the bottom up.”
The researchers sampled rock cores across a 22-kilometer (13.7-mile) transect and analyzed their physical properties, searching for differences in density, porosity and mineralogy between impacted and non-impacted rocks. They also modeled the impact event and what its effects on rock and mineral physics would be and compared that to what they saw in their samples.
What they found was not encouraging for the search for Earth’s oldest craters. While some impact melt and minerals remained, the rocks in the outer ridges of the Vredefort structure were essentially indistinguishable from the non-impact rocks around them when viewed through a geophysical lens.
“That was not exactly the result we were expecting,” Huber said. “The difference, where there was any, was incredibly muted. It took us a while to really make sense of the data. Ten kilometers of erosion and all the geophysical evidence of the impact just disappears, even with the largest craters,” confirming what geophysicists had estimated previously.
The researchers caught Vredefort just in time; if much more erosion occurs, the impact structure will be gone. The odds of finding buried impact structures from more than 2 billion years ago are low, Huber said.
“In order to have an Archean impact crater preserved until today, it would have to have experienced really unusual conditions of preservation,” Huber said. “But then, Earth is full of unusual conditions. So maybe there’s something unexpected somewhere, and so we keep looking.”
Reference:
M. S. Huber, E. Kovaleva, A. S. P. Rae, N. Tisato, S. P. S. Gulick. Can Archean Impact Structures Be Discovered? A Case Study From Earth’s Largest, Most Deeply Eroded Impact Structure. Journal of Geophysical Research: Planets, 2023; 128 (8) DOI: 10.1029/2022JE007721
Undersea images of lava from Kama’ehu volcano, contrasting fresh-looking young lavas (top) versus older sediment-covered lavas (bottom). The two images on the bottom are courtesy of JAMSTEC.
Kamaʻehuakanaloa (formerly Lōʻihi Seamount), a submarine Hawaiian volcano located about 20 miles off the south coast of the Big Island of Hawai’i, has erupted at least five times in the last 150 years, according to new research led by Earth scientists at the University of Hawai’i at Mānoa. For the first time, scientists were able to estimate the ages of the most recent eruptions of Kamaʻehu, as well as the ages of eight additional older eruptions at this volcano going back about 2,000 years. Their findings were published recently in Geology.
Hawaiian volcanoes are thought to transition through a series of growth stages. Kamaʻehu is currently in the earliest submarine “pre-shield” stage of growth, whereas the active neighboring volcano Kīlauea is in its main shield-building stage.
“Kamaʻehu is the only active and exposed example of a pre-shield Hawaiian volcano,” said Aaron Pietruszka, lead author of the study and associate professor in the Department of Earth Sciences at the UH Mānoa School of Ocean and Earth Science and Technology (SOEST). “On the other Hawaiian volcanoes, this early part of the volcanic history is covered by the great outpouring of lava that occurs during the shield stage. Thus, there is great interest in learning about the growth and evolution of Kama’ehu.”
Kama’ehu’s history revealed with chemistry and underwater videos
Previously, the only known and confirmed eruption of Kamaʻehu was the one that occurred in 1996, an event that was only discovered because it coincided with a large swarm of earthquakes that were detected remotely by seismometers on the Big Island.
“Seismometers can only be used to detect the ongoing active eruptions of submarine volcanoes because earthquakes are transient,” said Pietruszka. “In order to determine the ages of older eruptions at Kamaʻehu, we took a different approach. We used a mass spectrometer to measure tiny amounts of the isotope radium-226 in pieces of quenched glassy lava that were sampled from the seafloor outcrops of Kamaʻehu using a submersible.”
Magma naturally contains radium-226, which radioactively decays at a predictable rate. So, Pietruzska and co-authors used the amount of radium-226 in each sample to infer the approximate time elapsed since the lava was erupted on the seafloor, that is, the eruption age of the sample.
Pietruszka started this investigation many years ago as a postdoctoral researcher at the Carnegie Institution for Science, just after finishing his doctoral degree in Earth science from SOEST. Once he returned to UH Mānoa in 2019, he got access to submersible dive videos and photos around Kama’ehu and had the information he needed to finish connecting the dots.
“The submersible dive images and videos provided independent confirmation of our estimates of eruption ages,” said Pietruszka. “The lavas with the freshest appearance also had the most radium-226, and vice versa for the lavas with the ‘older’ appearance, that is, fractured and broken, and/or covered with marine sediment. I was surprised to discover that Kama’ehu had erupted five times within the last ~150 years, which implies a frequency of ~30 years between eruptions at this volcano. This is much slower than at Kīlauea, which erupts almost continuously (with infrequent pauses of only a few years).”
Chemical changes in lava over time
The chemistry of the lava erupted from Hawaiian volcanoes changes over time. The new eruption ages for the lavas from Kama’ehu, coupled with measurements of lava chemistry, reveal that the timescale of variation in lava chemistry at this pre-shield volcano is about 1200 years. In contrast, Kīlauea lava chemistry changes over a timescale of only a few years to decades, with a complete cycle over about 200 years.
“We think that the origin of this difference is related to the position of the two volcanoes over the Hawaiian hotspot,” said Pietruszka. “This is an area of Earth’s mantle that is rising toward the surface — a “mantle plume” that ultimately melts to form the magma that supplies Hawaiian volcanoes. Models and other isotope data from thorium-230 suggest that the center of a mantle plume should rise faster than its margin. Our results — specifically, the factor of six longer timescale of variation in lava chemistry at Kama’ehu — provides independent confirmation of this idea.”
The research team hopes to better understand how Hawaiian volcanoes work from their earliest growth stages to their full, and frequently active, maturity to help them understand the deep controls on volcanic eruptions that initiate within the mysterious, upwelling mantle plume under the Hawaiian hotspot.
Reference:
Aaron J. Pietruszka, Michael O. Garcia, Richard W. Carlson, Erik H. Hauri. Slow changes in lava chemistry at Kama‘ehuakanaloa linked to sluggish mantle upwelling on the margin of the Hawaiian plume. Geology, 2023; 51 (8): 713 DOI: 10.1130/G51350.1
Royal Ontario Museum (ROM) announces the oldest swimming jellyfish in the fossil record with the newly named Burgessomedusa phasmiformis. These findings are announced in the journal Proceedings of the Royal Society B.
Jellyfish belong to medusozoans, or animals producing medusae, and include today’s box jellies, hydroids, stalked jellyfish and true jellyfish. Medusozoans are part of one of the oldest groups of animals to have existed, called Cnidaria, a group which also includes corals and sea anemones. Burgessomedusa unambiguously shows that large, swimming jellyfish with a typical saucer or bell-shaped body had already evolved more than 500 million years ago.
Burgessomedusa fossils are exceptionally well preserved at the Burgess Shale considering jellyfish are roughly 95% composed of water. ROM holds close to two hundred specimens from which remarkable details of internal anatomy and tentacles can be observed, with some specimens reaching more than 20 centimetres in length. These details enable classifying Burgessomedusa as amedusozoan. By comparison with modern jellyfish, Burgessomedusa would also have been capable of free-swimming and the presence of tentacles would have enabled capturing sizeable prey.
“Although jellyfish and their relatives are thought to be one of the earliest animal groups to have evolved, they have been remarkably hard to pin down in the Cambrian fossil record. This discovery leaves no doubt they were swimming about at that time,” said co-author Joe Moysiuk, a Ph.D. candidate in Ecology & Evolutionary Biology at the University of Toronto, who is based at ROM.
This study, identifying Burgessomedusa, is based on fossil specimens discovered at the Burgess Shale and mostly found in the late 1980s and 1990s under former ROM Curator of Invertebrate Palaeontology Desmond Collins. They show that the Cambrian food chain was far more complex than previously thought, and that predation was not limited to large swimming arthropods like Anomalocaris (see field image showing Burgessomedusa and Anomalocaris preserved on the same rock surface).
“Finding such incredibly delicate animals preserved in rock layers on top of these mountains is such a wonderous discovery. Burgessomedusa adds to the complexity of Cambrian foodwebs, and like Anomalocaris which lived in the same environment, these jellyfish were efficient swimming predators,” said co-author, Dr. Jean-Bernard Caron, ROM’s Richard Ivey Curator of Invertebrate Palaeontology. “This adds yet another remarkable lineage of animals that the Burgess Shale has preserved chronicling the evolution of life on Earth.”
Cnidarians have complex life cycles with one or two body forms, a vase-shaped body, called a polyp, and in medusozoans, a bell or saucer-shaped body, called a medusa or jellyfish, which can be free-swimming or not. While fossilized polyps are known in ca. 560-million-year-old rocks, the origin of the free-swimming medusa or jellyfish is not well understood. Fossils of any type of jellyfish are extremely rare. As a consequence, their evolutionary history is based on microscopic fossilized larval stages and the results of molecular studies from living species (modelling of divergence times of DNA sequences). Though some fossils of comb-jellies have also been found at the Burgess Shale and in other Cambrian deposits, and may superficially resemble medusozoan jellyfish from the phylum Cnidaria, comb-jellies are actually from a quite separate phylum of animals called Ctenophora. Previous reports of Cambrian swimming jellyfish are reinterpreted as ctenophores.
The Burgess Shale fossil sites are located within Yoho and Kootenay National Parks and are managed by Parks Canada. Parks Canada is proud to work with leading scientific researchers to expand knowledge and understanding of this key period of Earth history and to share these sites with the world through award-winning guided hikes. The Burgess Shale was designated a UNESCO World Heritage Site in 1980 due to its outstanding universal value and is now part of the larger Canadian Rocky Mountain Parks World Heritage Site.
Reference:
Justin Moon, Jean-Bernard Caron, Joseph Moysiuk. A macroscopic free-swimming medusa from the middle Cambrian Burgess Shale. Proceedings of the Royal Society B: Biological Sciences, 2023; 290 (2004) DOI: 10.1098/rspb.2022.2490
Mesozoic mural depicting different ocean species that have evolved through time. [Credit: Smithsonian Institution]Movement in the Earth’s tectonic plates indirectly triggers bursts of biodiversity in 36-million-year cycles by forcing sea levels to rise and fall, new research has shown.
Researchers including geoscientists at the University of Sydney believe these geologically driven cycles of sea level changes have a significant impact on the diversity of marine species, going back at least 250 million years.
As water levels rise and fall, different habitats on the continental shelves and in shallow seas expand and contract, providing opportunities for organisms to thrive or die. By studying the fossil record, the scientists have shown that these shifts trigger bursts of new life to emerge.
The research has been published in the journal Proceedings of the National Academy of Sciences, led by Associate Professor Slah Boulila from Sorbonne University in Paris.
Study co-author Professor Dietmar Müller, from the School of Geosciences at the University of Sydney, said: “In terms of tectonics, the 36-million-year cycle marks alterations between faster and slower seafloor spreading, leading to cyclical depth changes in ocean basins and in the tectonic transfer of water into the deep Earth.
“These in turn have led to fluctuations in the flooding and drying up of continents, with periods of extensive shallow seas fostering biodiversity.
“This work was enabled by the GPlates plate tectonic software, developed by the EarthByte Group at the University of Sydney, supported by Australia’s National Collaborative Research Infrastructure Strategy (NCRIS) via AuScope.”
The team based their findings on the discovery of strikingly similar cycles in sea-level variations, Earth’s interior mechanisms and marine fossil records.
Scientists now have overwhelming evidence that tectonic cycles and global sea level change driven by Earth’s dynamics have played a crucial role in shaping the biodiversity of marine life over millions of years.
“This research challenges previous ideas about why species have changed over long periods,” Professor Müller said.
“The cycles are 36 million years long because of regular patterns in how tectonic plates are recycled into the convecting mantle, the mobile part of the deep Earth, similar to hot, thick soup in a pot, that moves slowly.”
Professor Müller said the Cretaceous Winton Formation in Queensland serves as a prime example of how sea-level changes have shaped ecosystems and influenced biodiversity in Australia.
The formation, renowned for its collection of dinosaur fossils and precious opal, provides a valuable window into a time when much of the Australian continent was flooded.
As sea levels rose and fell, the flooding of the continent created expanding and contracting ecological recesses in shallow seas, providing unique habitats for a wide range of species.
“The Cretaceous Winton Formation stands as a testament to the profound impact of these sea-level changes, capturing a snapshot of a time when Australia’s landscape was transformed and fascinating creatures roamed the land,” Professor Müller said.
Reference:
Slah Boulila, Shanan E. Peters, R. Dietmar Müller, Bilal U. Haq, Nathan Hara. Earth’s interior dynamics drive marine fossil diversity cycles of tens of millions of years. Proceedings of the National Academy of Sciences, 2023; 120 (29) DOI: 10.1073/pnas.2221149120
In this overview map of Utah earthquakes, the dotted line marks the approximate location of the transition zone between the Basin and Range province and the Colorado Plateau and the blue rectangle indicates the study area. Historic seismic events in the study area (1900–1981, 4.5 ≤ M ≤ 6.6) from UUSS and USGS catalogs, and location of basins and ranges mentioned in the text. Horizontal purple dashed lines indicate approximate locations of Blue Ribbon (BRT) and Cove Fort (CVT) Transverse Zones (P. D. Rowley, 1998), thin black lines indicate Quaternary faults. MP: Markagunt Plateau Volcanic Field. The larger map (c) shows seismicity in the study area since 1981, ML ≥ 2.5 (UUSS). PHOTO CREDIT: University of Utah
Most of the earthquakes rumbling under the West’s Great Basin come in surges, clustered together in time and place. Scientists call these seismic groups “swarms,” which are a distinct category from the numerous aftershocks following a big shake, such as the 5.7 magnitude Magna quake of 2020 on the Wasatch Fault.
Rather than getting spread out evenly over time, many of these small, often imperceptible quakes strike a region in a short period of time, say a few days or weeks.
Central Utah has been the stage for dozens of earthquake swarms that have been recorded over the past 40 years by an ever-expanding network of seismic arrays managed by the University of Utah.
Now U seismologists are analyzing decades of seismic data in hopes of discerning the significance of these swarms in a geologically complex region known as a geothermal hotspot and for recent — geologically speaking — volcanism.
“In central Utah, seismic swarms are much more common than any other type of sequence. We looked into all types of sequences, but 80% of the sequences are swarms. That’s remarkable,” said Gesa Petersen, a post-doctoral research fellow. “We also saw that these are very heterogeneous. So one location in central Utah can have a very, very different behavior than other locations just 30, 40, 50 kilometers away.”
With U. geology professor Kristine Pankow, Petersen publish the latest findings July 13 in the journal Geochemistry, Geophysics, Geosystems. Funding came from the state of Utah and the $220 million Department of Energy grant supporting the U’s geothermal research station known as Utah FORGE.
Located outside Milford, FORGE is within the research area that spans Beaver, Iron, Sevier and Paiute counties. The research area is home to three geothermal power-generating plants and includes the towns of Circleville, Beaver and Richfield.
The researchers suspect the earthquakes are triggered by hot water, powered by geothermal activity, coursing through fissures in Earth’s crust.
During the past 40 years, the U of U Seismograph Stations detected earthquake sequences featuring earthquakes of magnitude 1.5 or greater. But in further examining the data, Peterson and Pankow were able to identify hundreds of additional smaller earthquakes, as small as magnitude 0.5 recorded in 50 distinct sequences.
They concluded 40 qualified as swarms. Much can be learned from these smaller quakes, but they are hard to study, according to Pankow, who is the Seismograph Stations associate director.
(BRT) and Cove Fort (CVT) Transverse Zones (P. D. Rowley, 1998), thin black lines indicate Quaternary faults. MP: Markagunt Plateau Volcanic Field. The larger map (c) shows seismicity in the study area since 1981, ML ? 2.5 (UUSS).
“We’re all worried about the Wasatch Front, but the other thing to know is we have earthquakes all over Utah,” said Pankow. “We recorded a certain level, but in some of these places there’s probably earthquakes happening all the time that we just don’t see. That’s something that’s really important to get an understanding of.”
Thousands of earthquakes
All told the research analyzed 2,300 earthquakes, most of which were between magnitude 1 and 3. The largest was a magnitude 5.1 that hit east of Richfield in 1989. That one was not part of a swarm, but rather was a mainshock followed by numerous aftershocks. The full catalog for the study area contains 20,000 events between 1981 and 2023, according to Petersen.
“However, we cannot exactly say how many of them are part of a sequence because we limit the study for sequences that have at least 20 earthquakes within 10 days. We do not look into smaller sequences because we need some minimum to look at statistical parameters and to compare characteristic patterns of the sequences,” she said. “However, in the 1980s and 1990s, the seismic network of Utah was not as dense as today. There were significantly less stations. Therefore we can only study larger sequences with larger magnitudes from these times. There were likely many more swarms or seismic sequences.”
The study greatly expanded on another recent study that focused exclusively on a swarm of hundreds of small quakes around Milford in the spring of 2021. That area had not experienced much earthquake activity during the entire 40-year window of seismograph data. Meanwhile, earthquakes have been happening as frequently as every few months in the nearby Mineral Mountains to the west during this same time period, Petersen said.
“So it’s a very heterogeneous system there,” she said. “You have a bunch of earthquakes in the same place and you can start learning about the structures that are activated in the place. If you have like only a single earthquake, you can’t learn that much then.”
The Mineral Mountains swarms were first detected a few years ago when new seismometers were installed for the FORGE geothermal research project.
“Before that we didn’t have the resolution, but now we can see there are events always coming, and it’s rapid,” Petersen said. “Within a couple of hours, you suddenly have 30, 40, 50 events and then it’s pausing again. You have this repeatedly, you have lots of activity. You can’t really feel it. It’s too small for that, but we can see it on the seismometers.”
The paper, titled “Small-Magnitude Seismic Swarms in Central Utah (US): Interactions of Regional Tectonics, Local Structures and Hydrothermal Systems,” can be found here.
Reference:
G. M. Petersen, K. L. Pankow. Small‐Magnitude Seismic Swarms in Central Utah (US): Interactions of Regional Tectonics, Local Structures and Hydrothermal Systems. Geochemistry, Geophysics, Geosystems, 2023; 24 (7) DOI: 10.1029/2023GC010867
Note: The above post is reprinted from materials provided by University of Utah. Original written by Brian Maffly.
Today an international team of researchers has chosen the location which best represents the beginnings of what could be a new geological epoch, the Anthropocene.
The Anthropocene Working Group have put forward Crawford Lake, in Canada, as a Global Boundary Stratotype Section and Point (GSSP) for the Anthropocene. A GSSP is an internationally agreed-upon reference point to show the start of a new geological period or epoch in layers of rock that have built up through the ages.
It’s been proposed by some geologists that we are now living in the Anthropocene — a new geological epoch in which human activity has become the dominant influence on the world’s climate and environment.
The concept has significant implications for how we consider our impact on the planet. But there is disagreement in the scientific community about when the Anthropocene began, how it is evidenced and whether human influence has been substantial enough to constitute a new geological age, which usually span millions of years.
To help answer these questions, the International Commission on Stratigraphy (ICS) set up the Anthropocene Working Group.
“The sediments found at the bottom of Crawford Lake provide an exquisite record of recent environmental change over the last millennia,” says Dr Simon Turner, Secretary of the Anthropocene Working Group from UCL. “Seasonal changes in water chemistry and ecology have created annual layers that can be sampled for multiple markers of historical human activity. It is this ability to precisely record and store this information as a geological archive that can be matched to historical global environmental changes which make sites such as Crawford Lake so important. A GSSP is used to correlate similar environmental changes seen in other sites worldwide, so it is critical to have a robust and reproducible record at this type locality.”
The team has gathered core sample sections from a variety of environments around the world, from coral reefs to ice sheets. Samples from a range of these sites were then sent for analysis to the University of Southampton’s GAU-Radioanalytical labs at the National Oceanography Centre in Southampton. Researchers there processed the samples to detect a key marker of human influence on the environment — the presence of plutonium.
Professor Andrew Cundy, Chair in Environmental Radiochemistry at the University of Southampton and member of the Anthropocene Working Group, explains: “The presence of plutonium gives us a stark indicator of when humanity became such a dominant force that it could leave a unique global ‘fingerprint’ on our planet.
“In nature, plutonium is only present in trace amounts. But in the early-1950s, when the first hydrogen bomb tests took place, we see an unprecedented increase and then spike in the levels of plutonium in core samples from around the world. We then see a decline in plutonium from the mid-1960s onwards when the Nuclear Test-Ban Treaty came into effect.”
Other geological indicators of human activity include high levels of ash from coal-fired power stations, high concentrations of heavy metals, such as lead, and the presence of plastic fibres and fragments. These coincide with ‘The Great Acceleration’ — a dramatic surge across a range of human activity, from transportation to energy use, starting in the mid-20th century and continuing today.
From the hundreds of samples analysed, the core from Crawford Lake has been proposed as the GSSP, along with secondary supporting sites that show similar high-resolution records of human impact. Evidence from the sites will now be presented to the ICS, which will decide next year whether to ratify the Anthropocene as a new geological epoch.
The fossil showing the entangled skeletons of the dinosaur (Psittacosaurus) and the mammal (Repenomamus). Scale bar equals 10 cm.
Canadian and Chinese scientists have described an unusual fossil from around 125 million years ago that shows a dramatic moment in time when a carnivorous mammal attacked a larger plant-eating dinosaur.
“The two animals are locked in mortal combat, intimately intertwined, and it’s among the first evidence to show actual predatory behaviour by a mammal on a dinosaur,” explains Dr. Jordan Mallon, palaeobiologist with the Canadian Museum of Nature and co-author on the study published today in the journal Scientific Reports.
The fossil’s presence challenges the view that dinosaurs had few threats from their mammal contemporaries during the Cretaceous, when dinosaurs were the dominant animals. The rare fossil is now in the collections of the Weihai Ziguang Shi Yan School Museum in China’s Shandong Province.
The dinosaur in the well-preserved fossil is identified as a species of Psittacosaurus, which is about the size of a large dog. Plant-eating psittacosaurs are among the earliest known horned dinosaurs and lived in Asia during the Early Cretaceous, from around 125 to 105 million years ago. The mammal in the fossil pair is a badger-like animal, called Repenomamus robustus. Although not large by dinosaur standards, it was among the largest mammals during the Cretaceous, at a time when mammals had not yet come to dominate the Earth.
Prior to this discovery, palaeontologists knew that Repenomamus preyed on dinosaurs including Psittacosaurus because of fossilized baby bones of the herbivore found in the mammal’s stomach.
“The co-existence of these two animals is not new, but what’s new to science through this amazing fossil is the predatory behaviour it shows,” says Mallon.
The fossil was collected in China’s Liaoning Province in 2012, and both skeletons are nearly complete. Their completeness is due to the fact that they come from an area known as the Liujitun fossil beds, which have been dubbed “China’s Dinosaur Pompeii.”
The name refers to the many fossils of dinosaurs, small mammals, lizards and amphibians in the area, animals that were buried suddenly en masse by mudslides and debris following one or more volcanic eruptions. The existence of volcanic material in the rock matrix of the study’s fossil was confirmed following analysis by Canadian Museum of Nature mineralogist Dr. Aaron Lussier.
The Psittacosaurus-Repenomamus fossil was in the care of study co-author Dr. Gang Han in China, who brought it to the attention of Canadian Museum of Nature palaeobiologist Xiao-Chun Wu. Dr. Wu has worked with researchers in China for decades and knew it was special when he saw it.
A close examination of the fossil pair shows that the Psittacosaurus is lying prone, with its hindlimbs folded on either side of its body. The body of the Repenomamus coils to the right and sits atop its prey, with the mammalgripping the jaw of the larger dinosaur. The mammal is also biting into some of the ribs, and the back foot of Repenomamus is gripping onto the dino’s hind leg. “The weight of the evidence suggests that an active attack was underway,” says Dr. Mallon.
Mallon, Wu and colleagues ruled out the possibility that the mammal was simply scavenging a dead dinosaur. The bones of the dinosaur have no tooth marks, for example, suggesting it was not being scavenged, but rather was being preyed upon. And it’s unlikely the two animals would have become so entangled if the dinosaur had been dead before the mammal came upon it. The position of the Repenomamus over top of the Psittacosaurus suggests it was also the aggressor.
Analogies of smaller animals attacking larger prey are known in the modern world. Mallon and Wu note that some lone wolverines are known to hunt larger animals, including caribou and domestic sheep. And on the African savanna, wild dogs, jackals and hyenas will attack prey that are still alive, with the prey collapsing, often in a state of shock.
“This might be the case of what’s depicted in the fossil, with the Repenomamus actually eating the Psittacosaurus while it was still alive — before both were killed in the roily aftermath,” explains Mallon.
The research team speculates in their paper that the volcanically derived deposits from the Lujiatun fossil beds in China will continue to yield new evidence of interactions among species, otherwise unknown from the rest of the fossil record.
Reference:
Gang Han, Jordan C. Mallon, Aaron J. Lussier, Xiao-Chun Wu, Robert Mitchell, Ling-Ji Li. An extraordinary fossil captures the struggle for existence during the Mesozoic. Scientific Reports, 2023; 13 (1) DOI: 10.1038/s41598-023-37545-8
Did the pterosaurs, flying reptiles from the days of the dinosaurs, practice parental care or not? New research by scientists from Ireland (University College Cork), China (Nanjing and Yunnan Universities) and the UK (University of Bristol and Queen Mary University of London) shows that pterosaurs were indeed caring parents — but only the larger species.
This solves a long-standing conundrum. To be able to fly soon after hatching from the egg, a bird or pterosaur must have well-developed wings. Studies of smaller pterosaurs from the Jurassic showed that their babies already had large wings when they hatched and they could have wobbled into flight within a few days of birth.
But did this work for the later pterosaurs which were much larger in size? In the Cretaceous, pterosaurs usually had wingspans of 5 metres, and some even reached 10-15 metres, the size of a small glider.
“This was a difficult project,” says the study leader, Dr Zixiao Yang from University College Cork (UCC). ‘We needed examples of pterosaurs where we had at least one hatchling or very young specimen as well as adults so we could study their growth rates. But baby pterosaurs are really rare.”
Dr Yang collaborated with Professor Baoyu Jiang from Nanjing University, Professor Michael Benton of University of Bristol, Professor Xu Xing of Yunnan University, and Professor Maria McNamara of UCC on the research.
“Luckily, we were able to use some classic specimens from the Jurassic of Europe and the Cretaceous of North America, together with new finds from China. By measuring the skulls, backbones, wings, and hind legs, we were able to test for differences in the relative growth of different parts of the body.”
The research focussed on testing the allometry, or how the creatures’ characteristics changed with size.
“We are all familiar with allometry in human babies, puppies and kittens — their heads, eyes and knees are huge, and the rest of the body grows faster to get to adult proportions. It’s the same with many animals, including dinosaurs and pterosaurs. The babies have cute faces, with short noses, big eyes, and big heads,” Dr Yang said.
“The small, bird-sized, Jurassic pterosaurs were born with large wings and strong arms and legs, evidence that the babies could fly from birth. As they grew from baby to adult, their arms and legs showed negative allometry, meaning they started large and were then growing more slowly than the rest of the body.”
“But it was different for the Cretaceous giants. They also started as small babies, but the key limb bones show positive allometry through growth, suggesting a very different developmental model.”
“This means that the pterosaur giants had sacrificed low-input childcare to the need to grow huge eventually as adults. Minimal childcare makes sense in the early evolutionary history of these ancient reptiles because it saves energy. But to grow huge, the larger pterosaurs had a problem — it basically took much longer to become an adult, and therefore parents needed to protect their young from accidents. The babies of all pterosaurs, large and small, were small because of the limitations of egg size. Investing in childcare by having non-flying babies was offset in evolutionary terms by allowing pterosaurs to evolve truly huge sizes.”
“We see the same thing in birds and mammals today. Some birds fly very young, and of course some mammals like cattle and antelopes are on their feet the day they are born. But this kind of behaviour is risky for the babies because they are often clumsy and are easy targets for predators; it’s costly also for the mother because the babies must have highly developed wings or legs at the point of birth. So, we see the same thing in extinct pterosaurs. They were restricted in maximum body size until the end of the Jurassic, at which point their parental care behaviour changed, and then they could achieve huge sizes.”
Reference:
Zixiao Yang, Baoyu Jiang, Michael J. Benton, Xing Xu, Maria E. McNamara, David W. E. Hone. Allometric wing growth links parental care to pterosaur giantism. Proceedings of the Royal Society B: Biological Sciences, 2023; 290 (2003) DOI: 10.1098/rspb.2023.1102
A new 145-million-year-old pterosaur. Credit: René Lauer
A new 145-million-year-old pterosaur (extinct flying reptiles that lived alongside the dinosaurs) was named today by a team of British, American and German researchers. The animal was nicknamed ‘Elvis’ when the fossil was first unearthed in Bavaria, Germany because of the giant pompadour-like bony crest on its skull.
Now the animal has been given a formal scientific name of Petrodactyle wellnhoferi. The name translates as ‘Wellnhofer’s stone-finger’ honouring legendary German palaeontologist Peter Wellnhofer who spent his career working on German pterosaurs. Petrodactyle is a member of a group of pterosaurs called the ctenochasmatids that were mostly small filter feeders. Petrodactyle is a very complete skeleton with nearly every bone preserved and in remarkable detail.
Many pterosaurs are known with bony crests which they used primarily as sexual signals to other members of the species, but Pterodactyle has by far the largest crest even seen in a ctenochasmatid. Dr David Hone of Queen Mary University of London was the lead author on the study said, “Big though this crest is, we know that these pterosaurs had skin-like extensions attached to it, so in life Petrodactyle would have had an even larger crest.”
The details of the specimen are especially clear under UV light which helps show the difference between the bones and the rock in which they are embedded, which under natural light are a very similar colour. René Lauer of the Lauer Foundation, an author on the study said, “The use of UV Induced Fluorescence digital photography provided the ability to discern fine structures small bones and provided additional information regarding the structures of the bony crest which aided in the interpretations and conclusions of this unique new species.”
Petrodactyle was unusually large too. It has a wingspan of around 2 meters, but it was still an older ‘teenager’ by pterosaur standards and would have been even larger as a fully mature animal. Even so, it is one of the largest pterosaurs known from the Late Jurassic period. Bruce Lauer of the Lauer Foundation, an author on the study said “The specimen was located in a quarry which is producing scientifically important fossils that provide additional insights into Late Jurassic Pterosaurs. This research is a great example of the benefits of cooperation between amateur collectors, commercial fossil dealers, our Foundation and research scientists to advance science.”
Like other ctenochasmatids, Petrodactyle was at home on the shore of shallow seas but might have ventured into estuaries or to lakes. It’s long jaw with many small teeth would have been good for grabbing at small fish, shrimp and other aquatic prey. However, unlike most other ctenochasmatids, it had an expansion at the back of the skull to attach large jaw muscles and give it a stronger bite than many of its contemporaries. Frederik Spindler of the Dinosaurier Museum in Germany, an author on the study said, “It is amazing to document an increasingly wide range of adaptations. Pterosaurs were a fundamental part of the Jurassic ecology.”
Dr Hone concluded “Peter Wellnhofer is long overdue having a species of German pterosaur named after him to honour his lifelong contribution to the study of these amazing animals.”
The Lauer Foundation acquires, curates, and provides access to a collection of scientifically important Palaeontological specimens. The collection is available to the scientific community for research, publication, exhibition and educational outreach.
Reference:
David W.E. Hone, René Lauer, Bruce Lauer, Frederik Spindler. Petrodactyle wellnhoferi gen. et sp. nov.: A new and large ctenochasmatid pterosaur from the Late Jurassic of Germany. Palaeontologia Electronica, 2023; DOI: 10.26879/1251
Left: Feathers from a baby bird that lived 99 million years ago, preserved in amber. Photo by Shundong Bi. Right: Illustration of what a newly hatched Enantiornithine bird may have looked like.
Every bird you’ve ever seen — every robin, every pigeon, every penguin at the zoo — is a living dinosaur. Birds are the only group of dinosaurs that survived the asteroid-induced mass extinction 66 million years ago. But not all the birds alive at the time made it. Why the ancestors of modern birds lived while so many of their relatives died has been a mystery that paleontologists have been trying to solve for decades. Two new studies point to one possible factor: the differences between how modern birds and their ancient cousins molt their feathers.
Feathers are one of the key traits that all birds share. They’re made of a protein called keratin, the same material as our fingernails and hair, and birds rely on them to fly, swim, camouflage, attract mates, stay warm, and protect against the sun’s rays. But feathers are complex structures that can’t be repaired, so as a means of keeping them in good shape, birds shed their feathers and grow replacements in a process called molting. Baby birds molt in order to lose their baby feathers and grow adult ones; mature birds continue to molt about once a year.
“Molt is something that I don’t think a lot of people think about, but it is fundamentally such an important process to birds, because feathers are involved in so many different functions,” says Jingmai O’Connor, associate curator of fossil reptiles at Chicago’s Field Museum. “We want to know, how did this process evolve? How did it differ across groups of birds? And how has that shaped bird evolution, shaped the survivability of all these different clades?” Two of O’Connor’s recent papers examine the molting process in prehistoric birds.
A paper in the journal Cretaceous Research published in May 2023 detailed the discovery of a cluster of feathers preserved in amber from a baby bird that lived 99 million years ago.
Today, baby birds are on a spectrum in terms of how developed they are when they’re born and how much help they need from their parents. Altricial birds hatch naked and helpless; their lack of feathers means that their parents can more efficiently transmit body heat directly to the babies’ skin. Precocial species, on the other hand, are born with feathers and are fairly self-sufficient.
All baby birds go through successive molts — periods when they lose the feathers they have and grow in a new set of feathers, before eventually reaching their adult plumage. Molting takes a lot of energy, and losing a lot of feathers at once can make it hard for a bird to keep itself warm. As a result, precocial chicks tend to molt slowly, so that they keep a steady supply of feathers, while altricial chicks that can rely on their parents for food and warmth undergo a “simultaneous molt,” losing all their feathers at roughly the same time.
The amber-preserved feathers in this study are the first definitive fossil evidence of juvenile molting, and they reveal a baby bird whose life history doesn’t match any birds alive today. “This specimen shows a totally bizarre combination of precocial and altricial characteristics,” says O’Connor, who was the first author of the paper alongside senior author Shundong Bi of the Indiana University of Pennsylvania. “All the body feathers are basically at the exact same stage in development, so this means that all the feathers started growing simultaneously, or near simultaneously.” However, this bird was almost certainly part of a now-extinct group called the Enantiornithines, which O’Connor’s previous work has shown were highly precocial.
O’Connor hypothesizes that the pressures of being a precocial baby bird that had to keep itself warm, while undergoing a rapid molt, might have been a factor in the ultimate doom of the Enantiornithines. “Enantiornithines were the most diverse group of birds in the Cretaceous, but they went extinct along with all the other non-avian dinosaurs,” says O’Connor. “When the asteroid hit, global temperatures would have plummeted and resources would have become scarce, so not only would these birds have even higher energy demands to stay warm, but they didn’t have the resources to meet them.”
Meanwhile, an additional study published July 3 in Communications Biology by O’Connor and Field Museum postdoctoral researcher Yosef Kiat examines molting patterns in modern birds to better understand how the process first evolved.
In modern adult birds, molting usually happens once a year in a sequential process, in which they replace just a few of their feathers at a time over the course of a few weeks. That way, they’re still able to fly throughout the molting process. Simultaneous molts in adult birds, in which all the flight feathers fall out at the same time and regrow within a couple weeks, are rarer and tend to show up in aquatic birds like ducks that don’t absolutely need to fly in order to find food and avoid predators.
It’s very rare to find evidence of molting in fossil birds and other feathered dinosaurs, and O’Connor and Kiat wanted to know why. “We had this hypothesis that birds with simultaneous molts, which occur in a shorter duration of time, will be less represented in the fossil record,” says O’Connor — less time spent molting means fewer opportunities to die during your molt and become a fossil showing signs of molting. To test their hypothesis, the researchers delved into the Field Museum’s collection of modern birds.
“We tested more than 600 skins of modern birds stored in the ornithology collection of the Field Museum to look for evidence of active molting,” says Kiat, the first author of the study. “Among the sequentially molting birds, we found dozens of specimens in an active molt, but among the simultaneous molters, we found hardly any.”
While these are modern birds, not fossils, they provide a useful proxy. “In paleontology, we have to get creative, since we don’t have complete data sets. Here, we used statistical analysis of a random sample to infer what the absence of something is actually telling us,” says O’Connor. In this case, the absence of molting fossil birds, despite active molting being so prevalent in the sample of modern bird specimens, suggests that fossil birds simply weren’t molting as often as most modern birds. They may have undergone a simultaneous molt, or they may not have molted on a yearly basis the way most birds today do.
Both the amber specimen and the study of molting in modern birds point to a common theme: prehistoric birds and feathered dinosaurs, especially ones from groups that didn’t survive the mass extinction, molted differently from today’s birds.
“All the differences that you can find between crown birds and stem birds, essentially, become hypotheses about why one group survived and the rest didn’t,” said O’Connor. “I don’t think there’s any one particular reason why the crown birds, the group that includes modern birds, survived. I think it’s a combination of characteristics. But I think it’s becoming clear that molt may have been a significant factor in which dinosaurs were able to survive.”
Reference:
Yosef Kiat, Jingmai Kathleen O’Connor. Rarity of molt evidence in early pennaraptoran dinosaurs suggests annual molt evolved later among Neornithes. Communications Biology, 2023; 6 (1) DOI: 10.1038/s42003-023-05048-x
![Mesozoic mural depicting different ocean species that have evolved through time. [Credit: Smithsonian Institution]](https://www.geologypage.com/wp-content/uploads/2023/08/Scientists-discover-36-million-year-geological-cycle-that-drives-biodiversity-GeologyPage-300x81.jpg)
