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Scientists and philosopher team up, propose a new way to categorize minerals

Representative Image

A diamond lasts forever, but that doesn’t mean all diamonds have a common history.

Some diamonds were formed billions of years ago in space as the carbon-rich atmospheres of dying stars expanded and cooled. In our own planet’s lifetime, high-temperatures and pressures in the mantle produced the diamonds that are familiar to us as gems. 5,000 years ago, a large meteorite that struck a carbon-rich sediment on Earth produced an impact diamond.

Each of these diamonds differs from the others in both composition and genesis, but all are categorized as “diamond” by the authoritative guide to minerals—the International Mineralogical Association’s Commission on New Minerals, Nomenclature and Classification.

For many physical scientists, this inconsistency poses no problem. But the IMA system leaves unanswered questions for planetary scientists, geobiologists, paleontologists and others who strive to understand minerals’ historical context.

So, Carnegie’s Robert Hazen and Shaunna Morrison teamed up with CU Boulder philosophy of science professor Carol Cleland to propose that scientists address this shortcoming with a new “evolutionary system” of mineral classification—one that includes historical data and reflects changes in the diversity and distribution of minerals through more than 4 billion years of Earth’s history.

Their work is published by the Proceedings of the National Academy of Sciences.

“We came together from the very different fields of philosophy and planetary science to see if there was a rigorous way to bring the dimension of time into discussions about the solid materials that compose Earth,” Hazen said.

The IMA classification system for minerals dates to the 19th century when geologist James Dwight Dana outlined a way to categorize minerals on the basis of unique combinations of idealized compositions of major elements and geometrically idealized crystal structure.

“For example, the IMA defines quartz as pure silicon dioxide, but the existence of this idealized version is completely fictional,” said Morrison. “Every specimen of quartz contains imperfections—traces of its formation process that makes it unique.”

This approach to the categorization system means minerals with distinctly different historical origins are lumped together—as with the example of diamonds—while other minerals that share a common causal history are split apart.

“The IMA system is typical,” said lead author Cleland, explaining that most classification systems in the natural sciences, such as the periodic table of the elements, are time independent, categorizing material things “solely on the basis of manifest similarities and differences, regardless of how they were produced or what modifications they have undergone.”

For many researchers, a time-independent system is completely appropriate. But this approach doesn’t work well for planetary and other historically oriented geosciences, where the emphasis is on understanding the formation and development of planetary bodies.

Differences in a diamond or quartz crystal’s formative history are critical, Cleland said, because the conditions under which a sample was formed and the modifications it has undergone “are far more informative than the mere fact that a crystal qualifies as diamond or quartz.”

She, Hazen, and Morrison argue that what planetary scientists need is a new system of categorizing minerals that includes historical “natural kinds.”

Biology faced an analogous issue before Darwin put forward his theory of evolution. For example, lacking an understanding of how organisms are historically related through evolutionary processes, 17th century scholars debated whether bats are birds. With the advent of Darwin’s work in the 19th century, however, biologists classified them separately on evolutionary grounds, because they lack a common ancestor with wings.

Because a universal theory of “mineral evolution” does not exist, creating such a classification system for the geosciences is challenging. Hazen, Morrison, and Cleland’s proposed solution is what they call a “bootstrap” approach based on historically revelatory, information-rich chemical, physical, and biological attributes of solid materials. This strategy allows scientists to build a historical system of mineral kinds while remaining agnostic about its underlying theoretical principles.

“Minerals are the most durable, information-rich objects we can study to understand our planet’s origin and evolution,” Hazen said. “Our new evolutionary approach to classifying minerals complements the existing protocols and offers the opportunity to rigorously document Earth’s history.”

Morrison concurred, adding: “Rethinking the way we classify minerals offers the opportunity to address big, outstanding scientific mysteries about our planet and our Solar System, through a mineralogical lens. In their imperfections and deviations from the ideal, minerals capture the story of what has happened to them through deep time—they provide a time machine to go back and understand what was happening on our planet and other planets in our solar system millions or billions of years ago.”

Reference:
Carol E. Cleland el al., “Historical natural kinds and mineralogy: Systematizing contingency in the context of necessity,” PNAS (2020). www.pnas.org/cgi/doi/10.1073/pnas.2015370118

Note: The above post is reprinted from materials provided by Carnegie Institution for Science.

Deep, slow-slip action may direct largest earthquakes and their tsunamis

Map of the Cascadia subduction zone. Credit: Public Domain
Map of the Cascadia subduction zone. Credit: Public Domain

Megathrust earthquakes and subsequent tsunamis that originate in subduction zones like Cascadia — Vancouver Island, Canada, to northern California — are some of the most severe natural disasters in the world. Now a team of geoscientists thinks the key to understanding some of these destructive events may lie in the deep, gradual slow-slip behaviors beneath the subduction zones. This information might help in planning for future earthquakes in the area.

“What we found was pretty unexpected,” said Kirsty A. McKenzie, doctoral candidate in geoscience, Penn State.

Unlike the bigger, shallower megathrust earthquakes that move and put out energy in the same direction as the plates move, the slow-slip earthquakes’ energy may move in other directions, primarily down.

Subduction zones occur when two of the Earth’s plates meet and one moves beneath the other. This typically creates a fault line and some distance away, a line of volcanoes. Cascadia is typical in that the tectonic plates meet near the Pacific coast and the Cascade Mountains, a volcanic range containing Mount St. Helens, Mount Hood and Mount Rainier, forms to the east.

According to the researchers, a megathrust earthquake of magnitude 9 occurred in Cascadia in 1700 and there has not been a large earthquake there since then. Rather, slow-slip earthquakes, events that happen deeper and move very short distances at a very slow rate, happen continuously.

“Usually, when an earthquake occurs we find that the motion is in the direction opposite to how the plates have moved, accumulating that slip deficit,” said Kevin P. Furlong, professor of geosciences, Penn State. “For these slow-slip earthquakes, the direction of movement is directly downward in the direction of gravity instead of in the plate motion directions.”

The researchers have found that areas in New Zealand, identified by other geologists, slow slip the same way Cascadia does.

“But there are subduction zones that don’t have these slow-slip events, so we don’t have direct measurements of how the deeper part of the subducting plate is moving,” said Furlong. “In Sumatra, the shallower seismic zone, as expected, moves in the plate-motion direction, but even though there are no slow-slip events, the deeper plate movement still appears to be primarily controlled by gravity.”

Slow-slip earthquakes occur at a deeper depth than the earthquakes that cause major damage and earth-shaking events, and the researchers have analyzed how this deep slip may affect the timing and behavior of the larger, damaging megathrust earthquakes.

“Slow-slip earthquakes rupture over several weeks, so they are not just one event,” said McKenzie. “It’s like a swarm of events.”

According to the researchers, in southern Cascadia, the overall plate motion is about an inch of movement per year and in the north by Vancouver Island, it is about 1.5 inches.

“We don’t know how much of that 30 millimeters (1 inch) per year is accumulating to be released in the next big earthquake or if some movement is taken up by some non-observable process,” said McKenzie. “These slow-slip events put out signals we can see. We can observe the slow-slip events going east to west and not in the plate motion direction.”

Slow-slip events in Cascadia occur every one to two years, but geologists wonder if one of them will be the one that will trigger the next megathrust earthquake.

The researchers measure surface movement using permanent, high-resolution GPS stations on the surface. The result is a stair step pattern of loading and slipping during slow-slip events. The events are visible on the surface even though geologists know they are about 22 miles beneath the surface. They report their results in Geochemistry, Geophysics, Geosystems.

“The reason we don’t know all that much about slow-slip earthquakes is they were only discovered about 20 years ago,” said Furlong. “It took five years to figure out what they were and then we needed precise enough GPS to actually measure the motion on the Earth’s surface. Then we had to use modeling to convert the slip on the surface to the slip beneath the surface on the plate boundary itself, which is bigger.”

The researchers believe that understanding the effects of slow-slip earthquakes in the region at these deeper depths will allow them to understand what might trigger the next megathrust earthquake in the area. Engineers want to know how strong shaking in an earthquake will be, but they also want to know the direction the forces will be in. If the difference in direction of slow-slip events indicates a potential change in behavior in a large event, that information would be helpful in planning.

“More fundamentally, we don’t know what triggers the big earthquake in this situation,” said McKenzie. “Every time we add new data about the physics of the problem, it becomes an important component. In the past, everyone thought that the events were unidirectional, but they can be different by 40 or 50 degrees.”

While the slow-events in Cascadia are shedding light on potential megathrust earthquakes in the area and the tsunamis they can trigger, Furlong thinks that other subduction zones may also have similar patterns.

“I would argue that it (differences in direction of motion) is happening in Alaska, Chile, Sumatra,” said Furlong. “It is only in a few that we see the evidence of it, but it may be a universal process that has been missed. Cascadia exhibits it because of the slow-slip events, but it may be fundamental to subduction zones.”

Also working on this project was Matthew W. Herman, assistant professor of geology, California State University, Bakersfield.

The National Science Foundation supported this work.

Reference:
K. A. McKenzie, K. P. Furlong, M. W. Herman. Bidirectional Loading of the Subduction Interface: Evidence From the Kinematics of Slow Slip Events. Geochemistry, Geophysics, Geosystems, 2020; 21 (9) DOI: 10.1029/2020GC008918

Note: The above post is reprinted from materials provided by Penn State. Original written by A’ndrea Elyse Messer.

Lava lake forms as Hawaii volcano erupts after 2-year break

A plume rises near active fissures in the crater of Hawaii's Kilauea volcano on Monday, Dec. 21, 2020. People are lining up to try to get a look at the volcano on the Big Island, which erupted last night and spewed ash and steam into the atmosphere. A spokeswoman for Hawaii Volcanoes National Park says the volcanic activity is a risk to people in the park Monday and that caution is needed. (M. Patrick/U.S. Geological Survey via AP)
A plume rises near active fissures in the crater of Hawaii’s Kilauea volcano on Monday, Dec. 21, 2020. People are lining up to try to get a look at the volcano on the Big Island, which erupted last night and spewed ash and steam into the atmosphere. A spokeswoman for Hawaii Volcanoes National Park says the volcanic activity is a risk to people in the park Monday and that caution is needed. (M. Patrick/U.S. Geological Survey via AP)

Lava was rising more than 3 feet (1 meter) per hour in the deep crater of a Hawaii volcano that began erupting over the weekend after a two-year break, scientists said Tuesday.

Kilauea volcano within Hawaii Volcanoes National Park on the Big Island was gushing molten rock from at least two vents inside its summit crater, the U.S. Geological Survey said. A lava lake has formed, rising about 440 feet (134 meters) from the bottom of the crater.

Since the eruption began Sunday night, Kilauea has spewed some 2 billion gallons of lava (10 million cubic meters), enough to cover 33 acres (13 hectares). The lava has been contained inside the deep crater.

It isn’t threatening to get close to people or cover property, like when Kilauea erupted from vents in the middle of a residential neighborhood in 2018 and destroyed more than 700 homes.

Still, the Hawaiian Volcano Observatory has warned residents to beware of potentially high levels of volcanic gas, rockfalls and explosions.

When erupting, Kilauea tends to spew large volumes of sulfur dioxide, which forms volcanic smog, or vog, when it mixes with oxygen, sunlight and other gases in the air. The state Department of Health warned residents to reduce their outdoor activities if they encounter volcanic smog conditions.

Kilauea is one of the world’s most active volcanoes, having erupted some 50 times in the last century. Between 1983 and 2018, it erupted almost continuously. It had a lava lake in its crater for the last decade of that eruption.

Note: The above post is reprinted from materials provided by The Associated Press. All rights reserved.

New model reveals previously unrecognized complexity of oceanic earthquake zones

Overview of the study area and the schematic illustration of interaction of fault motion and the seafloor subsidence. Credit: University of Tsukuba
Overview of the study area and the schematic illustration of interaction of fault motion and the seafloor subsidence. Credit: University of Tsukuba

Researchers from the University of Tsukuba applied seismic data from around the world to build a model of the 2020 Caribbean earthquake. Oceanic transform faults are generally considered to be linear and simple and have been widely used in studies of earthquake dynamics. However, the research team found that high complexity in rupture speed and direction can occur even in a supposedly simple linear fault system.

On 28 January 2020, a large oceanic earthquake with magnitude 7.7 occurred at the Oriente transform fault in the Caribbean Sea, between Jamaica and Cuba. It caused a minor tsunami of 0.11 m height and was felt as far afield as Florida.

A research team at the University of Tsukuba have developed a new finite-fault inversion method for building models based on teleseismic waveform data from earthquake monitoring stations. This new approach to using the data takes a more flexible approach to resolving the fault geometry. Rather than relying on prior assumptions, the faulting components are separately evaluated in a wider model in both time and space, allowing all possible rupture evolutions to be considered. The team were keen to use the Caribbean earthquake to help to understand the faulting processes that occur during these shallow oceanic quakes.

“Some cases of complex rupture dynamics have recently been reported in previous earthquake studies, raising the question of whether or not we are correctly modeling these even in supposedly simple fault systems,” says study author Professor Yuji Yagi. “The initial monitoring of this January 2020 event suggested variations in the waveform shape between two stations at similar distances from the epicenter, suggesting that there remains complexity to be explored at this fault.”

This was an excellent opportunity to test the new method developed by the team, which used data from 52 seismic stations to construct a detailed model of the geophysical processes within the fault that gave rise to the earthquake.

“The results revealed complex rupture during the earthquake, caused by a bend in the fault that led to the changes in rupture speed and direction detected in the monitoring data,” explains author Professor Ryo Okuwaki. “These variations triggered several successive rupture episodes that occurred along the 300-km-long fault.” The modeling approach also allows some suggestions to be made about the possible occurrence of subsidence and the shape of the surrounding seabed following the earthquake event.

These findings reveal that oceanic transform faults, considered to be simple and linear, may be much more complicated than previously accepted, and therefore require a more comprehensive approach to earthquake modeling. This work will shed light on a possible interaction between the earthquake-fault motion and the evolution of the ocean floor around the transform boundary.

Reference:
Tira Tadapansawut, Ryo Okuwaki, Yuji Yagi, Shinji Yamashita. Rupture Process of the 2020 Caribbean Earthquake along the Oriente Transform Fault, Involving Supershear Rupture and Geometric Complexity of Fault. Geophysical Research Letters, 2020; DOI: 10.1029/2020GL090899

Note: The above post is reprinted from materials provided by University of Tsukuba.

Volcanic eruptions directly triggered ocean acidification during Early Cretaceous

Calcium carbonate samples from a sediment core drilled from the mid-Pacific Mountains. Credit: Northwestern University
Calcium carbonate samples from a sediment core drilled from the mid-Pacific Mountains. Credit: Northwestern University

Around 120 million years ago, the earth experienced an extreme environmental disruption that choked oxygen from its oceans.

Known as oceanic anoxic event (OAE) 1a, the oxygen-deprived water led to a minor — but significant — mass extinction that affected the entire globe. During this age in the Early Cretaceous Period, an entire family of sea-dwelling nannoplankton virtually disappeared.

By measuring calcium and strontium isotope abundances in nannoplankton fossils, Northwestern earth scientists have concluded the eruption of the Ontong Java Plateau large igneous province (LIP) directly triggered OAE1a. Roughly the size of Alaska, the Ontong Java LIP erupted for seven million years, making it one of the largest known LIP events ever. During this time, it spewed tons of carbon dioxide (CO2) into the atmosphere, pushing Earth into a greenhouse period that acidified seawater and suffocated the oceans.

“We go back in time to study greenhouse periods because Earth is headed toward another greenhouse period now,” said Jiuyuan Wang, a Northwestern Ph.D. student and first author of the study. “The only way to look into the future is to understand the past.”

The study was published online last week (Dec. 16) in the journal Geology. It is the first study to apply stable strontium isotope measurements to the study of ancient ocean anoxic events.

Andrew Jacobson, Bradley Sageman and Matthew Hurtgen — all professors of earth and planetary sciences at Northwestern’s Weinberg College of Arts and Sciences — coauthored the paper. Wang is co-advised by all three professors.

Clues inside cores

Nannoplankton shells and many other marine organisms build their shells out of calcium carbonate, which is the same mineral found in chalk, limestone and some antacid tablets. When atmospheric CO2 dissolves in seawater, it forms a weak acid that can inhibit calcium carbonate formation and may even dissolve preexisting carbonate.

To study the earth’s climate during the Early Cretaceous, the Northwestern researchers examined a 1,600-meter-long sediment core taken from the mid-Pacific Mountains. The carbonates in the core formed in a shallow-water, tropical environment approximately 127 to 100 million years ago and are presently found in the deep ocean.

“When you consider the Earth’s carbon cycle, carbonate is one of the biggest reservoirs for carbon,” Sageman said. “When the ocean acidifies, it basically melts the carbonate. We can see this process impacting the biomineralization process of organisms that use carbonate to build their shells and skeletons right now, and it is a consequence of the observed increase in atmospheric CO2 due to human activities.”

Strontium as corroborating evidence

Several previous studies have analyzed the calcium isotope composition of marine carbonate from the geologic past. The data can be interpreted in a variety of ways, however, and calcium carbonate can change throughout time, obscuring signals acquired during its formation. In this study, the Northwestern researchers also analyzed stable isotopes of strontium — a trace element found in carbonate fossils — to gain a fuller picture.

“Calcium isotope data can be interpreted in a variety of ways,” Jacobson said. “Our study exploits observations that calcium and strontium isotopes behave similarly during calcium carbonate formation, but not during alteration that occurs upon burial. In this study, the calcium-strontium isotope ‘multi-proxy’ provides strong evidence that the signals are ‘primary’ and relate to the chemistry of seawater during OAE1a.”

“Stable strontium isotopes are less likely to undergo physical or chemical alteration over time,” Wang added. “Calcium isotopes, on the other hand, can be easily altered under certain conditions.”

The team analyzed calcium and strontium isotopes using high-precision techniques in Jacobson’s clean laboratory at Northwestern. The methods involve dissolving carbonate samples and separating the elements, followed by analysis with a thermal ionization mass spectrometer. Researchers have long suspected that LIP eruptions cause ocean acidification. “There is a direct link between ocean acidification and atmospheric CO2 levels,” Jacobson said. “Our study provides key evidence linking eruption of the Ontong Java Plateau LIP to ocean acidification. This is something people expected should be the case based on clues from the fossil record, but geochemical data were lacking.”

Modeling future warming

By understanding how oceans responded to extreme warming and increased atmospheric CO2, researchers can better understand how earth is responding to current, human-caused climate change. Humans are currently pushing the earth into a new climate, which is acidifying the oceans and likely causing another mass extinction.

“The difference between past greenhouse periods and current human-caused warming is in the timescale,” Sageman said. “Past events have unfolded over tens of thousands to millions of years. We’re making the same level of warming (or more) happen in less than 200 years.”

“The best way we can understand the future is through computer modeling,” Jacobson added. “We need climate data from the past to help shape more accurate models of the future.”

Reference:
Jiuyuan Wang, Andrew D. Jacobson, Bradley B. Sageman, Matthew T. Hurtgen. Stable Ca and Sr isotopes support volcanically triggeredbiocalcification crisis during Oceanic Anoxic Event 1a. Geology, 2020; DOI: 10.1130/G47945.1

Note: The above post is reprinted from materials provided by Northwestern University. Original written by Amanda Morris.

Scientists develop new approach to understanding massive volcanic eruptions

Pululagua in Ecuador
Pululagua in Ecuador

A geosciences team led by the University of South Florida (USF) has developed a new way to reconstruct the sizes of volcanic eruptions that occurred thousands of years ago, creating a first-of-its kind tool that can aid scientists in understanding past explosive eruptions that shaped the earth and improve the way of estimating hazards of future eruptions.

The advanced numerical model the USF team developed allows scientists to reconstruct eruption rates through time by estimating the dimensions of the umbrella clouds that contribute to the accumulation of vast deposits of volcanic ash. The research is published in the new edition of the Nature Journal, Communications, Earth and Environment.

The research, which was used to decipher the 2,500-year-old eruption of a volcano in Ecuador, was led by USF doctoral candidate Robert Constantinescu in collaboration with USF colleagues Research Associate Laura Connor, Professor Chuck Connor, Associate Professor Sylvain Charbonnier, doctoral alum Alain Volentik and other members of an international team. USF’s Volcanology Group is one of the world’s leading centers of volcano science and hazard assessment.

When large explosive eruptions occur, they form laterally spreading umbrella clouds into the stratosphere, facilitating the transport of fine-grained ash over hundreds of miles that settles and covers large swaths of land.

Current technology allows scientists to observe ash clouds. However, past eruptions are characterized based on the geological interpretation of their tephra deposits — the pieces and fragments of rock ejected into the air by an erupting volcano. By estimating the erupted volume and mass, plume height, umbrella cloud dimensions and other characteristics, the scientists are able to understand and characterize the volcanic eruptions, therefore improving the forecast of future events.

Using a series of field techniques combined with statistical and numerical modeling, volcanologists extract information from the deposits in order to characterize and classify an eruption on one of the most commonly used scales, the Volcanic Explosivity Index (VEI). Until now, the most sought-after information is the eruption column height and the total erupted mass or volume, Constantinescu said.

But over time, deposits erode and can provide an uncertain picture of older eruptions. Also, current models have been limited in that they assume all volcanic eruptions created mostly vertical plumes, Constantinescu said, and don’t account for large explosive eruptions that form laterally spreading umbrella ash clouds.

The USF team’s work shows that it is the dimensions of the umbrella clouds that is the telling factor in reconstructing past large explosive eruptions.

“The better we can reconstruct the nature of past eruptions from deposit data, the better we can anticipate potential hazards associated with future explosive eruptions,” the team wrote in the new journal article.

The researchers propose updating the VEI scale with the umbrella cloud dimensions, which can now be easily estimated using the mathematical models they’ve developed.

The researchers applied their model to the tephra deposit of the eruption of Pululagua, a now dormant volcano about 50 miles north of the capital city of Quito. Ecuador is considered one of the world’s most hazardous countries for volcanoes. The volcano last erupted an estimated 2,500 years ago and the area is now a geobotanical reserve renowned for its biodiversity and lush green landscape.

There are about 1,500 potentially active volcanoes worldwide, in addition to those that lurk beneath the world’s oceans. In 2020, there were at least 67 confirmed eruptions from 63 different volcanoes, according to the Smithsonian Institution Global Volcanism Program. “If in modern times the umbrella clouds of large eruptions are easily observed, we now have the ability to estimate the umbrella clouds of past eruptions,” Constantinescu said. “Our numerical model enables us to better characterize past volcanic eruptions and inform models for future hazard assessment.”

The USF team was joined in the research by Aurelian Hopulele-Gligor of Cluj-Napoca, Romania; Costanza Bonadonna of the University of Geneva; and Jan M. Lindsay of the University of Auckland. The research was funded in part by the National Science Foundation.

Reference:
Robert Constantinescu, Aurelian Hopulele-Gligor, Charles B. Connor, Costanza Bonadonna, Laura J. Connor, Jan M. Lindsay, Sylvain Charbonnier, Alain C. M. Volentik. The radius of the umbrella cloud helps characterize large explosive volcanic eruptions. Communications Earth & Environment, 2021; 2 (1) DOI: 10.1038/s43247-020-00078-3

Note: The above post is reprinted from materials provided by University of South Florida (USF Innovation).

Slow start of plate tectonics despite a hot early Earth

Photo: © Christian S. Marien
Photo: © Christian S. Marien

Writing in PNAS, scientists from Cologne university present important new constraints showing that plate tectonics started relatively slow, although the early Earth’s interior was much hotter than today.

In an international collaboration earth scientists at the University of Cologne discovered that during Earth’s early history mantle convection on, i.e. the internal mixing of our planet, was surprisingly slow and spatially restricted. This finding is unexpected because our planet was much hotter during the first hundreds of million years after its formation. Therefore, it has been assumed that mantle convection on Earth was much faster in its infancy. According to their study “Convective isolation of Hadean mantle reservoirs through Archean time,” however, the earth did not experience full speed mantle convection until 3 billion years ago, when modern plate tectonics is believed to have fully operated.

For their study, the geologists investigated up to 3.5 billion years old igneous rocks from NW Australia that cover 800 million years of Earths early history. The analysis of these rock successions revealed that the oldest samples exhibit small anomalies in the isotope abundances of the element tungsten (W) that progressively diminish with time. The origin of these anomalies, namely the relative abundance of 182W, relates to ancient heterogeneities in the terrestrial mantle that must have formed immediately after formation of the Earth more than 4.5 billion years ago. The preservation of these 182W anomalies in the igneous rocks from NW Australia demonstrate that pristine mantle reservoirs from the beginning of our planet were conserved over timescales exceeding more than one billion years.

This finding is very surprising, because higher mantle temperatures in the early Earth suggest that mantle convection was more extensive and much faster than today. Interestingly, the observed 182W anomalies start to diminish at around 3 billion years ago, within a geological era that is assumed to mark the beginning of modern plate tectonics. The onset of modern plate tectonics, involving subduction processes and mountain uplift, has been shown to be a key event triggering the emergence of large continental masses and an oxygen-rich atmosphere, all of which set the stage for the origin of more complex life.

Reference:
Jonas Tusch, Carsten Münker, Eric Hasenstab, Mike Jansen, Chris S. Marien, Florian Kurzweil, Martin J. Van Kranendonk, Hugh Smithies, Wolfgang Maier, and Dieter Garbe-Schönberg. Convective isolation of Hadean mantle reservoirs through Archean time. PNAS, 2020 DOI: 10.1073/pnas.2012626118

Note: The above post is reprinted from materials provided by University of Cologne.

Leaf fossils show severe end-Cretaceous plant extinction in southern Argentina

The scientists examined more than 3,500 fossils to identify survivor pairs - plants that grew in both the Cretaceous and Paleogene periods. The two fossils on the left are from the Cretaceous, and the two on the right are from the Paleogene. Credit: Elena Stiles
The scientists examined more than 3,500 fossils to identify survivor pairs – plants that grew in both the Cretaceous and Paleogene periods. The two fossils on the left are from the Cretaceous, and the two on the right are from the Paleogene. Credit: Elena Stiles

The asteroid impact 66 million years ago that ushered in a mass extinction and ended the dinosaurs also killed off many of the plants that they relied on for food. Fossil leaf assemblages from Patagonia, Argentina, suggest that vegetation in South America suffered great losses but rebounded quickly, according to an international team of researchers.

“Every mass extinction event is like a reset button, and what happens after that reset depends on which organisms survive and how they shape the biosphere,” said Elena Stiles, a doctoral student at the University of Washington who completed the research as part of her master’s thesis at Penn State. “All the biodiversity that we observe today is related to the organisms that made it past the last big reset 66 million years ago.”

Stiles and her colleagues examined more than 3,500 leaf fossils collected at two sites in Patagonia to identify how many species from the geologic period known as the Cretaceous survived the mass extinction event into the Paleogene period. Although plant families in the region fared well, the scientists found a surprising species-level extinction rate that may have reached as high as 92% in Patagonia, higher than previous studies have estimated for the region.

“There’s this idea that the Southern Hemisphere got off easier from the Cretaceous-Paleogene extinction than the Northern Hemisphere because we keep finding plant and animal groups that no one thought survived,” said Peter Wilf, professor of geosciences at Penn State and associate in the Earth and Environmental Systems Institute. “We went into this study expecting that Patagonia was a refuge, and instead we found a complex story of extinction and rebound.”

Researchers from Penn State; the Museo Paleontologico Egidio Feruglio (MEF), Chubut, Argentina; Universidad Nacional del Comahue INIBIOMA, Rio Negro, Argentina; and Cornell University had been collecting the fossils for years from the two sites, in what is now Chubut province. Unlike North America, where the Cretaceous-Paleogene (K-Pg) boundary is well known from many sites in the western United States, the fossil record from this period is fragmented across the Southern Hemisphere, a result of rapidly changing ancient environments.

“Most of the Cretaceous-Paleogene boundary interval known from the Southern Hemisphere is marine,” said Ari Iglesias, a researcher at Universidad Nacional del Comahue INIBIOMA. “We were interested in obtaining the continental record, what happened on land. So, in this study we tried to get as close to the K-Pg boundary as possible, and we reached it in a small area in Chubut province. There we found floras right before the K-Pg boundary, or Maastrichtian floras, and right after the K-Pg boundary, so Danian age floras.”

The assemblages that the team obtained constitute the most complete collection of late Cretaceous and early Paleogene fossil floras in the Southern Hemisphere, added Iglesias.

The researchers studied the assemblages for survivor pairs — plants that grew in both the Cretaceous and Paleogene periods — and found few species-level matches. They then compared their findings to previous pollen and insect herbivory studies from the same area and to North American fossil records. Their study, which is the first of its kind in the Southern Hemisphere, appears in the journal Paleobiology.

“The 92% extinction estimate we get when we consider fossil leaf species across the K-Pg boundary should be taken as a maximum” Stiles said. “We were surprised to find such high extinction levels compared with the 60% extinction rate seen in North America. Nonetheless, we observed a sharp drop in plant species diversity and a high species-level extinction.”

Ecosystem recovery likely took millions of years, added Stiles, which is a small fraction of Earth’s nearly 4.5-billion-year history.

Stiles also led a novel morphospace analysis to identify changes in leaf shape from the Cretaceous to the Paleogene, as such changes could provide clues to the kinds of environmental and climatic occurrences that took place across the boundary interval. She studied each leaf fossil for nearly 50 features, including shape, size and venation patterns.

The analysis showed a higher diversity of leaf forms in the Paleogene, which surprised the researchers given the high species-level extinction and drop in number of species at the end of the Cretaceous. They also found an increase in the proportion of leaf shapes typically found in cooler environments, which suggests that climatic cooling occurred after the end-Cretaceous extinction event.

The researchers’ findings, combined with those of previous studies, suggest that despite the high species-level extinction at the end of the Cretaceous, South American plant families largely survived and grew more diverse during the Paleogene. Among the survivors were the laurel family, which today includes plants such as bay leaves and avocados, and the rose family, which includes fruit like raspberries and strawberries.

“Plants are often overlooked in these big events in geologic history,” Stiles said. “But really, because plants are the primary producers on terrestrial landscapes and sustain all other life forms on Earth, we should be paying closer attention to the plant fossil record. It can tell us how the landscape changed and how those changes affected different groups of organisms.”

The Geological Society of America, Mid-American Paleontological Society, National Science Foundation and Penn State, through a Charles E. Knopf, Sr. Memorial Scholarship and the Paul D. Krynine Memorial Fund, supported this research.

Reference:
Elena Stiles, Peter Wilf, Ari Iglesias, María A. Gandolfo, N. Rubén Cúneo. Cretaceous–Paleogene plant extinction and recovery in Patagonia. Paleobiology, 2020; 46 (4): 445 DOI: 10.1017/pab.2020.45

Note: The above post is reprinted from materials provided by Penn State. Original written by Francisco Tutella.

When dinosaurs disappeared, forests thrived

Researcher overlooking one of the two field sites for the study, the Frenchman Valley in Chambery Coulee Saskatchewan in July 2017. Credit: McGill University
Researcher overlooking one of the two field sites for the study, the Frenchman Valley in Chambery Coulee Saskatchewan in July 2017. Credit: McGill University

It’s known that the primary cause of the mass extinction of dinosaurs, about 66 million years ago, was a large asteroid impact. But the exact mechanisms that linked the impact to mass extinction remain unclear, though climactic changes are thought to have played a part.

To understand how the mass extinction and associated climate changes affected specific ecosystems, a team of McGill scientists has analyzed the microscopic remains of plants from this period, found in the sediment of rivers in southern Saskatchewan. In a recent article in Palaeogeography, Palaeoclimatology, Palaeoecology they show that in this area, local plant communities and ecosystems experienced a long-term shift towards fewer aquatic plants and an increase in terrestrial plants, including trees such as birches and elms. The researchers speculate that this increase was due to the extinction of large plant-eating dinosaurs. They also found, unexpectedly, that changes in rainfall patterns during the extinction event were relatively minor and short-lived.

“This could be important as we look to the future of global warming, where many scientists have predicted that changes in precipitation could have big impacts on humans and ecosystems,” says Peter Douglas from McGill’s Department of Earth and Planetary Scientists and senior author on the paper. “At other times of major climate change in Earth’s history we typically do see evidence for such changes. The absence of such a signal during the most recent mass extinction event is intriguing.”

Douglas adds, “Surprisingly, scientists know more about what happened in the oceans at the end-Cretaceous extinction than on land. By clarifying the environmental changes occurring during this period, we narrowed down the factors that are likely to have caused the disappearance of dinosaurs. The research also provides an important analogue for environmental changes humans are causing to the planet, and the potential for future mass extinction.”

Reference:
Robert D. Bourque, Peter M.J. Douglas, Hans C.E. Larsson. Changes in terrestrial ecosystems across the Cretaceous-Paleogene boundary in western Canada inferred from plant wax lipid distributions and isotopic measurements. Palaeogeography, Palaeoclimatology, Palaeoecology, 2020; 110081 DOI: 10.1016/j.palaeo.2020.110081

Note: The above post is reprinted from materials provided by McGill University.

The ‘crazy beast’ that lived among the dinosaurs

2D Life reconstruction Atuchin. Credit: © Andrey Atuchin
2D Life reconstruction Atuchin. Credit: © Andrey Atuchin

New research published today in the Journal of Vertebrate Paleontology describes a bizarre 66 million-year-old mammal that provides profound new insights into the evolutionary history of mammals from the southern supercontinent Gondwana — recognized today as Africa, South America, Australia, Antarctica, the Indian subcontinent, and the Arabian Peninsula.

Named Adalatherium, which, translated from the Malagasy and Greek languages means “crazy beast,” it is described based on a nearly complete, exquisitely preserved skeleton, the most complete for any mammal yet discovered in the southern hemisphere prior to the extinction of the dinosaurs.

The research, carried out over 20 years, demonstrates that Adalatherium was a “giant” relative to the mostly shrew- or mouse-sized mammals that lived during the Cretaceous period.

Its “bizarre” features include more trunk vertebrae than most other mammals, muscular hind limbs that were placed in a more sprawling position (similar to modern crocodiles) coupled with brawny sprinting front legs that were tucked underneath the body (as seen in most mammals today), front teeth like a rabbit and back teeth completely unlike those of any other known mammal, living or extinct, and a strange gap in the bones at the top of the snout.

A team of 14 international researchers led by Dr David Krause (Denver Museum of Nature & Science) and Dr Simone Hoffmann (New York Institute of Technology) published the comprehensive description and analysis of this opossum-sized mammal that lived among dinosaurs and massive crocodiles near the end of the Cretaceous period (145¬-66 million years ago) on Madagascar.

The 234-page monographic treatment, consisting of seven separate chapters, is part of the Society of Vertebrate Paleontology (SVP) Memoir Series, a special yearly publication that provides a more in-depth treatment of the most significant vertebrate fossils. Initial announcement of the discovery was made in the journal Nature earlier this year.

Adalatherium, from Madagascar, belongs to an extinct group of mammals known as gondwanatherians, which were first discovered in the 1980s and, until recently, were only represented by a few isolated teeth and jaw fragments. But even those meager remains already indicated that gondwanatherians were very different from other contemporaneous mammals. So many mysteries had surrounded gondwanatherians that it was unclear how they fit into the mammalian family tree.

Now the research team presents the first skeleton for this mysterious group that once roamed much of South America, Africa, Madagascar, the Indian subcontinent, and even Antarctica.

The completeness and excellent preservation of the skeleton of Adalatherium opens new windows into what gondwanatherians looked like and how they lived, but the bizarre features still have the team perplexed.

“Knowing what we know about the skeletal anatomy of all living and extinct mammals, it is difficult to imagine that a mammal like Adalatherium could have evolved; it bends and even breaks a lot of rules,” Krause explains.

Although the life-like reconstruction of Adalatherium is superficially similar to a run-of-the-mill badger, its “normality” is only skin deep. Below the surface, its skeleton is nothing short of outlandish.

As Hoffmann puts it, “Adalatherium is simply odd. Trying to figure out how it moved, for instance, was challenging because its front end is telling us a completely different story than its back end.”

While its muscular hind legs and big claws on the back feet may indicate that Adalatherium was a powerful digger (like badgers), its front legs were less brawny and are more similar to those of living mammals that can run fast.

The limbs of Adalatherium also indicate that its posture was a hybrid between those of living mammals and more ancient relatives. Its forelimbs were tucked underneath the body (as seen in most mammals today) but its hind limbs were more sprawling (as in crocodiles and lizards).

This is not were the strangeness stops.

The teeth of Adalatherium, reconstructed by employing high-resolution micro-computed tomography and extensive digital modeling, are indicative of herbivory but are otherwise beyond bizarre.

Not only did Adalatherium have rabbit- or rodent-like ever-growing front teeth, but the back teeth are completely unlike those of any other known mammal, living or extinct. If just these teeth had been found, the mystery of what this animal was would likely not have been solved! Added to the seeming chaos is a hole in the top of the snout for which there is simply no parallel.

About the size of a Virginia opossum, the 3.1 kg Adalatherium was very large for its day. While not particularly large by today’s standards, it was a giant compared to the mostly shrew- and mouse-sized mammals living in the Cretaceous.

The geological history of Gondwana provides clues as to why Adalatherium is so bizarre.

Adalatherium was found in rocks dated to near the end of the Cretaceous, at roughly 66 million years ago. At this time Madagascar had already been an island separated from Africa for over 150 million years and from the Indian subcontinent for over 20 million years. “Islands are the stuff of weirdness,” says Krause, “and there was therefore ample time for Adalatherium to develop its many extraordinarily peculiar features in isolation.”

“Adalatherium is an important piece in a very large puzzle on early mammalian evolution in the southern hemisphere, one in which most of the other pieces are still missing,” adds Hoffmann.

More than anything, the discovery of Adalatherium underscores how much more remains to be learned from new finds of early mammals in Madagascar and other parts of the southern hemisphere.

Reference:
David W. Krause, Joseph R. Groenke, Simone Hoffmann, Raymond R. Rogers, Lydia J. Rahantarisoa. Introduction to Adalatherium hui (Gondwanatheria, Mammalia) from the Late Cretaceous of Madagascar. Journal of Vertebrate Paleontology, 2020; 40 (sup1): 4 DOI: 10.1080/02724634.2020.1805455

Note: The above post is reprinted from materials provided by Taylor & Francis Group.

New dinosaur showed descendants how to dress to impress

Ubirajara jubatus is named after a Tupi Indian name for 'lord of the spear', in reference to the creature's stiffened, elongate integumentary structures, and jubatus from the Latin meaning 'maned' or 'crested'. Image must be credited Credit: Artwork © Bob Nicholls / Paleocreations.com 2020
Ubirajara jubatus is named after a Tupi Indian name for ‘lord of the spear’, in reference to the creature’s stiffened, elongate integumentary structures, and jubatus from the Latin meaning ‘maned’ or ‘crested’. Image must be credited Credit: Artwork © Bob Nicholls / Paleocreations.com 2020

Scientists have found the most elaborately dressed-to-impress dinosaur ever described and say it sheds new light on how birds such as peacocks inherited their ability to show off.

The new species, Ubirajara jubatus, was chicken-sized with a mane of long fur down its back and stiff ribbons projecting out and back from its shoulders, features never before seen in the fossil record.

It is thought its flamboyant features were used to dazzle mates or intimidate foe.

An international team of scientists co-led by Professor David Martill and researcher Robert Smyth, both at the University of Portsmouth, and Professor Dino Frey at the State Museum of Natural History, Karlsruhe, Germany discovered the new species while examining fossils in Karlsruhe´s collection.

The study is published in the scientific journal Cretaceous Research.

Professor Martill said: “What is especially unusual about the beast is the presence of two very long, probably stiff ribbons on either side of its shoulders that were probably used for display, for mate attraction, inter-male rivalry or to frighten off foe.

“We cannot prove that the specimen is a male, but given the disparity between male and female birds, it appears likely the specimen was a male, and young, too, which is surprising given most complex display abilities are reserved for mature adult males.

“Given its flamboyance, we can imagine that the dinosaur may have indulged in elaborate dancing to show off its display structures.”

The ribbons are not scales or fur, nor are they feathers in the modern sense. They appear to be structures unique to this animal.

Mr Smyth said: “These are such extravagant features for such a small animal and not at all what we would predict if we only had the skeleton preserved. Why adorn yourself in a way that makes you more obvious to both your prey and to potential predators?

“The truth is that for many animals, evolutionary success is about more than just surviving, you also have to look good if you want to pass your genes on to the next generation.

“Modern birds are famed for their elaborate plumage and displays that are used to attract mates — the peacock’s tail and male birds-of-paradise are textbook examples of this. Ubirajara shows us that this tendency to show off is not a uniquely avian characteristic, but something that birds inherited from their dinosaur ancestors.”

Ubirajara jubatus lived about 110 million years ago, during the Aptian stage of the Cretaceous period, and is closely related to the European Jurassic dinosaur Compsognathus.

A section of the long, thick mane running down the animal´s back is preserved nearly intact. The arms were also covered in fur-like filaments down to the hands.

The mane is thought to have been controlled by muscles allowing it to be raised, in a similar way a dog raises its hackles or a porcupine raises its spines when threatened.

Ubirajara could lower its mane close to the skin when not in a display mode allowing the creature to move fast without getting tangled in vegetation.

Professor Martill said: “Any creature with movable hair or feathers as a body coverage has a great advantage in streamlining the body contour for faster hunts or escapes but also to capture or release heat.”

The mane isn’t the only extraordinary feature.

The researchers describe as ‘enigmatic’ the creature’s long, flat, stiff shoulder ribbons of keratin, each with a small sharp ridge running along the middle. These ribbons were positioned to not impede freedom of movement in its arms and legs, so wouldn’t have limited the animal’s ability to hunt, preen and send signals.

Mr Smyth argues the elaborate plumage of Ubirajara might have improved its chances of survival.

He said: “We know lots of dinosaurs had bony crests, spines and frills that were probably used for display but we don’t see these very often in living birds. In birds, crests are made of feathers.

“This little dinosaur provides some insight into why this might be the case.

“Bone requires a lot of energy for a body to grow and maintain, it’s also heavy and can cause serious injury if broken.

“Keratin — the material that makes up hair, feathers and scales — is a much better display alternative for a small animal like this one. Keratin is less costly for a body to produce, it’s also lightweight, flexible and can be regularly replaced if damaged.

“Ubirajara is the most primitive known dinosaur to possess integumentary display structures. It represents a revolution in dinosaur communication, the effects of which we can still see today in living birds.”

Professor Frey excavated the specimen from the two slabs of stone in which it lay and, using x-ray, found previously hidden skeletal elements and soft tissue, allowing the researchers to build a clear picture of its features.

Ubirajara jubatus is the first non-avian dinosaur to be described from Brazil’s Crato Formation, a shallow inland sea laid down about 110 million years ago. It is also the first non-avian dinosaur found on the ancient supercontinent of Gondwana with preserved skin.

Another of the researchers on the team, Hector Rivera Sylva, from Museo del Desierto, Mexico, said as well as the discovery being a watershed in this field, it was also important for the Americas.

He said: “The Ubirajara jubatus is not only important because of the integumentary structures present for the first time in a non-avian dinosaur, completely changing the way of seeing the behaviour of certain dinosaurs. Rather, the scientific value transcends, forming a watershed, since it is the first evidence for this group in Latin America, as well as one of the few reported for the subcontinent of Gondwana, expanding the knowledge about non-avian feathered dinosaurs for America, whose evidence is very scarce.”

Reference:
Robert S.H. Smyth, David M. Martill, Eberhard Frey, Héctor E. Rivera-Sylva, Norbert Lenz. A maned theropod dinosaur from Gondwana with elaborate integumentary structures. Cretaceous Research, 2020; 104686 DOI: 10.1016/j.cretres.2020.104686

Note: The above post is reprinted from materials provided by University of Portsmouth.

World’s earliest python identified from 47 million-year-old fossil remains

The head and body of the Messel python are almost completely preserved. Credit: Hessian State Museum Darmstadt
The head and body of the Messel python are almost completely preserved. Credit: Hessian State Museum Darmstadt

Together with his colleague Hussam Zaher of the University in São Paulo, Senckenberg scientist Krister Smith described the world’s oldest known fossils of a python. The almost completely preserved snakes with a length around one meter were discovered in the UNESCO World Heritage Site “Messel Pit” and are about 47 million years old. The new python species, Messelopython freyi, was named in honor of paleontologist Eberhard “Dino” Frey of the State Museum of Natural History in Karlsruhe. The study was published today in the scientific journal Biology Letters.

Reaching a length of more than six meters, pythons are among the world’s largest snakes. Today, various species of these constrictors are found primarily in Africa, Southern and Southeast Asia, and Australia. “The geographic origin of pythons is still not clear. The discovery of a new python species in the Messel Pit is therefore a major leap forward in understanding these snakes’ evolutionary history,” explains Dr. Krister Smith of the Senckenberg Research Institute and Natural History Museum in Frankfurt.

The new python species Messelopython freyi described by Smith and his Brazilian colleague, Dr. Hussam Zaher, is the oldest known fossil record of a python anywhere in the world. “According to our findings, these snakes already occurred in Europe at the time of the Eocene, over 47 million years ago. Our analyses trace their evolutionary history to Europe!” adds Zaher.

However, the large constrictor snakes subsequently disappeared from the European continent for quite some time. Fossils of this snake family did not appear again until the Miocene—between 23 and 5 million years ago. “As the global climate began to cool again after the Miocene, the pythons once again disappeared from Europe,” says Smith.

Contrary to the primeval python from Messel, modern pythons live in complete spatial separation from their anatomically very similar relatives, the boas. “However, in Messel, both Messelopython freyi as well as primitive boas such as Eoconstrictor fischeri lived together in the same ecosystem—we therefore have to revisit the thesis that these two groups of snakes competed with each other, making them unable to share the same habitats,” explains Smith.

The snake’s scientific name is a combination of the locality where it was found and the snake’s family. The specific epithet of the newly discovered fossil is owed to Prof. Dr. Eberhard Frey of the State Museum of Natural History Karlsruhe. “Eberhard Frey bears the nickname “Dino’ for a good reason—he is world-renowned for his exacting studies of fossil reptiles. By naming a new species after him, we wanted to honor his accomplishments in the field of paleontology,” adds Smith to explain the fossil’s naming.

Reference:
Hussam Zaher et al. Pythons in the Eocene of Europe reveal a much older divergence of the group in sympatry with boas, Biology Letters (2020). DOI: 10.1098/rsbl.2020.0735

Note: The above post is reprinted from materials provided by Senckenberg Research Institute and Natural History Museum.

Primitive fish fossils reveal developmental origins of teeth

Part of a jawbone of the 422-million-year-old fossil bony fish Lophosteus, visualized with a high-resolution X-ray technique. On the right, the surface of the jawbone is shown in gray. In the middle, exposed teeth are highlighted in gold and dermal odontodes in shades of purple, pink and red. On the left, the bone itself is made transparent, revealing internal blood vessels and pulp cavities, shown in blue and green, as well as the embedded teeth and dermal odontodes. Credit: Chen et al. (CC BY 4.0)
Part of a jawbone of the 422-million-year-old fossil bony fish Lophosteus, visualized with a high-resolution X-ray technique. On the right, the surface of the jawbone is shown in gray. In the middle, exposed teeth are highlighted in gold and dermal odontodes in shades of purple, pink and red. On the left, the bone itself is made transparent, revealing internal blood vessels and pulp cavities, shown in blue and green, as well as the embedded teeth and dermal odontodes. Credit: Chen et al. (CC BY 4.0)

Teeth and hard structures called dermal odontodes are evolutionarily related, arising from the same developmental system, a new study published today in eLife shows.

These findings in ancient fish fossils contradict established claims about the difference between the two structures based on modern sharks, and provide potential new insights into the origins and development of teeth.

Odontodes are hard structures made of dentine, the main substance in ivory, and are found on the outside surfaces of animals with backbones (vertebrates). Teeth are an example of odontodes but some animals also have them on their skin, such as the tooth-like ‘scales’ of sharks. These are known as dermal odontodes.

“Teeth and dermal odontodes are thought to have evolved separately because they seem to develop in different ways,” says lead author Donglei Chen, a researcher at the Department of Organismal Biology, Uppsala University, Sweden. “However, most of what we know is limited to modern sharks in which the difference between these structures has become very distinct. To understand the relationship between the two more clearly, we needed to turn to the fossil record.”

The team looked at fossils of one of the earliest bony fishes called Lophosteus which lived more than 400 million years ago. They chose this fish because it represents an early stage of tooth evolution, bringing them closer to the time when teeth and dermal odontodes could have separated in the hopes that any developmental similarities between the two would be more obvious.

The researchers used high-resolution X-ray imaging to look at the three-dimensional structure of odontodes in Lophosteus at different stages of development. They found that the appearance of odontodes were similar at the early stages of development but would change depending on whether they grew into the mouth or the face. This suggests there were different chemical signals in each area directing their development. At the later stages, some dermal odontodes would move from the face to the mouth and begin to look like teeth.

These findings suggest that both types of odontodes are able to respond to the same signals controlling each other’s development and are made by the same developmental system — not separate systems as previously thought.

“In addition to casting light on the early evolution of our own teeth, our results point to a previously unrecognised evolutionary-developmental relationship between teeth and dermal odontodes,” says senior author Per Ahlberg, PhD, Professor at the Department of Organismal Biology, Uppsala University. “This has potential implications for understanding the signalling that occurs during development and could inspire new lines of developmental research in other organisms.”

Reference:
Donglei Chen, Henning Blom, Sophie Sanchez, Paul Tafforeau, Tiiu Märss, Per E Ahlberg. The developmental relationship between teeth and dermal odontodes in the most primitive bony fish Lophosteus. eLife, 2020; 9 DOI: 10.7554/eLife.60985

Note: The above post is reprinted from materials provided by eLife.

Research reveals unexpected insights into early dinosaur’s brain, eating habits and agility

Braincase and endocast of Thecodontosaurus antiquus. From CT scans of the braincase fossil, 3-D models of the braincase and the endocast were generated and studied. Credit: Created by Antonio Ballell with BioRender, Thecodontosaurus silhouette from PhyloPic.org.
Braincase and endocast of Thecodontosaurus antiquus. From CT scans of the braincase fossil, 3-D models of the braincase and the endocast were generated and studied. Credit: Created by Antonio Ballell with BioRender, Thecodontosaurus silhouette from PhyloPic.org.

A pioneering reconstruction of the brain belonging to one of the earliest dinosaurs to roam the Earth has shed new light on its possible diet and ability to move fast.

Research, led by the University of Bristol, used advanced imaging and 3-D modelling techniques to digitally rebuild the brain of Thecodontosaurus, better known as the Bristol dinosaur due to its origins in the UK city. The palaeontologists found Thecodontosaurus may have eaten meat, unlike its giant long-necked later relatives including Diplodocus and Brontosaurus, which only fed on plants.

Antonio Ballell, lead author of the study published today in Zoological Journal of the Linnean Society, said: “Our analysis of Thecodontosaurus’ brain uncovered many fascinating features, some of which were quite surprising. Whereas its later relatives moved around ponderously on all fours, our findings suggest this species may have walked on two legs and been occasionally carnivorous.”

Thecodontosaurus lived in the late Triassic age some 205 million years ago and was the size of a large dog. Although its fossils were discovered in the 1800s, many of which are carefully preserved at the University of Bristol, scientists have only very recently been able to deploy imaging software to extract new information without destroying them. 3-D models were generated from CT scans by digitally extracting the bone from the rock, identifying anatomical details about its brain and inner ear previously unseen in the fossil.

“Even though the actual brain is long gone, the software allows us to recreate brain and inner ear shape via the dimensions of the cavities left behind. The braincase of Thecodontosaurus is beautifully preserved so we compared it to other dinosaurs, identifying common features and some that are specific to Thecodontosaurus,” Antonio said. “Its brain cast even showed the detail of the floccular lobes, located at the back of the brain, which are important for balance. Their large size indicate it was bipedal. This structure is also associated with the control of balance and eye and neck movements, suggesting Thecodontosaurus was relatively agile and could keep a stable gaze while moving fast.”

Although Thecodontosaurus is known for being relatively small and agile, its diet has been debated.

Antonio, a Ph.D. student at the University of Bristol’s School of Earth Sciences, said: “Our analysis showed parts of the brain associated with keeping the head stable and eyes and gaze steady during movement were well-developed. This could also mean Thecodontosaurus could occasionally catch prey, although its tooth morphology suggests plants were the main component of its diet. It’s possible it adopted omnivorous habits.”

The researchers were also able to reconstruct the inner ears, allowing them estimate how well it could hear compared to other dinosaurs. Its hearing frequency was relatively high, pointing towards some sort of social complexity—an ability to recognize varied squeaks and honks from different animals.

Professor Mike Benton, study co-author, said: “It’s great to see how new technologies are allowing us to find out even more about how this little dinosaur lived more than 200 million years ago.

“We began working on Thecodontosaurus in 1990, and it is the emblem of the Bristol Dinosaur Project, an educational outreach scheme where students go to speak about science in local schools. We’re very fortunate to have so many well-preserved fossils of such an important dinosaur here in Bristol. This has helped us understand many aspects of the biology of Thecodontosaurus, but there are still many questions about this species yet to be explored.”

Reference:
Antonio Ballell et al, The braincase, brain and palaeobiology of the basal sauropodomorph dinosaur Thecodontosaurus antiquus, Zoological Journal of the Linnean Society (2020). DOI: 10.1093/zoolinnean/zlaa157

Note: The above post is reprinted from materials provided by University of Bristol.

First-known fossil iguana burrow found in the Bahamas

Illustration shows a cross section of the prehistoric iguana burrow, and how the surrounding landscape may have looked during the Late Pleistocene Epoch. Credit: Anthony Martin.
Illustration shows a cross section of the prehistoric iguana burrow, and how the surrounding landscape may have looked during the Late Pleistocene Epoch. Credit: Anthony Martin.

The discovery of the first known fossil iguana nesting burrow, on an outer island of the Bahamas, fills in a gap of scientific knowledge for a prehistoric behavior of an iconic lizard. PLOS ONE published the finding by scientists from Emory University, which also uncovers new clues to the geologic and natural history of the Bahamas.

The fossilized burrow dates back to the Late Pleistocene Epoch, about 115,000 years ago, and is located on the island of San Salvador — best known as the likely spot where Christopher Columbus made his first landfall in his 1492 voyage.

“San Salvador is one of the outer-most islands in the Bahamas chain and really isolated,” says Anthony Martin, a professor in Emory’s Department of Environmental Sciences and senior author of the PLOS ONE paper. “It’s a mystery how and when the modern-day San Salvadoran rock iguanas arrived there. Today, they are among the rarest lizards in the world, with only a few hundred of them left.”

Martin’s specialty is ichnology — the study of traces of life, such as tracks, nests and burrows. He documents modern-day traces to help him identify trace fossils from the deep past to learn about prehistoric animal behaviors.

The current discovery was made during a class field trip to San Salvador as part of the course “Modern and Ancient Tropical Environments,” co-taught by Martin and Melissa Hage, an assistant professor of environmental science at Emory’s Oxford College and a co-author of the paper. Co-authors also include two former undergraduates from the class: Dottie Stearns (now in medical school at the University of Colorado) and Meredith Whitten (who now works in fisheries management for the state of North Carolina).

“No matter how much you read about things in a textbook, a lot of concepts in geology just don’t click until you see them in real life,” Hage says. “It sparks a lot of excitement in students when they experience the process of scientific discovery in the field.”

“Students get to actually see the connections of the past and the present,” Martin adds. “On the north point of San Salvador, for instance, the undulating landscape consists of ancient sand dunes that turned into rock. We can walk across these ancient dunes to look at the rock record and get an idea of how the island changed over time.”

During a stop on the shoreline road on the south end of the island, Martin happened to notice what looked like the trace of a fossil iguana burrow on a limestone outcrop exposed by a roadcut.

The fossil record for iguanas goes back to the Late Cretaceous in South America. Today iguanas are found in tropical areas of Mexico, Central America, South America, the Caribbean and the Bahamas.

Iguanas can grow up to six feet in length, including their tails. Despite their large size, formidable claws and fierce-looking spikes arrayed on their backs, iguanas are mostly herbivores.

The now endangered San Salvador rock iguana, Cyclura riyeli riyeli, and other Cyclura species were plentiful throughout the Bahamas before 1492, when European ships began introducing rats, pigs and other invasive species that feed on the lizards’ eggs.

“One of the cool things about iguanas is that they are survivors,” Martin says. “And one of the main ways that they survive is through burrowing. Digging burrows has helped them survive hurricanes, droughts and other bad things that might be in their environment, like most predators. But burrows are not as helpful when it comes to rats and pigs.”

After further investigation, Martin and his co-authors determined that the trace fossil he noticed on the limestone outcrop was that of a nesting iguana burrow. Ample evidence, including a nearby fossil land-crab burrow discovered by Hage, showed that the outcrop was a former inland sand dune, where iguanas prefer to lay their eggs.

The iguana trace revealed the distinctive pattern of a female creating a nest. “Iguanas have evolved a behavior where a female actually buries herself alive in sand, lays her eggs, and then ‘swims’ out, packing the loose sand behind her as she leaves the burrow to hide the eggs from predators,” Martin says.

This backfilling technique created compaction zones that weathered out over time from the surrounding limestone because they were more durable. “It’s like when you pack sand to build a sandcastle at the beach,” Martin explains. “It’s a similar principle but, in the case of the iguana burrow, it happens underground.”

The lack of burrows from hatchlings digging their way to the surface, however, suggests that the nest failed and that the eggs never produced young.

The researchers were able to date the iguana trace to about 115,000 years ago due to tell-tale red paleosols, or fossilized soils. “The red indicates oxidized iron minerals and there are no native iron minerals in that area,” Martin explains. “But whenever there is a drop in sea level, the Sahara expands in size creating big dust storms. The trade winds take this red dust across the Atlantic and deposit it in the Caribbean.”

The oldest iguana skeletons found on San Salvador only date back less than 12,000 years, in the Holocene Epoch, so the discovery of the iguana trace pushes their presence on the islands back significantly.

Most of the Bahamian islands sit on a relatively shallow platform, making it easy to imagine how iguanas might have migrated there during sea-level lows. San Salvador, however, is a small, isolated island surrounded by deep ocean, setting up the mystery for how the first iguanas arrived there at least 115,000 years ago.

“We’re hoping researchers who study iguana evolution will be inspired by our paper to dig deeper into this question,” Martin says.

The researchers also hope that the paper draws attention to the plight of modern-day San Salvador rock iguanas. “When it comes to species preservation, many people think of panda bears and other cuddly mammals,” Hage says. “Making the connection between how long iguanas have been on the island and how the modern-day San Salvador rock iguanas are endangered may help more people understand why they are worth preserving.”

Additional authors on the paper include Michael Page, a geographer in the Emory Department of Environmental Sciences and the Emory Center for Digital Scholarship; and Arya Basu; a visual information specialist and research scientist in the Emory Center for Digital Scholarship.

Reference:
Anthony J. Martin, Dorothy Stearns, Meredith J. Whitten, Melissa M. Hage, Michael Page, Arya Basu. First known trace fossil of a nesting iguana (Pleistocene), The Bahamas. PLOS ONE, 2020; 15 (12): e0242935 DOI: 10.1371/journal.pone.0242935

Note: The above post is reprinted from materials provided by Emory Health Sciences. Original written by Carol Clark.

Prehistoric ‘sea dragon’ discovered on English Channel Coast is identified as new species

Illustration of Thalassodraco etchesi. Credit: Megan Jacobs
Illustration of Thalassodraco etchesi. Credit: Megan Jacobs

A mysterious small marine reptile dating from 150 million years ago has been identified as a new species that may have been capable of diving very deeply. The well-preserved specimen was found in a Late Jurassic deep marine deposit along the English Channel coastline in Dorset, England.

The aquatic reptile has been determined to be part of the group known as ichthyosaurs, which were streamlined marine predators from the Late Jurassic period, according to paleontologist Megan L. Jacobs, a Baylor University doctoral candidate in geosciences and co-author of a study published in the journal PLOS ONE.

“This ichthyosaur has several differences that makes it unique enough to be its own genus and species,” Jacobs said. “New Late Jurassic ichthyosaurs in the United Kingdom are extremely rare, as these creatures have been studied for 200 years. We knew it was new almost instantly, but it took about a year to make thorough comparisons with all other Late Jurassic ichthyosaurs to make certain our instincts were correct. It was very exciting to not be able to find a match.”

The specimen, estimated to have been about 6 feet long, was discovered in 2009 by fossil collector Steve Etches MBE after a cliff crumbled along the seaside. He found it encased in a slab that would originally have been buried 300 feet deep in a limestone seafloor layer. The specimen since has been housed in The Etches Collection Museum of Jurassic Marine Life in Kimmeridge, Dorset. Jacobs named it Thalassodraco etchesi, meaning “Etches sea dragon” after Etches.

“Now that the new sea dragon has been officially named, it’s time to investigate its biology,” said study co-author David Martill, Ph.D., professor of paleontology at the University of Portsmouth in Portsmouth, United Kingdom. “There are a number of things that make this animal special.”

Investigating the Differences

“This animal was obviously doing something different compared to other ichthyosaurs. One idea is that it could be a deep diving species, like sperm whales,” Jacobs said. “The extremely deep rib cage may have allowed for larger lungs for holding their breath for extended periods, or it may mean that the internal organs weren’t crushed under the pressure. It also has incredibly large eyes, which means it could see well in low light. That could mean it was diving deep down, where there was no light, or it may have been nocturnal.”

With the deep rib cage, the creature would have looked very barrel-like, she said. Given its comparatively small flippers, it may have swum with a distinctive style from other ichthyosaurs.

The specimen’s hundreds of tiny teeth would have been suited for a diet of squid and small fish, and “the teeth are unique by being completely smooth,” Jacobs said. “All other ichthyosaurs have larger teeth with prominent striated ridges on them, so we knew pretty much straight away this animal was different.”

Changes Through History

Ichthyosaurs originated as lizard-like creatures living on land and slowly evolved into the dolphin/shark-like creature found as fossils. Their limbs evolved into flippers, most of them very long or wide.

“They still had to breathe air at the surface and didn’t have scales,” Jacobs said. “There is hardly anything actually known about the biology of these animals. We can only make assumptions from the fossils we have, but there’s nothing like it around today. Eventually, to adapt to being fully aquatic, they no longer could go up onto land to lay eggs, so they evolved into bearing live young, tail first. There have been skeletons found with babies within the mother and also ones that were actually being born.”

Thalassodraco etchesi is closely related to Nannopterygius, a widespread genus of ichthyosaurs which inhabited Late Jurassic seas across Europe, Russia and the Arctic around 248 million years ago before becoming extinct around 90 million years ago. The largest ichthyosaurs, found in North America, had skulls nearly 16 feet long.

Jacobs said that the new specimen likely died from old age or attack by predators, then sank to the seafloor.

“The seafloor at the time would have been incredibly soft, even soupy, which allowed it to nose-dive into the mud and be half buried,” she said. “The back end didn’t sink into the mud, so it was left exposed to decay and scavengers, which came along and ate the tail end. Being encased in that limestone layer allowed for exceptional preservation, including some preserved internal organs and ossified ligaments of the vertebral column.”

“It’s excellent that new species of ichthyosaurs are still being discovered, which shows just how diverse these incredible animals were,” Martill said.

Note: The above post is reprinted from materials provided by Baylor University.

Paleontologists find pterosaur precursors that fill a gap in early evolutionary history

A partial skeleton of Lagerpeton (hips, leg, and vertebrae) from ~235 million years from Argentina. Further examination of this specimen helped tie features of lagerpetids to pterosaurs. Photo courtesy of Sterling Nesbitt. Credit: Virginia Tech
A partial skeleton of Lagerpeton (hips, leg, and vertebrae) from ~235 million years from Argentina. Further examination of this specimen helped tie features of lagerpetids to pterosaurs. Photo courtesy of Sterling Nesbitt. Credit: Virginia Tech

Here’s the original story of flight. Sorry, Wright Brothers, but this story began way before your time — during the Age of the Dinosaurs.

Pterosaurs were the earliest reptiles to evolve powered flight, dominating the skies for 150 million years before their imminent extinction some 66 million years ago.

However, key details of their evolutionary origin and how they gained their ability to fly have remained a mystery; one that paleontologists have been trying to crack for the past 200 years. In order to learn more about their evolution and fill in a few gaps in the fossil record, it is imperative that their closest relatives are identified.

With the help of newly discovered skulls and skeletons that were unearthed in North America, Brazil, Argentina, and Madagascar in recent years, Virginia Tech researchers Sterling Nesbitt and Michelle Stocker from the Department of Geosciences in the College of Science have demonstrated that a group of “dinosaur precursors,” called lagerpetids, are the closest relatives of pterosaurs.

“Where did pterosaurs come from?’ is one of the most outstanding questions in reptile evolution; we think we now have an answer,” said Sterling Nesbitt, who is an associate professor of geosciences and an affiliated faculty member of the Fralin Life Sciences Institute and the Global Change Center.

Their findings were published in Nature.

Fossils of Dromomeron gregorii, a species of lagerpetid, were first collected in Texas in the 1930s and 1940s, but they weren’t properly identified until 2009. Unique to this excavation was a well-preserved partial skull and braincase, which, after further investigation, revealed that these reptiles had a good sense of equilibrium and were likely agile animals.

After finding more lagerpetid species in South America, paleontologists were able to create a pretty good picture of what the lagerpetids were; which were small, wingless reptiles that lived across Pangea during much of the Triassic Period, from 237 to 210 million years ago.

And in the past 15 years, five research groups from six different countries and three continents have come together to right some wrongs in the evolutionary history of the pterosaur, after the recent discovery of many lagerpetid skulls, forelimbs, and vertebrae from the United States, Brazil, Argentina, and Madagascar.

You may be asking yourself, what gave paleontologists the idea to take a closer look at lagerpetids as the closest relatives of pterosaurs? Well, paleontologists have been studying the bones of lagerpetids for quite some time, and they have noted that the length and shape of their bones were similar to the bones of pterosaurs and dinosaurs. But with the few fossils that they had before, it could only be assumed that lagerpetids were a bit closer to dinosaurs.

What really caused a shift in the family tree can be attributed to the recently collected lagerpetid skulls and forelimbs, which displayed features that were more similar to pterosaurs than dinosaurs. And with the help of new technological advances, researchers found that pterosaurs and lagerpetids share far more similarities than meet the eye.

Using micro-computed tomographic (?CT) scanning to reconstruct their brains and sensory systems within the recently discovered skulls, paleontologists determined that the brains and sensory systems of lagerpetids had many similarities with those of pterosaurs.

“CT data has been revolutionary for paleontology,” said Stocker, who is an assistant professor of vertebrate paleontology and an affiliated faculty member of the Fralin Life Sciences Institute and the Global Change Center.

“Some of these delicate fossils were collected nearly 80 years ago, and rather than destructively cutting into this first known skull of Dromomeron, we were able to use this technology to carefully reconstruct the brain and inner ear anatomy of these small fossils to help determine the early relatives of pterosaurs.”

One stark and mystifying finding was that the flightless lagerpetids had already evolved some of the neuroanatomical features that allowed the pterosaurs to fly, which brought forth even more information on the origin of flight.

“This study is a result of an international effort applying both traditional and cutting-edge techniques,” said Martín D. Ezcurra, lead author of the study from the Museo Argentino de Ciencias Naturales in Buenos Aires, Argentina. “This is an example of how modern science and collaboration can shed light on long-standing questions that haunted paleontologists during more than a century.”

Ultimately, the study will help bridge the anatomical and evolutionary gaps that exist between pterosaurs and other reptiles. The new evolutionary relationships that have emerged from this study will create a new paradigm, providing a completely new framework for the study of the origin of these reptiles and their flight capabilities.

With the little information that paleontologists had about early pterosaurs, they had often attributed extremely fast evolution for the acquisition of their unique body plan. But now that lagerpetids are deemed the precursors of pterosaurs, paleontologists can say that pterosaurs evolved at the same rate as other major reptile groups, thanks to the newly discovered “middle man.”

“Flight is such a fascinating behaviour, and it evolved multiple times during Earth’s history,” said Serjoscha W. Evers, of the University of Fribourg. “Proposing a new hypothesis of their relationships with other extinct animals is a major step forward in understanding the origins of pterosaur flight.”

Some questions still remain in this evolutionary mystery. Now that lagerpetids are the closest relatives of pterosaurs, why are they still lacking some of the key characteristics of pterosaurs, including the most outstanding of those — wings?

“We are still missing lots of information about the earliest pterosaurs, and we still don’t know how their skeletons transformed into an animal that was capable of flight,” said Nesbitt.

Nesbitt, Stocker, and a team of Virginia Tech graduate and undergraduate students will continue to study animals that appeared in the Triassic Period — a period of time in Earth history when many familiar groups of vertebrates, such as dinosaurs, turtles, mammal relatives, and amphibians, first appeared. If and when conditions are safe, they plan on going into the field to collect more fossils from the Triassic Period.

Maybe soon, we will have more information to put some finishing touches on the original story of flight.

Reference:
Martín D. Ezcurra, Sterling J. Nesbitt, Mario Bronzati, Fabio Marco Dalla Vecchia, Federico L. Agnolin, Roger B. J. Benson, Federico Brissón Egli, Sergio F. Cabreira, Serjoscha W. Evers, Adriel R. Gentil, Randall B. Irmis, Agustín G. Martinelli, Fernando E. Novas, Lúcio Roberto da Silva, Nathan D. Smith, Michelle R. Stocker, Alan H. Turner, Max C. Langer. Enigmatic dinosaur precursors bridge the gap to the origin of Pterosauria. Nature, 2020; DOI: 10.1038/s41586-020-3011-4

Note: The above post is reprinted from materials provided by Virginia Tech. Original written by Kendall Daniels and Steven Mackay.

Archaeopteryx fossil provides insights into the origins of flight

Remnants of feather sheaths on the wings of the fossil bird Archaeopteryx, shows the earliest evidence of a complex moulting strategy. The white arrows indicate the feather sheaths. Scale bar is 1 cm. Credit: Kaye et al. 2020.
Remnants of feather sheaths on the wings of the fossil bird Archaeopteryx, shows the earliest evidence of a complex moulting strategy. The white arrows indicate the feather sheaths. Scale bar is 1 cm. Credit: Kaye et al. 2020.

Flying birds moult their feathers when they are old and worn because they inhibit flight performance, and the moult strategy is typically a sequential molt. Moulting is thought to be unorganised in the first feathered dinosaurs because they had yet to evolve flight, so determining how moulting evolved can lead to better understanding of flight origins.

However, evidence of the transition to modern moulting strategies is scarce in the fossil record. Recently, Research Assistant Professor Dr Michael PITTMAN from the Research Division for Earth and Planetary Science, as well as Vertebrate Palaeontology Laboratory, at the Faculty of Science of the University of Hong Kong (HKU), Thomas G KAYE of the Foundation for Scientific Advancement (Arizona, USA) and William R WAHL of the Wyoming Dinosaur Center (Wyoming, USA), jointly discovered the earliest record of feather moulting from the famous early fossil bird Archaeopteryx found in southern Germany in rocks that used to be tropical lagoons ~150 million years ago. The findings were published in Communications Biology.

Archaeopteryx moulting strategy used to preserve maximum flight performance

The most common moult strategy in modern birds is a sequential moult, where feathers are lost from both wings at the same time in a symmetrical pattern. The sequence of feather loss follows two different strategies: The first strategy is a numerically sequential molt where feathers are lost in numerical order and is the most common among passerines birds, also known as songbirds and perching birds; the second strategy is a centre-out strategy where a centre feather is lost first, and then subsequent feathers are shed outwards from this centre point; this is more common in non-passerine birds such as falcons. This strategy minimises the size of the aerodynamic hole in the wing, which allows falcons to better maintain their flight performance during the moult for hunting.

Laser-Stimulated Fluorescence imaging co-developed at HKU revealed feather sheaths on the Thermopolis specimen of Archaeopteryx that are otherwise invisible under white light. “We found feather sheaths mirrored on both wings. These sheaths are separated by one feather and are not in numerical sequential order. This indicates that Archaeopteryx used a sequential centre-out moulting strategy, which is used in living falcons to preserve maximum flight performance,” said Kaye. This strategy was therefore already present at the earliest origins of flight.

“The centre-out moulting strategy existed in early flyers and would have been a very welcome benefit because of their otherwise poor flight capabilities. They would have appreciated any flight advantage they could obtain,” said Pittman. “This discovery provides important insights into how and when birds refined their early flight capabilities before the appearance of iconic but later flight-related adaptations like a keeled breastbone (sternum), fused tail tip (pygostyle) and the triosseal canal of the shoulder,” added Pittman.

This study is part of a larger long-term project by Pittman and Kaye and their team of collaborators to better understand the origins of flight (see notes).

Reference:
Thomas G. Kaye, Michael Pittman, William R. Wahl. Archaeopteryx feather sheaths reveal sequential center-out flight-related molting strategy. Communications Biology, 2020; 3 (1) DOI: 10.1038/s42003-020-01467-2

Note: The above post is reprinted from materials provided by The University of Hong Kong.

Rainbow Cave, Hormuz Island, Iran

Rainbow Cave, Hormuz Island, Iran
Rainbow Cave, Hormuz Island, Iran

Hormuz Island

Hormuz Island has an area of 42 km2 (16 sq mi). It is covered by sedimentary rock and layers of volcanic material on its surface. The highest point of the island is about 186 metres (610 ft) above sea level. Due to a lack of precipitation, the soil and water are salty.

Hormuz Island is a salt dome situated in the Persian Gulf waters near the mouth of Hormuz Strait in Hormuzgan province, at 8 kilometers distance from Bandar Abbas. The island is elliptical, and its rock is mostly of the igneous and often volcanic type. Hormuz is one of the most beautiful Islands of the Persian Gulf due to its geological phenomena and related landforms. This island is a mature salt diapir with great mineralogical and lithological diversity. In this research, we focused on fieldwork, which included data gathering and taking photographs and also a review of the published papers and books.

The main geotourism attractions of the island include various landforms resulted from differential erosion, as well as very attractive geomorphologic structures such as rocky and sandy beaches, sea caves, colorful salt domes, coral reefs, etc. Besides the geological and geomorphological sites of the region, the ancient and cultural features are also potential attractions for tourism development on the island.

The rocks show that, over thousands of years that the island of Hormuz gradually comes out of the water, the wear and tear on it makes different shapes. According to researches, geological age of the Hormuz island is about 600 million years ago and its life when coming out of the water is about 50 thousand years.

Rainbow Cave

This cave is created by the flow of water to the sea and its passage under the salt mountain. The depth of the cave is about 30 to 40 meters. In some parts of the cave, several corridors can be seen, which, according to geologists, have caused these corridors. The height of the roof varies along the cave and in some parts you need to bend your head to cross

Inside the cave, sedimentary and salt rocks are stacked layer by layer, creating a smooth surface just like a rainbow. The most beautiful part of the cave is the end where the colors reach their peak. The color spectrum seen in this cave is about seventy spectrums

The colors in this cave are due to their mineral composition. These compounds are metals such as iron that combine with other elements to form colored minerals. Salt rocks can be seen at the beginning of the cave, but gradually colors and colorful stones appear on the cave walls

Crystals may help reveal hidden Kilauea Volcano behavior

A lava fountain during the 1959 eruption of Kilauea Iki. Credit: USGS
A lava fountain during the 1959 eruption of Kilauea Iki. Credit: USGS

Scientists striving to understand how and when volcanoes might erupt face a challenge: many of the processes take place deep underground in lava tubes churning with dangerous molten Earth. Upon eruption, any subterranean markers that could have offered clues leading up to a blast are often destroyed.

But by leveraging observations of tiny crystals of the mineral olivine formed during a violent eruption that took place in Hawaii more than half a century ago, Stanford University researchers have found a way to test computer models of magma flow, which they say could reveal fresh insights about past eruptions and possibly help predict future ones.

“We can actually infer quantitative attributes of the flow prior to eruption from this crystal data and learn about the processes that led to the eruption without drilling into the volcano,” said Jenny Suckale, an assistant professor of geophysics at Stanford’s School of Earth, Energy & Environmental Sciences (Stanford Earth). “That to me is the Holy Grail in volcanology.”

The millimeter-sized crystals were discovered entombed in lava after the 1959 eruption of Kilauea Volcano in Hawaii. An analysis of the crystals revealed they were oriented in an odd, but surprisingly consistent pattern, which the Stanford researchers hypothesized was formed by a wave within the subsurface magma that affected the direction of the crystals in the flow. They simulated this physical process for the first time in a study published in Science Advances Dec. 4.

“I always had the suspicion that these crystals are way more interesting and important than we give them credit for,” said Suckale, who is senior author on the study.

Detective work

It was a chance encounter that prompted Suckale to act upon her suspicion. She had an insight while listening to a Stanford graduate student’s presentation about microplastics in the ocean, where waves can cause non-spherical particles to assume a consistent misorientation pattern. Suckale recruited the speaker, then-Ph.D. student Michelle DiBenedetto, to see if the theory could be applied to the odd crystal orientations from Kilauea.

“This is the result of the detective work of appreciating the detail as the most important piece of evidence,” Suckale said.

Along with Zhipeng Qin, a research scientist in geophysics, the team analyzed crystals from scoria, a dark, porous rock that forms upon the cooling of magma containing dissolved gases. When a volcano erupts, the liquid magma—known as lava once it reaches the surface—is shocked by the cooler atmospheric temperature, quickly entrapping the naturally occurring olivine crystals and bubbles. The process happens so rapidly that the crystals cannot grow, effectively capturing what happened during eruption.

The new simulation is based on crystal orientations from Kilauea Iki, a pit crater next to the main summit caldera of Kilauea Volcano. It provides a baseline for understanding the flow of Kilauea’s conduit, the tubular passage through which hot magma below ground rises to the Earth’s surface. Because the scoria can be blown several hundred feet away from the volcano, these samples are relatively easy to collect. “It’s exciting that we can use these really small-scale processes to understand this huge system,” said DiBenedetto, the lead author of the study, now a postdoctoral scholar at the Woods Hole Oceanographic Institution.

Catching a wave

In order to remain liquid, the material within a volcano needs to be constantly moving. The team’s analysis indicates the odd alignment of the crystals was caused by magma moving in two directions at once, with one flow directly atop the other, rather than pouring through the conduit in one steady stream. Researchers had previously speculated this could happen, but a lack of direct access to the molten conduit barred conclusive evidence, according to Suckale.

“This data is important for advancing our future research about these hazards because if I can measure the wave, I can constrain the magma flow—and these crystals allow me to get at that wave,” Suckale said.

Monitoring Kilauea from a hazard perspective is an ongoing challenge because of the active volcano’s unpredictable eruptions. Instead of leaking lava continuously, it has periodic bursts resulting in lava flows that endanger residents on the southeast side of the Big Island of Hawaii.

Tracking crystal misorientation throughout the different stages of future Kilauea eruptions could enable scientists to deduce conduit flow conditions over time, the researchers say.

“No one knows when the next episode is going to start or how bad it’s going to be—and that all hinges on the details of the conduit dynamics,” Suckale said.

Reference:
“Crystal aggregates record the pre-eruptive flow field in the volcanic conduit at Kilauea, Hawaii” Science Advances (2020). DOI: 10.1126/sciadv.abd4850

Note: The above post is reprinted from materials provided by Stanford University.

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