Chemical Formula: (Ni,Co)As3-x Locality: Schneeberg, Saxony, Germany. Name Origin: Named as the nickel-rich version of skutterudite.
Skutterudite is a cobalt arsenide mineral that has variable amounts of nickel and iron substituting for cobalt with a general formula: (Co,Ni,Fe)As3. Some references give the arsenic a variable formula subscript of 2-3. High nickel varieties are referred to as nickel-skutterudite, previously chloanthite. It is a hydrothermal ore mineral found in moderate to high temperature veins with other Ni-Co minerals. Associated minerals are arsenopyrite, native silver, erythrite, annabergite, nickeline, cobaltite, silver sulfosalts, native bismuth, calcite, siderite, barite and quartz. It is mined as an ore of cobalt and nickel with a by-product of arsenic.
The crystal structure of this mineral has been found to have important technological uses for several compounds isostructural with the mineral.
The mineral has a bright metallic luster, and is tin white or light steel gray in color with a black streak. The specific gravity is 6.5 and the hardness is 5.5-6. Its crystal structure is isometric with cube and octahedron forms similar to that of pyrite. The arsenic content gives a garlic odor when heated or crushed.
It was discovered in Skuterud Mines, Modum, Buskerud, Norway, in 1845. Smaltite is a synonym for the mineral. Notable occurrences include Cobalt, Ontario, Skuterud, Norway, and Franklin, New Jersey in the United States. The rare arsenide minerals are classified in Dana’s sulfide mineral group, even though it contains no sulfur.
The dinosaur named ”Sue,” a 41-foot-long Tyrannosaurus rex, is shown on display at the Field Museum in Chicago, Illinois in this May 17, 2000 file photo. Credit: Reuters/Sue Ogrocki/Files
The hot question of whether dinosaurs were warm-blooded like birds and mammals or cold blooded like reptiles, fish and amphibians finally has a good answer.
Dinosaurs, for eons Earth’s dominant land animals until being wiped out by an asteroid 65 million years ago, were in fact somewhere in between.
Scientists said on Thursday they evaluated the metabolism of numerous dinosaurs using a formula based on their body mass as revealed by the bulk of their thigh bones and their growth rates as shown by growth rings in fossil bones akin to those in trees.
The study, published in the journal Science, assessed 21 species of dinosaurs including super predators Tyrannosaurus and Allosaurus, long-necked Apatosaurus, duckbilled Tenontosaurus and bird-like Troodon as well as a range of mammals, birds, bony fish, sharks, lizards, snakes and crocodiles.
“Our results showed that dinosaurs had growth and metabolic rates that were actually not characteristic of warm-blooded or even cold-blooded organisms. They did not act like mammals or birds nor did they act like reptiles or fish,” said University of Arizona evolutionary biologist and ecologist Brian Enquist.
“Instead, they had growth rates and metabolisms intermediate to warm-blooded and cold-blooded organisms of today. In short, they had physiologies that are not common in today’s world.”
There has been a long-standing debate about whether dinosaurs were slow, lumbering cold-blooded animals – as scientists first proposed in the 19th century – or had a uniquely advanced, more warm-blooded physiology.
As scientists unearthed remains of more and more fast-looking dinosaurs like Velociraptor, some championed the idea dinosaurs were as active and warm–blooded as mammals and birds. The realization that birds arose from small feathered dinosaurs seemed to support that view.
University of New Mexico biologist John Grady said the idea that creatures must be either warm-blooded or cold-blooded is too simplistic when looking over the vast expanse of time. Like dinosaurs, some animals alive today like the great white shark, leatherback sea turtle and tuna do not fit easily into either category, Grady added.
“A better answer would be ‘in the middle.’ By examining animal growth and rates of energy use, we were able to reconstruct a metabolic continuum, and place dinosaurs along that continuum. Somewhat surprisingly, dinosaurs fell right in the middle,” Grady said.
The researchers called creatures with this medium-powered metabolism mesotherms, as contrasted to ectotherms (cold–blooded animals with low metabolic rates that do not produce much heat and bask in the sun to warm up) and endotherms (warm–blooded animals that use heat from metabolic reactions to maintain a high, stable body temperature).
Grady said an intermediate metabolism may have allowed dinosaurs to get much bigger than any mammal ever could. Warm–blooded animals need to eat a lot so they are frequently hunting or munching on plants. “It is doubtful that a lion the size of T. rex could eat enough to survive,” Grady said.
Note : The above story is based on materials provided by Will Dunham; Editing by Marguerita Choy “Reuters”
A group of men attending a bachelor party stumbled across a rare fossil of a mastodon skull, complete with its tusks, in sand at a lakeshore in a New Mexico state park, a museum spokesman said on Thursday.
Randall Gann of the New Mexico Museum of Natural History and Science said the partygoers discovered the fossil earlier this week in Elephant Butte State Park, an area of arid hills surrounding a reservoir about 155 miles (250 km) south of Albuquerque.
He said the museum’s head paleontologist was amazed by the find, calling it “the most complete mastodon skull with attached tusks he has seen in 20 years.”
Mastodons were Ice Age relatives of the elephant that stood 10 feet (3 meters) tall and migrated to North America some 15 million years ago. They ranged across the continent with saber tooth tigers, giant sloths and American camels, before becoming extinct about 10,000 years ago.
The revelers who made the discovery first contacted a professor at the University of New Mexico, who then put them in touch with the museum’s head paleontologist Gary Morgan.
Gann said scientists from the museum planned to act quickly.
“Because it is in sand and not buried in rock, Dr. Morgan feels he can excavate the skull, cast it, and remove it today,” the spokesman said.Shannon Parill, an employee of Elephant Butte State Park, said it was surprising the fossil was found in such a popular area, which attracts thousands of outdoor enthusiasts every year with its boating, hiking, fishing and camping opportunities.
Beth Wojahn, spokeswoman for New Mexico’s Energy, Minerals and Natural Resources Department, praised the group involved.
“What is noteworthy is the men who found the skull did not disturb it and called the right people,” Wojahn said.
Note : The above story is based on materials provided by Daniel Wallis and Will Dunham ” Reuters “
Chemical Formula: Mg(HPO4)·3H2O Locality: Skipton lava tube caves, 40 km southwest of Ballarat, Victoria, Australia. Name Origin: Named for James Cosmo Newbery (1843-1895), geologist, Melbourne, Australia, who initially found the mineral.
History
Discovery date : 1879 Town of Origin: GROTTES DE SKIPTON, BALLARAT, VICTORIA Country of Origin: AUSTRALIE
Optical properties
Optical and misc. Properties : Fragile, cassant – Transparent Refractive Index: from 1,51 to 1,53 Axial angle 2V : 45°
Metasprigina fossil from Marble Canyon, which lived about 514 to 505 million years ago during the Cambrian period is shown in this handout image. Credit: Reuters/Jean-Bernard Caron/ROM/Handout via Reuters
This is certainly not just another fish tale.
A tiny jawless fish that lived more than half a billion years ago is providing scientists with a treasure trove of information about the very dawn of vertebrate life on Earth.
Researchers on Wednesday described about 100 fossil specimens of the fish unearthed at the Burgess Shale site in the Canadian Rockies and other locales, many exquisitely preserved showing the primitive body structures that would later evolve into jaws.
The fish, Metaspriggina, lived about 515 to 500 million years ago amid the astonishing flourishing of complex life during the Cambrian Period. While two fragmentary specimens had been found previously, the new ones revealed unprecedented detail about one of the earliest known vertebrates.
Creatures like Metaspriggina began the lineage of vertebrates – animals with backbones – that later would include the whole range of jawed fishes, amphibians, reptiles, birds and mammals including people.
“It allows an understanding of where we come from and what our most distant relatives might have looked like,” said Jean-Bernard Caron, a paleontologist at the Royal Ontario Museum in Toronto. “Because of its great age – more than half a billion year old – Metaspriggina provides a deep down view at the origins of the vertebrates.”
Metaspriggina was a soft-bodied jawless fish no bigger than a person’s thumb – about 2-1/2 inches (6 cm) long, with a small head, a narrow, tapering body, a pair of large eyes atop the head and a pair of small nasal sacs.
It did not have bones but possessed a skull possibly made of cartilage as well as precursors to vertebrae and a skeletal rod called a “notochord” that provided body support like backbones would do in later vertebrates. It is unclear if it had fins.
The scientists were especially excited about the gill structure of the fish because of the preview it gives to the anatomy of later vertebrates – paving the way for the jaws that would open a world of possibilities for so many later creatures.
Metaspriggina boasted seven pairs of rod-like structures called gill arches, or branchial arches, that functioned for both filtration of food particles and respiration. The first pair of these gill arches was more robust than the others and presaged the first step in the evolution of jaws, Caron said.
Scientists have known about the importance of these arches in the evolution of vertebrates but had never before been able to see such an early example.
“Metaspriggina is important because it both fills an important gap in our understanding of the early evolution of the group to which we belong, but in particular shows with remarkable clarity the arrangement of the so-called branchial arches,” University of Cambridge paleontologist Simon Conway Morris said.
Part of the jaw bones eventually evolved into tiny middle ear bones in mammals, Caron added, noting that the evolution of these arches “had a profound impact on how vertebrates look, live and function today.”
The study was published in the journal Nature.
Note : The above story is based on materials provided by Will Dunham; Editing by Tom Brown ” Reuters”
Three-quarters of the Earth’s water may be locked deep underground in a layer of rock, scientists say. Photograph: Blue Line Pictures/Getty Images
After decades of searching scientists have discovered that a vast reservoir of water, enough to fill the Earth’s oceans three times over, may be trapped hundreds of miles beneath the surface, potentially transforming our understanding of how the planet was formed.
The water is locked up in a mineral called ringwoodite about 660km (400 miles) beneath the crust of the Earth, researchers say. Geophysicist Steve Jacobsen from Northwestern University in the US co-authored the study published in the journal Science and said the discovery suggested Earth’s water may have come from within, driven to the surface by geological activity, rather than being deposited by icy comets hitting the forming planet as held by the prevailing theories.
“Geological processes on the Earth’s surface, such as earthquakes or erupting volcanoes, are an expression of what is going on inside the Earth, out of our sight,” Jacobsen said.
“I think we are finally seeing evidence for a whole-Earth water cycle, which may help explain the vast amount of liquid water on the surface of our habitable planet. Scientists have been looking for this missing deep water for decades.”
Jacobsen and his colleagues are the first to provide direct evidence that there may be water in an area of the Earth’s mantle known as the transition zone. They based their findings on a study of a vast underground region extending across most of the interior of the US.
Ringwoodite acts like a sponge due to a crystal structure that makes it attract hydrogen and trap water.
If just 1% of the weight of mantle rock located in the transition zone was water it would be equivalent to nearly three times the amount of water in our oceans, Jacobsen said.
The study used data from the USArray, a network of seismometers across the US that measure the vibrations of earthquakes, combined with Jacobsen’s lab experiments on rocks simulating the high pressures found more than 600km underground.
It produced evidence that melting and movement of rock in the transition zone – hundreds of kilometres down, between the upper and lower mantles – led to a process where water could become fused and trapped in the rock.
The discovery is remarkable because most melting in the mantle was previously thought to occur at a much shallower distance, about 80km below the Earth’s surface.
Jacobsen told the New Scientist that the hidden water might also act as a buffer for the oceans on the surface, explaining why they have stayed the same size for millions of years. “If [the stored water] wasn’t there, it would be on the surface of the Earth, and mountaintops would be the only land poking out,” he said.
Note : The above story is based on materials provided by Melissa Davey For The Guardian
Chemical Formula: Na2KLi(Fe2+,Mn2+)2Ti2(Si8O24) Locality: Benitoite mine, San Benito, Co., California, USA. Name Origin: Named for Neptune, the Roman god of the sea, because it was found with aegirine, named for the Scandinavian god of the sea.
Neptunite is a silicate mineral with the formula Na2KLi(Fe2+,Mn2+)2Ti2(Si8O24). With increasing manganese it forms a series with mangan-neptunite. Watatsumiite is the variety with vanadium replacing the titanium in the formula.
It was first described in 1893 for an occurrence in the Narssârssuk pegmatite of West Greenland. It is also found within natrolite veins in glaucophane schist within serpentinite in San Benito County, California, USA. It also occurs in Mont Saint-Hilaire, Quebec and in the Kola Peninsula of Russia.
The mineral is named for Neptune, Roman god of the sea because of its association with aegirine from Àgir, the Scandinavian sea-god.
The Gemological Institute of America (GIA) identified an 11.78-carat faceted specimen as neptunite based on Raman spectroscopy.
History
Discovery date : 1893 Town of Origin : NARNARSUK Country of Origin: GROENLAND
Optical properties
Optical and misc. Properties: Translucide – Opaque Refractive Index: from 1,69 to 1,73 Axial angle 2V : ~40°
Physical Properties
Cleavage: {110} Good Color: Black, Red. Density: 3.23 Diaphaneity: Translucent Fracture: Conchoidal – Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz). Hardness: 5-6 – Between Apatite and Orthoclase Luminescence: Non-fluorescent. Luster: Vitreous (Glassy) Streak: brown
Researchers used comprehensive two-dimensional gas chromatography (GCxGC) in their oil spill forensics to measure levels of degradation in biomarkers. THe biomarkers here are shown inside the dotted line. Credit: Christoph Aeppli, Bigelow Laboratory for Ocean Sciences
Years after the 2010 Deepwater Horizon Oil spill, oil continues to wash ashore as oil-soaked “sand patties,” persists in salt marshes abutting the Gulf of Mexico, and questions remain about how much oil has been deposited on the seafloor. Scientists from Woods Hole Oceanographic Institution and Bigelow Laboratory for Ocean Sciences have developed a unique way to fingerprint oil, even after most of it has degraded, and to assess how it changes over time. Researchers refined methods typically used to identify the source of oil spills and adapted them for application on a longer time frame to successfully identify Macondo Well oil, years after the spill.
“We were looking at two questions: how could we identify the oil on shore, now four years after the spill, and how the oil from the spill was weathering over time,” explained Christoph Aeppli, Senior Research Scientist at Bigelow Laboratory for Ocean Sciences in East Boothbay, Maine, and lead author of the study reported in Environmental Science & Technology. Aeppli worked with his then-colleagues at Woods Hole Oceanographic Institution, and University of California, Santa Barbara on the investigation and report.
Researchers used comprehensive two-dimensional gas chromatography (GCxGC) in their oil spill forensics to measure levels of degradation in biomarkers. Biomarkers are molecular fossils. Each reservoir has specific amounts of different biomarkers, so oil biomarkers serve as identifiers much like human fingerprints. Biomarkers are usually recalcitrant in reservoirs, but when exposed for a long time to the environment, some are altered due to natural processes. Oil consists of tens of thousands of compounds, and many of them can be degraded by bacteria or broken down by sunlight. This research was designed to determine the resiliency of specific biomarkers and to see how they held up when exposed to environmental conditions on shore.
“We found that some biomarkers — homohopanes and triaromoatic steroids (TAS), specifically — degraded within a few years following the Deepwater Horizon spill,” said Chris Reddy, a scientist at Woods Hole Oceanographic Institution and co-author of the paper. “These biomarkers are not as resilient as once thought and they may provide a future window into determining how much, and how quickly, these oil components may linger in the environment when exposed to air, sunlight, and the elements.”
Researchers sought to determine the specific source of the biomarkers degradation. Through analysis of oil-soaked “sand patties” collected along the Gulf shore over a 28-month period, they found that most biomarker compounds were recalcitrant and could be used to identify DWH oil. Some biomarkers, however, degraded. “This knowledge is helping us improve our oil spill forensics. It is providing a foundation for better, longer-term identification techniques that account for exposure of oil to wind, waves, sunlight, and microbial degradation over long times,” added Aeppli.
Aeppli, Reddy and colleague Dave Valentine from UC Santa Barbara will apply this new oil fingerprinting technique to process tens of thousands of samples collected shortly after the DWH spill.
Note : The above story is based on materials provided by Bigelow Laboratory for Ocean Sciences.
The tectonic plates of the world were mapped in the second half of the 20th century. usgs
Two studies show that the movement rate of plates carrying Earth’s crust may not be constant over time. This could provide a new explanation for the patterns observed in the speed of evolution and has implications for the interpretation of climate models. The work is presented today at Goldschmidt 2014, the premier geochemistry conference taking place in Sacramento, California, USA.
Earth’s continental crust can be thought of as an archive of Earth’s history, containing information on rock formation, the atmosphere and the fossil record. However, it is not clear when and how regularly crust formed since the beginning of Earth history, 4.5 billion years ago.
Researchers led by Professor Peter Cawood, from the University of St. Andrews, UK, examined several measures of continental movement and geologic processes from a number of previous studies. They found that, from 1.7 to 0.75 billion years ago (termed Earth’s middle age), Earth appears to have been very stable in terms of its environment, with little in the way of crust building activity, no major fluctuations in atmospheric composition and few major developments seen in the fossil record. This contrasts markedly with the time periods either side of this, which contained major ice ages and changes in oxygen levels. Earth’s middle age also coincides with the formation of a supercontinent called Rodinia, which appears to have been stable throughout this time.
Professor Cawood suggests this stability may have been due to the gradual cooling of Earth’s crust over time. “Before 1.7 billion years ago, the Earth’s crust would have been substantially hotter, meaning that continental plate movement may have been governed by different rules to those that operate today,” said Professor Cawood. “0.75 billion years ago, the crust reached a point where it had cooled sufficiently to allow modern day plate tectonics to start working, in particular allowing subduction zones to form (where one plate of the crust moves under another). This increase in activity could have kick-started a myriad of changes including the break-up of Rodinia and changes to levels of key elements in the atmosphere and seas, which in turn may have induced evolutionary changes in the life forms present.”
This view is backed up by work from Professor Kent Condie from New Mexico Tech, USA, which suggests the movement rate of Earth’s crust is not constant but may be speeding up over time. Professor Condie examined how supercontinents assemble and break up. “Our results challenge the view that the rate of plate movement is stable over time,” said Professor Condie. “The interpretation of data from many other disciplines such as stable isotope geochemistry, palaeontology and paleoclimatology in part rely on the assumption that the movement rate of the Earth’s crust is constant.”
Results from these fields may now need to be re-examined in light of Condie’s findings. “We now urgently need to collect further data on critical time periods to understand more about the constraints on plate speeds and the frequency of collision between continental blocks,” concluded Professor Condie.
Note : The above story is based on materials provided by European Association of Geochemistry.
Chemical Formula: (Na,K)AlSiO4 Locality: Magnet Cove, Magnet Cove, Ouachita Mountains, Hot Spring County, Arkansas, USA. Name Origin: From the Greek nephele, “cloud,” because it becomes clouded when put in strong acid.
Nepheline, is a feldspathoid: a silica-undersaturated aluminosilicate, Na3KAl4Si4O16, that occurs in intrusive and volcanic rocks with low silica, and in their associated pegmatites.
Nepheline crystals are rare and belong to the hexagonal system, usually having the form of a short, six-sided prism terminated by the basal plane. The unsymmetrical etched figures produced artificially on the prism faces indicate, however, that the crystals are hemimorphic and tetartohedral, the only element of symmetry being a polar hexad axis. It is found in compact, granular aggregates, and can be white, yellow, gray, green, or even reddish (in the eleolite variety). The hardness is 5.5 – 6, and the specific gravity 2.56 – 2.66. It is often translucent with a greasy luster.
History
Discovery date : 1801 Town of Origin : MONTE SOMMA, MT. VESUVE (VOLCAN), NAPLES, CAMPANIE Country of Origin : ITALIE
Optical properties
Optical and misc. Properties: Transparent – Opaque – Translucide Refractive Index: from 1,52 to 1,54
Physical Properties
Cleavage: {1010} Poor Color: White, Gray, Brown, Brownish gray, Reddish white. Density: 2.55 – 2.65, Average = 2.59 Diaphaneity: Transparent to translucent to opaque Fracture: Sub Conchoidal – Fractures developed in brittle materials characterized by semi-curving surfaces. Hardness: 6 – Orthoclase Luminescence: Non-fluorescent. Luster: Vitreous – Greasy Streak: white
The Finlay River is a 402 km long river in north-central British Columbia flowing north and thence south from Thutade Lake in the Omineca Mountains to Williston Lake, the impounded waters of the Peace River formed by the completion of the W.A.C. Bennett Dam in 1968. Prior to this, the Finlay joined with the Parsnip River to form the Peace. The headwaters of the Finlay at Thutade Lake are considered the ultimate source of the Mackenzie River. Deserters Canyon is located just north of Williston Lake.
The Finlay drains an area of 43,000 square kilometres and discharges at a mean rate of 600 cubic metres per second. Major tributaries of the Finlay include the Ospika, Ingenika, Warneford, Fox, Toodoggone, and Firesteel Rivers (the Ospika now enters Lake Williston directly, however). Located in a remote part of the province, there are no population centres along the river, however, there is a small First Nations community, Fort Ware, located at the junction of the Finlay and Warneford. Tatlatui Provincial Park protects the area of the Tatlatui Range, where Thutade Lake is located.
Map of the Stikine Territory. The line of the Finlay River is the southeast boundary of the territory, which was absorbed into the Colony of British Columbia in 1863.
The Finlay River is named for the explorer John Finlay, who travelled a short way up the river in 1797. The first European to journey its length to its source was the fur trader and explorer Samuel Black in 1824. The river was the eastern half of the northern boundary of the Colony of British Columbia at the time of its creation in 1858, north of which was the North-Western Territory; the western half of the boundary was the Nass River and from 1862 to 1863 it was briefly the southern boundary of the Stickeen Territories (Stikine Territory) which had been formed from the North-Western Territory in response to the Peace and Stikine Gold Rushes and which was amalgamated with the Colony of British Columbia in the following year.
Note : The above story is based on materials provided by Wikipedia
Photomicrographs of a subseafloor thermophile isolated from deep-sea hydrothermal vent fluids. This organism eats sulfur and hydrogen and fixes its own carbon from carbon dioxide. (A, B) Scanning electron micrographs, and (C, D) transmission electron micrographs thin sections. Image courtesy of Julie Huber.
The subseafloor is home to over 1/3 of the bacteria on the planet, but up until recently it was unclear if this huge microbial biosphere was alive and dividing. Now the same group that demonstrated this activity has shown that bacteria from the hostile sea-floor environment have adapted by over-activating stress response and DNA-repair mechanisms, to cope with the harsh conditions.
Subseafloor sediment contains Earth’s largest habitat for microbial life — over 1/3 of all the planets microbial biomass. By drilling deep into the sea floor and taking samples, it can be proven that the subseafloor contains a variety of microbial lifeforms, but it’s only in the last year that researchers have proven that sea floor microbes are actually active in in their natural sea-bed situation — it is difficult to analyse lifeforms which live hundreds of metres below the sea surface because of their low activity levels. A group of researchers at Woods Hole Oceanographic Institute and University of Delaware developed techniques to analyse the messenger
RNA (mRNA) molecules produced by subseafloor microbes. Unlike DNA, which is a fairly robust molecule that can survive intact for thousands of years under certain conditions, mRNA (messenger RNA) has a short half-life. It is produced by cells, which are “turning on” genes, so it is an indication that genes are active. This means that mRNA can be used as evidence (a proxy) for present biological activity.
Lead researcher William Orsi said: “This is the largest microbial biosphere on Earth, composed of cells living deep beneath the surface. We have recently shown for the first time that these cells, the “deep biosphere,” are actually dividing and not in a dormant state. This means that the deep biosphere is active and due to its sheer size likely plays an important role in global elemental cycles over geological timescales.” Now in a presentation to the Goldschmidt conference in Sacramento, California, Dr Orsi will detail just how these seabed bacteria had managed to survive in such an inhospitable environment.
“It’s a really difficult environment to study, so understanding how microbes survive there has been a puzzle” he said, “but we have discovered that they ramp-up some coping mechanisms which have helped them adapt to this stressful environment, where they exist under high pressure and are starved of nutrients.”
The group sampled drill cores from the continental shelf off the coast of Peru. They compared gene expression at several depths spanning 5-159 meters below the seafloor. They found that the expression of DNA repair genes, such as recA, increases with the amount of time the microbes have been buried in the seafloor.
Dr Orsi continued: “Subseafloor microbes have adapted to live in especially harsh conditions. We found that they significantly overexpress genes involved in cellular stress responses like recA. This gene is a central to the bacterial “SOS response,” which is a way bacteria cope with many different environmental stressors including antibiotics. We have found that subseafloor microbes increasingly express this gene with time after they become “buried alive” in the subseafloor.”
“High-throughput omics techniques are proving to have a range of applications in sedimentary systems. For example, marine sedimentary paleogenomics is a new field, which is opening windows into the past effects of climate on marine life. Dr Marco Coolen is the leader of this new field, and we worked together to analyse ancient plankton DNA from the Black Sea. We showed that it opened to the oceans around 9,600 years ago and that historical large-scale climate changes had a significant effect on marine plankton. These techniques are difficult, but they can tell us how biology responds to climate changes over geological timescales. Looking into the past can help us predict the future effects of climate change on marine life.”
Note : The above story is based on materials provided by European Association of Geochemistry.
Chemical Formula: Pb5Au(Te,Sb)4S5-8 Locality: Nagyag mine (now Sacaramb), Romania. Name Origin: Named after the locality.
Nagyágite (Pb5Au(Te,Sb)4S5-8) is a rare sulfide mineral with known occurrence associated with gold ores. Nagyágite crystals are opaque, monoclinic and dark grey to black coloured.
It was first described in 1845 for an occurrence at the type locality of the Nagyág mine, Săcărâmb, Hunedoara County, Romania.
It occurs in gold–tellurium epithermal hydrothermal veins. Minerals associated with nagyágite include: altaite, petzite, stutzite, sylvanite, tellurantimony, coloradoite, krennerite, native arsenic, native gold, proustite, rhodochrosite, arsenopyrite, sphalerite, tetrahedrite, calaverite, tellurobismuthite, galena and pyrite.
History
Discovery date : 1845 Town of Origin: SACARAMB (NAGYAG), COMTE DE HUNEDOARA, TRANSYLVANIE Country of Origin: ROUMANIE
Optical properties
Optical and misc. Properties : Opaque Reflective Power: 37,5-41,5% (580)
A major fossil discovery in Canada sheds new light on the development of the earliest vertebrates, including the origin of jaws, the first time this feature has been seen so early in the fossil record.
A key piece in the puzzle of the evolution of vertebrates has been identified, after the discovery of fossilised fish specimens, dating from the Cambrian period (around 505 million years old), in the Canadian Rockies. The fish, known as Metaspriggina, shows pairs of exceptionally well-preserved arches near the front of its body. The first of these pairs, closest to the head, eventually led to the evolution of jaws in vertebrates, the first time this feature has been seen so early in the fossil record.
Fish fossils from the Cambrian period are very rare and usually poorly preserved. This new discovery shows in unprecedented detail how some of the earliest vertebrates developed — the starting point of a story which led to animals such as later fish species, but also dinosaurs and mammals such as horses and even ourselves. The findings are published in the 11 June edition of the journal Nature.
Fossils of Metaspriggina were recovered from several locations including the Burgess Shale site in Canada’s Rocky Mountains, one of the richest Cambrian fossil deposits in the world. These fossils shed new light on the Cambrian ‘explosion’, a period of rapid evolution starting around 540 million years ago, when most major animal phyla originated.
Previously, only two incomplete specimens of Metaspriggina had been identified. During expeditions conducted by the Royal Ontario Museum in 2012, 44 new Burgess Shale fossils were collected near Marble Canyon in Kootenay National Park in British Columbia, which provide the basis for this study. Researchers from the University of Cambridge and the Royal Ontario Museum/University of Toronto used these fossils, along with several more specimens from the eastern United States, to reclassify Metaspriggina as one of the first vertebrates.
The fossils, which date from 505 million years ago, also show clearly for the first time how a series of rod-like structures, known as the gill or branchial arches, were arranged in the earliest vertebrates. These arches have long been known to have played a key role in the evolution of vertebrates, including the origin of jaws, and some of the tiny bones in the ear which transmit sound in mammals. Until now, however, a lack of quality fossils has meant that the arrangement of these arches in the first vertebrates had been hypothetical.
Vertebrates first appear in the fossil record slightly earlier than these finds, but pinpointing exactly how they developed is difficult. This is because fossils of such animals are rare, incomplete and open to varying interpretations, as they show soft tissues which are difficult to identify with complete certainty.
The new fossils of Metaspriggina are remarkably well-preserved. The arrangement of the muscles shows these fish were active swimmers, not unlike a trout, and the animals saw the world through a pair of large eyes and sensed their surrounding environment with nasal structures.
“The detail in this Metaspriggina fossil is stunning,” said lead author Professor Simon Conway Morris of Cambridge’s Department of Earth Sciences. “Even the eyes are beautifully preserved and clearly evident.”
But it is the branchial arches which makes this discovery so important. Previously, they were thought to exist as a series of single arches, but Metaspriggina now shows that they in fact existed in pairs. The anteriormost pair of arches is also slightly thicker than the remainder, and this subtle distinction may be the very first step in an evolutionary transformation that in due course led to the appearance of the jaw. “Once the jaws have developed, the whole world opens,” said Professor Conway Morris. “Having a hypothetical model swim into the fossil record like this is incredibly gratifying.”
Reference:
Simon Conway Morris, Jean-Bernard Caron. A primitive fish from the Cambrian of North America. Nature, 2014; DOI: 10.1038/nature13414
Note : The above story is based on materials provided by University of Cambridge.
This artist concept shows Pluto and some of its moons, as viewed from the surface of one of the moons. Pluto is the large disk at center. Charon is the smaller disk to the right. Credit: NASA, ESA and G. Bacon (STScI)
If the icy surface of Pluto’s giant moon Charon is cracked, analysis of the fractures could reveal if its interior was warm, perhaps warm enough to have maintained a subterranean ocean of liquid water, according to a new NASA-funded study.
Pluto is an extremely distant world, orbiting the sun more than 29 times farther than Earth. With a surface temperature estimated to be about 380 degrees below zero Fahrenheit (around minus 229 degrees Celsius), the environment at Pluto is far too cold to allow liquid water on its surface. Pluto’s moons are in the same frigid environment.
Pluto’s remoteness and small size make it difficult to observe, but in July of 2015, NASA’s New Horizons spacecraft will be the first to visit Pluto and Charon, and will provide the most detailed observations to date.
“Our model predicts different fracture patterns on the surface of Charon depending on the thickness of its surface ice, the structure of the moon’s interior and how easily it deforms, and how its orbit evolved,” said Alyssa Rhoden of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “By comparing the actual New Horizons observations of Charon to the various predictions, we can see what fits best and discover if Charon could have had a subsurface ocean in its past, driven by high eccentricity.” Rhoden is lead author of a paper on this research now available online in the journal Icarus.
Some moons around the gas giant planets in the outer solar system have cracked surfaces with evidence for ocean interiors — Jupiter’s moon Europa and Saturn’s moon Enceladus are two examples.
As Europa and Enceladus move in their orbits, a gravitational tug-of-war between their respective parent planets and neighboring moons keeps their orbits from becoming circular. Instead, these moons have eccentric (slightly oval-shaped) orbits, which raise daily tides that flex the interior and stress the surface. It is thought that tidal heating has extended the lifetimes of subsurface oceans on Europa and Enceladus by keeping their interiors warm.
In Charon’s case, this study finds that a past high eccentricity could have generated large tides, causing friction and surface fractures. The moon is unusually massive compared to its planet, about one-eighth of Pluto’s mass, a solar system record. It is thought to have formed much closer to Pluto, after a giant impact ejected material off the planet’s surface. The material went into orbit around Pluto and coalesced under its own gravity to form Charon and several smaller moons.
Initially, there would have been strong tides on both worlds as gravity between Pluto and Charon caused their surfaces to bulge toward each other, generating friction in their interiors. This friction would have also caused the tides to slightly lag behind their orbital positions. The lag would act like a brake on Pluto, causing its rotation to slow while transferring that rotational energy to Charon, making it speed up and move farther away from Pluto.
“Depending on exactly how Charon’s orbit evolved, particularly if it went through a high-eccentricity phase, there may have been enough heat from tidal deformation to maintain liquid water beneath the surface of Charon for some time,” said Rhoden. “Using plausible interior structure models that include an ocean, we found it wouldn’t have taken much eccentricity (less than 0.01) to generate surface fractures like we are seeing on Europa.”
“Since it’s so easy to get fractures, if we get to Charon and there are none, it puts a very strong constraint on how high the eccentricity could have been and how warm the interior ever could have been,” adds Rhoden. “This research gives us a head start on the New Horizons arrival — what should we look for and what can we learn from it. We’re going to Pluto and Pluto is fascinating, but Charon is also going to be fascinating.”
Based on observations from telescopes, Charon’s orbit is now in a stable end state: a circular orbit with the rotation of both Pluto and Charon slowed to the point where they always show the same side to each other. Its current orbit is not expected to generate significant tides, so any ancient underground ocean may be frozen by now, according to Rhoden.
Since liquid water is a necessary ingredient for known forms of life, the oceans of Europa and Enceladus are considered to be places where extraterrestrial life might be found. However, life also requires a useable energy source and an ample supply of many key elements, such as carbon, nitrogen, and phosphorus. It is unknown if those oceans harbor these additional ingredients, or if they have existed long enough for life to form. The same questions would apply to any ancient ocean that may have existed beneath the icy crust of Charon.
This research was funded by the NASA Postdoctoral Program at the NASA Goddard Space Flight Center, administered by Oak Ridge Associated Universities, and NASA Headquarters through the Science Innovation Fund.
Journal Reference:
Alyssa Rose Rhoden, Wade Henning, Terry A. Hurford, Douglas P. Hamilton. The interior and orbital evolution of Charon as preserved in its geologic record. Icarus, 2014; DOI: 10.1016/j.icarus.2014.04.030
Note : The above story is based on materials provided by NASA/Goddard Space Flight Center.
Nadorite Djebel Debar, Hamman, Meskhootine, Constantine Province, Algeria (TYPE LOCALITY) Miniature, 4.7 x 2.9 x 2.7 cm “Courtesy of Rob Lavinsky, The Arkenstone, www.iRocks.com”
Chemical Formula: PbSbClO2 Locality: Djebel Nador, Constantine, Algeria. Name Origin: Named for the locality
Nadorite is a mineral with the chemical formula PbSbClO2. It crystallizes in the orthorhombic crystal system and is brown, brownish-yellow or yellow in colour, with a white or yellowish-white streak.
Nadorite is named after Djebel Nador in Algeria, where it was first identified in 1870. Djebel Nador and Djebel Debbar (both in the Constantine Province of Algeria) are its co-type localities.
History
Discovery date : 1870 Town of Origin: DJEBEL NADOR ET DJEBEL DEBAR, QACENTINA (CONSTANTINE) Country of Origin: ALGERIE
Optical properties
Optical and misc. Properties: Translucide Refractive Index: from 2,30 to 2,40 Axial angle 2V : LARGE
Physical Properties
Cleavage: {010} Perfect Color: Brown, Brownish yellow, Grayish brown, Yellow. Density: 7.02 Diaphaneity: Translucent Fracture: Brittle – Generally displayed by glasses and most non-metallic minerals. Hardness: 3.5-4 – Copper Penny-Fluorite Luster: Adamantine – Resinous Streak: yellow white
A radical new approach to analysing sedimentary basins also harnesses technology in a completely novel way. An international research group, led by the University of Sydney, will use big data sets and exponentially increased computing power to model the interaction between processes on the earth’s surface and deep below it in ‘five dimensions’.
As announced by the Federal Minister for Education today, the University’s School of Geosciences will lead the Basin GENESIS Hub that has received $5.4 million over five years from the Australian Research Council (ARC) and industry partners.
The multitude of resources found in sedimentary basins includes groundwater and energy resources. The space between grains of sand in these basins can also be used to store carbon dioxide.
“This research will be of fundamental importance to both the geo-software industry, used by exploration and mining companies, and to other areas of the energy industry,” said Professor Dietmar Müller, Director of the Hub, from the School of Geosciences.
“The outcomes will be especially important for identifying exploration targets in deep basins in remote regions of Australia. It will create a new ‘exploration geodynamics’ toolbox for industry to improve estimates of what resources might be found in individual basins.”
Sedimentary basins form when sediments eroded from highly elevated regions are transported through river systems and deposited into lowland regions and continental margins. The Sydney Basin is a massive basin filled mostly with river sediments that form Hawkesbury sandstone. It is invisible to the Sydney population living above it but has provided building material for many decades.
“Previously the approach to analysing these basins has been based on interpreting geological data and two-dimensional models. We apply infinitely more computing power to enhance our understanding of sedimentary basins as the product of the complex interplay between surface and deep Earth processes,” said Professor Müller.
Associate Professor Rey, a researcher at the School of Geosciences and member of the Hub said, “Our new approach is to understand the formation of sedimentary basins and the changes they undergo, both recently and over millions to hundreds of millions of years, using computer simulations to incorporate information such as the evolution of erosion, sedimentary processes and the deformation of the earth’s crust.”
The researchers will incorporate data from multiple sources to create ‘five-dimensional’ models, combining three-dimensional space with the extra dimensions of time and estimates of uncertainty.
The modelling will span scales from entire basins hundreds of kilometres wide to individual sediment grains.
Key geographical areas the research will focus on are the North-West shelf of Australia, Papua New Guinea and the Atlantic Ocean continental margins.
The Hub’s technology builds upon the exponential increase in computational power and the increasing amount of available big data (massive data sets of information). The Hub will harness the capacity of Australia’s most powerful computer, launched in 2013.
Note : The above story is based on materials provided by University of Sydney
Figure 1: The Earth consists of a surficial crust, a hot, viscous mantle of silicate minerals, a liquid outer core of iron and nickel, and a solid inner core. The D” layer occurs just above the core–mantle boundary. Credit: Alfred Baron, RIKEN SPring-8 Center
Seismic studies enable geoscientists to map the Earth’s internal structure. Certain seismic observations, however, remain puzzling, such as the unexpected spatial variability in the speed of seismic waves in a thin zone called the D′′ layer at the boundary between the core and mantle (Fig. 1).
Alfred Baron who leads the Materials Dynamics Laboratory at the RIKEN SPring-8 Center, along with Akira Yoneda of Okayama University and colleagues, have now found that these observations can be explained by the structure and orientation of microcrystals that comprise the D′′ layer.
The D′′ layer is composed mainly of magnesium silicate (MgSiO3) microcrystals with a post-perovskite (pPv) structure. Seismological studies have shown that in the D′′ layer beneath the rim of the Pacific Ocean, horizontal shear waves travel faster than vertical shear waves. Beneath the central Pacific Ocean, however, the relative speeds differ, and underneath the Atlantic Ocean they become equal.
The speed of shear waves through a crystal is related to the crystal’s elasticity. The researchers therefore measured the elasticity of microcrystals with the pPv structure. As pPv-MgSiO3 is unstable at ambient pressure, a more stable mineral with the same crystal structure, pPv-calcium iridate (CaIrO3), was studied. “Even that easier experiment is challenging,” says Baron, “as the very small crystals of CaIrO3 are not amenable to most methods of sound velocity measurement.” Fortunately, such measurements are possible using the inelastic x-ray scattering (IXS) spectrometer built by Baron and his colleagues at the SPring-8 synchrotron radiation facility.
Applying an analysis technique developed by co-author Hiroshi Fukui, the researchers were able to measure the different speeds that shear waves travel through pPv-CaIrO3. The results indicate that the elasticity of the pPv structure is strongly directional, suggesting that the different shear wave velocities observed for the D′′ layer are due to regional differences in the predominant orientation of the microcrystals in the layer.
To explain the observed variation, the researchers suggest that when a slab of material moves downward beneath the Pacific rim, it transforms into pPv-MgSiO3 with a crystallographic orientation that allows horizontal shear waves to travel faster than vertical shear waves. As the slab moves under the central Pacific Ocean, it deforms, leading to a change in crystal orientation and a change in the relative seismic velocities.
Baron’s laboratory is now using the IXS technique to determine the speed of sound waves in polycrystalline materials and liquid iron alloys under extreme conditions similar to those of the Earth’s core.
More information:
Yoneda, A., Fukui, H., Xu, F., Nakatsuka, A., Yoshiasa, A., Seto, Y., Ono, K., Tsutsui, S., Uchiyama, H. & Baron, A. Q. R. “Elastic anisotropy of experimental analogues of perovskite and post-perovskite help to interpret D” diversity.” Nature Communications 5, 3453 (2014). DOI: 10.1038/ncomms4453
Note : The above story is based on materials provided by RIKEN
Chemical Formula: KAl2(AlSi3O10)(OH)2 Locality: Common world wide. Name Origin: From Muscovy glass, alluding to the Russian province of Muscovy.
Muscovite is a phyllosilicate mineral of aluminium and potassium . It has a highly-perfect basal cleavage yielding remarkably-thin laminæ (sheets) which are often highly elastic. Sheets of muscovite 5×3 m have been found in Nellore, India.
Muscovite has a Mohs hardness of 2–2.25 parallel to the [001] face, 4 perpendicular to the [001] and a specific gravity of 2.76–3. It can be colorless or tinted through grays, browns, greens, yellows, or (rarely) violet or red, and can be transparent or translucent. It is anisotropic and has high birefringence. Its crystal system is monoclinic. The green, chromium-rich variety is called fuchsite; mariposite is also a chromium-rich type of muscovite.
Muscovite is the most common mica, found in granites, pegmatites, gneisses, and schists, and as a contact metamorphic rock or as a secondary mineral resulting from the alteration of topaz, feldspar, kyanite, etc. In pegmatites, it is often found in immense sheets that are commercially valuable. Muscovite is in demand for the manufacture of fireproofing and insulating materials and to some extent as a lubricant.
The name muscovite comes from Muscovy-glass, a name given to the mineral in Elizabethan England due to its use in medieval Russia as a cheaper alternative to glass in windows. This usage became widely known in England during the sixteenth century with its first mention appearing in letters by George Turberville, the secretary of England’s ambassador to the Russian tzar Ivan the Terrible, in 1568.
History
Discovery date : 1850
Optical properties
Optical and misc. Properties: Transparent – Translucent Refractive Index : from 1,55 to 1,61 Axial angle 2V : 30-47°
Physical Properties
Cleavage: {001} Perfect Color: White, Gray, Silver white, Brownish white, Greenish white. Density: 2.77 – 2.88, Average = 2.82 Diaphaneity: Transparent to translucent Fracture: Brittle – Sectile – Brittle fracture with slightly sectile shavings possible. Hardness: 2-2.5 – Gypsum-Finger Nail Luminescence: Non-fluorescent. Luster: Vitreous (Glassy) Streak: white
If you thought the largest dinosaurs to have walked the Earth produced the biggest eggs, you’d be mistaken. Scientists have discovered that both individual egg size and clutch size for the sauropods — which includes Diplodocus — were a lot smaller than might be expected for such enormous creatures.
A team of scientists have suggested reasons why the largest dinosaurs ever to have walked the Earth produced smaller eggs than might be expected.
One of the defining characteristics of the dinosaurs was their vast size, and the sauropods — a suborder of dinosaurs which includes the famous Diplodocus — were the largest of all.
Yet scientists have been puzzled at the relatively small size of sauropod eggs. Both individual egg size and clutch size are smaller than might be expected for such enormous creatures, relative to modern egg-laying animals.
Researchers have now concluded that the substantial incubation time required for sauropod embryos to develop and hatch may have been an important constraint and that this could explain the small individual size of sauropod eggs.
The findings are published in the summer 2014 issue of the Paleontological Society’s journal, Paleobiology. The team, which included biologists from the University of Lincoln, UK, and George Mason University, Virginia, US, with lead researcher Professor Graeme Ruxton from the University of St Andrews, used data from modern birds and reptiles to investigate factors affecting clutch size in this group of dinosaurs.They estimated that the time from laying to hatching of eggs, which were incubated in underground nests, was between 65 and 82 days.
This long incubation time increases the risk of predation, which coupled with the relatively low temperatures expected in the nest, may have been a significant factor in limiting the egg and clutch size.
Having larger eggs than are in the fossil record may have been advantageous because of larger hatchling size but this may have been outweighed by the increased risk of predation during the egg stage.
Dr Charles Deeming, from the School of Life Sciences, University of Lincoln, UK, said: “We think that a long incubation period of sauropods is likely to have led to very high mortality through predation. We suggest that the females laid their eggs in small clutches, possibly in different nesting sites, as an adaptive strategy to mitigate the high predation risk associated with long time of exposure in the egg stage.”
Professor Ruxton, from the School of Biology at the University of St Andrews, added: “The living bird with the largest eggs, the ostrich, has to incubate its eggs for 42 days; during which time many eggs are lost to predators. An ostrich weighs about 100kg and lays a 1.5kg egg; a sauropod dinosaur might be 50 times heavier than an adult ostrich but its eggs were only a little heavier than an ostrich egg. Some people might find it a bit disappointing that giant dinosaurs didn’t lay equally giant eggs — but it’s very satisfying to think that we might finally understand why.”
There may also have been a finite limit to the period over which environmental temperatures are high enough for egg development.
The team believe their conclusions could be extended to other groups of dinosaurs.
Journal Reference:
Graeme D. Ruxton, Geoffrey F. Birchard, D. Charles Deeming. Incubation time as an important influence on egg production and distribution into clutches for sauropod dinosaurs. Paleobiology, 2014; 40 (3): 323 DOI: 10.1666/13028
Note : The above story is based on materials provided by University of Lincoln.
