Short lives, violent deaths: Two CT-scanned Siberian mammoth calves yield trove of insights

July 16, 2014

CT images showing a side-by-side comparison of skulls from Lyuba (left) and Khroma, with bones of the front of the skull shown below. Credit: University of Michigan Museum of Paleontology

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CT scans of two newborn woolly mammoths recovered from the Siberian Arctic are revealing previously inaccessible details about the early development of prehistoric pachyderms. In addition, the X-ray images show that both creatures died from suffocation after inhaling mud.
Lyuba and Khroma, who died at ages 1 and 2 months, respectively, are the most complete and best-preserved baby mammoth specimens ever found. Lyuba’s full-body CT scan, which used an industrial scanner at a Ford testing facility in Michigan, was the first of its kind for any mammoth.

“This is the first time anyone’s been able to do a comparative study of the skeletal development of two baby mammoths of known age,” said University of Michigan paleontologist Daniel Fisher.

“This allowed us to document the changes that occur as the mammoth body develops,” Fisher said. “And since they are both essentially complete skeletons, they can be thought of as Rosetta Stones that will help us interpret all the isolated baby mammoth bones that show up at other localities.”

Fisher, director of the U-M Museum of Paleontology, is lead author of a paper published online July 8 in a special issue of the Journal of Paleontology. The paper provides a detailed discussion of the findings from the Lyuba and Khroma CT scans and includes about 30 previously unpublished CT images.

The paper’s 10 authors are from the United States, Russia and France. They include three recent U-M graduates and a collections manager at the U-M paleontology museum.

Siberian permafrost yields mammoth surprises

Lyuba and Khroma lived more than 40,000 years ago and belonged to mammoth populations separated by roughly 3,000 miles. Lyuba was found by reindeer herders in May 2007 on the banks of the Yuribei River on the Yamal Peninsula, in northwest Siberia. She was found frozen and partially dehydrated but otherwise appeared to be intact, except for the loss of most of her hair and all of her nails.

Khroma was found in October 2008 near the Khroma River in northernmost Yakutia, in northeast Siberia. She was frozen in permafrost in an upright position. Ravens and possibly arctic foxes scavenged exposed portions of her carcass, including parts of the trunk and skull and the fat hump that likely covered the back of her neck. Otherwise, the body was recovered in good condition.

Because of the remarkable preservation of Lyuba and Khroma, stringent conditions were placed on their study. Some dissection and limited sampling were allowed, but both specimens were left mostly intact. CT scans offered a non-destructive means of visualizing and analyzing much of their anatomy without compromising exhibit potential or options for future analysis.

CT scans of Lyuba were done in Tokyo in 2009 and in Wisconsin in 2010, using medical scanners. But because of Lyuba’s size (about 110 pounds and slightly smaller than a baby elephant), the researchers could not acquire 3-D data from her entire body. They finally succeeded in October 2010 at Ford Motor Co.’s Nondestructive Evaluation Laboratory in Livonia, Mich., using a scanner designed for finding flaws in vehicle transmissions.

Khroma’s CT scans were done at two French hospitals. Micro-CT scans of teeth from both mammoth calves were conducted at the University of Michigan School of Dentistry. From the dental studies, Fisher and colleagues determined that Lyuba died 30 to 35 days after birth and estimated that Khroma’s age at death was between 52 and 57 days.

Dating technique more than 30 years in the making

The researchers used a technique developed by Fisher over the past 30-plus years that involves counting daily growth layers inside the teeth, a bit like counting the annual growth rings on a tree to determine its age. The dental studies also indicate that both mammoths were born in the spring.

Scans of Khroma’s skull showed she had a brain slightly smaller than that of a newborn elephant, which hints at the possibility of a shorter gestation period for mammoths.

Lyuba’s skull is conspicuously narrower than Khroma’s, and her upper jawbones are more slender, while Khroma’s shoulder blades and foot bones are more developed. These differences may simply reflect the one-month age difference between the calves, or they could relate to the different populations from which the two calves derived.

The researchers refer to both calves as mummies due to the high level of soft-tissue preservation. In addition to fully articulated skeletons, the carcasses held preserved muscle, fat, connective tissue, organs and skin. Khroma even had clotted blood inside intact blood vessels and undigested milk in the stomach.

“These two exquisitely preserved baby mammoths are like two snapshots in time. We can use them to understand how factors like location and age influenced the way mammoths grew into the huge adults that captivate us today,” said co-author Zachary T. Calamari of the American Museum of Natural History, who began investigating mammoths as a U-M undergraduate working with Fisher.

Short lives, violent deaths

In addition to providing unprecedented insights into mammoth development, the CT scans of Lyuba and Khroma show that both youngsters died after inhaling mud, then suffocating, according to the authors of the Journal of Paleontology paper. This death scenario was suggested for Lyuba shortly after she was first examined. The Khroma CT scans demonstrate that she suffered a similar fate.

In Lyuba, the scans revealed a solid mass of fine-grained sediment blocking the air passages in the middle of the trunk. Sediment was also seen in Lyuba’s throat and bronchial passages. If Lyuba had died by drowning rather than suffocation — as some have suggested — then traces of sediment should also have been detected in parts of the lungs beyond the bronchial passages, but that was not the case.

Slightly coarser sediment was found in Khroma’s trunk, mouth and throat. Her lungs weren’t available for study because they were scavenged before the carcass was recovered. Since both animals appear to have been healthy at the time of death, a “traumatic demise” involving the inhalation of mud and suffocation appears to be the most likely cause of death in both cases, according to the authors.

The researchers suspect that Lyuba died in a lake because sediments found in her respiratory tract include fine-grained vivianite, a deep blue iron- and phosphate-bearing mineral that commonly forms in cold, oxygen-poor settings such as lake bottoms.

It’s possible that Lyuba crashed through the ice while crossing a lake during the spring melt. If she was struggling to breathe while submerged in a frigid lake, the mammalian “diving reflex” may have kicked in during her final moments, Fisher said. The reflex is triggered by cold water contacting the face, and it initiates physiological changes that enable animals to stay underwater for extended periods of time.

Those changes include a shifting of blood from the extremities to the body’s core, including the brain and heart. The blood shift would help explain small vivianite nodules found on Lyuba’s facial tissues during a necropsy. The CT scans revealed vivianite nodules, up to several millimeters in length, on the surface of the skull and inside it.

Blood provided iron source for vivianite nodules?

Blood coursing into Lyuba’s brain, due to the mammalian diving reflex, may have provided the iron source for the vivianite nodules, according to the authors. Lactic acid-producing bacteria ate away at her bones after death, possibly liberating the phosphate ions used to make vivianite, Fisher said.

A possible death scenario for Khroma places the calf and her mother on a riverbank in the spring. Khroma had been nursing less than an hour before her death, as evidenced by undigested milk found in her stomach during a necropsy by a team of scientists that included Fisher.

“It looked like you’d just popped the top on a container of yogurt,” Fisher recalled. “It was that white. It was that smooth. Just fresh, creamy milk from mama mammoth.”

Perhaps the riverbank collapsed and the two mammoths, mother and daughter, plunged into the river. A fall would account for the fractured spinal column revealed by Khroma’s CT scan, as well as the mud she inhaled.

The CT scan paper is part of a special Journal of Paleontology issue on three-dimensional visualization and analysis of fossils. In addition to Fisher and Calamari, the paper’s authors are Ethan A. Shirley, Christopher D. Whalen and Adam Rountrey of the U-M Museum of Paleontology; Alexei N. Tikhonov of the Russian Academy of Sciences; Bernard Buigues of the International Mammoth Committee in France; Frederic Lacombat of the Musee de Paleontologie de Chilhac in France; and Semyon Grigoriev and Piotr A. Lazarev of the North-Eastern Federal University in Russia.

Fisher is the Claude W. Hibbard Collegiate Professor of Paleontology, a professor in the Department of Earth and Environmental Sciences, and a professor in the Department of Ecology and Evolutionary Biology. Calamari, Shirley and Whalen are recent U-M graduates and spent a month in Siberia with Fisher in 2012, searching for mammoth remains. Rountrey is the collections manager for vertebrates at the U-M Museum of Paleontology.

The research was supported by the U.S. National Science Foundation and by the National Geographic Society.

Note : The above story is based on materials provided by University of Michigan.

Pyrophyllite

July 15, 2014

Table of Contents

Chemical Formula: Al₂(Si₄O₁₀)(OH)₂
Locality: Tres Cerritos, California, USA; Pyschminsk and Beresovsk, Ural Mountains, Russia.
Name Origin: From the Greek for fie and leaf, in allusion to its tendency to exfoliate into fan shapes when heated.

Pyrophyllite is a phyllosilicate mineral composed of aluminium silicate hydroxide: Al₂(Si₄O₁₀)(OH)₂. It occurs in two more or less distinct varieties, namely, as crystalline folia and as compact masses; distinct crystals are not known.

The folia have a pronounced pearly lustre, owing to the presence of a perfect cleavage parallel to their surfaces: they are flexible but not elastic, and are usually arranged radially in fan-like or spherical groups. This variety, when heated before the blowpipe, exfoliates and swells up to many times its original volume, hence the name pyrophyllite, from the Greek pyros (fire) and phyllos (a leaf), given by R. Hermann in 1829. The color of both varieties is white, pale green, greyish or yellowish; they are very soft (hardness of 1 to 1.5) and are greasy to the touch. The specific gravity is 2.65 – 2.85. The two varieties are thus very similar to talc.

History

Authors: WARDLE & BRINDLEY
Discovery date : 1972
Town of Origin : PYSCHMINSK et BEREZOV, OURAL
Country of Origin: RUSSIE ex-URSS

Chemical properties

Chemical Class : PHYLLOSILICATES
Subclass : Phyllosilicates
Chemical Formula : Al₂(Si₄O₁₀)(OH)₂

Crystallographical properties

Crystalline System: Triclinic
Symmetry Class: 31;32
Network System: Center C –
a : 5,16
b : 8,96
c : 9,34
Alpha : 91,18
Beta : 100,46
Gamma : 89,64
Z : Formula units per unit cell : 2

Optical properties

Optical and misc. Properties: Translucide – Opaque

Physical properties

Hardness : from 1,00 to 2,00
Density : 2,70
Color : pearl-white; yellow; brown yellow; pale blue; grey green; grayish green; bluish green
Streak: white
Cleavage: yes

Photos:

Pyrophyllite Locality: Hillsboro District, Orange County, North Carolina, USA Size: 11 x 7.3 x 6.6 cm. © Rob Lavinsky / iRocks

Locality: Cottonstone Mountain, Mecklenburg County, North Carolina, USA Source: University of Arizona Mineral Museum 13207 [view label] Owner: RRUFF

Pyrophyllite Locality: Hillsboro District, Orange County, North Carolina, USA 9.6 x 5.5 x 5.4 cm © Rob Lavinsky / iRocks

from Indian Gulch, Mariposa County, California. Theis sample displayed in the Smithsonian Museum of Natural History.

What geology has to say about global warming

July 15, 2014

Cobscook Bay State Park, Maine. Credit: W. Menke

Last month I gave a public lecture entitled, “When Maine was California,” to an audience in a small town in Maine. It drew parallels between California, today, and Maine, 400 million years ago, when similar geologic processes were occurring. Afterward, a member of the audience asked me what geology had to say about global warming. The following is an expanded version of my answer. Note that I use the word geology to mean any element of the earth sciences that is focused on earth history, and do not distinguish the many sub-disciplines about which a specialist would be familiar.
Geologists think of the last 50 million years as the recent past, both because they represents only about one percent of the age of the earth, and because plate tectonics, the geologic process that controls conditions within the solid part of the earth, has operated without major change during that time period. This is the time period that is most relevant to gaining insights about earth’s climate that can be applied to the present-day global warming debate.

The geological record of ancient climate is excellent. Ancient temperatures can be determined very precisely, because the composition of the shells of corals and other marine organisms varies measurably with it. Furthermore, the plants and animals that lived during a given time and are now preserved as fossils indicate whether the climate was wet or dry. The overall climatic trend has been cooling, from an unusually warm period, called the Eocene Optimum, 55-45 million years ago, to an unusually cool period, colloquially called the Ice Age, which ended just 20,000 years ago. The overall range in temperature was enormous, about 35°F. The earth was so warm during the Eocene Optimum that Antarctica was ice-free; ice caps did not start to form there until about 35 million years ago. Palm trees grew at high latitudes and cold-blooded animals, such as crocodiles, lived in the Arctic.

Lesson 1. The earth’s climate (including its average temperature) is highly variable.

Notwithstanding very divergent conditions, life flourished both during the Eocene Optimum and the Ice Age, though in both cases life was more abundant in some parts of the world than in others. The fossil record indicates that forests were common during the Eocence Optimum, yet some areas were sparsely vegetated steppes and deserts. While the great glaciers of the Ice Age were lifeless, extremely large mammals such as Woolly Mammoth and Giant Ground Sloth inhabited lower latitudes. The changing climate produced both winners and losers. Some species adapted; others went extinct.

Lesson 2. Life flourished during both warm and cold periods; changes in climate produced both winners and losers.

An important issue is whether climate variability is due to processes occurring on the earth, or to changes in the intensity of sunlight – for it’s the sun that keeps our planet warm. The geological evidence, though subtle, strongly supports earthly, and not solar, causes. This evidence is drawn from the study of the many shorter period climate fluctuations, some which last millions of years and other just thousands, which are superimposed on the long-term cooling trend.

Climate during the Ice Age (the last 4 million years) has been particularly unstable, with many swings of more than 10°F. These fluctuations are recorded in the annual layers of snow preserved in glaciers and in marine sediments, whose properties track the temperature at which they were formed. The timing of these swings closely follows regular fluctuations in the tilt of the earth’s axis and the shape of its orbit around the sun. Called Milankovitch cycles, they are due to the gravitational influence of the moon and planets. Their magnitude can be reliably calculated, since they are due to fluctuations of the position and orientation of the earth relative to the sun, and not to any change in the sun’s brightness. Surprisingly, they are too small to account for the large swings in temperature, unless the earth’s climate system is acting to amplify them. Here’s the subtle part of the argument: This mismatch between the feeble amplitude of the Milankovitch cycles and the large swings in climate is strong evidence that internal processes can cause strong climate variability.

Lesson 3. Variations in climate are mainly due to processes occurring on the earth, as contrasted to in the sun.

Ice Age carbon dioxide levels are well known, because bubbles of Ice Age air are preserved within the Antarctic and Greenland glaciers. More ancient carbon dioxide levels are difficult to measure, since no samples of older air have been preserved. Several indirect methods are in use, one based on the effect of ocean carbon dioxide levels on the composition of marine sediments, and another on its effect on now-fossil plant leaves. These measurements show fairly convincingly that the long-term cooling trend over the last 50 million years is associated with a gradual decrease in carbon dioxide levels, from 2000-3000 parts per million during the Eocene Optimum to 200 p.p.m. during the Ice Age. The cause of this decrease is not fully understood, but seems to indicate that the total amount of carbon that can influence climate (carbon in the atmosphere, biosphere and ocean) is slowly decreasing, possibly because an increasing amount of carbon is being tied up in sedimentary rocks such as limestone.

Lesson 4. Atmospheric carbon dioxide levels are highly variable, with the highest levels being associated with warm periods and the lowest levels associated with cold periods.

The correlation of atmospheric temperature with carbon dioxide reflects the latter’s role as a greenhouse gas. By absorbing heat radiated from the earth’s surface and re-radiating it back downward, it causes the earth’s surface to be warmer than it otherwise would be. The earth would be uninhabitable without the greenhouse effect, as can be seen by comparing the earth’s average temperature of about 60°F to the minus 100°F average temperature of the moon, which receives exactly the same amount of sunlight. An important question is whether the high carbon dioxide level at the time of the Eocene Optimum was the cause of the high temperatures that occurred during that time period.

Ascribing causes to fluctuation in climate is a tricky business, because atmospheric carbon dioxide level is only one factor among several that determine earth’s climate. Other important factors include: the amount of water vapor (another greenhouse gas) in the atmosphere; the percentage of the sky covered by clouds, which reflect sunlight back into space; the percent of land covered with ice and snow, which are also very reflective; and the percentage covered by oceans and and forests, which are very absorbing. All factors act together to maintain a given temperature; yet they feed back upon one another in complicated ways. Thus, for instance, had the Antarctic been glaciated during the Eocene Optimum (and the geological evidence is that it was ice-free), the world would have been somewhat cooler due to the high reflectivity of the ice. On the other hand, glaciers were absent precisely because the world was so warm. Geologic evidence alone cannot prove that the high levels of atmospheric carbon dioxide during the Eocene Optimum caused the high temperatures then, since the contribution of other factors, such as clouds and water vapor are unknown. Nevertheless, global climate models seem to indicate that such a high temperature only can be maintained in a world with high carbon dioxide; no other combination of factors can explain it.

Changing global temperatures induce changes in patterns of rainfall, winds and ocean currents, all of which can have a profound effect on the ecosystem of a given region. A large decrease in rainfall will, of course, turn rainforest into a desert. However, geology has few specifics to offer on the subject of how any particular region will be affected. The factors that cause climate change at a given geographical location are too varied to allow convincing geological analogues. However, geology shows that variability is the norm. Some of today’s deserts were forested a few million years ago, and some of today’s forests were formerly deserts. From the human perspective, climate change has the potential of causing some areas to become less agriculturally productive (and therefore less inhabitable), and other to become more so.

Lesson 5. Local climates are very variable, changing dramatically over periods of thousands to millions of years.

Changing global temperature can cause a rise or fall in sea level due to the accumulation or melting of glacial ice. This effect is global in extent and one that can have an extremely deleterious effect on us human beings, since so many of us live near the coast. The geological evidence is very strong that sea level was higher by about 200 feet at times, such as during the Eocene Optimum, when Antarctica was ice-free, and was about 400 feet lower during the height of the Ice Age. The range is enormous; the world’s coastlines are radically altered by such changes. The continental shelves were substantially exposed during the low stands, and many low-lying coastal areas were underwater during the high stands. Woolly Mammoths roamed hundreds of miles offshore of Virginia during the Ice Age. Beach sand deposits in inland North Carolina indicate that the shoreline was far inland during the Eocene Optimum.

Lesson 6. Sea level has fluctuated as the world’s glaciers grow or recede, and was about 200 feet higher at times when Antarctica was ice-free.

Carbon dioxide levels have risen since the end of the Ice Age, first to a natural level of about 280 p.p.m. just before the start of the Industrial Era, and then to 400 p.p.m. as people burned coal and petroleum in large quantities. Carbon dioxide is currently increasing at a rate of about 2.6 p.p.m. per year.

A critical question is the level of atmospheric carbon dioxide 35 million years ago, when glaciers began to form in Antarctica, for it serves as a rough estimate of the concentration needed to melt present-day Antarctica. It’s a rough estimate only, for geological conditions were not exactly the same now and then. In particular, strong ocean currents that today keep warmer waters away from Antarctica were not present 35 million years ago, owing to the somewhat different configuration of tectonic plates. Unfortunately, the best currently-available estimates of atmospheric carbon dioxide during this critical time period have large uncertainties. Carbon dioxide decreased from 600-1400 p.p.m. at the start of the glaciations to 400-700 p.p.m. several million years later. These measurements are consistent with modeling results, which give a threshold of about 780 p.p.m. for the formation of a continental-scale ice cap on Antarctica. This value will be reached by the year 2150 at the present growth rate of atmospheric carbon dioxide – or sooner if emission rates continue to soar – suggesting that Antarctica will be at risk of melting at that time.

Antarctic ice will not melt overnight even should the threshold be reached. The deglaciation at the end of the Ice Age provides a useful example. The rate of sea level rise was initially low, just one-tenth of an inch per year. It then gradually increased, peaking at about 3 inches per year about 14,000 years ago, which was about 5,000 years after the start of the deglaciation. This rate persisted for 1,600 years, during which time sea level rose a total of 60 feet. The average rate of sea level rise was slower, about a half-inch per year.

Lesson 7. Sea level rise as fast as a few inches per year can persist over thousands of years.

The most extreme scenario for future carbon dioxide levels considered by the Intergovernmental Panel on Climate Change (IPCC) predicts about 0.4 inches per year of sea level rise over the next century. This rate is less than, but similar in magnitude, to the average rate during the Ice Age deglaciation, but considerably smaller than its peak. Because of its focus on the current century, a reader of the IPCC report might be left with the sense that sea level rise will be over by 2100. Precisely the opposite is true! Geology demonstrates that melting accelerates with time and can last for several thousand years.

The most important lessons drawn from geology are that the earth’s climate can change radically and that the pace of change can be rapid. Geology also supports the theory that past periods of especially warm temperature were caused by high atmospheric carbon dioxide level. Of the many effects of global warming, geology is currently most relevant to sea level rise caused by melting glaciers. The precision of the measurement is currently too poor to give an exact answer to a critical question, At what carbon dioxide level are we in danger of melting Antarctica? However, while crude, these estimates suggest that this threshold will be reached in 150-300 years, if carbon dioxide levels continue to rise at the current rate.

Note : The above story is based on materials provided by Columbia University

Study finds order in the apparent randomness of Earth’s evolving landscape

July 15, 2014

Stanford Earth scientists have created tools to analyze branched networks of Earth-bound channels formed by water and erosion. The work could provide insights into processes that form branched networks like those on the surface of Mars (left) and Titan (center) and in the human circulatory system. Credit: Images courtesy of NASA/JPL and Wikimedia Commons

As we all know, water runs downhill, forming channels and branched networks as it flows. It’s been that way forever. But, believe it or not, scientists’ understanding of these networks hasn’t changed much in the last century. Even modern techniques developed and employed since the 1960s cannot easily distinguish between channel networks generated randomly inside a computer and images of channels formed in the real world.
But work by Stanford School of Earth Sciences recent PhD recipient Eitan Shelef and George Hilley, an associate professor of geological and environmental sciences, is beginning to shed light on this fundamental problem, and the tools they created might shine light on not just Earth-bound channels but also those on Mars and even in the human circulatory system.

Shelef’s work, recently published in Geophysical Research Letters, challenges 50 years of research built on the assumption that the geometry of channel networks reflected a mathematically random process. Shelef and Hilley developed powerful mathematical relationships that captured not just the geometry of hillside channels but the geometry of the underlying landscape as well.

Shelef, now a postdoctoral scholar at Los Alamos National Laboratory, explained that in these equations, the researchers found a simple metric that distinguishes natural channel networks from those formed randomly within a computer, and in doing so, they firmly rejected the mathematically random hypothesis posed in the 1960s.

In rejecting this decades-old hypothesis, Shelef and Hilley can now extract invaluable three-dimensional data from two-dimensional images.

“The way in which branched networks were measured in the past relied only on the two-dimensional map patterns of the channels in the networks,” said Hilley, a leading researcher on landscape evolution.

Using high-resolution images captured with laser altimetry, the pair analyzed not only the channels but the ridgelines as well.

By incorporating information about the ridgelines separating the channels, Shelef and Hilley related channel network geometry to the two-dimensional signature left by three-dimensional erosion. Because different erosional processes leave different erosional signatures, which in turn affect channel patterns, Shelef and Hilley’s approach allows Earth scientists to infer the processes that erode the landscape simply by analyzing the overlying channel network.

Shelef expanded on this, pointing out that his mathematical tools can help decipher the processes that shape channel networks in areas in which scientists have good imagery but limited elevation data, such as channel networks now buried underground, or channel networks on Mars or Saturn’s largest moon, Titan.

For example, images from NASA’s Mars Reconnaissance Orbiter showed branched channel networks etched into the red planet’s surface. Images beamed back from the Huygens spacecraft as it landed on Titan also showed channels likely formed from flowing liquid methane. Shelef’s research could help scientists better understand the processes acting on Titan today and the processes that carved out channel networks on Mars millions, if not billions, of years ago.

“Channel networks are one of the most common and ubiquitous geometric forms found on the surface of this and some other planets,” Hilley said.

The pair’s analysis of branched networks needn’t be limited to flowing liquids. Branched networks appear in life sciences as well, found in tree leaves and even the human circulatory system. With such ubiquity of branched networks, Shelef’s Earth science research might reach across disciplines. Understanding the processes that form branched biological networks could provide valuable scientific insights.

By seeing past the randomness inferred from previous research, Shelef and Hilley can better understand the processes that shape the world around us.

More information:
‘Symmetry, randomness and process in the structure of branched channel networks,’ Geophysical Research Letters (DOI: 10.1002/2014GL059816)

Note : The above story is based on materials provided by Stanford University

Pyrope

July 13, 2014

Table of Contents

Chemical Formula: Mg₃Al₂(SiO₄)₃
Locality: Zoblitz, Germany.
Name Origin: From the Greek, pyropos, “fiery-eyed” in allusion to the red hue.

The mineral pyrope is a member of the garnet group. Pyrope is the only member of the garnet family to always display red colouration in natural samples, and it is from this characteristic that it gets its name: from the Greek for fire and eye. Despite being less common than most garnets, it is a widely used gemstone with numerous alternative names, some of which are misnomers. Chrome pyrope, and Bohemian garnet are two alternative names, the usage of the latter being discouraged by the Gemological Institute of America.Misnomers include Colorado ruby, Arizona ruby, California ruby, Rocky Mountain ruby, Elie Ruby, Bohemian carbuncle, and Cape ruby.

The composition of pure pyrope is Mg₃Al₂(SiO₄)₃, although typically other elements are present in at least minor proportions—these other elements include Ca, Cr, Fe and Mn. Pyrope forms a solid solution series with almandine and spessartine, which are collectively known as the pyralspite garnets (pyrope, almandine, spessartine). Iron and manganese substitute for the magnesium in the pyrope structure. The resultant, mixed composition garnets are defined according to their pyrope-almandine ratio. The semi-precious stone rhodolite is a garnet of ~70% pyrope composition.

The origin of most pyrope is in ultramafic rocks, typically peridotite from the Earth’s mantle: these mantle-derived peridotites can be attributed both to igneous and metamorphic processes. Pyrope also occurs in ultrahigh-pressure (UHP) metamorphic rocks, as in the Dora-Maira massif in the western Alps. In that massif, nearly pure pyrope occurs in crystals to almost 12 cm in diameter; some of that pyrope has inclusions of coesite, and some has inclusions of enstatite and sapphirine.

Pyrope is common in peridotite xenoliths from kimberlite pipes, some of which are diamond-bearing. Pyrope found in association with diamond commonly has a Cr2O3 content of 3-8%, which imparts a distinctive violet to deep purple colouration (often with a greenish tinge) and because of this is often used as a kimberlite indicator mineral in areas where erosive activity makes pin pointing the origin of the pipe difficult. These varieties are known as chrome-pyrope, or G9/G10 garnets.

History

Authors: WERNER
Discovery date: 1803
Town of Origin : LNS
Country of Origin : TCHECOSLOVAQUIE

Chemical properties

Chemical Class : NESOSILICATES
Subclass : Neosilicates
Group : GRENATS
Chemical Formula : Mg₃Al₂(SiO₄)₃
Impurities: Fe;Mn;Ca

Optical properties

Optical and misc. Properties : Transparent – Translucide – Fragile, cassant – Gemme, pierre fine
Refractive Index : 1,71

Physical properties

Morphology : DODECAEDRIQUE; TRAPEZOEDRIQUE; GRENU; MASSIF; GALET; GRAIN
Hardness: from 7,00 to 7,50
Density: 3,58
Color : pinkish red; violet red; orange red; black; purplish red; red; black red
Luster: vitreous; resinous
Streak: white
Break: conchoidal
Cleavage : NO

Photos:

Locality: Sunset Crater, Arizona, USA Source: Marcus Origlieri Owner: RRUFF

Pyrope Garnet Weight: 2.18 ct Exact Size: 8.02 mm x 4.51 mm © GemSelect

Pyrope Location: Governador Valadares, Rio Doce, Minas Gerais, Southeast Region, Brazil. Scale: 6x6x6 mm. Copyright: © John Betts – Fine Minerals

Pressure cell for reproducing deep-Earth chemistry

July 13, 2014

A new pressure cell invented by UC Davis researchers makes it possible to simulate chemical reactions deep in the Earth’s crust. Credit: Image courtesy of University of California – Davis

A new pressure cell invented by UC Davis researchers makes it possible to simulate chemical reactions deep in the Earth’s crust. The cell allows researchers to perform nuclear magnetic resonance (NMR) measurements on as little as 10 microliters of liquid at pressures up to 20 kiloBar.
“NMR is our window into the chemical world,” said Brent Pautler, a postdoctoral researcher in chemistry at UC Davis and first author on the paper published July 2 in the online edition of the journal Angewandte Chemie. “It lets us see chemical reactions as they are happening.”

The new device allows researchers for the first time to study chemical reactions in liquid water under pressure, without it freezing into a solid.

“We were able to get to the point where we could no longer ignore the compressibility of the water molecules,” Pautler said. “This is the first time this has ever been reported.”

Geochemists want to know what kind of chemistry is happening deep in the Earth’s crust, beyond the reach of boreholes. These chemical reactions could affect water and minerals that eventually migrate to the surface, or the behavior of carbon cycling between the Earth’s depths and the surface.

“Aqueous fluids deep in the Earth are the great unknown for geochemists,” said Chris Colla, a graduate student in Earth & Physical Sciences at UC Davis and co-author on the paper. “By doing NMR we can get an inside view of what is occurring deep in the Earth’s crust.”

For example, Pautler, Colla and colleagues have already looked at calcium ions in solution. Dissolved calcium ions can be surrounded by four, six or eight water molecules. High pressure forces dissolved calcium into an eight-water state, they found.

The high-pressure measurements could also shed light on chemical processes involved in hydraulic fracturing, or “fracking,” and the behavior of buried nuclear waste over long periods of time. Fracking is the process of extracting oil and gas by injecting liquids under high pressure into rocks.

The high-pressure NMR cell was built in the machine shop at the Crocker Nuclear Laboratory with the help of Peter Klavins, research specialist in the Department of Physics, and Steve Harley, a former UC Davis graduate student now at the Lawrence Livermore National Laboratory.

Other coauthors on the paper are, at UC Davis: Prof. William Casey and Rene Johnson, Department of Chemistry; Jeffrey Walton, NMR Facility; André Ohlin, at Monash University, Australia and Dimitri Sverjensky at Johns Hopkins University and the Carnegie Institution of New York. The work was supported by the U.S. Department of Energy.

Video :

Note : The above story is based on materials provided by University of California – Davis.

New study of largely unstudied mesophotic coral reef geology

July 13, 2014

Researcher David Weinstein recovers experimental coral substrates for bioerosion study at mid-patch reef site. Credit: Photo by Rick Gomez, UM Rosenstiel School Diving Safety Officer

Researchers compare bioerosion on deeper reef systems to better understand long-term structural sustainability

MIAMI – A new study on biological erosion of mesophotic tropical coral reefs, which are low energy reef environments between 30-150 meters deep, provides new insights into processes that affect the overall structure of these important ecosystems. The purpose of the study was to better understand how bioerosion rates and distribution of bioeroding organisms, such as fish, mollusks and sponges, differ between mesophotic reefs and their shallow-water counterparts and the implications of those variations on the sustainability of the reef structure.

Due to major advancements in deeper underwater diving technology, a large renewal of interest in mesophotic reefs has pulsed through the scientific community because of their high biodiversity, vast extent, and potential refuge for shallower water reef species at risk from the impacts of climate change.

“Studying how mesophotic reefs function and thrive is especially critical now, when considering results from the new IPCC report reviewed by over 1700 expects said that coral reefs are the most vulnerable marine ecosystems on Earth to the adverse effects of climate change,” said David Weinstein, Rosenstiel School Ph.D. student and lead author of the study. “Developing effective environmental management strategies for these important reef systems requires a basic fundamental understanding of the underlining architecture that supports and creates diverse biological ecosystems.”

Weinstein and his research team used previously identified mesophotic reefs at 30-50 meters deep located in the U.S. Virgin Islands composed of a surprising number of coral growing on top different types of reef structures (patches, linear banks, basins) to better understand the role sedimentary processes have in creating and maintaining so many different structures that are critical for maximizing the biodiversity and health of the ecosystem. Researchers analyzed coral rubble and coral skeleton discs collected after one and two years of exposure to determine the sources and rates of bioerosion at these reefs.

Results of the study found that the architecturally unique structures in the study area experience significantly different bioerosion rates.

“This has very important implications when trying to predict how these reefs will grow over time and where preservation efforts might be most effective,” said Weinstein.

Although erosion of the coral skeleton disks at the very deepest sites was more uniform, the researchers suggest that this is likely because the substrates used in the study were all of uniform composition, unlike the diverse composition of the sites. These results imply that bioerosional processes at these depths still exaggerate differences in reef structure depending on the amount of living and dead coral at each reef, the amount of time that material is exposed on the surface, and different localized current flows experienced.

The study also confirmed important concepts in coral geology research that lacked proof from studies venturing deeper than 35 meters. Coral reef bioerosion in the U.S. Virgin Islands and potentially in most of the Caribbean does generally decreases with depth. This result stems from the finding that parrotfish are now the most significant bioeroding group from shallow reefs down to a mesophotic reef transition zone identified by Weinstein at 30-35 meters in depth. The study also was able to conclude bioeroding sponges are the primary organisms responsible for long-term structural modification of mesophotic reefs beyond the transitional zone.

“Coral reefs are essentially a thin benthos veneer draped upon a biologically produced inorganic three-dimensional foundation that creates habitats for many marine organisms,” said Weinstein. “Since mesophotic reefs grow so much slower than shallower reefs, identifying the sources and rate of erosion on mesophotic reefs is even more important to understand the long-term structural sustainability of these tropical reefs systems.”

However, Weinstein suggests that other processes, such as coral growth rates and cementation, must also be more fully studied before scientists have a complete understanding of mesophotic coral reefs.

The paper, currently available online and scheduled for print in a special coral reef edition of the journal Geomorphology later this summer is one of the first to address mesophotic reef sedimentology.

More information, videos, pictures, and new developments can be found at: http://www.rsmas.miami.edu/users/dweinstein/

Note : The above story is based on materials provided by University of Miami Rosenstiel School of Marine & Atmospheric Science

Pyromorphite

July 11, 2014

Table of Contents

Chemical Formula: Pb₅(PO₄)₃Cl
Name Origin: From the Greek pyr – “fire” and morfe – “form” in allusion the recrystallization reaction of the molten mineral.

Pyromorphite is a mineral species composed of lead chlorophosphate: Pb₅(PO₄)₃Cl, sometimes occurring in sufficient abundance to be mined as an ore of lead. Crystals are common, and have the form of a hexagonal prism terminated by the basal planes, sometimes combined with narrow faces of a hexagonal pyramid. Crystals with a barrel-like curvature are not uncommon. Globular and reniform masses are also found. It is part of a series with two other minerals: mimetite (Pb₅(AsO₄)₃Cl) and vanadinite (Pb₅(VO₄)₃Cl), the resemblance in external characters is so close that, as a rule, it is only possible to distinguish between them by chemical tests.

They were formerly confused under the names green lead ore and brown lead ore (German: Grünbleierz and Braunbleierz). The phosphate was first distinguished chemically by M. H. Klaproth in 1784, and it was named pyromorphite by J. F. L. Hausmann in 1813. The name is derived from the Greek for pyr (fire) and morfe (form) due to its crystallization behavior after being melted.

History

Authors : HAUSMANN
Discovery date : 1813

Optical properties

Optical and misc. Properties : Transparent – Translucide – Fragile, cassant – Luminescent, fluorescent
Refractive Index : from 2,04 to 2,05

Physical properties

Hardness: from 3,50 to 4,00
Density : 7,04
Color : green; yellow; orange; brown; grey; colorless; white; red yellow; yellowish brown; purplish brown
Luster: sub-adamantine; resinous; greasy
Streak : white; grey; yellowish
Break: irregular; sub-conchoidal
Cleavage: yes

Photos:

Pyromorphite Mina San Andrés, Geoda Realces, Villaviciosa de Córdoba, Espiel, Córdoba Spain (10/11-1997) Specimen size: 3.7 × 2.5 × 1 cm = 1.5” × 1.0” × 0.4” Main crystal size: 0.3 × 0.3 cm = 0.1” × 0.1” © Fabre Minerals

Pyromorphite Rosenberg Mine, Braubach, Bad Ems District, Lahn valley, Rhineland-Palatinate, Germany Size: 6.0 x 2.5 x 1.6 cm (miniature) © danweinrich

Pyromorphite Mine des Farges, Ussel, Corrèze France Specimen size: 3 × 2.5 × 1.4 cm = 1.2” × 1.0” × 0.6” © Fabre Minerals

Pyromorphite Bunker Hill Mine, Kellogg, Coeur d’Alene District, Shoshone Co., Idaho, USA Size: 2.0 x 2.0 x 1.2 cm (thumbnail) © danweinrich

Evidence of super-fast deep earthquake

July 11, 2014

The supershear 2013 Sea of Okhotsk earthquake had similar magnitude and fault geometry as the damaging 1994 Northridge earthquake in California, but a much larger depth and faster rupture speed. The high rupture speed (approximately 8 kilometers per second, or 18,000 miles per hour) away from the hypocenter, shown as the red star, concentrates strong shaking on the “Mach front.” Credit: Image courtesy of University of California – San Diego

As scientists learn more about earthquakes that rupture at fault zones near the planet’s surface — and the mechanisms that trigger them — an even more intriguing earthquake mystery lies deeper in the planet.
Scientists at Scripps Institution of Oceanography at UC San Diego have discovered the first evidence that deep earthquakes, those breaking at more than 400 kilometers (250 miles) below Earth’s surface, can rupture much faster than ordinary earthquakes. The finding gives seismologists new clues about the forces behind deep earthquakes as well as fast-breaking earthquakes that strike near the surface.

Seismologists have documented a handful of these events, in which an earthquake’s rupture travels faster than the shear waves of seismic energy that it radiates. These “supershear” earthquakes have rupture speeds of four kilometers per second (an astonishing 9,000 miles per hour) or more.

In a National Science Foundation-funded study reported in the June 11, 2014, issue of the journal Science, Scripps geophysicists Zhongwen Zhan and Peter Shearer of Scripps, along with their colleagues at Caltech, discovered the first deep supershear earthquake while examining the aftershocks of a magnitude 8.3 earthquake on May 24, 2013, in the Sea of Okhotsk off the Russian mainland.

Details of a magnitude 6.7 aftershock of the event captured Zhan’s attention. Analyzing data from the IRIS (Incorporated Research Institutions for Seismology) consortium, which coordinates a global network of seismological instruments, Zhan noted that most seismometers around the world yielded similar records, all suggesting an anomalously short duration for a magnitude 6.7 earthquake.

Data from one seismometer, however, stationed closest to the event in Russia’s Kamchatka Peninsula, told a different story with intriguing details.

After closely analyzing the data, Zhan not only found that the aftershock ruptured extremely deeply at 640 kilometers (400 miles) below Earth’s surface, but its rupture velocity was extraordinary — about eight kilometers per second (five miles per second), nearly 50 percent faster than the shear wave velocity at that depth.

“For a 6.7 earthquake you would expect a duration of seven to eight seconds, but this one lasted just two seconds,” said Shearer, a geophysics professor in the Cecil H. and Ida M. Green Institute of Geophysics and Planetary Physics (IGPP) at Scripps. “This is the first definitive example of supershear rupture for a deep earthquake since previously supershear ruptures have been documented only for shallow earthquakes.”

“This finding will help us understand why deep earthquakes happen,” said Zhan. “One quarter of earthquakes occur at large depths, and some of these can be pretty big, but we still don’t understand why they happen. So this earthquake provides a new observation for deep earthquakes and high-rupture speeds.”

Zhan also believes the new information will be useful in examining ultra-fast earthquakes and their potential for impacting fault zones near Earth’s surface. Although not of supershear caliber, California’s destructive 1994 Northridge earthquake had a comparable size and geometry to that of the 6.7 Sea of Okhotsk aftershock.

“If a shallow earthquake such as Northridge goes supershear, it could cause even more shaking and possibly more damage,” said Zhan.

Note : The above story is based on materials provided by University of California – San Diego. The original article was written by Mario Aguilera.

NASA spacecraft observes further evidence of dry ice gullies on Mars

July 11, 2014

This pair of before (left) and after (right) images from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter documents formation of a new channel on a Martian slope between 2010 and 2013, likely resulting from activity of carbon-dioxide frost. Credit: NASA/JPL-Caltech/Univ. of Arizona

Repeated high-resolution observations made by NASA’s Mars Reconnaissance Orbiter (MRO) indicate the gullies on Mars’ surface are primarily formed by the seasonal freezing of carbon dioxide, not liquid water.

The first reports of formative gullies on Mars in 2000 generated excitement and headlines because they suggested the presence of liquid water on the Red Planet, the eroding action of which forms gullies here on Earth. Mars has water vapor and plenty of frozen water, but the presence of liquid water on the neighboring planet, a necessity for all known life, has not been confirmed. This latest report about gullies has been posted online by the journal Icarus.

“As recently as five years ago, I thought the gullies on Mars indicated activity of liquid water,” said lead author Colin Dundas of the U.S. Geological Survey’s Astrogeology Science Center in Flagstaff, Arizona. “We were able to get many more observations, and as we started to see more activity and pin down the timing of gully formation and change, we saw that the activity occurs in winter.”

Dundas and collaborators used the High Resolution Imaging Science Experiment (HiRISE) camera on MRO to examine gullies at 356 sites on Mars, beginning in 2006. Thirty-eight of the sites showed active gully formation, such as new channel segments and increased deposits at the downhill end of some gullies.

Using dated before-and-after images, researchers determined the timing of this activity coincided with seasonal carbon-dioxide frost and temperatures that would not have allowed for liquid water.

Frozen carbon dioxide, commonly called dry ice, does not exist naturally on Earth, but is plentiful on Mars. It has been linked to active processes on Mars such as carbon dioxide gas geysers and lines on sand dunes plowed by blocks of dry ice. One mechanism by which carbon-dioxide frost might drive gully flows is by gas that is sublimating from the frost providing lubrication for dry material to flow. Another may be slides due to the accumulating weight of seasonal frost buildup on steep slopes.

The findings in this latest report suggest all of the fresh-appearing gullies seen on Mars can be attributed to processes currently underway, whereas earlier hypotheses suggested they formed thousands to millions of years ago when climate conditions were possibly conducive to liquid water on Mars.

Dundas’s co-authors on the new report are Serina Diniega of NASA’s Jet Propulsion Laboratory in Pasadena, California, and Alfred McEwen of the University of Arizona, Tucson.

“Much of the information we have about gully formation, and other active processes, comes from the longevity of MRO and other orbiters,” said Diniega. “This allows us to make repeated observations of sites to examine surface changes over time.”

Although the findings about gullies point to processes that do not involve liquid water, possible action by liquid water on Mars has been reported in the past year in other findings from the HiRISE team. Those observations were of a smaller type of surface-flow feature.

An upcoming special issue of Icarus will include multiple reports about active processes on Mars, including smaller flows that are strong indications of the presence of liquid water on Mars today.

“I like that Mars can still surprise us,” Dundas said. “Martian gullies are fascinating features that allow us to investigate a process we just don’t see on Earth.”

HiRISE is operated by the University of Arizona, Tucson. The instrument was built by Ball Aerospace & Technologies Corp. of Boulder, Colorado. The Mars Reconnaissance Orbiter Project is managed for NASA’s Science Mission Directorate in Washington, by JPL, a division of the California Institute of Technology, Pasadena.

For more information about HiRISE, visit: http://hirise.lpl.arizona.edu

Additional information about MRO is online at: http://www.nasa.gov/mro

For recent findings suggesting the presence of liquid water on Mars, visit: http://go.nasa.gov/1q1VRLS

Note : The above story is based on materials provided by NASA/Jet Propulsion Laboratory.

Pyrolusite

July 10, 2014

Table of Contents

Chemical Formula: MnO₂
Name Origin: From the Greek, pyro and louein, “fire” and “to wash,” because it was used to remove the greenish color imparted to glass by iron compounds.

Pyrolusite is a mineral consisting essentially of manganese dioxide (MnO₂) and is important as an ore of manganese. It is a black, amorphous appearing mineral, often with a granular, fibrous or columnar structure, sometimes forming reniform crusts. It has a metallic luster, a black or bluish-black streak, and readily soils the fingers. The specific gravity is about 4.8. Its name is from the Greek for fire and to wash, in reference to its use as a way to remove tints from glass.

History

Authors : HAIDINGER
Discovery date : 1827

Optical properties

Optical and misc. Properties : Fragile, cassant – Opaque – Macles possibles –
Reflective Power: HAUT

Physical Properties

Hardness: from 6,00 to 6,50
Density : 5,06
Color : steel grey; black
Luster: metallic; unpolished
Streak : black; bluish black
Cleavage : yes

Photos:

Pyrolusite Ilfeld, Harz Mts., Germany Small Cabinet, 7.7 x 6.3 x 2.7 cm “Courtesy of Rob Lavinsky, The Arkenstone, www.iRocks.com”

Pyrolusite Dona Ana County, New Mexico, USA Small Cabinet, 6.5 x 3.2 x 1.7 cm “Courtesy of Rob Lavinsky, The Arkenstone, www.iRocks.com”

Locality: Unnamed prospect, Tal-Tal, Antofagasta Region, Chile Source: Bob Jenkins Owner: RRUFF

Macro of a pyrolusite mineral with dendrite crystal formations. It is approximately 3 ½ inches (9 cm) tall. © Jonathan Zander

Birdlike fossil challenges notion that birds evolved from ground-dwelling dinosaurs

July 10, 2014

This is a skeletal reconstruction of Scansoriopteryx with outlines to indicate the extent of the feathers. Credit: Stephen A. Czerkas

The re-examination of a sparrow-sized fossil from China challenges the commonly held belief that birds evolved from ground-dwelling theropod dinosaurs that gained the ability to fly. The birdlike fossil is actually not a dinosaur, as previously thought, but much rather the remains of a tiny tree-climbing animal that could glide, say American researchers Stephen Czerkas of the Dinosaur Museum in Blanding, Utah, and Alan Feduccia of the University of North Carolina. The study appears in Springer’s Journal of Ornithology.

The fossil of the Scansoriopteryx (which means “climbing wing”) was found in Inner Mongolia, and is part of an ongoing cooperative study with the Chinese Academy of Geological Sciences. It was previously classified as a coelurosaurian theropod dinosaur, from which many experts believe flying dinosaurs and later birds evolved. The research duo used advanced 3D microscopy, high resolution photography and low angle lighting to reveal structures not clearly visible before. These techniques made it possible to interpret the natural contours of the bones. Many ambiguous aspects of the fossil’s pelvis, forelimbs, hind limbs, and tail were confirmed, while it was discovered that it had elongated tendons along its tail vertebrae similar to Velociraptor.

Czerkas and Feduccia say that Scansoriopteryx unequivocally lacks the fundamental structural skeletal features to classify it as a dinosaur. They also believe that dinosaurs are not the primitive ancestors of birds. The Scansoriopteryx should rather be seen as an early bird whose ancestors are to be found among tree-climbing archosaurs that lived in a time well before dinosaurs.

Through their investigations, the researchers found a combination of plesiomorphic or ancestral non-dinosaurian traits along with highly derived features. It has numerous unambiguous birdlike features such as elongated forelimbs, wing and hind limb feathers, wing membranes in front of its elbow, half-moon shaped wrist-like bones, bird-like perching feet, a tail with short anterior vertebrae, and claws that make tree climbing possible. The researchers specifically note the primitive elongated feathers on the forelimbs and hind limbs. This suggests that Scansoriopteryx is a basal or ancestral form of early birds that had mastered the basic aerodynamic maneuvers of parachuting or gliding from trees.

Their findings validate predictions first made in the early 1900’s that the ancestors of birds were small, tree-dwelling archosaurs which enhanced their incipient ability to fly with feathers that enabled them to at least glide. This “trees down” view is in contrast with the “ground up” view embraced by many palaeontologists in recent decades that birds derived from terrestrial theropod dinosaurs.

“The identification of Scansoriopteryx as a non-dinosaurian bird enables a reevaluation in the understanding of the relationship between dinosaurs and birds. Scientists finally have the key to unlock the doors that separate dinosaurs from birds,” explained Czerkas.

Feduccia added, “Instead of regarding birds as deriving from dinosaurs, Scansoriopteryx reinstates the validity of regarding them as a separate class uniquely avian and non-dinosaurian.”

Note : The above story is based on materials provided by Springer.

One secret of ancient amber revealed

July 10, 2014

Studying this Canadian amber from the Late Cretaceous period, scientists have revealed one of its long-held secrets. Credit: © Government of Canada, Canadian Conservation Institute, CCI 123773-0025

The warm beauty of amber was captivating and mysterious enough to inspire myths in ancient times, and even today, some of its secrets remain locked inside the fossilized tree resin. But for the first time, scientists have now solved at least one of its puzzles that had perplexed them for decades. Their report on a key aspect of the gemstone’s architecture appears in the ACS journal Analytical Chemistry.

Jennifer Poulin and Kate Helwig of the Canadian Conservation Institute point out that much of the amber we see today had its origins millions of years ago, when it exuded from trees and then fossilized over time. Some of the oldest recovered samples even predate the rise of dinosaurs — and could outlast even the most advanced materials that science can make today. But it’s exactly that extreme durability that has made amber’s internal structure so difficult to understand. Scientists have used one particular technique to probe the inner molecular architecture of the ancient resin, but the process seemed to destroy evidence of certain relationships between compounds. Poulin and Helwig decided to try a new approach.

Building on past attempts using something called pyrolysis-gas chromatography-mass spectrometry, they slowed down the pyrolysis phase, which essentially uses heat to break down a substance. By doing so, the researchers were able to show that specific groups of atoms within their samples were bound to succinic acid, known historically as “spirit of amber.” “There can be no doubt that much of the stability and durability of certain kinds of amber comes from the succinic acid cross-linking within the matrix,” the researchers said.

Note : The above story is based on materials provided by American Chemical Society.

Pyrochroite

July 10, 2014

Locality: Långban, Filipstad, Värmland, Sweden Photo Copyright © Pavel M. Kartashov collection & photo

Table of Contents

Chemical Formula: Mn(OH)₂
Locality: Vermland at Pajsberg near Persberg, Sweden.
Name Origin: Named from the Greek, puro, “fire” and khroma, “color”, because of the change in color upon ignition.

History

Authors : IGELSTROEM
Discovery date: 1864
Town of Origin : PAJSBERG, FILIPSTAD, VARMLAND
Country of Origin : SUEDE

Optical properties

Optical and misc. Properties: Flexible – Transparent – Translucide – Opaque –
Refractive Index : from 1,68 to 1,72

Physical properties

Hardness : 2,50
Density : 3,25
Color: colorless; white; pale green; blue; brown; black; bronze yellow; bluish; greenish; bluish green
Luster: nacreous; unpolished
Streak : white
Cleavage : yes

Photos :

Pyrochroite Comments: Pseudo-cubic crystal of pyrochroite on matrix. Location: Franklin, Sussex County, New Jersey, USA. Copyright: © Lou Perloff / Photo Atlas of Minerals

Hauckite, Pyrochroite Locality: Sterling Mine, Sterling Hill, Ogdensburg, Franklin Mining District, Sussex County, New Jersey, USA Size: 2.6 x 1.7 x 1.1 cm. © Rob Lavinsky / iRocks

Pyroaurite, Pyrochroite Locality: Långban, Filipstad, Värmland, Sweden Size: 9.6 x 7.2 x 1.8 cm. © Rob Lavinsky / iRocks

Pyrochroite , Shigaite Location: N’Chwaning Mine, Kalahari Manganese Field, Northern Cape Province, South Africa. Scale: 2.8 x 2.3 cm. Copyright: © John Veevaert

Shark teeth analysis provides detailed new look at Arctic climate change

July 10, 2014

Both graceful and docile, this modern sandtiger shark swims through a school of round scad fish in the coastal waters off North Carolina. Modern sand tigers prefer waters of high salinity, though they tolerate brackish waters for short periods as well. Credit: Erik Rebeck

A new study shows that some shark species may be able to cope with the rising salinity of Arctic waters that may come with rising temperatures.
The Arctic today is best known for its tundra and polar bear population, but it wasn’t always like that. Roughly 53 to 38 million years ago during what is known as the Eocene epoch, the Arctic was more similar to a huge temperate forest with brackish water, home to a variety of animal life, including ancestors of tapirs, hippo-like creatures, crocodiles and giant tortoises. Much of what is known about the region during this period comes from well-documented terrestrial deposits. Marine records have been harder to come by.

A new study of shark teeth taken from a coastal Arctic Ocean site has expanded the understanding of Eocene marine life. Leading the study was Sora Kim, the T.C. Chamberlin Postdoctoral Fellow in Geophysical Sciences at the University of Chicago, in coordination with Jaelyn Eberle at the University of Colorado, Boulder, and their three co-authors. Their findings were published online June 30 by the journal Geology.

The Arctic is of special interest today because it is increasing in temperature at twice the global rate. According to Kim, past climate change in the Arctic can serve as a proxy to better understand our current climate change and aid future predictions. The Eocene epoch, she said, is like a “deep-time analogue for what’s going to happen if we don’t curb CO2 emissions today, and potentially what a runaway greenhouse effect looks like.”

Before this study, marine records primarily came from deep-sea cores pulled from a central Arctic Ocean site, the Lomonosov Ridge. Kim and Eberle studied shark teeth from a new coastal site on Banks Island. This allowed them to better understand the changes in ocean water salinity across a broader geographic area during a time of elevated global temperatures. Shark teeth are one of the few available vertebrate marine fossils for this time period. They preserve well and are incredibly abundant.

To arrive at their results, Kim isolated and measured the mass ratio of oxygen isotopes 18 to 16 found in the prepared enameloid (somewhat different from human tooth enamel) of the shark teeth. Sharks constantly exchange water with their environment, so the isotopic oxygen ratio found in the teeth is directly regulated by water temperature and salinity. With assumptions made about temperatures, the group was able to focus on extrapolating salinity levels of the water.

The results were surprising. “The numbers I got back were really weird,” Kim said. “They looked like fresh water.” The sand tiger sharks she was studying are part of a group called lamniform sharks, which prefer to stay in areas of high salinity.

“As more freshwater flows into the Arctic Ocean due to global warming, I think we are going to see it become more brackish,” said Eberle, associate professor of geological sciences at CU-Boulder. “Maybe the fossil record can shed some light on how the groups of sharks that are with us today may fare in a warming world.”

Because the teeth are 40 to 50 million years old, many tests were run to eliminate any possible contaminates, but the results were still the same. These findings suggest that sharks may be able to cope with rises in temperature and the subsequent decrease of water salinity. It has long been known that sharks are hardy creatures. They have fossil records dating back some 400 million years, surviving multiple mass extinctions, and have shown great ecological plasticity thus far.

Additionally, these results provide supporting evidence for the idea that the Arctic Ocean was most likely isolated from global waters.

“Through an analysis of fossil sand tiger shark teeth from the western Arctic Ocean, this study offers new evidence for a less salty Arctic Ocean during an ancient ‘greenhouse period,'” said Yusheng (Chris) Liu, program director in the National Science Foundation (NSF)’s Division of Earth Sciences, which co-funded the research with NSF’s Division of Polar Programs. “The results also confirm that the Arctic Ocean was isolated during that long-ago time.”

While Kim has hopes to expand her research both geographically and in geologic time in an effort to better understand the ecology and evolution of sharks, she remarked that “working with fossils is tricky because you have to work within the localities that are preserved. “You can’t always design the perfect experiment.”

Note : The above story is based on materials provided by University of Chicago.

Purus River

July 10, 2014

The Purus is a tributary of the Amazon River in South America. Its drainage basin is 63,166 km2 (24,389 sq mi), and the mean discharge is 8,400 m³/s.
It enters the Amazon River west of the Madeira River, which it parallels as far south as the falls of the latter stream. It runs through a continuous forest at the bottom of the great depression lying between the Madeira River, which skirts the edge of the Brazilian sandstone plateau, and the Ucayali which hugs the base of the Andes. The river forms a small part of the international boundary between Brazil and Peru.

One of its marked features is the five parallel furos which from the north-west at almost regular intervals the Amazon sends to the Purus; the most south-westerly one being about 150 miles (240 km) above the mouth of the latter river. They cut a great area of very low-lying country into five islands. Farther down the Purus to the right three smaller furos also connect it with the Amazon.

William Chandless found its elevation above sea-level to be only 107 feet (33 m) 590 miles (950 km) from its mouth. It is one of the most crooked streams in the world, and its length in a straight line is less than half that by its curves. It is practically only a drainage ditch for the half-submerged, lake-flooded district it traverses.

Its width is very uniform for 1000 miles (1600 km) up, and for 800 miles (1300 km) its depth is never less than 45 feet (15 m).

It is navigable by steamers for 1648 miles (2650 km) as far as the little stream, the Curumaha, but only by light-draft craft. Chandless ascended it 1866 miles (3,000 km). At 1792 miles (2,880 km) it forks into two small streams. Occasionally a cliff touches the river, but in general the lands are subject to yearly inundations throughout its course, the river rising at times above 50 feet (15 m), the numerous lakes to the right and left serving as reservoirs.[citation needed]

In 2008, a previously unknown precolumbian civilization was discovered in the upper region of the river close to the Bolivian border. After much of the forest in the region was cleared for agricultural use, satellite pictures revealed the remains of large geometric earthworks.

Note : The above story is based on materials provided by Wikipedia

Pyroaurite

July 9, 2014

Locality: Scotch Lake quarry, Scotch Lake, Cape Breton County, Nova Scotia, Canada Source: Donald Doell

Table of Contents

Chemical Formula: Mg₆Fe³⁺₂(OH)₁₆[CO₃]·4H₂O
Locality: Langbanshyttan, Sweden.
Name Origin: From the Greek, pyro and the Latin aurium, “fire” and “golden” because of the gold-like submetallic scales present in its type locality.

History

Authors (inventeurs) : IGELSTROEM
Discovery date: 1865
Town of Origin: MINE DE LANGBAN, FILIPSTAD, VARMLAND
Country of Origin : SUEDE

Optical properties

Optical and misc. Properties : Flexible – Transparent –
Refractive Index: from 1,54 to 1,56

Physical properties

Hardness : 2,50
Density: 2,12
Color : yellowish white; brownish white; greenish; colorless; brown; silver-white; green; brown yellow; pale blue
Luster: vitreous; waxy; nacreous
Streak/Trace : white
Cleavage : yes

Photos:

Pyroaurite Locality: Långban Mine, Filipstad, Värmland, Sweden (Type Locality for Pyroaurite) Overall Size: 7x4x2 cm Crystals: 0.5 mm © JohnBetts-FineMinerals

Pyroaurite from Langban, Varland, Sweden. Held in the A. E. Seaman Mineral Museum. © Chris857

Pyroaurite, Sjogrenite Locality: Palabora mine, Loolekop, Phalaborwa, Limpopo Province, South Africa Size: miniature, 6 x 3.4 x 2.6 cm “Courtesy of Rob Lavinsky, The Arkenstone, www.iRocks.com”

Ancient hedgehog and tapir once inhabited British Columbia

July 9, 2014

This image shows the teeth (above and middle) and a side view of the lower jaw (below) of Heptodon, an ancient cousin to tapirs, found in early Eocene (52-million-year-old) rocks of northern British Columbia. This extinct mammal was about half the size of today’s tapirs. Credit: Jaelyn J. Eberle, Natalia Rybczynski, and David R. Greenwood

The Earth has experienced many dramatic changes in climate since the dinosaurs went extinct 66 million years ago. One of the warmest periods was the early Eocene Epoch, 50 to 53 million years ago. During this interval, North American mammal communities were quite distinct from those of today. This is illustrated by a study published in the latest issue of the Journal of Vertebrate Paleontology that describes an ancient hedgehog and tapir that lived in what is now Driftwood Canyon Provincial Park, British Columbia, some 52 million years ago.
“Within Canada, the only other fossil localities yielding mammals of similar age are from the Arctic, so these fossils from British Columbia help fill a significant geographic gap,” said Dr. Natalia Rybczynski of the Canadian Museum of Nature, a co-author of the study. Other fossils of this age come from Wyoming and Colorado, some 2,700 miles to the south of the Arctic site of Ellesmere Island.

The ancient hedgehog is a species hitherto unknown to science. It is named Silvacola acares, which means “tiny forest dweller,” since this minute hedgehog likely had a body length of only 2 to 2.5 inches. The delicate fossil jaw of Silvacola was not freed from the surrounding rock as is typical for fossils. Rather, it was scanned with an industrial, high resolution CT (computed tomography) scanner at Penn State University so it could be studied without risking damage to its tiny teeth. Modern hedgehogs and their relatives are restricted to Europe, Asia, and Africa.

The other mammal discovered at the site, Heptodon, is an ancient relative of modern tapirs, which resemble small rhinos with no horns and a short, mobile, trunk or proboscis.

“Heptodon was about half the size of today’s tapirs, and it lacked the short trunk that occurs on later species and their living cousins. Based upon its teeth, it was probably a leaf-eater, which fits nicely with the rainforest environment indicated by the fossil plants at Driftwood Canyon,” said Dr. Jaelyn Eberle of the University of Colorado, lead author of the study.

Most of the fossil-bearing rocks at Driftwood Canyon formed on the bottom of an ancient lake and are well-known for their exceptionally well-preserved leaves, insects, and fishes. But no fossils of mammals had ever before been identified at the site. The fieldwork that resulted in these discovered was supported by Natural Sciences and Engineering Research Council of Canada.

“The discovery in northern British Columbia of an early cousin to tapirs is intriguing because today’s tapirs live in the tropics. Its occurrence, alongside a diversity of fossil plants that indicates a rainforest, supports an idea put forward by others that tapirs and their extinct kin are good indicators of dense forests and high precipitation,” said Eberle.

Fossil plants from the site indicate the area seldom experienced freezing temperatures and probably had a climate similar to that of Portland, Oregon, located roughly 700 miles to the south.

“Driftwood Canyon is a window into a lost world — an evolutionary experiment where palms grew beneath spruce trees and the insects included a mixture of Canadian and Australian species. Discovering mammals allows us to paint a more complete picture of this lost world,” said Dr. David Greenwood of Brandon University, a co-author of the study. “The early Eocene is a time in the geological past that helps us understand how present day Canada came to have the temperate plants and animals it has today. However, it can also help us understand how the world may change as the global climate continues to warm.”

Note: The above story is based on materials provided by Society of Vertebrate Paleontology.

Giant earthquakes help predict volcanic eruptions

July 9, 2014

Imaging seismic susceptibility makes it possible to detect regions affected by high-pressure volcanic fluids. The image in the background is catalogued as ‘Red Fuji’ (Katsushika Hokusai, 1830). Credit: Copyright Florent Brenguier

Researchers at the Institut des Sciences de la Terre (CNRS/Université Joseph Fourier/Université de Savoie/IRD/IFSTTAR) and the Institut de Physique du Globe de Paris (CNRS/Université Paris Diderot/IPGP), working in collaboration with Japanese researchers, have for the first time observed the response of Japanese volcanoes to seismic waves produced by the giant Tohoku-oki earthquake of 2011. Their conclusions, published in Science on July 4, 2014, reveal how earthquakes can impact volcanoes and should help to assess the risk of massive volcanic eruptions worldwide.
Until the early 2000s, seismic noise* was systematically removed from seismological analyses. This background noise is in fact associated with seismic waves caused by ocean swell. These waves, which can be compared to permanent, continuous microseisms, can be used by seismologists instead of earthquakes (which are highly localized over a limited time period) to image Earth’s interior and its evolution over time, rather like an ultrasound scan on a global scale.

Now, seismic noise has been used for the continuous measurement of perturbations of the mechanical properties of Earth’s crust. Researchers at the Institut des Sciences de la Terre (CNRS/Université Joseph Fourier/Université de Savoie/IRD/IFSTTAR) and the Institut de Physique du Globe de Paris (CNRS/Université Paris Diderot/IPGP) have applied this novel method while working in collaboration with Japanese colleagues using the Hi-net network, which is the world’s densest seismic network (comprising more than 800 seismic detectors throughout Japan).

After the giant Tohoku-oki earthquake of 2011, the researchers analyzed over 70 terabytes of seismic data from the network. For the first time, they showed that the regions where the perturbations of Earth’s crust were the greatest were not those where the shocks were the strongest. They were in fact localized under volcanic regions, especially under Mount Fuji. The new method thus enabled the scientists to observe the anomalies caused by the perturbations from the earthquake in volcanic regions under pressure. Mount Fuji, which exhibits the greatest anomaly, is probably under great pressure, although no eruption has yet followed the Tohoku-oki earthquake. The 6.4-magnitude seism that occurred four days after the 2011 quake confirms the critical state of the volcano in terms of pressure. These findings lend support to theories that the last eruption of Mount Fuji in 1707 was probably triggered by the giant 8.7-magnitude Hoei earthquake, which took place 49 days before the eruption.

More generally, the results show how regions affected by high-pressure volcanic fluids can be characterized using seismic data from dense seismic detector networks. This should help to anticipate the risk of major volcanic eruptions worldwide.

*Seismic noise includes all the unwanted components affecting an analysis, such as the noise produced by the measuring device itself or external perturbations inadvertently picked up by the measuring devices.

Note : The above story is based on materials provided by CNRS.

Pyrite

July 9, 2014

Table of Contents

Chemical Formula: FeS₂
Locality: Common world wide.
Name Origin: From the Greek, pyrites lithos, “stone which strikes fire,” in allusion to the sparking produced when iron is struck by a lump of pyrite.

The mineral pyrite, or iron pyrite, also known as fool’s gold, is an iron sulfide with the formula FeS₂. This mineral’s metallic luster and pale brass-yellow hue give it a superficial resemblance to gold, hence the well-known nickname of fool’s gold. The color has also led to the nicknames brass, brazzle, and Brazil, primarily used to refer to pyrite found in coal.

Pyrite is the most common of the sulfide minerals. The name pyrite is derived from the Greek πυρίτης (pyritēs), “of fire” or “in fire”, in turn from πύρ (pyr), “fire”. In ancient Roman times, this name was applied to several types of stone that would create sparks when struck against steel; Pliny the Elder described one of them as being brassy, almost certainly a reference to what we now call pyrite. By Georgius Agricola’s time, the term had become a generic term for all of the sulfide minerals.

Pyrite is usually found associated with other sulfides or oxides in quartz veins, sedimentary rock, and metamorphic rock, as well as in coal beds and as a replacement mineral in fossils. Despite being nicknamed fool’s gold, pyrite is sometimes found in association with small quantities of gold. Gold and arsenic occur as a coupled substitution in the pyrite structure. In the Carlin–type gold deposits, arsenian pyrite contains up to 0.37 wt% gold.

History

Authors(inventeurs) : DIOSCORIDES
Discovery date: 50

Optical properties

Optical and misc. Properties : Fragile, cassant – Opaque – Gemme, pierre fine
Reflective Power: 55% (580)

Physical properties

Hardness : from 6,00 to 6,50
Density : 5,02
Color : pale yellow; irised; brass yellow
Luster: bright metallic
Streak/Trace : blackish green; brownish black; greenish black
Break: conchoidal; irregular
Cleavage : yes

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