Chemical Formula: (K,Ba)[Al(Si,Al)Si2O8] Locality: Imfield, Switzerland. Name Origin: From the Greek hyalos – “glass” and phanos – “to appear.”
Hyalophane or jaloallofane is a crystalline mineral, part of the feldspar group of tectosilicates. It is considered a barium-rich potassium feldspar. Its chemical formula is (K,Ba)[Al(Si,Al)Si2O8], and it has a hardness of 6 – 6½. The name hyalophane comes from the Greek hyalos, meaning “glass”, and phanos meaning “to appear”.
An occurrence of hyalophane was discovered in 1855 in Lengenbach Quarry, Imfield, in the municipality of Binn, Switzerland. The mineral is found predominantly in Europe, with occurrences in Switzerland, Australia, Bosnia, Germany, Japan, New Jersey, and the west coast of North America.
Physical Properties
Cleavage: {001} Perfect, {010} Imperfect Color: Colorless, Yellow, White, Red. Density: 2.81 Diaphaneity: Transparent to translucent Fracture: Brittle – Generally displayed by glasses and most non-metallic minerals. Hardness: 6-6.5 – Orthoclase-Pyrite Luminescence: Non-fluorescent. Luster: Vitreous (Glassy) Magnetism: Nonmagnetic Streak: white
Geologic map showing seismic stations used in the study by C.H. Jones and colleagues, “P-wave tomography of potential convective down-wellings and their source regions, Sierra Nevada, California.” Credit: Image courtesy of Geological Society of America
In an addition to Geosphere’s ongoing themed issue series, “Geodynamics and Consequences of Lithospheric Removal in the Sierra Nevada, California,” Craig H. Jones of the University of Colorado Boulder and colleagues examine the seismological study of the entire extent of the U.S. Sierra Nevada range using seismograms collected in the Sierra Nevada EarthScope field experiment from 2005 to 2007.
Their results reveal that the entire eastern Sierra overlies low-velocity upper mantle and lacks the dense, quartz-poor lower crust that they say must have existed 80 million years ago when the granites of the range were created.
Jones and colleagues write that this missing dense material probably was removed within the past 10 million years. “Previous workers,” they note, “have suggested it might be within a high-velocity mantle anomaly under the southeastern San Joaquin Valley,” which is “the right size to be the old, dense rock previously under the eastern Sierra.”
They argue, however, that the geometry and extent of earth within the anomaly does not appear to be consistent with it being a piece of old subducted ocean floor. This would mean that a long strip of dense rock under the Sierra somehow deformed into a steeply plunging ellipsoid at the southwestern edge of the range. This conclusion suggests that the range rose within the past 10 million years as this dense material fell away to the west and south. Finally, Jones and colleagues note that something similar might be underway at the northern edge of the range.
Note : The above story is based on materials provided by Geological Society of America.
Chemical Formula: TlPbAs5S9 Locality: Binnental, Valais, Switzerland. Name Origin: Named for Arthur Hitchinson (1866-1937), Professor of Mineralogy, Cambridge University, England.
Hutchinsonite is a sulfosalt mineral of thallium, arsenic and lead with formula TlPbAs5S9. Hutchinsonite is a rare hydrothermal mineral.
It was first discovered in Binnental, Switzerland in 1904 and named after Cambridge mineralogist Arthur Hutchinson, F.R.S. (1866–1937).
Physical Properties
Cleavage: {100} Good Color: Cherry red, Pink, Black. Density: 4.6 Diaphaneity: Subtranslucent to opaque Fracture: Brittle – Conchoidal – Very brittle fracture producing small, conchoidal fragments. Hardness: 1.5-2 – Talc-Gypsum Luster: Sub Metallic Streak: red
Yellowstone National Park are fighting viral rumors of an impending, cataclysmic eruption of a mega volcano slumbering at the US Western preserve known for its geothermal features.
Volcanologists said reams of geological data have given them a deep of understanding of the Yellowstone Caldera—and all signs point to calm.
Over the past several weeks, the Internet has been abuzz with speculation over worrying signs suggesting an explosive awakening for the so-called supervolcano, whose last catastrophic eruption was 640,000 years ago.
That eruption covered a good portion of North America in ash several inches (centimeters) thick, and had a long-lasting impact on the Earth’s climate.
A video showing a herd of bison fleeing the iconic Wyoming park went viral.
And several days later, a 4.8-magnitude earthquake, the strongest in three decades, fed the rumor mill still further.
But Yellowstone spokesman Al Nash said there was nothing out of the ordinary in the animals’ behavior.
“We do have bison, elk and other animals that have moved out of the park recently,” he said.
“They tend to migrate at this time… to lower elevations, where they think they can get food, and then they come back.”
No cause for fear
As for the quake: “It was the strongest in 30 years, but it was not that strong,” said Peter Cervelli, a volcano expert at the US Geological Survey.
And such jolts are not exactly rare, with an estimated 1,000 to 3,000 quakes a year at the park.
Like many similar volcanoes in the world, Yellowstone’s has a way of breathing, the magma trapped underneath lifting or subsiding in phases.
And because the earth’s crust is just four to six miles (six to 10 kilometers) thick at Yellowstone, compared to an average of 18 miles, any pressure exerted by the magma is felt strongly.
“Recently, over the last six months, we are in an episode of uplift,” Cervelli said. “This probably explains the recent earthquake.”
But he rebuffed rumors that a big eruption was coming.
“I have not made yet an observation at Yellowstone that causes me to be afraid or causes me to wonder if an eruption was coming,” Cervelli said.
“We are always prepared to be surprised, and we don’t claim to understand everything perfectly.”
But he predicted there won’t be another major eruption “for the next ten thousands of years.”
His confidence was based in part on the many instruments, including dozens of GPS receivers and seismometers, that monitor activity in the volcano whose giant magma chamber measures 55 miles long, 18 miles wide and nine miles deep.
Around a dozen experts are also permanently stationed at Yellowstone.
Asteroid strike more likely
Geologist Ilya Bindeman was equally confident, based on his isotopic analysis of the minerals in the volcanic rocks at Yellowstone.
“We know the behavior of the past, and we know at what comparative stage Yellowstone is right now,” the University of Oregon professor explained.
And based on that analysis, the volcano is in the process of dying out.
“Caldera cycles go on for maybe several million years, and then it is done,” he said.
“I don’t think another major eruption is going to happen anytime soon—at least not for another one million to two million years.”
Such an eruption would destroy everything within a radius of several hundred miles and would cover North America in ash, putting an end to agriculture and cooling the Earth’s climate for at least 10 years.
The last time the Earth experienced such an eruption was in Indonesia, 70,000 years ago.
But the experts were in agreement: it’s nothing we will see during our lifetimes.
“We are more likely to see a major asteroid impact,” Cervelli said.
The Chambeshi River is the easternmost stream in red.
The Chambeshi (or Chambezi) River of northeastern Zambia is the most remote headstream of the Congo River (in terms of length) and therefore considered its source. (However, in terms of volume of water, the Lualaba River is the greater “source” of the Congo.)
The Chambeshi rises as a stream in the mountains of northeast Zambia near Lake Tanganyika at an elevation of 1760 metres above sea level. It flows for 480km into the Bangweulu Swamps, which are part of Lake Bangweulu, and by the end of the rainy season in May, it delivers a flood which recharges the swamps and inundates a vast floodplain to the southeast, supporting the Bangweulu Wetlands ecosystem. The water then flows out of the swamps as the Luapula River.
For more than 100 km of its length as it flows to the east of Kasama the river consists of a maze of channels in swamps about 2 km wide, in a floodplain up to 25 km wide. Further downstream, where it is bridged by the Kasama-Mpika road and the Tazara Railway, the permanent main channel is about 100 m wide, and up to 400 m wide in flood.
The above story is based on materials provided by Wikipedia
Chemical Formula: (Mn,Fe)5(PO4)2(HPO4)2·4H2O Locality: Hureaux in St. Silvestre and Vilate near Chanteloube, N of Limoges, Haute Vienne, France. Name Origin: Named for the locality.
Hureaulite is a manganese phosphate with the formula (Mn,Fe)5(PO4)2(HPO4)2·4H2O. It was discovered in 1825 and named in 1826 for the type locality, Les Hureaux, Saint-Sylvestre, Haute-Vienne, Limousin, France.
A complete series exists from lithiophilite, LiMn2+PO4 to triphylite, LiFe2+PO4, including hureaulite, strengite, FePO4·2H2O, stewartite, Mn2+Fe3+2(OH,PO4)2·8H2O, and sicklerite, (LiMn2+,Fe3+)PO4.
Some of the most famous and devastating natural disasters in history relate to volcano eruptions. It is estimated that more than 260 000 people have died in the past 300 years from eruptions and their aftermath. But volcanoes should not be judged as purely destructive forces – they may also have played a vital part in ensuring life could evolve on Earth and they may now be helping to slow down the warming of the atmosphere.
According to New Scientist, we now have the best evidence yet that volcanoes were responsible for pulling the Earth out of period of frigid chill over 600 million years ago. This may make them the driving force for evolutionary explosions that made life more diverse and laid the foundations for future animal species.
New Scientist reports that Ryan McKenzie of the University of Texas at Austin and colleagues have shown that volcanism may have shaped life during the crucial Cambrian period. Kenzie’s study of volcanic rocks from early in life’s evolutionary story shows that volcanic eruptions coincided with a change in the climate from frigid chill to sweltering heat.
This swing, and the way it affected the oceans, caused an explosion of evolutionary diversity, followed by a mass extinction when temperatures got too hot. Then, when Gondwana had formed and the volcanism died down, the planet cooled and life began to bloom again.
Volcanic activity during the formation of Gondwana had previously been suggested as a driver of these violent changes, but McKenzie’s new evidence (based on counts of zircon crystals formed in particular volcanic eruptions) strengthens the argument.
Volcanoes are also getting good press in the Guardian which reports on a study which focused extensively on volcanoes as a factor in the slowed warming of the atmosphere. In the study, Dr. Ben Santer and colleagues asked whether small volcanoes could be causing a slight reduction in the amount of sunlight that reaches the Earth.
The Guardian quotes co-author Carl Mears who says, ‘We were able to show that part of the cause of the recent lack of temperature increase is the large number of minor volcanic eruptions during the last 15 years. The ash and chemicals from these eruptions caused less sunlight than usual to arrive at the Earth’s surface, temporarily reducing the amount of temperature increase we measured at the surface and in the lower troposphere. The most recent round of climate models studied for the IPCC report did not adequately include the effects of these volcanoes, making their predictions show too much warming. For climate models to make accurate predictions, it is necessary that the input data that is fed into the model is accurate. Examples of input data include information about changes in greenhouse gases, atmospheric particles and solar output.’
Note : The above story is based on materials provided by CORDIS
An atomic force microscope image of the bacterial strain AltSIO. Credit: Alteromonas Scripps Institution of Oceanography
It’s broadly understood that the world’s oceans play a crucial role in the global-scale cycling and exchange of carbon between Earth’s ecosystems and atmosphere. Now scientists at Scripps Institution of Oceanography at UC San Diego have taken a leap forward in understanding the microscopic underpinnings of these processes.
When phytoplankton use carbon dioxide to make new cells, a substantial portion of that cellular material is released into the sea as a buffet of edible molecules collectively called “dissolved organic carbon.” The majority of these molecules are eventually eaten by microscopic marine bacteria, used for energy, and recycled back into carbon dioxide as the bacteria exhale. The amount of carbon that remains as cell material determines the role that ocean biology plays in locking up atmospheric carbon dioxide in the ocean.
Thus, these “recycling” bacteria play an important role in regulating how much of the planet’s carbon dioxide is stored in the oceans. The detailed mechanisms of how the oceans contribute to this global carbon cycle at the microscopic scale, and which microbes have a leadership role in the breakdown process, are complex and convoluted problems to solve.
In a study published in the Proceedings of the National Academy of Sciences, Scripps scientists have pinpointed a bacterium that appears to play a dominant role in carbon consumption. Scripps’s Byron Pedler, Lihini Aluwihare, and Farooq Azam found that a single bacterium called Alteromonas could consume as much dissolved organic carbon as a diverse community of organisms.
“This was a surprising result,” said Pedler. “Because this pool of carbon is comprised of an extremely diverse set of molecules, we believed that many different microbes with complementary abilities would be required to breakdown this material, but it appears that individual species may be pulling more weight than others when it comes to carbon cycling.”
Pedler, a marine biology graduate student at Scripps, spent several years working with Scripps marine microbiologist Azam and chemical oceanographer Aluwihare in designing a system that would precisely measure carbon consumption by individual bacterial species. Because carbon in organic matter is essentially all around us, the most challenging part of conducting these experiments is avoiding contamination.
“Much of the carbon cycling in the ocean happens unseen to the naked eye, and it involves a complex mix of processes involving microbes and molecules,” said Azam, a distinguished professor of marine microbiology. “The complexity and challenge is not just that we can’t see it but that there’s an enormous number of different molecules involved. The consequences of these microbial interactions are critically important for the global carbon cycle, and for us.”
By demonstrating that key individual species within the ecosystem can play a disproportionally large role in carbon cycling, this study helps bring us a step closer to understanding the function these microbes play in larger questions of climate warming and increased acidity in the ocean.
“In order to predict how ecosystems will react when you heat up the planet or acidify the ocean, we first need to understand the mechanisms of everyday carbon cycling—who’s involved and how are they doing it?” said Pedler. “Now that we have this model organism that we know contributes to ocean carbon cycling, and a model experimental system to study the process, we can probe further to understand the biochemical and genetic requirements for the breakdown of this carbon pool in the ocean.”
While the new finding exposes the unexpected capability of a significant species in carbon cycling, the scientists say there is much more to the story since whole communities of microbes may interact together or live symbiotically in the microscopic ecosystems of the sea.
Pedler, Aluwihare, and Azam are now developing experiments to test other microbes and their individual abilities to consume carbon.
Note : The above story is based on materials provided by University of California – San Diego
Chemical Formula: (Fe2+,Mg)2(Fe3+,Sn)(BO3)O2 Locality: Brooks mountain, Seward peninsula, Alaska. Name Origin: Named for Alfred Hulse Brooks (1871-1924), U. S. Geologist.
Physical Properties
Cleavage: {110} Good Color: Black. Density: 4.3 Diaphaneity: Opaque Hardness: 3 – Calcite Luminescence: Non-fluorescent. Luster: Sub Metallic Streak: black
New research has shown that there was liquid water on Mars as recently as 200,000 years ago. The results have been published in the international scientific journal Icarus.
“We have discovered a very young crater in the southern mid-latitudes of Mars that shows evidence of liquid water in Mars’ recent past” says Andreas Johnsson at the University of Gothenburg.
The southern hemisphere of Mars is home to a crater that contains very well-preserved gullies and debris flow deposits. The geomorphological attributes of these landforms provide evidence that they were formed by the action of liquid water in geologically recent time.
Evidence of liquid water
When sediment on a slope becomes saturated with water, the mixture may become too heavy to remain in place, leading to a flow of debris and water as a single-phase unit. This is called a debris flow. Debris flows on Earth often cause significant material destruction and even human casualties, when they occur in built-up areas. During a debris flow, a mixture of stones, gravel, clay and water moves rapidly down a slope. When the sediment subsequently stops, it displays characteristic surface features such as lobate deposits and paired levees along flow channels.
It is these landforms that Andreas Johnsson has identified on Mars. The research group has been able to compare the landforms on Mars with known debris flows on Svalbard with the aid of aerial photography and field studies. The debris flows on Mars provide evidence that liquid water has been present in the region.
“Our fieldwork on Svalbard confirmed our interpretation of the Martian deposits. What surprised us was that the crater in which these debris flows have formed is so young,” says Andreas Johnsson of the Department of Earth Sciences, University of Gothenburg.
After the ice age
Crater statistics allowed Andreas Johnsson and his co-authors to determine that the age of the crater to be approximately 200,000 years. This means that the crater was formed long after the most recent proposed ice age on Mars, which ended around 400,000 years ago.
“Gullies are common on Mars, but the ones which have been studied previously are older, and the sediments where they have formed are associated with the most recent ice age. Our study crater on Mars is far too young to have been influenced by the conditions that were prevalent then. This suggests that the meltwater-related processes that formed these deposits have been exceptionally effective also in more recent times,” says Andreas Johnsson, principal author of the article.
Impact in wet ground
The study crater is situated in the mid-latitudes of Mars’ southern hemisphere, superposed on what is known as the rampart ejecta of a nearby larger crater. A rampart ejecta display a “flowerlike” form around the host crater, and scientists have interpreted this as being the result of an impact in wet or ice-rich ground.
“My first thought was that the water that formed these debris flows had come from preserved ice within the rampart ejecta. But when we looked more closely, we didn’t find any structures such as faults or fractures in the crater that could have acted as conduits for the meltwater. It is more likely that the water has come from melting snow packs, when the conditions were favorable for snow formation. This is possible, since the orbital axis of Mars was more tilted in the past than it is today,” says Andreas Johnsson.
Note : The above story is based on materials provided by University of Gothenburg.
Simplified model for the tectonic evolution of the Taconic orogeny and closure of the Iapetus Ocean. Horizontal distances are not to scale.
When and where did the ancient Iapetus Ocean suture (the most fundamental Appalachian structure) form? Is part of New England made up of ancient African-derived rocks? What is the Moretown terrane? This new GEOLOGY study by researchers from Harvard, Middlebury College, Boise State University, and Williams College finds new evidence for an earlier closing of the Iapetus that is farther west than previous studies have reported.
Mountain-building events, called “orogenies,” in the northern U.S. Appalachia record the closure of the Iapetus Ocean, an ancient precursor to the Atlantic. The Iapetus separated continental fragments of ancestral North America and Africa more than 450 million years ago
The mountain-building period that affected most of modern-day New England, known as the “Taconic orogeny,” is commonly depicted as a collision during the Ordovician period (435 to 500 million years ago) of a North American-derived arc (the Shelburne Falls arc) and the North American margin, followed by accretion of African-derived terranes (groups of rocks with geologic histories different from surrounding rocks) during the Silurian period (410 to 435 million years ago).
New uranium-lead (U-Pb) zircon dating presented here by Harvard researcher Francis A. Macdonald and colleagues demonstrates instead that the Shelburne Falls arc was constructed on an African-derived terrane, which they have named the Moretown terrane. Their geochronologic data reveal that the main Iapetan suture, which marks the location of the Iapetus as it was consumed through subduction, is more than 50 km west than previously suspected.
Macdonald and colleagues conclude that the Moretown terrane lies below North American-derived volcanic and sedimentary rocks of the Hawley Formation, which proves a link between North American- and African-derived terranes. The Moretown terrane and Hawley Formation were both intruded by 475-million-year-old plutonic rocks (rocks formed by magma rising from great depths beneath Earth’s surface), suggesting that these terranes were together by this time and that the Iapetus Ocean closed approx. 20 million years earlier than documented elsewhere.
Note : The above story is based on materials provided by Geological Society of America, The.
Chemical Formula: MnWO4 Locality: Erie and Enterprise veins, Ellsworth (Mammoth) district, Nye County, Nevada, USA. Name Origin: After the German mineralogist, Adolph Huebner.
Hübnerite or hubnerite is a mineral consisting of manganese tungsten oxide (chemical formula: MnWO4, it isn’t a tungstate). It is the manganese endmember of the manganese – iron wolframite solid solution series. It forms reddish brown to black monoclinic prismatic submetallic crystals. The crystals are typically flattened and occur with fine striations. It has a high specific gravity of 7.15 and a Mohs hardness of 4.5. It is transparent to translucent with perfect cleavage. Refractive index values are nα=2.170 – 2.200, nβ=2.220, and nγ=2.300 – 2.320.
Typical occurrence is in association with high-temperature hydrothermal vein deposits and altered granites with greisen, granite pegmatites and in alluvial deposits. It occurs associated with cassiterite, arsenopyrite, molybdenite, tourmaline, topaz, rhodochrosite and fluorite.
It was first described in 1865 for an occurrence in the Erie and Enterprise veins, Mammoth district, Nye County, Nevada, and named after the German mining engineer and metallurgist, Adolf Huebner from Freiberg, Saxony
Physical Properties
Cleavage: {010} Perfect Color: Brown, Reddish brown, Brownish black. Density: 7.2 – 7.1, Average = 7.15 Diaphaneity: Transparent to Translucent Fracture: Brittle – Generally displayed by glasses and most non-metallic minerals. Hardness: 4.5 – Between Fluorite and Apatite Luster: Sub Metallic Streak: reddish brown
A team of scientists from the UK, the US, Australia and New Zealand have modelled the fate of a huge floating raft of volcanic rocks that formed in 2012 during a submarine eruption of a Pacific volcano.
Described in this month’s edition of Nature Communications, they show how satellite images of the floating-rock raft’s passage across the Pacific can be used to test models of ocean circulation. Their results could be used to forecast the dispersal of future pumice (volcanic rock) islands, and protect shipping from the hazards they pose.
The eruptions of the Icelandic volcano, Eyjafjallajökull, in 2010 brought the hazards associated with volcanic ash sharply into focus. Air routes across northern Europe were disrupted, leaving many passengers stranded and far from home for days on end.
Ocean hazard
But hazards of floating islands of pumice spewed into the ocean from erupting volcanoes are less well-known.
One such island grew from an explosion of the Havre volcano in the South Pacific, between Tonga and New Zealand, in July 2012. The volcano threw out a cubic kilometre of molten magma, which suddenly froze to form bubble-filled pumice.
It is the bubbles trapped in pumice that make it so light – half the density of water – so the rock floats on water. Like natural flotsam, pebble to boulder-sized lumps of pumice clump together. This can create huge floating rafts in the seas around erupting volcanoes, and they can be tens of centimetres thick but thousands of kilometres in length.
Havre’s pumice raft drifting in the Pacific. The scale bar is 20km. Credit: Nature Communications
Records of the use of pumice exist since the time of the Romans and Ancient Greeks. Its rough texture made them effective abrasives to remove dead skin from calluses and corns.
However, today, such floating pumice can pose a hazard for shipping. Hulls can be damaged by abrasion from the hard but light pumice, and when it approaches land these pumice rafts can block harbours and disrupt navigation.
Havre’s pumice island affected an area of ocean twice as big as both islands of New Zealand put together, floating atop the sea. Boats entering the volcanic debris reported engine problems, as the rock and dust clogged their water cooling intakes.
Threat to ocean life
It is not just the effects on shipping that have been a worry. The rafts of pumice stones block the sunlight from reaching plankton in the seas beneath. These plankton form the base of food chain when they convert sunlight to food through photosynthesis, and can be severely affected by floating pumice.
Floating rocks can also act as ferries for exotic invading species, such as shellfish and other organisms that make them their floating home. Indeed, it has been speculated that pumice islands like these were the first home that early life on Earth could have clung to and sprung from.
The study, led by Martin Jutzeler at the National Oceanography Centre in Southampton, UK, shows how the rafts eventually break up into ribbons of rock that can cover a wide area. The simulation techniques that the team has developed will allow the progress of future volcanic rafts to be predicted, and warnings issued to shipping, in the same way as volcanic ash clouds can be forecast for aircraft approaching stratospheric eruptions.
Note : The above story is based on materials provided by The Conversation
This story is published courtesy of The Conversation (under Creative Commons-Attribution/No derivatives). The above story is based on materials provided by
Phosphatized S Bacterium: Round- to oval-shaped apatite-rich nodules in Karelian rocks. These are widespread and have diameters of c. 300-500 micrometers, which are sizes and shapes typical of sulfur-oxidizing bacteria that mediate modern phosphogenesis and used as evidence supporting the interpretation that the ancient nodules represent phosphatized sulfur bacteria. Credit: Avio Lepland/Norges geologiske undersøkelse
Two billion years ago, Earth was recovering from a major environmental upheaval that had caused widespread changes in the planet’s surface conditions.
The oxygenation of the atmosphere and oceans had altered global biogeochemical cycles and triggered the formation of the earliest worldwide phosphorite deposits. These are rocks that contain abundant phosphorus, a key building block of life.
Scientists are now linking the deposition of phosphorus during that time period to the establishment of sulphur bacteria habitats, potentially paving the way for a new approach to astrobiology research.
A recent paper, “Potential influence of sulphur bacteria on Palaeoproterozoic phosphogenesis,” published in the journal Nature Geoscience, concludes that the formation of these phosphorite beds was strongly influenced, if not completely controlled by, the activity of sulphur bacteria. The search for life on other planets might pick up on such geological signposts.
“It would be of great interest to identify P-rich deposits in astrobiology research,” said the paper’s lead author Aivo Lepland at the Geological Survey of Norway (NGU). “Such deposits from extraterrestrial environments may serve as unique archives of geochemical setting and biologic activity.”
Unique Rock Formation
Lepland and his project team drew on research from the organic-rich rocks of the Zaonega Formation in Karelia, Northwest Russia as part of the International Continental Scientific Drilling Program’s Fennoscandian Arctic Russia – Drilling Early Earth Project (FAR DEEP) project in 2007.
Lepland said the project provided a “unique rock record” of drill cores from the early part of the Paleoproterozoic Era (2 to 2.5 billion years ago) to study the causes and consequences of Earth’s oxygenation. Two rock cores contained 2 billion year old phosphorites, which were supplemented with samples collected from nearby outcrops. The project team investigated the micro-fabric (the shapes and sizes) of the samples and analyzed trace elements, including molybdenum (Mo) and uranium (U). The goal was to assess whether or not oxygen was present in the depositional setting. The team also looked at the carbon isotope ratios of the biomass to assess the origin of the organic matter.
The appearance of the first significant worldwide phosphorites has long been seen as a consequence of Earth’s oxygenation more than two billion years ago. However, as Lepland explained, the mechanism and triggers of the event have been poorly understood.
Significant Environmental Change
According to Lepland, the sulphur bacteria that thrive in shallow sediments exert a strong influence on the formation of phosphorite beds. The scientists call the process “S bacteria mediated phosphogenesis,” and propose that it was happening during the early Paleoproterozoic Era.
“The establishment of an environmental niche for S bacteria during that time was the consequence of the increased weathering of landmasses and the supply of sulphur to the ocean—triggered by the oxygenation of the Earth,” said Lepland.
“This, the oldest known and presumed global phosphogenesis event, likely operated the same way as in the modern world,” he added.
P-rich rocks the Zaonega Formation, Karelia: Phosphorous-rich intervals occur within a succession of organic-rich sedimentary rocks that are 2.0 Ga old and record major global environmental changes in the aftermath the rise of atmospheric oxygen at 2.3 Ga. Credit: Avio Lepland/Norges geologiske undersøkelse
Even so, Lepland pointed out that the rocks studied do not provide an answer to the question of how life formed. Primitive life had likely existed on Earth already some 2 billion years before the accumulation of the phosphorus-rich deposits. Cyanobacteria, a phylum of bacteria capable of oxygenic photosynthesis, are thought to have triggered what Lepland describes as “the most significant environmental change in Earth history”: the rise of atmospheric oxygen and the establishment of an aerobic planet.
“Major environmental changes bring about the establishment of new habitats, which in turn set the stage for evolutionary innovation and the diversification and complexity of life,” he said.
Namely, oxygenation brought about important alterations to the sulphur cycle, which provided an environmental niche for sulphur bacteria to create phosphorite beds.
“S bacteria and phosphorite formation thus go together,” he added.
Planets and Water Moons
Matthew Pasek, a planetary scientist and geologist at the University of South Florida (USF), said the study is important in that it identifies microbes as a principle agent in the phosphorus cycle, a useful tool for astrobiologists. “These deposits may serve as good biomarkers on other worlds, indicating a significant amount of biological diversity on an exoplanet,” said Pasek.
He said that an understanding of how phosphate ore is formed helps to give us an idea of how to recognize it in the geologic sequence.
“From a basic science perspective, we’ve known for a while that formation of phosphate ore was likely bio-mediated, but the who, when, and why of these formations wasn’t clear. These deposits followed the rise of oxygen, implying some fairly-advanced microbial metabolism might have been necessary to form these things. This suggests that phosphorite deposits on other worlds might serve as an indicator of advanced microbial life,” he added.
Pasek also speculated that the research, which was carried out in a very specific geological region, may help astrobiological researchers form a better understanding of the type of extraterrestrial environments where such processes are more likely to occur.
“The environment required for the formation of these rocks needs to be a planet or a large moon,” he said. “Small objects in space, such as comets, are not very active and do not vary a lot over small distance scales, so these objects would not be good places to find these types of rocks.”
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Note : The above story is based on materials provided by Astrobio net
Chemical Formula: Ca2B5SiO9(OH)5 Locality: Tick Canyon, Los Angeles Co., California. Name Origin: Named after Henry How of Nova Scotia when he first described it in 1868.
Howlite, a calcium borosilicate hydroxide (Ca2B5SiO9(OH)5), is a borate mineral found in evaporite deposits. Howlite was discovered near Windsor, Nova Scotia in 1868 by Henry How (1828–1879), a Canadian chemist, geologist, and mineralogist. How was alerted to the unknown mineral by miners in a gypsum quarry, who found it to be a nuisance. He called the new mineral silico-boro-calcite; it was given the name howlite by James Dwight Dana shortly thereafter.
The most common form of howlite is irregular nodules, sometimes resembling cauliflower. Crystals of howlite are rare, having been found in only a couple localities worldwide. Crystals were first reported from Tick Canyon, California, and later at Iona, Nova Scotia. Crystals reach a maximum size of about 1 cm. The nodules are white with fine grey or black veins in an erratic, often web-like pattern, opaque with a sub-vitreous lustre. The crystals at Iona are colorless, white or brown and are often translucent or transparent.
Its structure is monoclinic with a Mohs hardness of 3.5 and lacks regular cleavage. Crystals are prismatic and flattened on {100}. The crystals from Tick Canyon are elongated along the 010 axis, while those from Iona are elongated along the 001 axis.
Howlite is commonly used to make decorative objects such as small carvings or jewelry components. Because of its porous texture, howlite can be easily dyed to imitate other minerals, especially turquoise because of the superficial similarity of the veining patterns. The dyed howlite (or magnesite) is marketed as turquenite. Howlite is also sold in its natural state, sometimes under the misleading trade names of “white turquoise” or “white buffalo turquoise,” or the derived name “white buffalo stone.”
This photo of volcanoes in Guatemala was taken from NASA’s C-20A aircraft during a four-week Earth science radar imaging mission deployment over Central and South America. The conical volcano in the center is “Volcan de Agua.” The two volcanoes behind it are, right to left, “Volcan de Fuego” and “Acatenango.” “Volcan de Pacaya” is in the foreground.
The radar imaging mission got underway in early April when the C-20A departed its base in Palmdale, Calif., to collect data over targets in the Gulf Coast area of the southeastern United States. The aircraft, a modified Gulfstream III, is carrying NASA’s Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) instrument in a specialized pod. Developed by NASA’s Jet Propulsion Laboratory in Pasadena, Calif., UAVSAR measures ground deformation over large areas to a precision of 0.04 to 0.2 inches (0.1 to 0.5 centimeters).
The mission schedule calls for the aircraft to make stops in 10 international and U.S. locations, including the Gulf Coast. Research during the deployment is covering a variety of topics, including volcanoes, glaciers, forest structure, levees, and subsidence. It is also providing vegetation data sets for satellite algorithm development. The volcanoes of Central and South America are of interest because of the hazard they pose to nearby population centers. A majority of the research will focus on gathering volcano deformation measurements, with many flight lines being repeats from previous deployments. Surface deformation often precedes other signs of renewed volcanic activity.
Note : The above story is based on materials provided by NASA
Visualization of a computer model. The pathways for the hydrothermal vents at a mid ocean ridge are marked clearly. The arrows indicate the movement of the Earths’ plates at the plate boundaries. Credit: Graphics J. Hasenclever, GEOMAR
Hydrothermal vents in the deep sea, the so-called “black smokers,” are fascinating geological formations. They are home to unique ecosystems, but are also potential suppliers of raw materials for the future. They are driven by volcanic “power plants” in the seafloor and release amounts of energy that could meet the needs of a small town. But how exactly do they extract this energy from the volcanic rock? Researchers at GEOMAR Helmholtz Centre for Ocean Research Kiel have now used computer simulations to understand the underground supply routes. The study is published in the international journal Nature.
About ten years after the first moon landing, scientists on earth made a discovery that proved that our home planet still holds a lot of surprises in store for us. Looking through the portholes of the submersible ALVIN near the bottom of the Pacific Ocean in 1979, American scientists saw for the first time chimneys, several meters tall, from which black water at about 300 degrees and saturated with minerals shot out. What we have found out since then: These “black smokers,” also called hydrothermal vents, exist in all oceans. They occur along the boundaries of tectonic plates along the submarine volcanic chains. However, to date many details of these systems remain unexplained.
One question that has long and intensively been discussed in research is: Where and how deep does seawater penetrate into the seafloor to take up heat and minerals before it leaves the ocean floor at hydrothermal vents? This is of enormous importance for both, the cooling of the underwater volcanoes as well as for the amount of materials dissolved. Using a complex 3-D computer model, scientists at GEOMAR Helmholtz Centre for Ocean Research Kiel were now able to understand the paths of the water toward the black smokers.
In general, it is well known that seawater penetrates into Earth’s interior through cracks and crevices along the plate boundaries. The seawater is heated by the magma; the hot water rises again, leaches metals and other elements from the ground and is released as a black colored solution. “However, in detail it is somewhat unclear whether the water enters the ocean floor in the immediate vicinity of the vents and flows upward immediately, or whether it travels long distances underground before venting,” explains Dr. Jörg Hasenclever from GEOMAR.
This question is not only important for the fundamental understanding of processes on our planet. It also has very practical implications. Some of the materials leached from the underground are deposited on the seabed and form ore deposits that may be of economically interest. There is a major debate, however, how large the resource potential of these deposits might be. “When we know which paths the water travels underground, we can better estimate the quantities of materials released by black smokers over thousands of years,” says Hasenclever.
Hasenclever and his colleagues have used for the first time a high-resolution computer model of the seafloor to simulate a six kilometer long and deep, and 16 kilometer wide section of a mid-ocean ridge in the Pacific. Among the data used by the model was the heat distribution in the oceanic crust, which is known from seismic studies. In addition, the model also considered the permeability of the rock and the special physical properties of water.
The simulation required several weeks of computing time. The result: “There are actually two different flow paths — about half the water seeps in near the vents, where the ground is very warm. The other half seeps in at greater distances and migrates for kilometers through the seafloor before exiting years later.” Thus, the current study partially confirmed results from a computer model, which were published in 2008 in the scientific journal Science. “However, the colleagues back then were able to simulate only a much smaller region of the ocean floor and therefore identified only the short paths near the black smokers,” says Hasenclever.
The current study is based on fundamental work on the modeling of the seafloor, which was conducted in the group of Professor Lars Rüpke within the framework of the Kiel Cluster of Excellence “The Future Ocean.” It provides scientists worldwide with the basis for further investigations to see how much ore is actually on and in the seabed, and whether or not deep-sea mining on a large scale could ever become worthwhile. “So far, we only know the surface of the ore deposits at hydrothermal vents. Nobody knows exactly how much metal is really deposited there. All the discussions about the pros and cons of deep-sea ore mining are based on a very thin database,” says co-author Prof. Dr. Colin Devey from GEOMAR. “We need to collect a lot more data on hydrothermal systems before we can make reliable statements.”
Note : The above story is based on materials provided by Helmholtz Centre for Ocean Research Kiel (GEOMAR).
Chemical Formula: (Ca,Na)2–3(Mg,Fe,Al)5(Al,Si)8O22(OH,F)2
Hornblende is a complex inosilicate series of minerals (ferrohornblende – magnesiohornblende). It is not a recognized mineral in its own right, but the name is used as a general or field term, to refer to a dark amphibole.
Hornblende is an isomorphous mixture of three molecules; a calcium-iron-magnesium silicate, an aluminium-iron-magnesium silicate, and an iron-magnesium silicate.
The general formula can be given as (Ca,Na)2–3(Mg,Fe,Al)5(Al,Si)8O22(OH,F)2
Occurrence
Hornblende is a common constituent of many igneous and metamorphic rocks such as granite, syenite, diorite, gabbro, basalt, andesite, gneiss, and schist.
It is the principal mineral of amphibolites. Very dark brown to black hornblendes that contain titanium are ordinarily called basaltic hornblende, from the fact that they are usually a constituent of basalt and related rocks. Hornblende alters easily to chlorite and epidote.
A rare variety of hornblende contains less than 5% of iron oxide, is gray to white in color, and named edenite, from its locality in Edenville, Orange County, New York.
Other minerals in the hornblende series include:
pargasite
hastingsite
tschermakite
Physical Properties
Color: black to dark green. Luster: vitreous to dull. Transparency: Crystals are generally opaque but thin crystals or exceptional specimens can be translucent. Crystal System : Monoclinic; 2/m Cleavage : imperfect in two directions at 56 and 124 degrees. Fracture : uneven. Hardness : 5 – 6. Specific Gravity : approximately 2.9 – 3.4 (somewhat above average for translucent minerals) Streak : brown to gray.
The preserved bones of Kryptodrakon progenitor (shown here in different views) has yielded new discoveries on the origin of the pterodactyloids, a group of flying reptiles that would go on to become the largest known flying creatures to have ever existed. Credit: Illustration by Brian Andres
An international research team, including a George Washington University (GW) professor, has discovered and named the earliest and most primitive pterodactyloid — a group of flying reptiles that would go on to become the largest known flying creatures to have ever existed — and established they flew above Earth some 163 million years ago, longer than previously known.
Working from a fossil discovered in northwest China, the project — led by University of South Florida (USF) paleontologist Brian Andres, James Clark of the GW Columbian College of Arts and Sciences and Xu Xing of the Chinese Academy of Sciences — named the new pterosaur species Kryptodrakon progenitor.
Through scientific analysis the team established it as the first pterosaur to bear the characteristics of the Pterodactyloidea, which would become the dominant winged creatures of the prehistoric world. Their research will be published online Thursday in the journal Current Biology.
“This finding represents the earliest and most primitive pterodactyloid pterosaur, a flying reptile in a highly specialized group that includes the largest flying organisms,” says Chris Liu, program director in the National Science Foundation’s Division of Earth Sciences. “The research has extended the fossil record of pterodactyloids by at least five million years to the Middle-Upper Jurassic boundary about 163 million years ago.”
Kryptodrakon progenitor lived around the time of the Middle-Upper Jurassic boundary. Through studying the fossil fragments, researchers also determined that the pterodactyloids originated, lived, and evolved in terrestrial environments — rather than marine environments where other specimens have been found.
The fossil is of a small pterodactyloid with a wingspan estimate of about 4.5 feet. Pterodactyloids — who went on to evolve into giant creatures, some as big as small planes — went extinct with the dinosaurs, about 66 million years ago. Pterosaurs are considered close relatives to the dinosaurs, but are not dinosaurs themselves.
The discovery provides new information on the evolution of pterodactyloids, Dr. Andres said. This area was likely a flood plain at the time the pterosaur lived, Dr. Andres said. As the pterosaurs evolved, their wings changed from being narrow, which are more useful for marine environments, to being more broad near the origin of the pterodactyloids — helpful in navigating land environments.
“He (Kryptodrakon progenitor) fills in a very important gap in the history of pterosaurs,” Dr. Andres said. “With him, they could walk and fly in whole new ways.”
The fossil that became the centerpiece of the research was discovered in 2001 by Chris Sloan, formerly of National Geographic and now president of Science Visualization. It was found in a mudstone of the Shishugou Formation of northwest China on an expedition led by Drs. Xu and Clark when Dr. Andres was a graduate student with Dr. Clark at GW. The desolate and harsh environment has become known to scientists worldwide as having “dinosaur death pits” for the quicksand in the area that trapped an extraordinary range of prehistoric creatures, stacking them on top of each other, including one of the oldest tyrannosaurs, Guanlong. Kryptodrakon progenitor was found 35 meters below an ash bed that has been dated back to more than 161 million years.
The specimen is housed at the Institute of Vertebrate Paleontology and Paleoanthropology, Beijing, China. The name Kryptodrakon progenitor comes from Krypto (hidden) and drakon (serpent), referring to “Crouching Tiger, Hidden Dragon” filmed near where the species was discovered, and progenitor (ancestral or first-born), referring to its status as the earliest pterodactyloid, Dr. Andres said.
“Kryptodrakon is the second pterosaur species we’ve discovered in the Shishugou Formation and deepens our understanding of this unusually diverse Jurassic ecosystem,” said Dr. Clark, GW’s Ronald B. Weintraub Professor of Biology. “It is rare for small, delicate fossils to be preserved in Jurassic terrestrial deposits, and the Shishugou fauna is giving us a glimpse of what was living alongside the behemoths like Mamenchisaurus.”
The scientists write that the pterosaurs were a diverse group of Mesozoic flying reptiles that underwent a body plan reorganization, adaptive radiation, and replacement of earlier forms midway through their long history, resulting in the origin of the Pterodactyloidea, a highly-specialized group of pterosaurs of which Kryptodrakon is the earliest and most primitive species.
This new take on the ecological history of pterosaurs is supported by a significant correlation found between wing shape and environment in pterosaurs and modern flying vertebrates, like bats and birds, the researchers said. Pterosaurs, however, are not the ancestors of birds — those are the dinosaurs — and scientists still believe that pterosaurs did not evolve into birds or other modern animals humans would know.
The fieldwork was supported by the National Natural Science Foundation of China, the National Science Foundation Division of Earth Sciences of the USA, the Chinese Academy of Sciences, the National Geographic Society, the Jurassic Foundation, the Hilmar Sallee bequest, and the George Washington University. Study of the specimen was supported by the Chinese Academy of Sciences, the National Science Foundation Division of Earth Sciences and the National Natural Science Foundation of China.
Note : The above story is based on materials provided by George Washington University.
A reconstruction of Earth’s earliest ocean in the laboratory revealed the spontaneous occurrence of the chemical reactions used by modern cells to synthesize many of the crucial organic molecules of metabolism (bottom pathway). Whether and how the first enzymes adopted the metal-catalyzed reactions described by the scientists remain to be established. Credit: Molecular Systems Biology / Creative Commons Attribution Non Commercial License (CC BY-NC 3.0)
Researchers from the University of Cambridge have published details about how the first organisms on Earth could have become metabolically active. The results, which are reported in the journal Molecular Systems Biology, permit scientists to speculate how primitive cells learned to synthesize their organic components — the molecules that form RNA, lipids and amino acids. The findings also suggest an order for the sequence of events that led to the origin of life.
A reconstruction of Earth’s earliest ocean in the laboratory revealed the spontaneous occurrence of the chemical reactions used by modern cells to synthesize many of the crucial organic molecules of metabolism. Previously, it was assumed that these reactions were carried out in modern cells by metabolic enzymes, highly complex molecular machines that came into existence during the evolution of modern organisms.
Almost 4 billion years ago life on Earth began in iron-rich oceans that dominated the surface of the planet. An open question for scientists is when and how cellular metabolism, the network of chemical reactions necessary to produce nucleic acids, amino acids and lipids, the building blocks of life, appeared on the scene.
The observed chemical reactions occurred in the absence of enzymes but were made possible by the chemical molecules found in the Archean sea. Finding a series of reactions that resembles the “core of cellular metabolism” suggests that metabolism predates the origin of life. This implies that, at least initially, metabolism may not have been shaped by evolution but by molecules like RNA formed through the chemical conditions that prevailed in the earliest oceans.
“Our results demonstrate that the conditions and molecules found in the Earth’s ancient oceans assisted and accelerated the interconversion of metabolites that in modern organisms make up glycolysis and the pentose-phosphate pathways, two of the essential and most centrally placed reaction cascades of metabolism,” says Dr. Markus Ralser, Group Leader at the Department of Biochemistry at the University of Cambridge and the National Institute for Medical Research. “In our reconstructed version of the ancient Archean ocean, these metabolic reactions were particularly sensitive to the presence of ferrous iron that helped catalyze many of the chemical reactions that we observed.” From the analysis of early oceanic sediments, geoscientists such as Alexandra V. Turchyn from the Department of Earth Sciences at the University of Cambridge, one of the co-authors of the study, concluded that soluble forms of iron were one of the most frequently found molecules in the prebiotic oceans.
The scientists reconstructed the conditions of this prebiotic sea based on the composition of various early sediments described in the scientific literature. The different metabolites were incubated at high temperatures (50-90oC) similar to what might be expected close to a hydrothermal vent of an oceanic volcano, a temperature that would not support the activity of conventional protein enzymes. The chemical products were separated and analyzed by liquid chromatography tandem mass spectrometry.
Some of the observed reactions could also take place in water but were accelerated by the presence of metals that served as catalysts. “In the presence of iron and other compounds found in the oceanic sediments, 29 metabolic-like chemical reactions were observed, including those that produce some of the essential chemicals of metabolism, for example precursors of the building blocks of proteins or RNA,” says Ralser. “These results indicate that the basic architecture of the modern metabolic network could have originated from the chemical and physical constraints that existed on the prebiotic Earth.”
The detection of one of the metabolites, ribose 5-phosphate, in the reaction mixtures is particularly noteworthy. Its availability means that RNA precursors could in theory give rise to RNA molecules that encode information, catalyze chemical reactions and replicate. Whether and how the first enzymes adopted the metal-catalyzed reactions described by the scientists remain to be established.
Note : The above story is based on materials provided by European Molecular Biology Organization.
