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Taking the temperature of deep geothermal reservoirs

Scientists collect water samples from a hot spring near Dixie Valley, Nevada. Berkeley Lab scientists are developing a computer program that calculates the temperature of subsurface geothermal reservoirs that feed such springs.

CA lot can happen to water as it rises to the surface from deep underground. It can mix with groundwater, for example. This makes it difficult for scientists to estimate the temperature of a geothermal reservoir, which is an important step as they decide whether a site merits further exploration as a source of clean, renewable energy.
Now, Berkeley Lab researchers have developed a new way to take a geothermal reservoir’s temperature.

The method isn’t new really, but rather a high-tech makeover of a 20-year-old technique. It’s a computer program, called GeoT, which calculates a deep reservoir’s temperature by starting with the concentrations of dissolved salts in a fluid sample obtained at the surface, such as from a hot spring. It then reconstructs the data to reflect what the water composition would be in a deep geothermal reservoir, which can be one kilometer underground.

Because the solubility of a mineral is a function of temperature, this reconstruction can indicate the temperature of the subsurface reservoir.

Initial tests show that the technique has the potential to be more reliable than current methods for thermal waters that have mixed with groundwater, lost gases, or both. As such, it could become a valuable tool to help scientists evaluate geothermal sites.

“Our method is not intended to replace older techniques, but to complement them and advance a way of investigating deep reservoirs in a more integrated manner,” says Nicolas Spycher, a scientist in Berkeley Lab’s Earth Sciences Division who leads the project.

“It’s another way of increasing our confidence over whether a geothermal resource is worth further study,” Spycher adds.

The technique is based on a time-tested method called solute geothermometry, in which the temperature of a deep reservoir is estimated by measuring the concentrations of dissolved minerals in a water sample. Simple tests are based on the concentration of silica, while others use elements such as sodium and potassium.

But these chemical signatures can change as fluid rises. Minerals can reach a new equilibrium, water can boil away as pressure changes, or the fluid can mix with saline water. When this happens, a fluid sample obtained at the surface may not be a good indicator of a subsurface reservoir’s temperature.

Back in the mid 1980s, Spycher, then a graduate student at the University of Oregon, helped Prof. Mark Reed develop a method that estimates a reservoir’s temperature by measuring the full water composition, not just one or two elements. This “whole-water analysis” irons out some of the influences that perturb traditional solute geothermometry measurements.

Working with several scientists, Spycher has now modernized this approach by developing GeoT. The program automatically reconstructs the deep-reservoir composition of a fluid sample, and then estimates the reservoir temperature by numerically lining up the myriad saturation points of the minerals in the sample. Unknown or poorly understood variables are estimated by numerical optimization.

The software has been tested on a well-characterized geothermal system at Dixie Valley, Nevada.

“In the past, processing whole-water analyses was time-consuming, and lining-up mineral saturation points required eyeballing and trial and error,” says Spycher. “Our new software makes the process much easier, and allows processing multiple waters at the same time.”

More information:
N. Spycher, L. Peiffer, E.L. Sonnenthal, G. Saldi, M.H. Reed, B.M. Kennedy, “Integrated multicomponent solute geothermometry,” Geothermics, Volume 51, July 2014, Pages 113-123, ISSN 0375-6505, dx.doi.org/10.1016/j.geothermics.2013.10.012 (www.sciencedirect.com/science/… ii/S0375650513001016)

Note : The above story is based on materials provided by Lawrence Berkeley National Laboratory

Rocha River

Topographic map of Rocha Department showing main populated places and roads Map of Rocha Department, Uruguay. © Hoverfish

CRocha is a Portuguese family name. It literally means “rock” or “boulder” in Portuguese; for instance, “rochas sedimentares, metamórficas e magmáticas” means “sedimentary, metamorphic and magmatic rocks”. It is also a topographical surname that is found in Portugal as “da Rocha” or simply Rocha, literally, “one who is from/of the rock”.
The first documented usage of the surname in Portugal was from a Monsignor de la Roche who arrived in Portugal on his way to the Holy Land from possibly Flanders during the reign of Afonso III of Portugal and assisted in the taking of Silves from the Moors. Afonso III of Portugal granted this gentlemen lands in Torres Novas and other locales for his services. His descendants used the Portuguese version of the word, ‘da Rocha’.

Another wave of the Roche family arrived from the Diocese of Fermoy, Ireland where they were viscounts during the reign of Joao I. This family helped with the Portuguese war against Castile and this gentlemen had three sons, Gomes, Louis, and Raymond. It is from D. Gomes da Rocha where the Portuguese version of the name continued onto later generations.

According to the “Dicionário das Famílias Portuguesas” (Dictionary of Portuguese Families) by D. Luiz de Lancastre e Távora, Gomes da Rocha was commandante of Pombeiro, Portugal and other monasteries in 1482 before becoming bishop of Tripoli in the middle of the 15th century. Another Portuguese author, Felgueiras Gayo, states Gomes was married to a lady by the name of D. Ines de Meneses and after becoming a widow, he became commandante of Pombeiro. It is from this family that the current coat-of-arms bearing ‘da Rocha’ families of Portugal are said to be descended.

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

Pyrargyrite

Pyrargyrite Level 320, Cueva Santa Vein, Fresnillo, Zacatecas, Mexico Size: 3.0 x 3.0 x 2.2 cm (miniature) © danweinrich

Chemical Formula: Ag3SbS3
Locality: Fresnillo, Zacatecas, and Guanajuato, Mexico and other silver districts in the world.
Name Origin: From the Greek, pyr and argyros, “fire-silver” in allusion to color and silver content.

Pyrargyrite is a sulfosalt mineral consisting of silver sulfantimonide, Ag3SbS3. Known also as dark red silver ore or ruby silver, it is an important source of the metal.

It is closely allied to, and isomorphous with, the corresponding sulfarsenide known as proustite or light red silver ore. Ruby silver or red silver ore (German Rotgiiltigerz) was mentioned by Georg Agricola in 1546, but the two species so closely resemble one another that they were not completely distinguished until chemical analyses of both were made.

Both crystallize in the ditrigonal pyramidal (hemimorphic-hemihedral) class of the rhombohedral system, possessing the same degree of symmetry as tourmaline. Crystals are perfectly developed and are usually prismatic in habit; they are frequently attached at one end, the hemimorphic character being then evident by the fact that the oblique striations on the prism faces are directed towards one end only of the crystal. Twinning according to several laws is not uncommon. The hexagonal prisms of pyrargyrite are usually terminated by a low hexagonal pyramid or by a drusy basal plane.

History

Authors (inventeurs) : GLOCKER
Discovery date : 1831

Optical properties

Optical and misc. Properties : Translucide  –   Fragile, cassant  –   Macles possibles  –   Opaque  –
Reflective Power: 26,4-31,7% (580)
Refractive Index: from 2,88 to 3,08

Physical properties

Hardness : 2,50
Density : 5,82
Color : dark red; dark grey; black brown; violet red; red; grey black
Luster : adamantine; submetallic
Streak/Trace : dark red; red brown; purplish red
Break  : conchoidal; irregular
Cleavage: yes

Photos:

Pyrargyrite San Genaro Mine, Castrovirreyna District, Castrovirreyna Province, Huancavelica Department, Peru Size: 1.6 x 1.5 x 1.0 cm (thumbnail) © danweinrich
Pyrargyrite St Andreasberg District, Harz Mts, Lower Saxony, Germany Size: 4.0 x 3.5 x 2.0 cm (miniature) © danweinrich
Pyrargyrite Location: Fresnillo, Zacatecas, Mexico. Scale:     3 x 2.5 cm. Copyright: © Fabre Minerals

World’s biggest-ever flying bird discovered

This is a reconstruction of the world’s largest-ever flying bird, Pelagornis sandersi, identified by Daniel Ksepka, Curator of Science at the Bruce Museum in Greenwich, Conn. Reconstruction art is by Liz Bradford. Credit: Liz Bradford

Scientists have identified the fossilized remains of an extinct giant bird that could be the biggest flying bird ever found. With an estimated 20-24-foot wingspan, the creature surpassed size estimates based on wing bones from the previous record holder — a long-extinct bird named Argentavis magnificens — and was twice as big as the Royal Albatross, the largest flying bird today. Scheduled to appear online the week of July 7, 2014, in the journal Proceedings of the National Academy of Sciences, the findings show that the creature was an extremely efficient glider, with long slender wings that helped it stay aloft despite its enormous size.

The new fossil was first unearthed in 1983 near Charleston, South Carolina, when construction workers began excavations for a new terminal at the Charleston International Airport. The specimen was so big they had to dig it out with a backhoe. “The upper wing bone alone was longer than my arm,” said author Dan Ksepka of the National Evolutionary Synthesis Center in Durham, North Carolina.

Now in the collections at the Charleston Museum, the strikingly well-preserved specimen consisted of multiple wing and leg bones and a complete skull. Its sheer size and telltale beak allowed Ksepka to identify the find as a previously unknown species of pelagornithid, an extinct group of giant seabirds known for bony tooth-like spikes that lined their upper and lower jaws. Named ‘Pelagornis sandersi’ in honor of retired Charleston Museum curator Albert Sanders, who led the fossil’s excavation, the bird lived 25 to 28 million years ago — after the dinosaurs died out but long before the first humans arrived in the area.

Researchers have no doubt that P. sandersi flew. It’s paper-thin hollow bones, stumpy legs and giant wings would have made it at home in the air but awkward on land. But because it exceeded what some mathematical models say is the maximum body size possible for flying birds, what was less clear was how it managed to take off and stay aloft despite its massive size.

To find out, Ksepka fed the fossil data into a computer program designed to predict flight performance given various estimates of mass, wingspan and wing shape. P. sandersi was probably too big to take off simply by flapping its wings and launching itself into the air from a standstill, analyses show. Like Argentavis, whose flight was described by a computer simulation study in 2007, P. sandersi may have gotten off the ground by running downhill into a headwind or taking advantage of air gusts to get aloft, much like a hang glider.

Once it was airborne, Ksepka’s simulations suggest that the bird’s long, slender wings made it an incredibly efficient glider. By riding on air currents that rise up from the ocean’s surface, P. sandersi was able to soar for miles over the open ocean without flapping its wings, occasionally swooping down to the water to feed on soft-bodied prey like squid and eels.

“That’s important in the ocean, where food is patchy,” said Ksepka, who is now Curator of Science at the Bruce Museum in Greenwich Connecticut.

Researchers hope the find will help shed light on why the family of birds that P. sandersi belonged to eventually died out, and add to our understanding of how the giants of the skies managed to fly.

Note : The above story is based on materials provided by National Evolutionary Synthesis Center (NESCent).

Denali duck-billed dino tracks discovered

A–C: Size ranges of tracks found at Denali National Park, Alaska, tracksite. D: Adult hadrosaurid track with skin impressions. Scale bar for C1 is 5 cm. Credit: Fiorillo et al.

A trio of paleontologists has discovered a remarkable new tracksite in Alaska’s Denali National Park filled with duck-billed dinosaur footprints — technically referred to as hadrosaurs — that demonstrates they not only lived in multi-generational herds but thrived in the ancient high-latitude, polar ecosystem.
The paper provides new insight into the herd structure and paleobiology of northern polar dinosaurs in an arctic greenhouse world.

The article, “Herd structure in Late Cretaceous polar dinosaurs: A remarkable new dinosaur tracksite, Denali National Park, Alaska, USA,” was written for Geology by lead author Anthony R. Fiorillo, curator of earth sciences at the Perot Museum of Nature and Science, and co-authors Stephen Hasiotis of the University of Kansas and Yoshitsugu Kobayashi of the Hokkaido University Museum.

“Denali is one of the best dinosaur footprint localities in the world. What we found that last day was incredible — so many tracks, so big and well preserved,” said Fiorillo. “Many had skin impressions, so we could see what the bottom of their feet looked like. There were many invertebrate traces — imprints of bugs, worms, larvae and more — which were important because they showed an ecosystem existed during the warm parts of the years.”

Note : The above story is based on materials provided by Geological Society of America.

Pseudomalachite

Dark-green tabular crystals associated with chalcosiderite Locality: Cerro Negro mine, Carrizalillo, Chile Source: William W. Pinch

Chemical Formula: Cu5(PO4)2(OH)4
Locality: Virneberg Mine, Rheinbreitbach, Westerwald, Rhineland-Palatinate, Germany.
Name Origin: From the Greek, pseudo – “false” and malachite.

Pseudomalachite is a phosphate of copper with hydroxyl, named from the Greek for “false” and “malachite”, because of its similarity in appearance to the carbonate mineral malachite, Cu2(CO3)(OH)2. Both are green coloured secondary minerals found in oxidised zones of copper deposits, often associated with each other. Pseudomalachite is polymorphous with reichenbachite and ludjibaite. It was discovered in 1813. Prior to 1950 it was thought that dihydrite, lunnite, ehlite, tagilite and prasin were separate mineral species, but Berry analysed specimens labelled with these names from several museums, and found that they were in fact pseudomalachite. The old names are no longer recognised by the IMA.

History

Discovery date: 1813
Etymology:” PSEUDO” = faux” et MALACHITE

Optical properties

Refractive Index: from 1,79 to 1,86
Axial angle 2V : 48°

Physical properties

Hardness: from 4,50 to 5,00
Density : 4,35
Color : green; blackish green; bluish green; pale blue green; black green; blue green
Luster: vitreous; greasy
Streak : green blue; green
Break : splintery; conchoidal
Cleavage : yes

Photos:

Pseudomalachite, Quartz Locality: Old Gunnislake Mine, Gunnislake Area, Callington District, Cornwall, England, UK Size: small cabinet, 6.2 x 4.6 x 2.1 cm “Courtesy of Rob Lavinsky, The Arkenstone, www.iRocks.com”
Mineral: Halloysite , Pseudomalachite Location: Black Pine Mine, Philipsburg, Granite Co., Montana, USA. Scale:     Crystal size 1-2 mm. Copyright: © John Veevaert
Pseudomalachite Locality: Miguel Vacas Mine, Pardais, Vila Viçosa, Évora District, Portugal Picture width 1 mm. Collection and photograph Christian Rewitzer

New type of soot particle discovered from wildfire emissions

These images show typical soot superagregattes observed with an electron microscope in wildfire smoke samples collected from three fires in Northern California, New Mexico and Mexico City. Credit: Desert Research Institute

Every year, wildfires clear millions of hectares of land and emit around 34-percent of global soot mass into the atmosphere. In certain regions, such as Southeast Asia and Russia, these fires can contribute as much as 63-percent of regional soot mass.
In a paper published in Nature’s Scientific Reports, a team of scientists led by Rajan Chakrabarty from Nevada’s Desert Research Institute report the observation of a previously unrecognized form of soot particle, identified by the authors as “superaggregates,” from wildfire emissions. These newly identified particles were detected in smoke plumes from wildfires in Northern California, New Mexico, Mexico City, and India.

For several decades, scientists have been trying to quantitatively assess the impacts of wildfire soot particles on climate change and human health. However, due to the unpredictability of wildfire occurrences and the extreme difficulty in sampling smoke plumes in real-time, accurate knowledge of wildfire-emitted soot physical and optical properties has eluded the scientific community.

Unlike conventional sub-micrometer size soot particles emitted from vehicles and cook stoves, superaggregates are on average ten times longer and have a more compact shape. However, these particles have low effective densities which, according to the authors, gives them similar atmospheric long-range transportation and human lung-deposition characteristics to conventional soot particles.

“Our observations suggest that we cannot simply assume a universal form of soot to be emitted from all combustion sources. Large-scale combustion sources, such as wildfires, emit a different form of soot than say, a small-scale, controlled combustion source, such as vehicles.” says Chakrabarty, who also holds a faculty appointment at Washington University in St. Louis.

The study points to the need for revisiting the soot formation mechanism in wildfires, he adds.

The multi-institutional research team first detected the ubiquitous presence of soot superaggregates in smoke plumes from the 2012 Nagarhole National Forest fire in western India.

To verify the presence of superaggregate particles in other fires around the world, the team next analyzed smoke samples collected from the 2010 Millerton Lake fire in Northern California, and the 2011 Las Conchas fire in New Mexico, as well as wildfires near Mexico City. The authors found that a large portion of soot emitted during the flaming phase of these fires were superaggregates.

To assess the potential impact of superaggregates on global climate, scientists also calculated the radiative properties of soot superaggregates using numerically-exact electromagnetic theory.

“We found that superaggregates contribute up to 90-percent more warming than spherical sub-micrometer soot particles, which current climate models use,” said Chakrabarty. “These preliminary findings warrant further research to quantify the significant impact these particles may have on climate, human health, and air pollution around the world.”

More information:
Scientific Reports, www.nature.com/srep/2014/14070… /full/srep05508.html

Note : The above story is based on materials provided by Desert Research Institute

Researcher studies past climate change to understand future impact

New UAlberta assistant professor Alberto Reyes above a glacier at the edge of the Greenland ice sheet. New research by Reyes and colleagues indicates that ice disappeared from most of south Greenland during a long period of warm climate about 400,000 years ago. Credit: Robert Hatfield, Oregon State University

A former University of Alberta PhD student has come back to campus as an assistant professor, to explore and teach about the mysteries of natural climate warming and ice age history, on the heels of a newly published paper in Nature.
Alberto Reyes, an assistant professor in the Faculty of Science who received his PhD from the U of A in 2010, led a study which provides the first scientific evidence that the southern portion of Greenland’s ice sheet nearly disappeared in the geologically recent past, during a long period of warm climate about 400,000 years ago. The findings also indicate that the collapse of the ice sheet, which would have contributed 4.5 to six metres of global sea level rise, likely occurred under conditions that may have been only a few degrees warmer than the present day.

“The study highlights the sensitivity of the ice sheet to small levels of climate warming,” Reyes said.

Reyes, who led the study while at Queen’s University Belfast in collaboration with researchers from the University of Wisconsin-Madison and Oregon State University, spent several years collecting sediment samples from rivers in south Greenland to develop a chemical “fingerprint” of eroded rocks beneath the ice sheet. The group then used that fingerprint to determine when different parts of south Greenland stopped contributing sediment into the ocean.

“This only happens when there is no ice sheet or glacier to erode the rocks at the surface, so the chemistry allows us to broadly track retreat of the ice sheet,” he said.

Their findings indicated a near-complete absence of ice in the region just under a half-million years ago, which indicates the impact of just a small level of climate warming, Reyes noted.

Pointing to recent evidence that the west Antarctic ice sheet has begun collapsing, “This really highlights the sensitivity to the kind of magnitude of climate warming projected over the next several hundred years, so there are long-term consequences,” he added.

Reyes, who researched how permafrost and peatlands responded to past climate warming during his PhD studies at the U of A, will share his knowledge and sense of wonder with students as he teaches second- and third-year courses in global change and ice age history through the environmental earth sciences program.

“During my PhD I had the opportunity to do a lot of fieldwork, which the U of A is really strong in, and I spent a lot of time in the Yukon and Alaska learning about long-term environmental change and interactions between elements of Earth’s systems.

“It’s like history, but with science thrown in, so it’s very interesting.”

Reyes will also continue his research into long-term landscape and environmental change, through his appointment with the Department of Earth and Atmospheric Sciences.

Focused on the Arctic and subarctic regions, Yukon in particular, Reyes’ work will help address “what we might expect from a future warming climate in terms of how things like ice sheets and permafrost will respond.

“I want to understand how interactions between climate, environment and geological processes all work together to shape the landscape we see. The U of A has a strong history as a leader in northern research, so it’s really satisfying to return to the university as an educator and scientist.”

More information:
Nature, www.nature.com/nature/journal/… ull/nature13456.html

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

Pseudobrookite

Emmelberg, Üdersdorf, Daun, Eifel, Rhineland-Palatinate, Germany © Chinellato Matteo

Formula: Fe2TiO5
Environment:  Magmatic, post-volcanic or young volcanic rocks.
Locality: Vesuvius and Etna, Italy.
Name Origin: From the Greek pseudo – “I mislead” and the mineral brookite.

History

Authors (inventeurs) : KOCH
Discovery date: 1878
Town of Origin : DEALUL UROIU (ARANYI-HEGY), COMTE DE HUNEDOARA, TRANSYLVANIE
Country of Origin : ROUMANIE

Optical properties

Optical and misc. Properties :  Translucide  –   Opaque
Refractive Index: from 2,38 to 2,42
Axial angle 2V : 50°

Physical properties

Hardness : 6,00
Density : 4,39
Color : black; brownish black; reddish brown; yellow
Luster : adamantine; metallic
Streak : reddish brown; yellowish brown; yellow brown
Break : sub-conchoidal; irregular
Cleavage : yes

Photo:

A long thin Pseudobrookite (2 mm) glued together with Topaz crystals – Locality: Wannenköpfe, Ochtendung, Eifel region, Germany © Fred Kruijen.
Pseudobrookite Locality: Topaz Mountain, Thomas Range, Juab County, Utah, USA Size: 2.7 x 2.0 x 1.6 cm. © Rob Lavinsky / iRocks
A nice Pseudobrookite “brush”, 0.9mm long. – Locality: Wannenköpfe, Ochtendung, Eifel region, Germany © Fred Kruijen

.

Rewriting the history of volcanic forcing during the past 2,000 years

Locations of Antarctic ice core sites used for volcanic sulfate aerosol deposition reconstruction (right); a DRI scientist examines a freshly drilled ice core in the field before ice cores are analyzed in DRI’s ultra-trace ice core analytical laboratory. Credit: M. Sigl

A team of scientists led by Michael Sigl and Joe McConnell of Nevada’s Desert Research Institute (DRI) has completed the most accurate and precise reconstruction to date of historic volcanic sulfate emissions in the Southern Hemisphere.
The new record, described in a manuscript published today in the online edition of Nature Climate Change, is derived from a large number of individual ice cores collected at various locations across Antarctica and is the first annually resolved record extending through the Common Era (the last 2,000 years of human history).

“This record provides the basis for a dramatic improvement in existing reconstructions of volcanic emissions during recent centuries and millennia,” said the report’s lead author Michael Sigl, a postdoctoral fellow and specialist in DRI’s unique ultra-trace ice core analytical laboratory, located on the Institute’s campus in Reno, Nevada.

These reconstructions are critical to accurate model simulations used to assess past natural and anthropogenic climate forcing. Such model simulations underpin environmental policy decisions including those aimed at regulating greenhouse gas and aerosol emissions to mitigate projected global warming.

Powerful volcanic eruptions are one of the most significant causes of climate variability in the past because of the large amounts of sulfur dioxide they emit, leading to formation of microscopic particles known as volcanic sulfate aerosols. These aerosols reflect more of the sun’s radiation back to space, cooling Earth. Past volcanic events are measured through sulfate deposition records found in ice cores and have been linked to short-term global and regional cooling.

This effort brought together the most extensive array of ice core sulfate data in the world, including the West Antarctic Ice Sheet (WAIS) Divide ice core — arguably the most detailed record of volcanic sulfate in the Southern Hemisphere. In total, the study incorporated 26 precisely synchronized ice core records collected in an array of 19 sites from across Antarctica.

“This work is the culmination of more than a decade of collaborative ice core collection and analysis in our lab here at DRI,” said Joe McConnell, a DRI research professor who developed the continuous-flow analysis system used to analyze the ice cores.

McConnell, a member of several research teams that collected the cores (including the 2007-2009 Norwegian-American Scientific Traverse of East Antarctica and the WAIS Divide project that reached a depth of 3,405 meters in 2011), added, “The new record identifies 116 individual volcanic events during the last 2000 years.”

“Our new record completes the period from years 1 to 500 AD, for which there were no reconstructions previously, and significantly improves the record for years 500 to 1500 AD,” Sigl added. This new record also builds on DRI’s previous work as part of the international Past Global Changes (PAGES) effort to help reconstruct an accurate 2,000-year-long global temperature for individual continents.

This study involved collaborating researchers from the United States, Japan, Germany, Norway, Australia, and Italy. International collaborators contributed ice core samples for analysis at DRI as well as ice core measurements and climate modeling.

According to Yuko Motizuki from RIKEN (Japan’s largest comprehensive research institution), “The collaboration between DRI, National Institute of Polar Research (NIPR), and RIKEN just started in the last year, and we were very happy to be able to use the two newly obtained ice core records taken from Dome Fuji, where the volcanic signals are clearly visible. This is because precipitation on the site mainly contains stratospheric components.” Dr. Motizuki analyzed the samples collected by the Japanese Antarctic Research Expedition.

Simulations of volcanic sulfate transport performed with a coupled aerosol-climate model were compared to the ice core observations and used to investigate spatial patterns of sulfate deposition to Antarctica.

“Both observations and model results show that not all eruptions lead to the same spatial pattern of sulfate deposition,” said Matthew Toohey from the German institute GEOMAR Helmholtz Centre for Ocean Research Kiel. He added, “Spatial variability in sulfate deposition means that the accuracy of volcanic sulfate reconstructions depends strongly on having a sufficient number of ice core records from as many different regions of Antarctica as possible.”

With such an accurately synchronized and robust array, Sigl and his colleagues were able to revise reconstructions of past volcanic aerosol loading that are widely used today in climate model simulations. Most notably, the research found that the two largest volcanic eruptions in recent Earth history (Samalas in 1257 and Kuwae in 1458) deposited 30 to 35 percent less sulfate in Antarctica, suggesting that these events had a weaker cooling effect on global climate than previously thought.

Note : The above story is based on materials provided by Desert Research Institute.

Río Grande

Map of the Amazon Basin showing Río Grande (highlighted)

The Río Grande (or Río Guapay) in Bolivia rises on the southern slope of the Cochabamba mountains, east of the city Cochabamba, at 17°26′11″S 65°52′22″W. At its source it is known as the Rocha River. It crosses the Cochabamba valley basin in a westerly direction. After 65 km the river turns south east and after another 50 km joins the Arque River at 17°42′10″S 66°14′45″W and an elevation of 2.350 m.

From this junction the river receives the name Caine River for 162 km and continues to flow in a south easterly direction, before it is called Río Grande. After a total of 500 km the river turns north east and in a wide curve flows round the lowland city of Santa Cruz.

After 1.438 km, the Río Grande joins the Ichilo River at 15°48′09″S 64°43′47″W which is a tributary to the Mamoré.

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

Proustite

Locality: Chañarcillo, Copiapó Province, Atacama Region, Chile Fov 16×16 mm Photo Copyright © Maurizio Dini

Chemical Formula: Ag3AsS3
Locality: Himmelsfurst mine, Erbisdor, near Freiberg, Germany
Name Origin: After the French chemist, J. L. Proust (1755-1826).

Proustite is a sulfosalt mineral consisting of; silver sulfarsenide, Ag3AsS3, known also as light red silver or ruby silver ore, and an important source of the metal. It is closely allied to the corresponding sulfantimonide, pyrargyrite, from which it was distinguished by the chemical analyses of Joseph L. Proust (1754-1826) in 1804, after whom the mineral received its name.

The prismatic crystals are often terminated by the scalenohedron and the obtuse rhombohedron, thus resembling calcite (dog-tooth-spar) in habit. The color is scarlet-vermilion and the lustre adamantine; crystals are transparent and very brilliant, but on exposure to light they soon become dull black and opaque. The streak is scarlet, the hardness 2.5, and the specific gravity 5.57.

Proustite occurs in hydrothermal deposits as a phase in the oxidized and supergene zone. I is associated with other silver minerals and sulfides such as native silver, native arsenic, xanthoconite, stephanite, acanthite, tetrahedrite and chlorargyrite.

Magnificent groups of large crystals have been found at Chañarcillo in Chile; other localities which have yielded fine specimens are Freiberg and Marienberg in Saxony, Joachimsthal in Bohemia and Markirch in Alsace.

Optical properties

Optical and misc. Properties: Transparent  –   Translucinte
Reflective Power : 28,2-30,3% (580)
Refractive Index: from 2,79 to 3,08

Physical properties

Hardness: from 2,00 to 2,50
Density : 5,57
Color : red; cinnabar-red; reddish grey
Luster : adamantine; submetallic
Streak : brick-red; brownish; pale red
Break : conchoidal; irregular
Cleavage : yes

Photos:

Proustite Locality: Chañarcillo, Copiapó Province, Atacama Region, Chile
Proustite. Schneeberg, Erzgebirge, Saxony, Germany © Fabre Minerals
Proustite Location: Dolores I Mine, Chañarcillo, Atacáma Province, Chile. Scale: Specimen Size 6×8 cm. Copyright: © Dave Barthelmy

Terrawatch: The crash that splintered Earth’s crust

Artist’s impression of a massive asteroid impact, such as the one over three billion years ago, that may have splintered Earth’s crust

One of the things that distinguishes Earth from other planets is its plate tectonics. But how did this moving jigsaw surface begin? New research suggests that a 3.26 billion-year-old asteroid impact may have kick-started the process.

The impact crater has long since gone (recycled by plate tectonics), but Norman Sleep and Donald Lowe, both at Stanford University, have been able to study this cataclysmic event by looking at the fall-out it produced: tiny spherical rocks which rained down into an ocean, in what is now South Africa. These little grains, and the shattered rocks surrounding them, tell the story of what was probably one of the last major asteroid impacts during Earth’s violent early history.

And what an impact it was. Hurtling in at 72,000km per hour, this 37km wide asteroid (four times larger than the one that wiped out the dinosaurs) smashed into Earth, vaporising rock and creating a 500km wide crater. The impact triggered magnitude 10.8 earthquakes (100 times larger than the 2011 Japanese earthquake), set off tsunamis, and heated the atmosphere enough to make oceans boil.

Crucially the findings, published in the journal Geochemistry, Geophysics, Geosystems, also indicate that the impact could have initiated plate tectonics. Since then the heat from Earth’s mantle has kept the plates in a state of continuous agitation. Without that impact Earth’s surface might be more akin to Mars or Venus. And without the constant chemical recycling that plate tectonics brings (which stabilises Earth’s climate) we probably wouldn’t be here.

Note : The above story is based on materials provided by Kate Ravilious “The Guardian”

Ancient ice sheet may have melted later than previously thought

William Philipps, a UB geology graduate researcher, examines Greenland’s terrain as part of research on deglaciation and global climate change. Credit: Jason Briner

After one of the snowiest winters in recent history, William Philipps will forego the beach to spend the summer studying glaciers at the world’s northernmost university.
The University at Buffalo geology graduate student and self-proclaimed “nerd who likes rocks” will travel to the University Centre on Svalbard (UNIS) in Norway to collect data that proves the Svalbard-Barents Sea Ice-Sheet’s (SBSIS) time of deglaciation – the point when the ice began to melt – is older than its suggested age of 12,000 years.

Philipps, an Amherst native, will travel to Svalbard on July 12 through the UNIS’s Icebound Project, funded by the ConocoPhillips and Lundin Petroleum arctic research program, which seeks to improve understanding of the region for petroleum exploration. He will spend three months completing a mix of courses and research on global climate change.

The Norwegian archipelago of Svalbard is not the average study abroad or research experience. Philipps will visit during the region’s midnight sun season, a period when the sun is visible 24 hours a day. He will also undergo survival training that includes strapping on an insulated suit and learning to withstand the chilly artic water.

Fortunately, Philipps is familiar with the experience. A member of the paleoclimatology research group under Jason Briner, PhD, associate professor in the UB Department of Geology in the UB College of Arts and Sciences, he conducted similar research in Greenland as an undergraduate.

“I am incredibly fortunate to be where I am in life,” says Philipps. “I get to work in the most breathtaking settings in the world on complex scientific problems and learn from some of the foremost research scientists in my field.”

At their maximum extent, as long ago as 25,000 years ago, the SBSIS and other ice sheets – some over a mile thick – engulfed the northern hemisphere. But over time, the ice eroded, transporting pieces of rock, known as glacial erratics, up to hundreds of miles into different geologic areas.

Once the ice melted, the rocks were exposed to the sun and bombarded with cosmic radiation, causing a nuclear chemical reaction that produces beryllium. Through cosmogenic exposure dating, researchers measure the ratios of beryllium to determine the time of deglaciation.

The material used to date the SBSIS’s deglaciation were pieces of driftwood found on Kongsøya and Hopen, two of Svalbard’s eastern most islands. However, the conditions for the wood to be deposited on the islands indicate that the time between the ice beginning to drift and when the wood was deposited may be thousands of years off, says Philipps.

After collecting samples from several locations that are fractions of a gram in weight and about the size of a pinhead, the researchers will send the erratics to a mass spectrometer facility to measure their age.

The study’s results will increase the understanding of the SBSIS’s behavior and can potentially help predict the future behavior of the West Antarctic Ice Sheet.

Determining the age of the erratics will also improve constraints of glacial isostatic adjustment (GIA) values for the region, which detail the rise of land masses that were suppressed by the weight of ice sheets during a glacial period, says Philipps.

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

Probertite

Probertite 8.7×4.2×5.0 cm Cheverie Nova Scotia, Canada Copyright © David K. Joyce Minerals

Chemical Formula: NaCaB5O7(OH)4·3H2O
Locality: Boron, Kern Co., California.
Name Origin: Named for Frank H. Probert (1876-1940), University of California, who discovered the mineral.

History

Authors: EAKLE
Discovery date : 1929
Town of Origin: MINE BAKER, KRAMER DIST., KERN CO., CALIFORNIE
Country of Origin: USA

Optical properties

Optical and misc. Properties: Fragile, cassant  –   Transparent  –
Refractive Index : from 1,51 to 1,54
Axial angle 2V: 73°

Physical properties

Hardness : 3,50
Density : 2,14
Color : colorless
Luster: vitreous
Streak : white
Cleavage : yes

Photos:

Probertite Locality: Kohnstedt Quarry, Niedersachswerfin, Nordhausen, Thuringia, Germany Overall Size: 27x10x8 mm Crystals: 3-12 mm © JohnBetts-FineMinerals
Probertite Locality: Borax Pit #3, Ryan, Inyo County, California Overall Size: 5x3x1 cm Crystals: 4-5 cm © JohnBetts-FineMinerals
Probertite Location: Niedersachswerfen, Nordhausen, Erfurt district, Harz Mts, Thuringia, Germany. Scale:     Crystal length 4.7 cm. Copyright: © Thomas Witzke / Abraxas-Verlag

Coastal winds intensifying with climate change, study says

Cartoon of the wind intensification/upwelling process. Increasing winds and upwelling may increase nutrients in the lighted upper ocean, enhancing primary productivity, but excessive upwelling may increase turbulence, acidification and de-oxygenation of the photic zone. The ecological impacts of upwelling intensification are difficult to predict. Credit: Steve Ravenscraft for The Pew Charitable Trusts

Summer winds are intensifying along the west coasts of North and South America and southern Africa and climate change is a likely cause, a new study says.
The winds, which blow parallel to the shore and draw cold, nutrient-rich water from the deep ocean to the surface in a process known as coastal upwelling, have increased over the last 60 years in three out of five regions of the world, according to an analysis published Thursday in the journal Science.

Stronger winds have the potential to benefit coastal areas by bringing a surge of nutrients and boosting populations of plankton, fish and other species. But they could also harm marine life by causing turbulence in surface waters, disrupting feeding, worsening ocean acidification and lowering oxygen levels, the study says.

The shift could already be having serious effects on some of the world’s most productive marine fisheries and ecosystems off California, Peru and South Africa.

At this point “we don’t know what the implications are,” said William Sydeman, president of the Farallon Institute for Advanced Ecosystem Research in Petaluma, Calif., who led the study by seven scientists in the U.S. and Australia. “On the one hand it could be good. On the other hand, it could be really bad.”

The windier conditions are occurring in important currents along the eastern edges of the Pacific and Atlantic oceans. In those areas, the influx of nutrients from coastal upwelling fuels higher production of phytoplankton, tiny plant-like organisms that are eaten by fish, which in turn feed populations of seabirds, whales and other marine life.

Scientists said their results lend support to a hypothesis made more than two decades ago by oceanographer Andrew Bakun. He suggested that rising temperatures from the human-caused buildup of greenhouse gases, by causing steeper atmospheric pressure gradients between oceans and continents, would produce stronger winds during summer and drive more coastal upwelling.

To test that claim, researchers reviewed and analyzed 22 published studies that tracked winds in the world’s five major coastal upwelling regions using data from the 1940s to the mid-2000s.

Scientists found a trend of windier conditions in the California Current along the west coast of North America, the Humboldt Current off Peru and Chile and the Benguela Current off the west coast of southern Africa. In the Canary and Iberian currents off northern Africa and Spain, however, they found no clear signs of increasing winds.

Researchers can’t say for sure that human-caused climate change is to blame, but they said finding a pattern that was consistent across several parts of the planet gives a strong indication it is a factor. The study also found that the increase in winds was more pronounced at higher latitudes, which is in line with other observed effects of climate change.

The study’s conclusions are controversial among ocean scientists. They say the records used in the analysis do not go back far enough in time to rule out naturally occurring climate cycles such as the Pacific Decadal Oscillation, which shifts between warm and cool phases about every 20 to 30 years and also influences atmospheric conditions.

“It doesn’t prove that global warming is driving this,” said Art Miller, a climate scientist at Scripps Institution of Oceanography who was not involved in the study.

Similar limitations in the data have made it difficult for other researchers to link increases in coastal upwelling to climate change.

A study published last year by Canadian researchers, for instance, found huge year-to-year changes in coastal winds and the timing and intensity of upwelling from Vancouver Island to Northern California and urged caution in analyzing trends over short time periods.

“We found it extremely difficult to capture a climate change signal,” said Brian Bylhouwer, an environmental scientist with Stantec Consulting in Dartmouth, Canada, who led that study.

Sydeman acknowledged that scientists need more time and data to firmly establish that shifting winds are the result of climate change and not natural cycles.

He said future research will examine the mechanism behind the increase in coastal winds and study how a boost in upwelling might be affecting fish and seabirds off California and South Africa.

More information:
Climate change and wind intensification in coastal upwelling ecosystems, Science 4 July 2014: Vol. 345 no. 6192 pp. 77-80. DOI: 10.1126/science.1251635

Note : The above story is based on materials provided by ©2014 Los Angeles Times

Mamoré River

Map of the Amazon Basin with the Mamoré River highlighted

The Mamoré is a large river in Bolivia and Brazil, which unites with the Beni to form the Madeira, one of the largest tributaries of the Amazon. It rises on the northern slope of the Sierra de Cochabamba, east of the city of Cochabamba, and is known as the Chimoré down to its junction with the Chapare. Its larger tributaries are the Chapare, Secure, Apere, and Yacuma from the west, and the Ichilo, Guapay, Ivari, Manique, and Guapore from the east.

Taking into account its length only, the Guapay should be considered the upper part of the Mamore; but it is shallow and obstructed, and carries a much smaller volume of water. The Guapore also rivals the Mamore in length and volume, having its source in the Parecis plateau, Mato Grosso, Brazil, a few miles from streams flowing north-ward to the Tapajos and Amazon, and southward to the Paraguay and Paraná rivers. The Mamore is interrupted by rapids a few miles above its junction with the Beni, but a railway 300 km long has been undertaken from below the rapids of the Madeira. Above the rapids the river is navigable to Chimore, at the foot of the sierra, and most of its tributaries are navigable for long distances. In 1874, Franz Keller gave the outflow of the Mamoré at mean water level, and not including the Guapore, as 41,459 cm3/sec (2,530 cub. in. per second), and the area of its drainage basin, also not including the Guapore, as 24,299 km2 (9,382 square miles).

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

Prehnite

Prehnite Imilchil, Anti-Atlas  Morocco (04/2013) Specimen size: 9.5 × 5.7 × 4 cm = 3.7” × 2.2” × 1.6” © Fabre Minerals
Chemical Formula: Ca2Al2Si3O10(OH)2
Locality: Haslach, Harzburg and Oberstein, Germany.
Name Origin: Named after the Dutch Colonel, H. Von Prehn (1733-1785).Prehnite is a inosilicate of calcium and aluminium with the formula: Ca2Al2Si3O10(OH)2. Limited Fe3+ substitutes for aluminium in the structure. Prehnite crystallizes in the orthorhombic crystal system, and most oftens forms as stalactitic or botryoidal aggregates, with only just the crests of small crystals showing any faces, which are almost always curved or composite. Very rarely will it form distinct, well individualized crystals showing a square-like cross-section, like those found at the Jeffrey Mine in Asbestos, Quebec, Canada. It is brittle with an uneven fracture and a vitreous to pearly lustre. Its hardness is 6-6.5, its specific gravity is 2.80-2.90 and its color varies from light green to yellow, but also colorless, blue or white. In April 2000, a rare orange Prehnite was discovered at the famous Kalahari Manganese Fields in South Africa. It is mostly translucent, and rarely transparent.

Though not a zeolite, it is found associated with minerals such as datolite, calcite, apophyllite, stilbite, laumontite, heulandite etc. in veins and cavities of basaltic rocks, sometimes in granites, syenites, or gneisses. It is an indicator mineral of the prehnite-pumpellyite metamorphic facies.

It was first described in 1788 for an occurrence in the Karoo dolerites of Cradock, Eastern Cape Province, South Africa. It was named for Colonel Hendrik Von Prehn (1733–1785), commander of the military forces of the Dutch colony at the Cape of Good Hope from 1768 to 1780.

Extensive deposits of gem quality prehnite occur in the basalt tableland surrounding Wave Hill Station in the central Northern Territory, of Australia.

History

Authors : WERNER
Discovery date : 1788
Town of Origin : CAP DE BONNE ESPERANCE
Country of Origin: AFRIQUE DU SUD

Optical properties

Optical and misc. Properties : Macles possibles  –   Fragile, cassant  –   Transparent  –   Translucide  –   Gemme, pierre fine  –
Refractive Index : from 1,61 to 1,66
Axial angle 2V: 65-69°

Physical properties

Hardness : from 6,00 to 6,50
Density : from 2,80 to 2,95
Color : yellow; grey; white; colorless; pale green; dark green; green; greenish yellow; yellowish green; pink
Luster : vitreous; nacreous
Streak: white
Break: irregular
Cleavage: yes

Photos :

Prehnite 5.8×3.7×2.3 cm Jeffrey Mine Asbestos Quebec, Canada Copyright © David K. Joyce Minerals
Prehnite Merelani Mine, Arusha, Tanzania Miniature, 4.8 x 4.5 x 3.7 cm © irocks
Prehnite 3.5×2.2×1.8 cm Jeffrey Mine Asbestos Quebec, Canada Copyright © David K. Joyce Minerals
Prehnite Merelani Mine, Arusha, Tanzania Miniature, 4.5 x 3.1 x 2.6 cm © irocks

New specimen of Archaeopteryx reveals previously unknown features of the plumage

The new (eleventh) specimen of Archaeopteryx. Credit: H. Tischlinger

Paleontologists of Ludwig-Maximilians-Universitaet (LMU) in Munich are currently studying a new specimen of Archaeopteryx, which reveals previously unknown features of the plumage. The initial findings shed light on the original function of feathers and their recruitment for flight.
A century and a half after its discovery and a mere 150 million years or so since it took to the air, Archaeopteryx still has surprises in store: The eleventh specimen of the iconic “basal bird” so far discovered turns out to have the best preserved plumage of all, permitting detailed comparisons to be made with other feathered dinosaurs. The fossil is being subjected to a thorough examination by a team led by Dr. Oliver Rauhut, a paleontologist in the Department of Earth and Environmental Sciences at LMU Munich, who is also affiliated with the Bavarian State Collection for Paleontology and Geology in Munich. The first results of their analysis of the plumage are reported in the latest issue of Nature. The new data make a significant contribution to the ongoing debate over the evolution of feathers and its relationship to avian flight. They also imply that the links between feather development and the origin of flight are probably much more complex than has been assumed up to now.

“For the first time, it has become possible to examine the detailed structure of the feathers on the body, the tail and, above all, on the legs,” says Oliver Rauhut. In the case of this new specimen, the feathers are, for the most part, preserved as impressions in the rock matrix. “Comparisons with other feathered predatory dinosaurs indicate that the plumage in the different regions of the body varied widely between these species. That suggests that primordial feathers did not evolve in connection with flight-related roles, but originated in other functional contexts,” says Dr. Christian Foth of LMU and the Bavarian State Collection for Paleontology and Geology in Munich, first author on the new paper.

To keep warm and to catch the eye

Predatory dinosaurs (theropods) with body plumage are now known to predate Archaeopteryx, and their feathers probably provided thermal insulation. Advanced species of predatory dinosaurs and primitive birds with feathered forelimbs may have used them as balance organs when running, like ostriches do today. Moreover, feathers could have served useful functions in brooding, camouflage and display. Indeed, the feathers on the tail, wings and hind-limbs most probably fulfilled functions in display, although it is very likely that Archaeopteryx was also capable of flight. “Interestingly, the lateral feathers in the tail of Archaeopteryx had an aerodynamic form, and most probably played an important role in its aerial abilities,” says Foth.

On the basis of their investigation of the plumage of the new fossil, the researchers have been able to clarify the taxonomical relationship between Archaeopteryx and other species of feathered dinosaur. Here, the diversity in form and distribution of the feather tracts is particularly striking. For instance, among dinosaurs that had feathers on their legs, many had long feathers extending to the toes, while others had shorter down-like plumage. “If feathers had evolved originally for flight, functional constraints should have restricted their range of variation. And in primitive birds we do see less variation in wing feathers than in those on the hind-limbs or the tail,” explains Foth.

These observations imply that feathers acquired their aerodynamic functions secondarily: Once feathers had been invented, they could be co-opted for flight. “It is even possible that the ability to fly evolved more than once within the theropods,” says Rauhut. “Since the feathers were already present, different groups of predatory dinosaurs and their descendants, the birds, could have exploited these structures in different ways.” The new results also contradict the theory that powered avian flight evolved from earlier four-winged species that were able to glide.

Archaeopteryx represents a transitional form between reptiles and birds and is the best-known, and possibly the earliest, bird fossil. It proves that modern birds are directly descended from predatory dinosaurs, and are themselves essentially modern-day dinosaurs. The many new fossil species of feathered dinosaurs discovered in China in recent years have made it possible to place Archaeopteryx within a larger evolutionary context. However, when feathers first appeared and how often flight evolved are matters that are still under debate.

The eleventh known specimen of Archaeopteryx is still in private hands. Like all other examples of the genus, it was found in the Altmühl valley in Bavaria, which in Late Jurassic times lay in the northern tropics, and at the bottom of a shallow sea, as all Archaeopteryx fossils found so far have been recovered from limestone deposits.

Note : The above story is based on materials provided by Ludwig-Maximilians-Universitaet Muenchen (LMU).

2-D model may help explorers find reservoirs of the ‘ice that burns’

Scientists at Rice have reported the results of their decadelong effort to build a two-dimensional mathematical model that will help identify rich pockets of gas hydrate under the ocean floor. The model shows where hydrates – the “ice that burns” – are likely to be found based on extrapolating data from core samples, seismic signals and other geologic data. Click for larger image. Credit: Sayantan Chatterjee

A decade of research by Rice University scientists has produced a two-dimensional model to prove how gas hydrate, the “ice that burns,” is formed under the ocean floor.Gas hydrate—basically methane frozen under high pressures and low temperatures—has potential as a source of abundant energy, if it can be extracted and turned into usable form.

It also has potential to do great harm, if global warming results in melting hydrate that releases methane, a powerful greenhouse gas, into the atmosphere.

The award-winning mathematical model created by Rice alumnus Sayantan Chatterjee, who earned his doctorate in chemical engineer George Hirasaki’s group, is intended to help pinpoint abundant pockets of hydrate by extrapolating data from several sources: one-dimensional core samples, seismic surveys that image the fractures as well as stratified layers of sand and clay that build up over millennia, and the geochemistry of sediment and water near the ocean floor, which offers chemical clues to what lies beneath.

The research was published by the Journal of Geophysical Research – Solid Earth.

There’s a lot at stake for energy producers—and consumers—in finding hydrates in high concentrations, with as much as 20 trillion tons of methane under the sea. Japanese researchers are already testing production techniques in the Pacific, but extraction without reliable exploration tools is too expensive, Chatterjee said.

The Rice researchers’ two-dimensional model draws upon a variety of survey techniques to envision a more accurate slice of the deep-sea formation.

“Our modeling incorporates geologic processes like sedimentation and compaction that enable methane-rich fluids to flow through porous media,” Chatterjee said. Methane degraded by microbes from organic matter or rising from the depths turns into hydrate when it encounters the necessary pressure, temperature and salinity conditions in the gas hydrate stability zone, which can be as shallow as a few hundred meters.

“High-saturation hydrate deposits preferentially occur in fracture networks within fine-grained sediment and interbedded, permeable sand sequences, and we’re looking for such lithologic sweet spots,” he said.

Chatterjee explained the complex stratigraphy and lack of homogeneity of subsea formations limits the ability of one-dimensional modeling and core samples to scan a potential hydrate reservoir isolated in permeable sand sequences between dense layers of clay. “Marine lithologic layering is very complex, and we can’t replicate it in our models. But we have developed techniques to compute local fluid flow in lithologically complex reservoirs, which we correlate to local hydrate saturation,” he said.

“When people seismically image the submarine formations and recover sediment cores dominated with faults and fractures, they find these fractures to be filled with hydrates,” Chatterjee said. “Our model has explained this observation. It shows that these fracture networks and sand layers are the sweet spots for hydrate occurrence, the ones we want to pinpoint when it comes to exploration.”

The Rice team intends the model to locate these hydrate-rich pockets and estimate how saturated they’re likely to be based on the geologic setting and history. “Only when a pore space is highly saturated with hydrate is it economically feasible to drill at that location to extract these trapped hydrocarbons,” he said. “But first we have to estimate the fluid flow. No flow, no hydrates.”

More information:
Sayantan Chatterjee, Gaurav Bhatnagar, Brandon Dugan, Gerald R. Dickens, Walter G. Chapman and George J. Hirasaki “The Impact of Lithologic Heterogeneity and Focused Fluid Flow upon Gas Hydrate Distribution in Marine Sediments” Journal of Geophysical Research: Solid Earth. Accepted manuscript online: 25 JUN 2014 DOI: 10.1002/2014JB011236

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

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