Q&A: Will the fossil record preserve your computer?

June 23, 2014

Last week, scientists reported finding rocks made of plastic on a Hawaiian beach. Some researchers have speculated that these and other humanmade objects could become part of the fossil record, defining a human-dominated period of Earth’s history called the Anthropocene. Science chatted with Jan Zalasiewicz, a paleontologist at the University of Leicester in the United Kingdom and a leading scholar on the Anthropocene, about the kinds of things humans are leaving behind—and what they’ll look like millions of years hence.
This interview has been edited for clarity and brevity.

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Q: You have called these humanmade fossils “technofossils.” What are they, and how are they different from normal fossils?

A: Technofossils are basically all the things we manufacture, large and small. Because most of them are preservable, they can potentially become fossils—particularly since, unlike nature, we’re so poor at recycling the things we make. They can survive for thousands, millions, perhaps billions of years in rock strata [rock or sediment layers] in the future. We think they deserve a separate category because there’s so much about them that is distinct.

Q: What kinds of things can we expect to survive in the fossil record for millions of years, and what will they look like after all that time?

A: Looking around at my room, I’m struggling to see anything that is not fossilizable. So let’s take my desk—wood can fossilize really quite well. We’ve helped along the process of fossilization of this wood because it’s been seasoned, dried out, and varnished. It’s much less edible than it was in its original state on the tree.

With clothes, a lot of them are made from plastic polymer objects or cotton—plant materials. So they will fossilize just as plants do. They can preserve a good deal of the fabric. Under the right circumstances, one can preserve leaf cells and the like for millions of years—but the chemistry will change, they will become carbonized. You will lose the colors, and they’ll become black shapes.

Even paper is fossilizable. Now clearly, if that makes it into a stratum, it will become a carbonized lump. Probably the information on the pages is not easily fossilizable. It would be very hard to read newsprint from pages.

This computer I have in front of me, I see plastic, titanium, bits of rubber, a fair bit of this—if buried in the stratum—it will at least leave a nice oblong detail and impression, probably parts of the structure itself. But the information will be gone. Just as we can fossilize a songbird, it’s much harder to fossilize the song itself.

Q: Are some cities more likely to preserve technofossils than others?

A: In San Francisco, Earth’s crust is rising. It’s being eroded and the material is being washed away to areas where the crust is subsiding. So an upland place like San Francisco will be eroded, and the fragments will wash into the sea. Los Angeles and the northwest of Britain—Manchester, say—are also on long-term upward-moving crust. These are both also destined to be eroded away.

New Orleans, in contrast, is on a delta. It’s on what’s called a tectonic escalator, going downwards because that’s what the crust is doing, and because it’s being loaded by all the sand and mud being washed off from the Mississippi River. New Orleans is ripe for fossilization, all of the structures, the pilings, the concrete pilings, tens of meters into the ground to keep the skyscrapers up. And all of the stuff that’s underground: pipework, sewage, the electric.

Other places might be Amsterdam, Venice, Shanghai, coastal deltas on coastal plains. These places are ripe for fossilization.

Q: What will future beings be able to infer about us from these fossils?

A: The technofossils will strike them as quite different as anything that’s come before. We have the whole history we see through archaeology. Metals—Bronze [Age] first, then Iron and so on, different types of tools. And then we go into the Industrial Revolution and on to the space age and beyond.

If you’re looking at the point of the perspective of the future paleontologist, either human or nonhuman or space visitor or hyperevolved rat or whatever, as a geologist one thing will strike them. will be crammed into a very small physical space. The stratum itself may not be much more than a few meters thick. In many places, it may only be a few centimeters thick. It will probably appear instantaneous, and it will be very hard work to figure out the path of this hyperevolution of the technofossils within the human stratum.

Paramelaconite

June 23, 2014

Chemical Formula: Cu₂Cu₂O₃
Locality: Copper Queen mine, Bisbee, Arizona, USA.
Name Origin: Named from the Greek for near and melaconite, which in turn was named for black and dust, now a synonym for tenorite.

Paramelaconite is a rare, black-colored copper oxide mineral with formula Cu21+Cu22+O3 (or Cu4O3). It was discovered in the Copper Queen Mine in Bisbee, Arizona, about 1890. It was described in 1892 and more fully in 1941. Its name is derived from the Greek word for “near” and the similar mineral melaconite, now known as tenorite.

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Description and occurrence

Paramelaconite is black to black with a slight purple tint in color, and is white with a pinkish brown tint in reflected light. The mineral occurs with massive habit or as crystals up to 7.5 centimetres (3.0 in). A yellow color is formed when the mineral is dissolved in hydrochloric acid, a blue color when dissolved in nitric acid, and a slightly brown precipitate when exposed to ammonium hydroxide. When heated, paramelaconite breaks down into a mixture of tenorite and cuprite.

Paramelaconite is a very rare mineral; many specimens purported as such are in fact mixtures of cuprite and tenorite. Paramelaconite forms as a secondary mineral in hydrothermal deposits of copper. It occurs in association with atacamite, chrysocolla, connellite, cuprite, dioptase, goethite, malachite, plancheite, and tenorite. The mineral has been found in Cyprus, the United Kingdom, and the United States.

History

Discovery date: 1891
Town of Origin: MINE COPPER QUEEN, BISBEE, COCHISE CO., ARIZONA
Country of Origin: USA

Optical properties

Optical and misc. Properties : Opaque

Physical properties

Hardness: 4,50
Density: from 6,10 to 6,11
Color : black; purplish black
Luster : adamantine; bright
Streak: brownish black
Break: conchoidal
Cleavage: NO

Photos:

Paramelaconite, Brochantite, Cuprite Locality: Ojuela Mine, Mapimí, Mun. de Mapimí, Durango, Mexico © Rolf Luetcke specimen and photo.

Volcanic mayhem drove major burst of evolution

June 23, 2014

Life’s forge (Image: Sigurgeir Sigurjonsson/Plainpicture)

OUR planet is home to a glorious variety of animals, but it might not have been. Were it not for the birth pangs of a mega-continent, the evolution of animals could have stopped at its earliest stages.
We now have the best evidence yet that an enormous wave of volcanism, caused by several continents crashing together to form the even greater landmass known as Gondwana, was the reason for a sharp rise in global temperature. This change was the driving force for evolutionary explosions that made life more diverse and laid the foundations for all future animal species.

Volcanoes can cause global warming because eruptions often spew huge amounts of the greenhouse gas carbon dioxide. Now a study of volcanic rocks from early in life’s evolutionary story shows that such 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. The findings add to evidence that plate tectonics and living things are linked (see “Shaky worlds may harbour life”).

Last year, a study suggested that microbes helped form continents by encouraging volcanic activity (New Scientist, 23 November 2013, p 10). Now Ryan McKenzie of the University of Texas at Austin and colleagues have shown that, in turn, volcanism may have shaped life during the crucial Cambrian period .

Before the Cambrian, over 600 million years ago, Earth was virtually covered in ice. The first animals arose on this “Snowball Earth”, but these “Ediacarans” did not look like modern animals.

Then came the Cambrian explosion. “You had single cell organisms, single cell, single cell, then weird Ediacaran oddballs, and – suddenly – snails and bivalves and sea stars and a whole range of groups that typify the record for the rest of time,” says McKenzie’s colleague Paul Myrow of Colorado College in Colorado Springs.

The animals that appeared during the Cambrian explosion gave rise to all the major groups alive today, from worms to starfish. But each group only contained a few species, and got no further. The next period is known as the Dead Interval, and was marked by mass extinctions. It was another 50 million years before animal life blossomed once more, during the Ordovician.

We already knew that Earth’s temperature changed dramatically over these periods. It thawed in the early Cambrian then became stiflingly hot during the Dead Interval, before cooling again. “These are huge climate swings, from Snowball Earth to one of the warmest intervals of Earth history in the Cambrian,” says Lee Kump of Penn State University in University Park.

Volcanic activity during the formation of Gondwana has been suggested as a driver of these violent changes, but Kump says the evidence for increased volcanism was “a house of cards”.

McKenzie’s new evidence comes from tiny zircon crystals. Zircons are only formed in particular volcanic eruptions that are triggered when continental masses crash into each other, so they act as a record of past continental collisions. McKenzie assembled zircon counts from rocks laid down in the last 3 billion years, from all around the world.

He noticed that zircons were rare from Snowball Earth but common in the Cambrian. It seems a horde of volcanoes began spewing just before the Cambrian, and their activity reached a peak during the Dead Interval (Geology, doi.org/qvp).

“We hypothesise that CO2 outgassing from continental volcanic arcs drove major climate shifts,” says McKenzie.

Kump agrees: “This to my knowledge is the first direct and compelling assessment of changes in arc volcanism over this critical interval.”

“This is a fundamentally new and radical idea,” says Cin-ty Lee of Rice University in Houston, Texas.

Myrow says the formation of Gondwana offers the best explanation for the extra volcanoes. “Throughout the Cambrian two big continental masses were coming together to make Gondwana,” he says. The collision generated infernal heat that melted rock and created long chains of volcanoes. “You’re making volcanoes like mad,” says Myrow. “They produce carbon dioxide and temperatures get very, very hot.”

As well as heating the planet, the extra CO2 acidified the oceans. Many ocean creatures are sensitive to changes in acidity, so this could help explain the Dead Interval. Then the volcanism died off once Gondwana had formed, CO2 levels fell and a huge diversity of reef-based animals appeared.

“Now we have greater confidence that volcanism and its effect on the greenhouse gas content of the atmosphere drove climate change in deep time,” says Kump. “This had direct effects on rates of biotic diversification.”

Changes in tectonic activity would go on to affect life on Earth throughout its history, but not always in such a helpful way. For instance, almost all animal and plant life was abruptly wiped out at the end of the Permian period 251 million years ago, a time known as the Great Dying. Rapid climate change triggered by intense volcanic activity could well be to blame. Tectonics may give, but it also takes away.

Note : The above story is based on materials provided by Catherine Brahic Magazine issue 2952. © Copyright Reed Business Information Ltd.

New study suggests more and longer atmospheric stagnation events due to global warming

June 23, 2014

Characteristic change in air stagnation components. Credit: Nature Climate Change (2014) doi:10.1038/nclimate2272

A new study conducted by researchers at Stanford University has led to findings indicating that much of the world can expect to have more atmospheric stagnation events as the future unfolds. In their paper published in Nature Climate Change, the researchers describe how they ran a variety of computer models that took into account a continued increase in greenhouse gas emissions—they report that taken together, the models predict that approximately 55 percent of the world’s population can expect to be impacted by future stagnation events.

Stagnation is an atmospheric phenomenon where an air mass remains in place over a geographic region for an extended period of time. They tend to happen due to the convergence of specific weather conditions—light wind patterns near the surface, other light wind patterns occurring higher up, and a lack of rain. During normal weather periods, wind and rain combine to clean the air around metropolitan areas—when rain fails to fall and there is little wind to push pollution away from an area, particulates and other types of pollution levels climb, putting those that live in the area at risk of health problems.

The collection of computer models run by the team at Stanford also suggest that stagnation events are likely to last longer—increasing by an average of 40 days a year. The result the team notes, is likely to be an increase in heart and lung complications in people in those areas, contributing to an associated climb in the number of premature deaths due to air pollutants—numbering perhaps in the millions. They also note that Mexico, India and parts of the western U.S. are likely to be most at risk of health impacts from an increase in stagnation events, as all three will have more and longer such events and all three are heavily populated.

The researchers suggest that at some point, the entire planet will be impacted by stagnation events. That means governments and health workers will need to make plans on how to handle the problems as they begin to occur. They add that the only real solution to the problem is to begin curbing greenhouse gas emissions now, preventing the events from occurring in the first place.

More information: Occurrence and persistence of future atmospheric stagnation events, Nature Climate Change (2014) DOI: 10.1038/nclimate2272

Abstract
Poor air quality causes an estimated 2.6–4.4 million premature deaths per year. Hazardous conditions form when meteorological components allow the accumulation of pollutants in the near-surface atmosphere. Global-warming-driven changes to atmospheric circulation and the hydrological cycle are expected to alter the meteorological components that control pollutant build-up and dispersal, but the magnitude, direction, geographic footprint and public health impact of this alteration remain unclear. We used an air stagnation index and an ensemble of bias-corrected climate model simulations to quantify the response of stagnation occurrence and persistence to global warming. Our analysis projects increases in stagnation occurrence that cover 55% of the current global population, with areas of increase affecting ten times more people than areas of decrease. By the late twenty-first century, robust increases of up to 40 days per year are projected throughout the majority of the tropics and subtropics, as well as within isolated mid-latitude regions. Potential impacts over India, Mexico and the western US are particularly acute owing to the intersection of large populations and increases in the persistence of stagnation events, including those of extreme duration. These results indicate that anthropogenic climate change is likely to alter the level of pollutant management required to meet future air quality targets.

Paradamite

June 22, 2014

Ojuela Mine, Mapimí, Mun. de Mapimí, Durango, Mexico © MJO

Chemical Formula: Zn₂(AsO₄)(OH)
Locality: Ojuela mine, Mapimi, Durango, Mexico
Name Origin: Named as the dimorph of adamite.

Paradamite is dimorphous with a famous arsenic mineral, namely adamite. Dimorphous means that the two minerals have the same formula, but different structures (di means two; morphous means shape). Paradamite’s different structure produces only slight differences in physical properties. Most obvious however is the difference in crystal forms. Adamite’s typical form is wedge shaped prismatic crystals with diamond-shaped cross-sections. Paradamite’s form is more tabular in character and very different from adamite’s. Although their names are similar and their chemistry is the same; paradamite and adamite are absolutely distinct minerals.

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Optical properties

Optical and misc. Properties:Transparent
Refractive Index: from 1,72 to 1,78
Axial angle 2V : 50°

Physical properties

Color : pale yellow
Luster: vitreous.
Transparency: Crystals are transparent to translucent.
Crystal System: triclinic; bar 1.
Crystal Habits include rounded tabular crystals, usually aggregated.
Cleavage: perfect.
Fracture: uneven.
Hardness: 3.5.
Specific Gravity: approximately 4.5 – 4.6 (heavy for translucent minerals)
Streak: white.

Photos:

Paradamite Mina Ojuela, Mapimi, Durango,Mexico Miniature, 4.4 x 3.3 x 2.0 cm “Courtesy of Rob Lavinsky, The Arkenstone, www.iRocks.com”

Paradamite Location: Ojuela mine, Mapimi, Druango, Mexico. Copyright: © Lou Perloff / Photo Atlas of Minerals

Paradamite Locality: Ojuela Mine, Mapimí, Mun. de Mapimí, Durango, Mexico Photo Copyright © Marcus J. Origlieri

Paradamite Mina Ojuela, Mapimi, Durango, Mexico Miniature, 4.9 x 3.8 x 3.8 cm “Courtesy of Rob Lavinsky, The Arkenstone, www.iRocks.com”

Regional weather extremes linked to atmospheric variations

June 22, 2014

View on Europe from a height of satellites (stock image). Changes to air flow patterns around the Northern Hemisphere are a major influence on prolonged bouts of unseasonal weather – whether it be hot, cold, wet or dry. Credit: © Anton Balazh / Fotolia

Variations in high-altitude wind patterns expose particular parts of Europe, Asia and the US to different extreme weather conditions, a new study has shown.
Changes to air flow patterns around the Northern Hemisphere are a major influence on prolonged bouts of unseasonal weather — whether it be hot, cold, wet or dry.

The high altitude winds normally blow from west to east around the planet, but do not follow a straight path. The flow meanders to the north and south, in a wave-like path.

These wave patterns are responsible for sucking either warm air from the tropics, or cold air from the Arctic, to Europe, Asia, or the US. They can also influence rainfall by steering rain-laden storms.

Pioneering new research, carried out by the University of Exeter and the University of Melbourne, has shown that the development of these wave patterns leaves certain Northern Hemisphere regions more susceptible to different types of prolonged, extreme weather.

Dr James Screen, a Mathematics Research Fellow at the University of Exeter and lead author of the study, said: “The impacts of large and slow moving atmospheric waves are different in different places. In some places amplified waves increase the chance of unusually hot conditions, and in others the risk of cold, wet or dry conditions.”

The study showed that larger waves can lead to droughts in central North America, Europe and central Asia, and western Asia exposed to prolonged wet spells. It also shows western North America and central Asia are more prone to heat waves, while eastern North America is more likely to experience prolonged outbreaks of cold.

The collaborative study used detailed land-based climate observations to identify episodes of abnormal temperature and rainfall from 1979-2012 and then examined the wave patterns during these events.

Co-author Professor Ian Simmonds, from the School of Earth Sciences at the University of Melbourne, said the weather extremes they examined were month-long heat waves, cold spells, droughts and prolonged wet periods, which occurred over large areas.

He said: “The study revealed that these types of events are strongly related to well-developed wave patterns, and that these patterns increase the chance of heat waves in western North America and central Asia, cold outbreaks in eastern North America, droughts in central North America, Europe and central Asia, and wet spells in western Asia.

“The findings are very important for decision makers in assessing the risk of, and planning for the impacts of, extreme weather events in the future.”

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

Murray River

June 22, 2014

The Murray River (River Murray in South Australia) is Australia’s longest river. At 2,508 kilometres (1,558 mi) in length, the Murray rises in the Australian Alps, draining the western side of Australia’s highest mountains and, for most of its length, meanders across Australia’s inland plains, forming the border between the states of New South Wales and Victoria as it flows to the northwest, before turning south for its final 500 kilometres (310 mi) or so into South Australia, reaching the ocean at Lake Alexandrina.
The water of the Murray flows through several lakes that fluctuate in salinity (and were often fresh until recent decades) including Lake Alexandrina and The Coorong before emptying through the Murray Mouth into the southeastern portion of the Indian Ocean, often referenced on Australian maps as the Southern Ocean, near Goolwa. Despite discharging considerable volumes of water at times, particularly before the advent of largescale river regulation, the Mouth has always been comparatively small and shallow.

As of 2010, the Murray River system receives 58 percent of its natural flow. It is perhaps Australia’s most important irrigated region, and it is widely known as the food bowl of the nation.

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Geography

The Murray River forms part of the 3,750 km (2,330 mi) long combined Murray-Darling river system which drains most of inland Victoria, New South Wales, and southern Queensland. Overall the catchment area is one seventh of Australia’s total land mass. The Murray carries only a small fraction of the water of comparably-sized rivers in other parts of the world, and with a great annual variability of its flow. In its natural state it has even been known to dry up completely during extreme droughts, although that is extremely rare, with only two or three instances of this occurring since official record keeping began.

The Murray River makes up much of the border between the Australian states of Victoria and New South Wales. Where it does, the border is the top of the bank of the southern side of the river (i.e., none of the river itself is actually in Victoria). This boundary definition can be ambiguous, since the river changes course, and some of the river banks have been modified.

West of the line of longitude 141°E, the river continues as the border between Victoria and South Australia for 3.6 km (2.2 mi), where this is the only stretch where a state border runs down the middle of the river. This was due to a miscalculation during the 1840s, when the border was originally surveyed. Past this point, the Murray River is entirely within the state of South Australia.

River life

The Murray River (and associated tributaries) support a variety of unique river life adapted to its vagaries. This includes a variety of native fish such as the famous Murray cod, trout cod, golden perch, Macquarie perch, silver perch, eel-tailed catfish, Australian smelt, and western carp gudgeon, and other aquatic species like the Murray short-necked turtle, Murray River crayfish, broad-clawed yabbies, and the large clawed Macrobrachium shrimp, as well as aquatic species more widely distributed through southeastern Australia such as common longnecked turtles, common yabbies, the small claw-less paratya shrimp, water rats, and platypus. The Murray River also supports fringing corridors and forests of the river red gum.

The health of the Murray River has declined significantly since European settlement, particularly due to river regulation, and much of its aquatic life including native fish are now declining, rare or endangered. Recent extreme droughts (2000 – 07) have put significant stress on river red gum forests, with mounting concern over their long term survival. The Murray has also flooded on occasion, the most significant of which was the flood of 1956, which inundated many towns on the lower Murray and which lasted for up to six months.

Introduced fish species such as carp, gambusia, weather loach, redfin perch, brown trout, and rainbow trout have also had serious negative effects on native fish, while carp have contributed to environmental degradation of the Murray River and tributaries by destroying aquatic plants and permanently raising turbidity. In some segments of the Murray, carp have become the only species found.

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

Painite

June 21, 2014

Chemical Formula: CaZrAl₉(BO₃)O₁₅
Locality: Ohngaing, Mogok district, Sagaing, Myanmar.
Name Origin: Named for A. C. D. Pain (-1971), British gem collector who first noticed the mineral.
Painite is a very rare borate mineral. It was first found in Myanmar by British mineralogist and gem dealer Arthur C.D. Pain in the 1950s. When it was confirmed as a new mineral species, the mineral was named after him.

The chemical makeup of painite contains calcium, zirconium, boron, aluminium and oxygen (CaZrAl₉(BO₃)O₁₅). The mineral also contains trace amounts of chromium and vanadium. Painite has an orange-red to brownish-red color similar to topaz due to trace amounts of iron. The crystals are naturally hexagonal in shape, and, until late 2004, only two had been cut into faceted gemstones.

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Discovery and occurrence

For many years, only three small painite crystals were known to exist. Before 2005 there were fewer than 25 known crystals found, though more material has been unearthed recently in Myanmar.

More recently, painite specimens have been discovered at a new location in northern Myanmar. It is believed that further excavations in this area will yield more painite crystals.

Extensive exploration in the Mogok region has identified several new painite occurrences that have been vigorously explored resulting in several thousand new painite specimens. Most of the recent crystals and fragments are dark, opaque, incomplete crystals. A modest number of transparent crystals have been found and have been either saved as crystals or cut into gemstones.

Originally few of the known painite specimens were privately owned. The rest of the stones were distributed between the British Museum of Natural History, Gemological Institute of America, California Institute of Technology and the GRS Gem Research Laboratory in Lucerne, Switzerland.

History

Discovery date: 1956
Town of Origin : MOGOK, OHNGAING, SAGAING
Country of Origin : BIRMANIE

Optical properties

Optical and misc. Properties : Translucide – Transparent
Refractive Index: from 1,78 to 1,81

Physical properties

Hardness: 8,00
Density: 4,03
Color : garnet-red; orange red; red orange; brownish; brownish red
Luster : vitreous
Streak : white

Photos:

Painite with Corundum Mogok, Mandalay Burma Specimen size: 3.4 × 0.7 × 0.7 cm = 1.3” × 0.3” × 0.3” © Fabre Minerals

Could Pulses in Earth’s Magnetic Field Forecast Earthquakes?

June 21, 2014

In the days leading up to some recent moderate-sized earthquakes, instruments nearby have picked up brief low-frequency pulses in Earth’s magnetic field. A few scientists have proposed that such pulses, which seemed to become stronger and more frequent just before the earthquakes occurred, could serve as an early warning sign for impending seismic activity. Now, a team has come up with a model for how these magnetic pulses might be generated, though some critics say they may have a humanmade origin.

Brief fluctuations in Earth’s magnetic field have been detected before many earthquakes in the past 50 years, says Friedemann Freund, a crystallographer at San Jose State University in California. For example, in the weeks before a magnitude-5.4 quake struck about 15 kilometers northeast of San Jose in October 2007, an instrument near the epicenter sensed a number of unusual magnetic pulses, presumably emanating from deep in the Earth. (The largest of them measured 30 nanoteslas, which is about 1/100,000th the typical strength of the planet’s magnetic field measured at Earth’s surface.) Those blips became more frequent as the day of the earthquake approached, Freund says. More recently, prior to several medium- to moderate-sized quakes in Peru, two sensitive magnetometers recorded the same sort of pulses.

One big puzzle, Freund notes, has been how such pulses could be generated. Now, he and his colleagues suggest that these blips stem from microscopic changes in crystals in rocks under seismic stress deep within Earth. In many types of rocks, particularly volcanic rocks that have substantial amounts of water locked inside them, crystals are chock-full of oxygen-oxygen bonds called peroxy bonds. (These bonds formed long ago, after chemical changes split some of the water molecules, freeing the hydrogen atoms to bond together and then diffuse out of the rocks as gas.) When those rocks are squeezed, say, by the sides of a fault zone scraping past one another, some of the peroxy bonds break. Those broken bonds release negatively charged electrons, which remain trapped in place, and create positively charged “holes” in the crystal, Freund explains. In lab experiments, the electrical disturbances associated with those holes diffuse through the surrounding rocks at speeds of about 100 meters per second.

Freund and his team propose that the same process might be happening within Earth’s crust. As stress on large volumes of rock builds in advance of an impending quake, many, many of these electrical holes are created inside them. It’s the mass migration of such holes that creates the large electrical currents responsible for generating the low-frequency magnetic pulses that make their way to detectors on Earth’s surface, they say.

For the Peruvian quakes, most of the pulses sensed by the magnetometers ranged between one-sixth and one-quarter of a second long. But some lasted up to 2 seconds, Freund says—a length that strongly suggests that the pulses weren’t triggered by lightning, either nearby or far away, which some critics of his model have proposed as an alternative explanation. More importantly, he notes, with data from the two sensors in Peru he and his colleagues were able to pinpoint the strongest of those pulses as originating within a few kilometers of the epicenters of subsequent quakes, they report in a paper posted to the arXiv preprint server. For now, Freund admits, the team’s model is preliminary: The paper has been submitted to a journal and is now being reviewed by other scientists.

“This paper only makes sense if the observations [of magnetic pulses] are good,” says John Ebel, a seismologist at Boston College, who wasn’t involved in the research. He points out that two instruments aren’t sufficient to pinpoint the location of an event; to truly “triangulate” an event you need at least three sensors.

But another aspect of the team’s findings is even more worrying, he notes: “I’m concerned that the pulses are not originating deep within the Earth.” It’s possible, he continues, that the blips may have some inexplicable humanmade origin. Decades ago, Ebel notes, his Boston-based magnetometers started picking up a series of odd pulses every morning. Eventually, he and his colleagues identified the sources of those gremlins: It was the engineers cranking up Boston’s trolley cars at a rail yard a few kilometers away from the instruments.

Even if the magnetic pulses originate within Earth along seismic zones under stress, Freund says, the blips don’t always foretell a quake. It’s more likely to be the pattern of pulses—and, in particular, changes in their size and frequency—that Freund and his colleagues say might offer scientists a crystal ball for impending temblors.

Note : The above story is based on materials provided by Sid Perkins ” sciencemag “

How Did the Moon Really Form?

June 21, 2014

Planetary scientists have long believed that our moon formed following a collision between Earth and another planet, but studies of Earth and moon rocks suggest otherwise. A new analysis of the composition of moon rocks brought back by Apollo astronauts may help finally resolve the mystery.

Here’s the current thinking about how the moon formed. Early in its history, Earth was struck a glancing blow by a Mars-sized planet. That planet was destroyed by the impact, but much of its debris—and some of Earth’s—formed into a disk around Earth that eventually coalesced into the moon. Much evidence supports this scenario. The moon would have ended up hot, boiling off light elements and water, leaving the arid rocky moon we see today; the moon has a small core, consistent with being made from parts of the colliding planet and outer parts of Earth; the Earth-moon system rotates fast, consistent with a glancing blow.

But one bit of evidence just doesn’t fit: the composition of moon rocks. Researchers have found that rocks from different parts of the solar system (brought to Earth as meteorites) have subtle differences in their composition. Oxygen, for example, comes in different varieties, called isotopes. Oxygen-16 (O-16) is the most common type, followed by oxygen-17 (O-17)—which has one extra neutron in its nucleus—and oxygen-18, with two extra neutrons. Meteorites from different parts of the solar system have different proportions of these isotopes. So a rock from Mars would have a markedly different ratio of O-17 compared with O-16 than, say, a piece of an asteroid or a rock from Earth. These ratios are so reliable that researchers use them to identify where meteorites come from.

Here’s the puzzle: The giant impact hypothesis predicts that the moon should be made of about 70% to 90% material from the impactor, so its isotope ratios should be different from Earth’s. But ever since researchers got hold of Apollo moon rocks for analysis, they have failed to find any significant difference in isotope ratios on Earth and the moon. Studies of the isotopes of oxygen, titanium, calcium, silicon, and tungsten have all drawn a blank.

This discrepancy has troubled planetary scientists so much that in recent years they have put forward a number of alternative scenarios to explain the moon’s origins. One hypothesis suggests that there could have been much greater mixing between Earth and the debris disk as it coalesced after the impact, or if Earth was hit head-on by a similarly sized impactor, their remains could have mixed completely. Another possibility is that a fast-spinning Earth could have been hit by a much smaller impactor, which would have provided little material for the moon. Yet it has been hard to show how you could get from one of those events to the Earth-moon system we have today.

Researchers would prefer to stick with the original, plain vanilla impact scenario because it explains so many things so well. New results, published online today in Science, will give them some hope. Lunar rocks have a measurably higher ratio of O-17 over O-16 compared with those from Earth. The new study began because a team of researchers led by Daniel Herwartz of the University of Cologne in Germany had recently upgraded its mass spectrometer—a form of supersensitive atomic scale—and decided to test the device out on the Earth-moon isotope problem. “Our analysis is now an order of magnitude better than other laboratories,” says team member Andreas Pack of the University of Göttingen in Germany.

They started out analyzing moon rocks that arrived on Earth as meteorites but found that the weathering these rocks experienced on Earth was skewing the results. So they got hold of some rock samples from NASA that had been brought back by Apollo missions 11, 12, and 16. They extracted oxygen from all the samples and then passed it through the spectrometer to find out the proportions of each isotope. Their conclusion was that the lunar samples had an O-17 to O-16 ratio that was 12 parts per million higher than rocks derived from Earth’s mantle. This difference “supports the view that the Moon formed by a giant collision of the proto-Earth with [an impactor],” the team writes. “It is a relief that a [disparity in ratios] has been found, since the total absence of difference between Earth and moon would be hard to explain,” comments planetary scientist David Stevenson of the California Institute of Technology in Pasadena, in an e-mail.

The team acknowledges other possible explanations for the difference, including that Earth was bombarded by material with a lower oxygen isotope ratio at some time after the impact. “Now that a difference has been found, many will work to confirm or deny it and do battle over what it means,” Stevenson says.

The team says the results suggest that the moon is a roughly 50-50 mix of Earth and impactor material. Moreover, the high oxygen isotope ratio suggests that the impactor was principally made of a rare material called enstatite chondrite. The vast majority of meteorites that land on Earth are chondrites, but only about 2% of those are enstatite chondrites. “The possible significance of enstatite chondrites is interesting, but at present we are stuck with speculating about the bodies that went into making Earth, since they are no longer around,” Stevenson says.

Note : The above story is based on materials provided by Daniel Clery ” sciencemag “

Orthoclase

June 20, 2014

Chemical Formula: KAlSi₃O₈
Locality: Common world wide occurrences.
Name Origin: From the Greek orthos – “right” and kalo -” I cleave” in allusion to the mineral’s right angle of good cleavage.

Orthoclase (endmember formula KAlSi₃O₈) is an important tectosilicate mineral which forms igneous rock. The name is from the Greek for “straight fracture,” because its two cleavage planes are at right angles to each other. Alternate names are potassium feldspar and K-feldspar. The gem known as moonstone is largely composed of orthoclase.

Table of Contents

Formation and Subtypes

Orthoclase is a common constituent of most granites and other felsic igneous rocks and often forms huge crystals and masses in pegmatite.

Typically, the pure potassium endmember of orthoclase forms a solid solution with albite, the sodium endmember (NaAlSi3O8), of plagioclase. While slowly cooling within the earth, sodium-rich albite lamellae form by exsolution, enriching the remaining orthoclase with potassium. The resulting intergrowth of the two feldspars is called perthite.

The higher-temperature polymorph of orthoclase is sanidine. Sanidine is common in rapidly cooled volcanic rocks such as obsidian and felsic pyroclastic rocks, and is notably found in trachytes of the Drachenfels, Germany. The lower-temperature polymorph of orthoclase is microcline. Adularia is found in low temperature hydrothermal deposits, in the Adula Alps of Switzerland. The largest documented single crystal of orthoclase was found in Ural mountains, Russia. It measured ~10×10×0.4 m and weighed ~100 tons.

History

Discovery date : 1823

Optical properties

Optical and misc. Properties : Transparent – Translucide – fluorescent- Gemme, pierre fine
Refractive Index: from 1,51 to 1,52
Axial angle 2V: 35-75°

Physical properties

Hardness : from 6,00 to 6,50
Density: from 2,55 to 2,63
Color: colorless; white; grey; yellow; grey yellow; pink red; reddish; green; greenish; pink
Luster : vitreous; nacreous
Streak : white
Break : irregular; conchoidal; splintery
Cleavage : Yes

Photos:

Orthoclase 4.1×3.8×2.8 cm Bear Lake Diggings Gooderham Ontario, Canada Copyright © David K. Joyce Minerals

Orthoclase Montecatini quarry, Baveno, Piedmont, Italy Specimen weight:181 gr. Crystal size:40 mm Overall size: 78mm x 68 mm x 48 mm © minservice

Orthoclase Montecatini quarry, Baveno, Piedmont, Italy Specimen weight:135 gr. Crystal size:35 mm Overall size: 78mm x 62 mm x 55 mm © minservice

Earth’s breathable atmosphere tied to plate tectonics?

June 20, 2014

A new study links continents and plate tectonics to the rise of oxygen on Earth. Credit: The International Space Station

The rise of oxygen is one of the biggest puzzle in Earth’s history. Our planet’s atmosphere started out oxygen-free. Then, around 3.5 billion years ago, tiny microbes called cyanobacteria (or blue-green algae) learned out to carry out photosynthesis. They began using energy from sunlight to make their food from carbon dioxide and water, giving off oxygen as waste.
But it took another 3 billion years for oxygen levels to climb from trace amounts to at least 20 percent of the atmosphere, or high enough to support the emergence of complex life. And so far the mechanism behind that rise has remained unclear.

Now a new study by University of Exeter biochemist Benjamin Mills and his colleagues offers a new potential clue.

Using a computer model, they showed that plate tectonics may have indirectly fueled the sharp increase in oxygen between 1.5 billion and half a billion years ago. In particular, a process tied to the way continents remove carbon dioxide from the atmosphere may have increased the supply of phosphorus, a key nutrient for photosynthetic microbes in the ocean. The paper was published this month in the Proceedings of the National Academy of Science.

“This is a novel perspective for the late Proterozoic—a critical time of dramatic climate change, rising oxygen in the ocean and atmosphere, and origins and diversification of complex life,” says Timothy Lyons, a biogeochemist not involved in the study.

Table of Contents

From Seafloor to Terrestrial “Weathering’

Continents play a crucial role in the carbon cycle by removing carbon dioxide from the atmosphere. Carbon dioxide mixes with rain water, forming a weak acid (carbonic acid) which slowly wears down or “weathers” rocks on land.

The process releases minerals such as calcium and magnesium from the rocks. These minerals then combine with carbonate and settle at the bottom of the ocean forming layers of calcium carbonate, or limestone.

In other words, the weathering process simply pulls carbon from the atmosphere and turns it into a layer of sediment on the seafloor.

However, continental rocks aren’t the only route by which carbon is removed from the atmosphere. Ocean ridges, the places where fresh crust is made on the seafloor, can undergo a similar “weathering” process. In fact, seafloor weathering was the main route of carbon removal in the early chapter of Earth’s history, before the formation of continents.

According to the new study, the rise of oxygen may have been due to a shift in balance between the two processes—between seafloor and continental weathering.

Potential Culprits

What caused that shift? The model looked at two factors: a brighter sun, and a slowdown in fresh crust production.

Our sun has slowly been getting brighter. It’s now 20 to 30 percent brighter than when our Earth first formed. Because the weathering process depends on temperature, a brighter Sun may have sped up the process on land. What’s more, the amount of fresh ocean floor formed has slowed down over time. And the weathering process generally happens with the newer crust. Taken together, these two factor may have shifted the balance between the seafloor and the terrestrial process.

The Phosphorus Boost

But why does that shift matter? “Rocks on continents contain phosphorus, which is a key limiting nutrient for photosynthetic microbes,” Mills says.

The terrestrial weathering increases the amount of phosphorus in streams and rivers, and ultimately in the ocean. The amount of phosphorus then dictates how much photosynthesis, hence how much oxygen is produced.

“The paper a great step forward,” says Lyons. “The fundamental mechanistic perspective, particularly the co-consideration of seafloor and continental processes, is broadly relevant and clever.”

One drawback, though, Lyons says, is that the model doesn’t account for the shorter-term variations of oxygen’s up and down. “The model, as proposed, isn’t able to explain the details of the transition,” Lyons adds. “But overall it still support the long term increase in oxygen.”

Implications for Astrobiology

The study provides an indirect link between plate tectonic and continents on one hand and the evolution of complex life on the other, an idea worth keeping in mind in the search for life beyond our world.

“This is not the only reason oxygen rose to high levels, but it seems to be an important piece of the puzzle. Whilst the carbon cycle can function without large continents, it seems that their emergence was critical to our own evolution,” Mills says in a news release.

Mills later adds in a phone interview:

“A large number of key limiting nutrients, and not just phosphate, come from the continents. It seems that to develop a biosphere like we have on this planet, you’re going to need significant continental area.”

In fact, the recycling of continents via plate tectonics has become of major interest for many astrobiologists. Several have argued that, along with water, plate tectonics could be an essential requirement for life.

“What I like in particular is the rigorous links between tectonic drivers and oxygen (and life by association), which must be a considered in any view of extrasolar planets and their ability to sustain life through nutrient balances—with oxygenation as a possible consequence,” Lyons adds. “Plate tectonics and relationships to nutrient cycling, phosphorus in particular, should be an essential part in any exploration for life—on the early Earth and farther from home.”

More information:
Benjamin Mills, Timothy M. Lenton, and Andrew J. Watson. “Proterozoic oxygen rise linked to shifting balance between seafloor and terrestrial weathering.” PNAS 2014 ; published ahead of print June 9, 2014, DOI: 10.1073/pnas.1321679111

Note : The above story is based on materials provided by courtesy of NASA’s Astrobiology Magazine. Explore the Earth and beyond at Astrobio.net

Swarm reveals Earth’s changing magnetism

June 20, 2014

Changes in Earth’s magnetic field from January to June 2014 as measured by the Swarm constellation of satellites. These changes are based on the magnetic signals that stem from Earth’s core. Shades of red represent areas of strengthening, while blues show areas of weakening over the 6-month period. Credit: ESA/DTU Space

The first set of high-resolution results from ESA’s three-satellite Swarm constellation reveals the most recent changes in the magnetic field that protects our planet.
Launched in November 2013, Swarm is providing unprecedented insights into the complex workings of Earth’s magnetic field, which safeguards us from the bombarding cosmic radiation and charged particles.

Measurements made over the past six months confirm the general trend of the field’s weakening, with the most dramatic declines over the Western Hemisphere.

But in other areas, such as the southern Indian Ocean, the magnetic field has strengthened since January.

The latest measurements also confirm the movement of magnetic North towards Siberia.

These changes are based on the magnetic signals stemming from Earth’s core. Over the coming months, scientists will analyse the data to unravel the magnetic contributions from other sources, namely the mantle, crust, oceans, ionosphere and magnetosphere.

This will provide new insight into many natural processes, from those occurring deep inside our planet to space weather triggered by solar activity. In turn, this information will yield a better understanding of why the magnetic field is weakening.

“These initial results demonstrate the excellent performance of Swarm,” said Rune Floberghagen, ESA’s Swarm Mission Manager.

“With unprecedented resolution, the data also exhibit Swarm’s capability to map fine-scale features of the magnetic field.”

The first results were presented June 19, 2014 at the ‘Third Swarm Science Meeting’ in Copenhagen, Denmark.

Sofie Carsten Nielsen, Danish Minister of Higher Education and Science, highlighted the Danish contribution to the mission. Swarm continues the legacy of the Danish Ørsted satellite, which is still operational, as well as the German Champ mission. Swarm’s core instrument — the Vector Field Magnetometer — was provided by the Technical University of Denmark.

Denmark’s National Space Institute, DTU Space, has a leading role — together with 10 European and Canadian research institutes — in the Swarm Satellite Constellation Application and Research Facility, which produces advanced models based on Swarm data describing each of the various sources of the measured field.

“I’m extremely happy to see that Swarm has materialised,” said Kristian Pedersen, Director of DTU Space.

Note : The above story is based on materials provided by European Space Agency.

Opal

June 20, 2014

Chemical Formula: SiO₂·nH₂O
Locality: World wide occurrences.
Name Origin: From the Old Indian upala – “precious stone.”

Table of Contents

What is Opal?

“What is Opal?” Opal is a hydrated amorphous form of silica; its water content may range from 3% to 21% by weight, but is usually between 6% and 10%. Because of its amorphous character it is classed as a mineraloid, unlike the other crystalline forms of silica which are classed as minerals. It is deposited at a relatively low temperature and may occur in the fissures of almost any kind of rock, being most commonly found with limonite, sandstone, rhyolite, marl and basalt. Opal is the national gemstone of Australia, which produces 97% of the world’s supply. This includes the production of the state of South Australia, which accounts for approximately 80% of the world’s supply.

The internal structure of precious opal makes it diffract light; depending on the conditions in which it formed, it can take on many colors. Precious opal ranges from clear through white, gray, red, orange, yellow, green, blue, magenta, rose, pink, slate, olive, brown, and black. Of these hues, the reds against black are the most rare, whereas white and greens are the most common. It varies in optical density from opaque to semi-transparent.

Common opal, called “potch” by miners, does not show the display of color exhibited in precious opal.

Optical properties

Optical and misc. Properties: Transparent – Opaque – Translucide
Refractive Index: from 1,43 to 1,45

Physical Properties

Cleavage: None
Color: White, Yellow, Red, Brown, Blue.
Density: 1.9 – 2.3, Average = 2.09
Diaphaneity: Transparent to translucent to opaque
Fracture: Conchoidal – Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz).
Luminescence: Fluorescent, Short UV=greenish yellow, Long UV=white.
Luster: Vitreous – Dull
Streak: white

Photos :

OPAL Welo, Afar Province, Ethiopia Thumbnail, 3.1 x 2.3 x 0.8 cm “Courtesy of Rob Lavinsky, The Arkenstone, www.iRocks.com”

OPAL Welo, Afar Province, Ethiopia Thumbnail, 1.3 x 0.9 x 0.6 cm “Courtesy of Rob Lavinsky, The Arkenstone, www.iRocks.com”

OPAL Welo, Afar Province, Ethiopia Thumbnail, 1.9 x 1.2 x 0.5 cm “Courtesy of Rob Lavinsky, The Arkenstone, www.iRocks.com”

OPAL Welo, Afar Province, Ethiopia Thumbnail, 1.3 x 1.1 x 0.8 cm “Courtesy of Rob Lavinsky, The Arkenstone, www.iRocks.com”

Name: Opal Locality: Mexico Weight: 2.46 carats Size: 9.50 x 6.05 mm © minclassics.

Researchers find link between amount of silica in subduction zones and frequency of ‘slow’ earthquakes

June 19, 2014

Aerial photo of the San Andreas Fault in the Carrizo Plain, northwest of Los Angeles. Credit: Wikipedia.

A pair of researchers, Pascal Audet and Roland Burgmann of the Universities of Ottawa and California, respectively, has found a connection between the amount of silica rich quartz above subduction zones and the frequency rate of “slow” earthquakes. In their paper published in the journal Nature, the two describe how they measured quartz amounts in the Cascadia subduction zone using seismic waves, and how it relates to slow earthquakes.

Scientists have only known about slow earthquakes for a few years—since they can’t be felt, there was no real indication that they were occurring. They happen when silica rich sediment is pushed from below when one plate pushes beneath another. The fluid is trapped causing pressure to build—eventually that pressure is released by slow sliding (due to lubrication provided by the silica), rather than the jolt associated with surface quakes. After the sliding stops, the pressure begins to build up again and the whole process is repeated. Such quakes can occur over days or even weeks, releasing energy equivalent to large surface quakes. Scientists now know that such quakes occur off the coast of Japan, New Zealand, the United States and Canada, but, they all have a different frequency rate. They happen every two years in New Zealand, every six months in Japan and every 14 months beneath Canada’s Vancouver Island. The difference in rates, the researchers have found, is due to the amount of silica in the fluid—there more there is, the faster faults knit together after the sliding has stopped.

The pair of researchers note that much more study needs to be done before it can be determined if slow earthquakes can be used to help predict surface quakes. In their experiments, they found the crust to be 5 to 15 percent quartz above the plates in the Cascadia subduction zone, an area that experienced a magnitude 9 quake in 1700. Scientists believe a major quake will likely occur again there sometime over the next 200 years. If slow earthquakes are found to portend larger ones, perhaps enough warning time can be given to save lives in the heavily populated area.

More information:
Possible control of subduction zone slow-earthquake periodicity by silica enrichment, Nature 510, 389–392 (19 June 2014) DOI: 10.1038/nature13391

Abstract

Seismic and geodetic observations in subduction zone forearcs indicate that slow earthquakes, including episodic tremor and slip, recur at intervals of less than six months to more than two years. In Cascadia, slow slip is segmented along strike and tremor data show a gradation from large, infrequent slip episodes to small, frequent slip events with increasing depth of the plate interface. Observations and models of slow slip and tremor require the presence of near-lithostatic pore-fluid pressures in slow-earthquake source regions; however, direct evidence of factors controlling the variability in recurrence times is elusive. Here we compile seismic data from subduction zone forearcs exhibiting recurring slow earthquakes and show that the average ratio of compressional (P)-wave velocity to shear (S)-wave velocity (vP/vS) of the overlying forearc crust ranges between 1.6 and 2.0 and is linearly related to the average recurrence time of slow earthquakes. In northern Cascadia, forearc vP/vS values decrease with increasing depth of the plate interface and with decreasing tremor-episode recurrence intervals. Low vP/vS values require a large addition of quartz in a mostly mafic forearc environment. We propose that silica enrichment varying from 5 per cent to 15 per cent by volume from slab-derived fluids and upward mineralization in quartz veins can explain the range of observed vP/vS values as well as the downdip decrease in vP/vS. The solubility of silica depends on temperature, and deposition prevails near the base of the forearc crust. We further propose that the strong temperature dependence of healing and permeability reduction in silica-rich fault gouge via dissolution–precipitation creep can explain the reduction in tremor recurrence time with progressive silica enrichment. Lower gouge permeability at higher temperatures leads to faster fluid overpressure development and low effective fault-normal stress, and therefore shorter recurrence times. Our results also agree with numerical models of slip stabilization under fault zone dilatancy strengthening15 caused by decreasing fluid pressure as pore space increases. This implies that temperature-dependent silica deposition, permeability reduction and fluid overpressure development control dilatancy and slow-earthquake behaviour.

T. rex’s killer smile revealed

June 19, 2014

Miriam Reichel’s research shows that the T. rex’s front teeth gripped and pulled, while the teeth along the side of the jaw punctured and tore flesh. Credit: Image courtesy of University of Alberta

One of the most prominent features of life-size models of Tyrannosaurus rex is its fearsome array of flesh-ripping, bone-crushing teeth.

Until recently, most researchers who studied the carnivore’s smile only noted the varying sizes of its teeth. But University of Alberta paleontologist Miriam Reichel discovered that beyond the obvious size difference in each tooth family in T. rex’s gaping jaw, there is considerable variation in the serrated edges of the teeth.

“The varying edges, or keels, not only enabled T. rex’s very strong teeth to cut through flesh and bone,” says Reichel, “the placement and angle of the teeth also directed food into its mouth.”

Reichel analyzed the teeth of the entire tyrannosaurid family of meat-eating dinosaurs and found T. rex had the greatest variation in tooth morphology or structure. The dental specialization was a great benefit for a dinosaur whose preoccupation was ripping other dinosaurs apart.

Reichel’s research shows that the T. rex’s front teeth gripped and pulled, while the teeth along the side of the jaw punctured and tore flesh. The teeth at the back of the mouth did double duty: not only could they slice and dice chunks of prey, they forced food to the back of the throat.

Reichel says her findings add strength to the classification of tyrannosaurids as heterodont animals, which are animals with teeth adapted for different functions depending on their position in the mouth.

One surprising aspect of T. rex teeth, common to all tyrannosaurid’s, is that they weren’t sharp and dagger-like. “They were fairly dull and wide, almost like bananas,” said Reichel. “If the teeth were flat, knife-like and sharp, they could have snapped if the prey struggled violently when T. rex’s jaws first clamped down.”

Reichel’s research was published in The Canadian Journal of Earth Science.

Journal Reference:

Miriam Reichel, Hans-Dieter Sues. The variation of angles between anterior and posterior carinae of tyrannosaurid teeth. Canadian Journal of Earth Sciences, 2012; 49 (3): 477 DOI: 10.1139/e11-068

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

Olivenite

June 19, 2014

Locality: Clara Mine, Rankach valley, Oberwolfach, Wolfach, Black Forest, Baden-Württemberg, Germany Photo Copyright © Chinellato Matteo

Chemical Formula: Cu₂(AsO₄)(OH)
Locality: Carharrack mine, Gwennap, Cornwall, England, GB
Name Origin: From the German olivernerz, literally “olive” ore, in allusion to its typical color.

Olivenite is a copper arsenate mineral, formula Cu₂(AsO₄)(OH). It crystallizes in the monoclinic system (pseudo-orthorhombic), and is sometimes found in small brilliant crystals of simple prismatic habit terminated by domal faces. More commonly, it occurs as globular aggregates of acicular crystals, these fibrous forms often having a velvety lustre; sometimes it is lamellar in structure, or soft and earthy.

A characteristic feature, and one to which the name alludes (German, Olivenerz, of A. G. Werner, 1789), is the olive-green color, which varies in shade from blackish-green in the crystals to almost white in the finely fibrous variety known as woodcopper. The hardness is 3, and the specific gravity is 4.3. The mineral was formerly found in some abundance, associated with limonite and quartz, in the upper workings in the copper mines of the St Day district in Cornwall; also near Redruth, and in the Tintic Mining District in Utah. It is a mineral of secondary origin, a result of the oxidation of copper ores and arsenopyrite.

The arsenic of olivenite is sometimes partly replaced by a small amount of phosphorus, and in the species libethenite we have the corresponding copper phosphate Cu2PO4OH. This is found as small dark green crystals resembling olivenite at Libethen in the Slovak Republic, and in small amount also in Cornwall. Other members of this isomorphous group of minerals are adamite, Zn₂(AsO₄)(OH), and eveite, Mn₂(AsO₄)(OH).

Table of Contents

History

Discovery date : 1820
Town of Origin: CORNOUAILLES
Country of Origin: ANGLETERRE

Physical Properties

Hardness: 3,00
Density: from 4,37 to 4,38
Color : olive-green; greenish brown; yellow; grayish green; yellowish white; blackish green; brown; grayish white
Luster: vitreous;silky; greasy
Streak : green yellow; white
Break: irregular; conchoidal
Cleavage: {110} Indistinct, {010} Indistinct, {110} Indistinct

Photos:

OLIVENITE Wheal Phoenix, Linkinhorne, Liskeard, Cornwall, England, Europe Size: 6.5 x 6 x 3 cm (Small Cabinet) Owner: Crystal Classics

Olivenite Inubia mine, Bahia, Brazil Specimen weight:76 gr. Crystal size:3 mm Overall size: 72mm x 60 mm x 30 mm minservice

Olivenite Mine du Cap Garonne, Pradet, Var, Provence-Alpes-Côte d’Azur, France Specimen weight:18 gr. Crystal size:0,15 cm Overall size:4 x 3,7 x 1,3 cm minservice

OLIVENITE on CORNWALLITE Wheal Phoenix, Linkinhorne, Liskeard, Cornwall, England, Europe Size: 5 x 3 x 2.5 cm (Small Cabinet) Owner: Crystal Classics

Scientists ready to study magma formation beneath Mount St. Helens

June 19, 2014

Mount St. Helens as it appeared two years after its catastrophic eruption on May 18, 1980. Credit: U.S. Geological Survey

University and government scientists are embarking on a collaborative research expedition to improve volcanic eruption forecasting by learning more about how a deep-underground feeder system creates and supplies magma to Mount St. Helens.

They hope the research will produce science that will lead to better understanding of eruptions, which in turn could lead to greater public safety.

The Imaging Magma Under St. Helens project involves three distinct components: active-source seismic monitoring, passive-source seismic monitoring and magnetotelluric monitoring, using fluctuations in Earth’s electromagnetic field to produce images of structures beneath the surface.

Researchers are beginning passive-source and magnetotelluric monitoring, while active-source monitoring – measuring seismic waves generated by underground detonations – will be conducted later.

Passive-source monitoring involves burying seismometers at 70 different sites throughout a 60-by-60-mile area centered on Mount St. Helens in southwestern Washington. The seismometers will record data from a variety of seismic events.

“We will record local earthquakes, as well as distant earthquakes. Patterns in the earthquake signatures will reveal in greater detail the geological structures beneath St. Helens,” said John Vidale, director of the University of Washington-based Pacific Northwest Seismic Network.

Magnetotelluric monitoring will be done at 150 sites spread over an area running 125 miles north to south and 110 miles east to west, which includes both Mount Rainier and Mount Adams. Most of the sites will only be used for a day, with instruments recording electric and magnetic field signals that will produce images of subsurface structures.

Besides the UW, collaborating institutions are Oregon State University, Lamont-Doherty Earth Observatory at Columbia University, Rice University, Columbia University, the U.S. Geological Survey and ETH-Zurich in Switzerland. The work is being funded by the National Science Foundation.

Mount St. Helens has been the most active volcano in the Cascade Range during the last 2,000 years and has erupted twice in the last 35 years. It also is more accessible than most volcanoes for people and equipment, making it a prime target for scientists trying to better understand how volcanoes get their supply of magma.

The magma that eventually comes to the surface probably originates 60 to 70 miles deep beneath St. Helens, at the interface between the Juan de Fuca and North American tectonic plates. The plates first come into contact off the Pacific Northwest coast, where the Juan de Fuca plate subducts beneath the North American plate and reaches great depth under the Cascades. As the magma works its way upward, it likely accumulates as a mass several miles beneath the surface.

As the molten rock works its way toward the surface, it is possible that it gathers in a large chamber a few miles beneath the surface. The path from great depth to this chamber is almost completely unknown and is a main subject of the study.

The project is expected to conclude in the summer of 2016.

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

Unexpected findings: Small asteroids can be flying rock clusters or even clouds of dust surrouding solid rocks

June 19, 2014

An artist’s conception of two possible views of asteroid 2011 MD. Credit: Image courtesy NASA Jet Propulsion Laboratory

What seemed to be rock-solid assumptions about the nature of small asteroids may end in collections of rubble or even a cloud of dust, but in such findings lies the lure of the unexpected.

Northern Arizona University researchers David Trilling and Michael Mommert, while playing a well-defined role in the NASA Asteroid Initiative, are beginning to wonder if they have found a separate path of investigation.
The two researchers presented their findings about asteroid 2011 MD on Thursday during a NASA event updating progress on the path to capturing a small asteroid and relocating it for a closer look by astronauts in the 2020s.

The job of Trilling and Mommert was to use the infrared capabilities of the Spitzer Space Telescope to determine the size of 2011 MD, which needs to be within a narrow range for the mission to succeed. Trilling, an associate professor, explained that using infrared light is the most accurate way to determine an asteroid’s size because visible light through a traditional telescope fails to distinguish a small, highly reflective asteroid from a large one with little reflectivity.

At around 6 meters in diameter, 2011 MD is just right. But that’s not the whole story.

“People have assumed that small asteroids are debris from collisions of larger asteroids, so those really small guys would be just single slabs of rock flying in space,” said Mommert, a post-doctoral researcher. “But we found that this one is 65 percent empty.”

The findings, which suggest a flying cluster of rocks or a cloud of dust with a solid rock at its nucleus, are similar to observations the NAU researchers published earlier this year of yet another asteroid, 2009 BD.

Trilling said long-held assumptions are yielding to something “weirder and more exotic. The first time you see it, you think, ‘Well, that’s just an anomaly.’ But two out of two, and you start to think that maybe the small ones really don’t look like everyone thought.”

The latest findings appear online today in Astrophysical Journal Letters, coinciding with the NASA presentation. And while NASA seeks to use the asteroid mission to test the technologies and capabilities needed to send astronauts to Mars, Trilling and Mommert are setting their sights elsewhere.

“Now we can go back and propose some more observation time just for the science investigation,” Trilling said. “Now we want to learn something more about the universe.” Mommert said this is a prime opportunity to add data to a field — the study of small asteroids — that is sparsely populated.

“It’s a field that hasn’t been studied a lot because it’s really difficult to observe them and derive their physical properties,” he said. “The density of 99.9 percent of all asteroids is unknown.” He and Trilling have now added two to a single-digit list.

As far as 2011 MD is concerned, NASA will have to be satisfied with the information compiled by the full team, which includes NAU, the University of Hawaii and a number of other NASA and affiliated labs. The asteroid is about to disappear behind the sun, at least from Earth’s perspective, for the next seven years, and will not be observable again before the spacecraft to retrieve it would have to be launched.

Note : The above story is based on materials provided by Northern Arizona University.

Oligoclase

June 18, 2014

Chemical Formula: (Na,Ca)[Al(Si,Al)Si₂O₈]
Locality: Twedestrand, Norway.
Name Origin: From the Greek, oligos and kasein, “little cleavage.”
Oligoclase is a rock-forming mineral belonging to the plagioclase feldspars. In chemical composition and in its crystallographic and physical characters it is intermediate between albite (NaAlSi₃O₈) and anorthite (CaAl₂Si₂O₈). The albite:anorthite molar ratio ranges from 90:10 to 70:30.

Oligoclase is a high sodium feldspar crystallizing in the triclinic system. The Mohs hardness is 6 to 6.5 and the specific gravity is 2.64 to 2.66. The refractive indices are: nα=1.533–1.543, nβ=1.537–1.548, and nγ=1.542–1.552. In color it is usually white, with shades of grey, green, or red.

Table of Contents

Name and discovery

The name oligoclase was given by August Breithaupt in 1826 from the Greek oligos, little, and clasein, to break, because the mineral was thought to have a less perfect cleavage than albite. It had previously been recognized as a distinct species by J. J. Berzelius in 1824, and was named by him soda-spodumene (Natron-spodumen), because of its resemblance in appearance to spodumene.

History

Discovery date : 1826
Town of Origin: DANVIKS-ZOLL, STOCKHOLM
Country of Origin: SUEDE

Physical Properties

Cleavage: {001} Perfect, {010} Good
Color: Brown, Colorless, Greenish, Gray, Yellowish.
Density: 2.64 – 2.66, Average = 2.65
Diaphaneity: Transparent to Translucent
Fracture: Uneven – Flat surfaces (not cleavage) fractured in an uneven pattern.
Hardness: 7 – Quartz
Luminescence: Fluorescent, Long UV=yellow.
Luster: Vitreous (Glassy)
Streak: white

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Description and occurrence

History

Optical properties

Physical properties

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Optical properties

Physical properties

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Geography

River life

Discovery and occurrence

History

Optical properties

Physical properties

Photos:

Formation and Subtypes

History

Optical properties

Physical properties

Photos:

From Seafloor to Terrestrial “Weathering’

Potential Culprits

The Phosphorus Boost

Implications for Astrobiology

What is Opal?

Optical properties

Physical Properties

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Abstract

History

Physical Properties

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Name and discovery

History

Physical Properties

Photos:

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