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timothy oleson

Striped pyrites link earthquakes to gold deposition

Many of the world’s richest gold deposits are found in fault zones, where the precious metal is concentrated in quartz veins that cut through the surrounding rock. For several decades, scientists have suspected that earthquakes help form these deposits by releasing pressure and giving metals in mineral-rich hydrothermal fluids in the fault zone a chance to precipitate. But clear evidence for this so-called “fault-valve” process has been hard to come by. Now, researchers studying the geochemical makeup of tiny pyrite crystals from one well-known gold mine appear to have found some long-sought confirmation.

18 Jul 2014

Benchmarks: July 15, 1806: Zebulon Pike launches Southwest expedition

Of America’s early 19th-century western explorers, Meriwether Lewis and William Clark typically garner the most attention. But there was a third military man who, along with a detachment of U.S. Army troops and volunteers, also trekked into the newly acquired reaches of the young United States in the same era: Zebulon Pike.

15 Jul 2014

Solar wind gives lightning a boost

Strong gusts of solar wind appear to trigger lightning on Earth, according to a new study. Researchers studying patterns of lightning strikes in and around the U.K. over several years found a substantial uptick in lightning after high-speed streams of solar wind reached Earth. Given the regular timing of the streams’ arrivals and our ability to detect them with satellites, the findings could eventually help scientists better forecast lightning activity, potentially mitigating the hazard it poses to humans.

10 Jul 2014

Mars Monthly

As Curiosity and Opportunity rove around Mars, the Mars Reconnaissance Orbiter (MRO), Mars Express and Mars Odyssey orbit above, and scientists on Earth study the Red Planet from afar, new findings are announced almost weekly. Here are a few of the latest updates.
 

10 Jul 2014

Searching for evidence of ancient subduction

For billions of years, portions of Earth’s rigid surface have dipped and sunk along plate boundaries to be recycled back into the mantle below. Determining when the process of subduction began — a fundamental step in Earth’s physical, and possibly biological, evolution — has proved difficult for geoscientists due to the challenges of interpreting evidence from the few remnants of early Earth that remain. In a recent study, researchers have now proposed a new approach for identifying ancient subduction zones that could help tackle the longstanding question.
 

06 Jul 2014

Mercury's shrinkage underestimated

In addition to its myriad craters, Mercury is marked by mountainous ridges and faults that, similar to wrinkles that emerge on an overripe apple as it shrinks, are signs that Mercury’s surface has cracked and buckled as the planet has cooled. From previous observations, it was estimated that Mercury’s radius had decreased 1 to 3 kilometers in about the past 4 billion years, but according to a new study in Nature Geoscience, the amount of contraction has been greatly underestimated.
 

06 Jul 2014

Message in a bottle gourd

For about the last 10,000 years, bottle gourds (Lagenaria siceraria) have been cultivated the world over for food and crafted into canteens, instruments and other utilitarian goods. But just how they became globally ubiquitous by the Early Holocene has long been a subject of debate among anthropologists and archaeologists. Some scientists thought the plant migrated with humans from Africa to Asia and, eventually, across the Bering land bridge to the Americas. But a new study suggests it’s unlikely the plants would have survived the long trek through harsh Arctic conditions, and instead offers a different globe-tripping hypothesis for everyone’s favorite dried fruit-turned-drinking vessel.

04 Jul 2014

Down to Earth With: Steven Stanley

It’s no wonder Steven Stanley says he can’t imagine having pursued any career other than research and teaching in geology and paleontology. After studying under eminent scientists like Alfred Fischer, Colin Pittendrigh and Harry Hess while a student at Princeton and then Yale in the 1960s, Stanley went on to add many of his own paradigm-shifting contributions to our understanding of fossils, evolution and Earth’s environmental history. He has also authored several popular textbooks and has won numerous awards, including the prestigious Mary Clark Thompson Medal from the National Academy of Sciences in 2006 and, most recently in 2013, the Geological Society of America’s (GSA) highest honor, the Penrose Medal.
 

24 Jun 2014

Cryptic creatures made for a spectacular hanging garden

Researchers studying an outcrop of Middle Devonian-aged carbonate rock in the Hamar Laghdad area of Morocco have found the remains of a community of submarine cave-roof-dwelling corals, crinoids, cnidarians and sponges that, while living, would have constituted a “spectacular hanging garden.”

22 Jun 2014

Early Triassic fossil showed live birth in action

An exceptional case of fossil preservation has provided the oldest view yet of the moment of live birth in a vertebrate. The fossil contains parts of four marine reptile individuals — a mother and her three young — from the ichthyopterygian genus, Chaohusaurus, and was unearthed in the Anhui Province of eastern China. While one of the young is still inside the mother and a second is already outside (and mostly obscured from view by other portions of the fossil), the third juvenile can be clearly seen emerging headfirst from the mother’s pelvis. Thought to be about 1 meter long when fully grown, Chaohusaurus lived about 248 million years ago in the Early Triassic and was an ancestor of later ichthyosaurs.

22 Jun 2014

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