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timothy oleson

Thank subduction for Earth's nitrogen-rich air

Plate tectonics underlies many of Earth’s distinctive features, from its ever-shifting continents to its colliding mountain ranges and continuously forming crust at mid-ocean ridges. According to a new study, the process might also explain another of our planet’s peculiarities: its nitrogen-rich atmosphere.

 
08 Mar 2015

Fossil leaves reveal effect of "impact winter"

When the Chicxulub bolide struck the Yucatán Peninsula at the end of the Cretaceous about 66 million years ago, widespread extinctions of land and marine animals resulted. However, the blast’s lasting effects on plants, which tend to be more resilient against impact-related fallout, have been less clear. Now, a new analysis of fossil leaves dating to around the end-Cretaceous offers some of the first quantitative evidence of a substantial shift in plant communities — toward more deciduous plants — following the impact.

05 Mar 2015

Benchmarks: February 17, 1977: Hydrothermal vents are discovered

In early February 1977, as scientists aboard the research vessel (R/V) Knorr made their way across the Pacific waters off the northwest coast of South America, they had reason to suspect their expedition might find the success that had eluded others. Previous missions had identified their destination — a site on the ocean surface about 330 kilometers northeast of the Galápagos Islands, below which two tectonic plates rift apart — as a promising location from which to search for their intended target. Once there, the researchers would deploy a variety of tools, including manned and unmanned submersibles, to the ocean bottom in the hopes of directly spotting hydrothermal vents.

17 Feb 2015

Ice (Re) Cap: February 2015

From Antarctica to the Arctic; from polar caps, permafrost and glaciers to ocean-rafted sea ice; and from burly bears to cold-loving microbes, fascinating science is found in every nook and crevasse of Earth’s cryosphere, and new findings are announced often. Here are a few of the latest updates.

15 Feb 2015

Wealth of seafloor features emerges from new survey

A new survey of Earth’s deep ocean — 80 percent of which remains unmapped — has revealed a wealth of previously unknown features, including thousands of seamounts as well as a variety of undersea tectonic features that are either buried under too much sediment or were simply too small to be seen before.

14 Feb 2015

New nationwide soil map available online

The U.S. Geological Survey (USGS) recently completed a seven-year soil-mapping project detailing the mineralogy and geochemistry of soils across the lower 48 U.S. states. Bill Cannon, an emeritus scientist at the USGS in Reston, Va., and co-author of the report, which was published in 2014, discussed the effort last October at the Geological Society of America’s annual meeting in Vancouver, B.C.

13 Feb 2015

Scientists sequence oldest modern human genome to date

A chance fossil find along a Russian river has provided researchers with the oldest genomic data ever sequenced from a modern human. The fossil, a nearly complete left femur, was pulled from a bank along the Irtysh River near the Ust’-Ishim district in western Siberia in 2008 by a Russian artist before it made its way to scientists.

11 Feb 2015

Plate tectonics seen on Europa

Earth is no longer the only body in the solar system where plate tectonics operates, according to new research reported in Nature Geoscience. 

05 Feb 2015

California drying out

Offering another perspective on the ongoing drought in the western U.S., NASA recently released this three-panel image illustrating relative water loss from California’s Central Valley between 2002 and 2014 based on data from the Gravity Recovery and Climate Experiment (GRACE) satellites (hot colors indicate greater loss).

03 Feb 2015

Mantle plume alternative explains Australian volcanism

Magma often finds its way to the surface along Earth’s crustal boundaries as tectonic plates crash together, rift apart or grind past each other. Less understood is why volcanoes sometimes emerge far away from plate boundaries. Narrow plumes of buoyant mantle rock rising from hundreds of kilometers deep have long been supposed as the source of intraplate volcanoes, but evidence for plumes is lacking in many areas. Now, in a new study, researchers have reported evidence for an alternative process, known as edge-driven convection, which appears to be driving intraplate volcanism in southeastern Australia.

 
29 Jan 2015

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