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rachel crowell

Scientists discover granite crystallizes at lower temperatures

Investigating the properties of granite has given researchers insight into how gold and other economically important ores are produced, the thermal properties of Earth’s crust, the state of magma in active volcanic regions, and how Earth’s continents formed. “The temperature of granite crystallization underpins our thinking about many of these phenomena,” researchers note in a new study in Nature. “But evidence is emerging that this temperature may not be well constrained,” added the study authors, who found that certain granites crystallize at temperatures as much as 200 degrees Celsius lower than previously thought.

26 Nov 2018

Gulf Stream eddies transport iron to North Atlantic subtropical gyre

Dust from the Sahara Desert is a major supplier of iron to the North Atlantic subtropical gyre — the huge circular ocean current stretching between North America and the west coasts of Africa and Europe — where cyanobacteria use the scarce nutrient to fuel nitrogen fixation, which then fertilizes other organisms at the base of the marine food chain. Now, researchers have discovered that eddies spinning off the Gulf Stream also transport iron to the northwestern edge of the gyre.

22 Nov 2018

Dangers of Van Allen Belts driven by "local acceleration"

Between about 13,500 and 58,000 kilometers above Earth’s surface, billions of high-energy particles — predominately electrons — congregate to form the outer Van Allen Belt. Nearly 4,000 kilometers closer to Earth, the outermost boundary of its twin, the second Van Allen Belt, also encircles the planet.

25 Oct 2018

Benchmarks: September 6, 1869: Pennsylvania's Avondale coal mine fire kills 110, igniting reform

In the mid-19th century, American industry was fueled by coal, which was provided largely by the anthracite coal mines of eastern Pennsylvania. The work drew tens of thousands of immigrants, including experienced English and Welsh miners, and many fleeing the Irish Potato Famine. But the work was dangerous, and each year thousands of workers died in the mines and many thousands more were seriously injured. 

06 Sep 2018

Obliquity and eccentricity determine exoplanet habitability

Finding habitable Earth-like planets may be even more challenging than previously thought, suggests a recent Astronomical Journal study looking at how the planetary obliquity, or tilt relative to an orbital axis, and orbital eccentricity affect the habitability of planets orbiting G-dwarf stars — which are similar to the sun.

05 Sep 2018

Great Barrier Reef has died and recovered before

It’s hard to imagine Earth without the Great Barrier Reef, yet with the threats confronting it — including ocean warming and acidification — its demise is a possibility marine scientists are studying. A new study of how sea-level rise and sedimentation have impacted the reef over the last 30,000 years, however, shows it might be more resilient than previously thought.

22 Aug 2018

Natural solutions could save $50 billion in Gulf Coast flood damages

As coastal development skyrockets and the effects of climate change escalate, flooding is becoming an increasingly common threat. A new statistical analysis of the costs and benefits of various coastal protection methods along the U.S. Gulf Coast suggests communities could prevent a significant amount of flood damage by implementing a combination of natural defenses and built infrastructure.

10 Aug 2018

Island-dwelling mammal had small brain, keen senses

A host of fossils has been discovered near the Romanian town of Haţeg, including 15 species of Late Cretaceous dinosaurs — some of them dwarf dinosaurs — and enormous pterosaurs with 12-meter wingspans, prompting the establishment of the Haţeg Country Dinosaurs Geopark in 2005.

26 Jul 2018

Diamonds reveal water in deep mantle

Inclusions in diamonds often render them undesirable to consumers, but they can provide researchers with striking insights into Earth’s composition. Recently, scientists probing diamond samples for the presence of carbon dioxide stumbled instead upon inclusions of ice-VII — a type of crystallized water that forms at very high pressures, and has never before been found in nature.

07 Jul 2018

Benchmarks: May 3, 2003: New Hampshire's Old Man of the Mountain falls

On May 2, 2003, the Old Man of the Mountain, New Hampshire’s famous face-shaped granite formation, adorned the side of Cannon Mountain in Franconia Notch State Park, just as it had for millennia. But by the next morning, it was gone: The iconic stone face had fallen.

03 May 2018