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Ice (Re)Cap: March 2018

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.

12 Mar 2018

Heating up Enceladus' ice-covered ocean

Saturn’s sixth-largest moon, Enceladus, is covered by ice, but just beneath its icy surface lies an ocean of liquid water. New research suggests that this internal ocean may be maintained in a liquid state by heat generated by tidal friction within the moon’s fragmented, rocky core.

08 Mar 2018

Gettysburg rocks tell battlefield tales

Since the late 19th century, Civil War battlefield landscapes have changed. Some have been plowed under and developed, while elsewhere, woods have been cut down or become overgrown. But the rocks that dotted those battlefields from Gettysburg to Mississippi largely still stand. Historians are now using the steadfast boulders and ridges seen in the backgrounds of 154-year-old battlefield photographs to learn more about the skirmishes that took place at certain sites.

07 Mar 2018

Lakeshore shape influences lake-effect snow

On Dec. 11, 2013, Upstate New York’s Tug Hill region received more than 100 centimeters of snow in 24 hours. And annually, the region, which covers more than 5,000 square kilometers to the east of Lake Ontario, can see up to five times that amount. In comparison, Toronto, on the northwestern coast of the lake, averages less than 125 centimeters of snow each year.

06 Mar 2018

World's longest sauropod trackway exposed

Excavations at a dinosaur trackway found in 2009 in the French village of Plagne, 200 kilometers east of Lyon, revealed 110 sauropod footprints spanning a distance of 155 meters, making the site the world’s longest sauropod trackway. In a new study published in the journal Geobios, researchers report that the tracks were made roughly 150 million years ago and that the largest tracks measure more than a meter across. Analysis of the trackway suggested the prints were left by an animal at least 35 meters long and weighing more than 35 tons, that traveled about 4 kilometers per hour with an average stride of 2.8 meters. The prints were assigned to a new ichnospecies — a species only known from trace fossils — named Brontopodus plagnensis.

05 Mar 2018

Oldest blood cells found in Early Jurassic ichthyosaur

Since 2005, a steady trickle of reports detailing proteins and other soft tissues preserved in fossils of dinosaurs and other ancient animals has gradually worn down the disbelief that such tissues can last through geologic time. In a new study in Scientific Reports, scientists have now reported the oldest preserved red blood cells, white blood cells and platelets, found in the remains of an ancient marine reptile.

01 Mar 2018

Drought drove early humans from Africa

Genetics studies have dated the largest migrations of early Homo sapiens out of Africa to between 70,000 and 55,000 years ago, although smaller groups may have left earlier. The most widely accepted exodus theory, known as the “green carpet” or “green Sahara” hypothesis, holds that people likely left during wetter periods in the Sahara and Arabia, which would have allowed easier passage into Eurasia via the Middle East. But new research supports the opposite idea: that drier conditions may have triggered at least some of the exodus.

28 Feb 2018

Isotopes reveal sources of centuries-old alabaster artifacts

When geologists think of alabaster, they likely envision blocks of gypsum, its main mineral constituent; when art historians hear the word, statues crafted from the soft rock may come to mind. A new study focused on the sources of centuries-old alabaster artworks has geologists thinking about art history, and art historians pondering geochemistry. In the study, published in Proceedings of the National Academy of Sciences, researchers used isotope fingerprinting along with historical records to tie medieval and Renaissance alabaster sculptures to the quarries from which their materials were excavated.

26 Feb 2018

Spawning salmon engineer landscapes

All animals depend on their ecosystems for habitat. And, in turn, many animals impact their ecosystems by engineering the landscape to suit their needs. Beavers provide an iconic example of ecosystem engineering when they build dams, which influence streams and wetlands. The engineering efforts of salmon, meanwhile, can even shape the bedrock of the watersheds in which they live, according to a recent study that modeled the evolution of those watersheds over several million years.

23 Feb 2018

Meteorite impacts may have kick-started ancient subduction

Earth in the Hadean Eon, between 4.56 billion and 4 billion years ago, was much too hot to support active plate tectonics as we know it today, where cold, established plates slowly march around Earth. Yet some evidence, including from tiny zircon crystals dating to the Hadean, has suggested that a form of plate tectonics was active by about 4.1 billion years ago — about a billion years before many researchers think modern plate tectonics started. The mechanisms that could have initiated and sustained early tectonics are unclear, but according to a new study, constant bombardment of early Earth by meteorites could have triggered temporary bursts of early tectonism.

22 Feb 2018

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