Taxonomy term

January 2019

Deep drilling reveals how impact crater's hidden ring formed

When the 15-kilometer-wide Chicxulub meteorite slammed into what is now Mexico’s Yucatán Peninsula 66 million years ago, it was moving at more than 20 kilometers per second. The impact blasted a hole 200 kilometers wide and more than 30 kilometers deep in Earth’s surface. The forces involved in such impacts are colossal — many orders of magnitude greater than the largest human-made explosions — and scientists have traditionally relied on models to explain what happens in the moments after impact. But in a new study looking at shocked rocks retrieved from the depths of the buried Chicxulub Crater, scientists have determined how the crater’s “peak ring” formed in mere minutes.

05 Feb 2019

Redefining Dinosaurs: Paleontologists are Shaking the Dinosaur Family Tree to its Roots

A radical reconfiguration of the classification of dinosaurs challenges an orthodoxy built on roughly a century and a half of research. But many paleontologists are not ready to accept such a big shift in our understanding of dinosaur evolutionary history.

04 Feb 2019

Thirsty mantle: Subduction zones swallow more water than thought

For all the water stored in oceans, ice and other reservoirs at Earth’s surface, there’s likely even more in the planet’s interior, where it plays important roles in many geological processes, including the formation of magma and the lubrication of earthquake-producing fault zones. Uncovering just how much water is inside Earth — and the extent to which it moves back and forth between the surface and subsurface — has long been a challenge for scientists interested in understanding the planet’s water cycle. A new study peering beneath the Mariana Trench in the Western Pacific has revealed that some subduction zones might pull significantly more water into Earth’s interior than previously thought.

30 Jan 2019

Melting glaciers shift Earth's axis

A perfectly round desk globe spins evenly on a fixed axis, but that’s not the case with Earth, which wobbles as the position of its spin axis — the imaginary line running between the North and South poles — slowly drifts over time. In a new study in Earth and Planetary Science Letters, scientists suggest that there are three main reasons for the movement of Earth’s spin axis, called polar motion.

28 Jan 2019

Quirky lunar swirls expose the moon's secret past

Lunar observers have long noted mysterious “swirls,” patterns of alternating bright and dark shading, adorning the lunar surface. The popular Reiner Gamma formation — first described by Renaissance astronomers and now beloved by backyard astronomy enthusiasts — is one such lunar swirl.

25 Jan 2019

Oman ophiolite suggests subduction started with a shove

Plate tectonics is a fundamental control on how Earth operates and is important for the planet’s habitability, but how this crustal recycling process got started has long been a mystery. A new study examining some uniquely coupled metamorphic and volcanic rocks in Oman is adding some needed clarity about the initiation of subduction zones, a critical component in plate tectonics.

23 Jan 2019

Mesosaurs may have spent time on land

Mesosaurs are famous for being the earliest-known fully aquatic reptiles. With their whip-like tails, webbed feet and nostrils on top of their heads, the 2-meter-long reptiles appear to have been well adapted for life in the water. But in a new study, scientists have found fossil evidence that mesosaurs may have spent some of their adult lives on land.

21 Jan 2019

Ocean circulation change suffocating Gulf of St. Lawrence

Estuaries are among the most nutrient-rich and biologically productive areas of the ocean, and the Gulf of St. Lawrence, where freshwater from the Great Lakes and the St. Lawrence River meets the salty Atlantic Ocean in eastern Canada, is the largest estuary in the world. But the biodiversity and long-thriving fisheries of the Gulf of St. Lawrence could be threatened by declines in oxygen levels over the last half century. 

18 Jan 2019

Geologic Column: Muinntir a' ghlinne so

The author examines the idea of lament — for humanity, Earth and the universe — through the lens of the “pibroch,” a Gaelic word meaning a Scottish bagpiper’s variations on a musical theme, and the title of a Ted Hughes poem.

18 Jan 2019