Taxonomy term

plate tectonics

Did crustal chemistry buoy Western Plains?

The mighty mountains of the American West may captivate artists and adventurers with their rugged allure, but it’s the humble High Plains that intrigue certain geologists. For decades, scientists have puzzled over the origins of this vast plateau, which stretches for more than 500 kilometers east of the Rockies.
12 Jul 2015

Down to Earth With: Geophysicist Peter Molnar

As a graduate student in geophysics at Columbia University in the late 1960s, Peter Molnar — who had studied physics as an undergraduate — decided to sit in on a geology course for a term. When the professor began discussing cratons one day, Molnar raised his hand and asked what a craton was. Molnar still remembers the strange look he received, as if the professor were wondering, “Who let this guy in?”
20 Jun 2015

Getting to the bottom of a tectonic plate

Earth’s rigid, brittle lithosphere is broken into seven major plates, as well as many minor plates, which ride along atop a ductile layer of the upper mantle called the asthenosphere. For all we know about Earth’s cracked outer shell, however, a clear picture of the lithosphere-asthenosphere boundary at the bottom of the plates has proved elusive. Now, new research using explosives to image the oceanic plate dipping beneath New Zealand’s North Island is helping to blast away some of the uncertainty about this boundary by giving scientists a sharper look at a piece of the planet’s tectonic underbelly.

08 Jun 2015

Did a geographic shift trigger the Cambrian Explosion?

Roughly 530 million years ago, Earth’s living cast of characters ballooned as a surge of evolutionary development led to the sudden appearance of almost all modern animal groups. Fossils from this period document the change in species, but the geologic, atmospheric and/or biotic factors that may have caused the radiation remain mysterious. Now, a new study suggests that massive changes in the positions of the continents may have played a significant role in sparking the Cambrian Explosion.

27 Mar 2015

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

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

North American terranes not so exotic after all

The cordillera of western North America is a patchwork of various landmasses, or terranes, that assembled through collision and accretion to the Laurentian Shield, leaving a complicated tectonic history for geologists to unravel.

30 Jan 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

Skinned oceanic plates may be origin of ophiolites

Long recognized as slivers of oceanic crust incongruously emplaced on land, ophiolites are distinctive sequences of basalt, gabbro and peridotite found globally near former and current convergent zones, where oceanic tectonic plates subduct under continents. But scientists don’t have a clear idea why or how ophiolites split from downgoing plates and find their way onto land. Now, a new study suggests part of the answer may relate to weak layers of mantle that allow oceanic crust to be peeled, or “skinned,” from subducting slabs as they descend.

10 Jan 2015

Textbook mantle plume theory may need revision

Every basic geology textbook has a section on mantle plumes, which have long been thought to underlie certain island chains and other volcanic hot spots, but hard evidence in support of narrow columns of magma upwelling from deep within the Earth’s mantle remains scant. Now a new study suggests that the long-held plume theory should be abandoned altogether.

07 Jan 2015