Creative destruction: a thinner ocean plate sides under a continental plate, melting and recycling the ocean crust into the Earth’s interior and birthing volcanoes in this illustration of subduction, a consequence of modern plate tectonics. A new study reports evidence of a transition in multiple locations around the world, 3.8-3.6 billion years ago, from stable “protocrust” to pressures and processes that look a lot like modern subduction, suggesting a time when plates first got moving. Credit: Nikolas Midttun, CC-BY

Earliest geochemical evidence of plate tectonics found in 3.8-billion-year-old crystal

Basalt mit frischen Klinopyroxenen (credit Jonas Tusch)

Sampling the deep graveyard of Earth’s earliest crust

Painting of the Mid-Ocean Ridge with rift axis by Heinrich Berann based on the scientific profiles of Marie Tharp and Bruce Heezen (1977).

Seafloor spreading has been slowing down

California’s San Andreas Fault. The “creeping” central section, subject of a new study, is in yellow. Rock samples from almost 2 miles down were taken at the San Andreas Fault Observatory at Depth, or SAFOD, marked by the red star. (Adapted from Coffey et al., Geology, 2022)

A slow-motion section of the San Andreas fault may not be...

Earth

X-ray view of subducting tectonic plates

Minerals are visible in rock samples from the coast of Oman. Scientists said these rocks may reveal new information about subduction, an important tectonic process on Earth. Credit: Joshua Garber / Penn State.

Mineral dating reveals new clues about important tectonic process

A series of earthquakes and aftershocks shook the Ridgecrest area in Southern California in 2019. Distributed acoustic sensing (DAS) using fiber-optic cables enables high-resolution subsurface imaging, which can explain the observed site amplification of earthquake shaking. Credit: Yang et al., 2022

Fiber-optic cables can produce high-resolution underground maps

The edges of Earth’s tectonic plates, centered over the Pacific Ocean. Colors indicate whether plates are scraping past (yellow), diving under (green), or pulling away (red) from one another. Study site near New Zealand marks the location of a newly forming subduction zone. Credit: Brandon Shuck/University of Texas Institute for Geophysics

How does a major subduction zone get started? It may begin...

A view of the graben, which emerged near the Holuhraun lava field in Iceland. The western boundary of the graben is seen in the foreground, in the center-right portion of the image, where the land begins to dip down. Credit: Stephan Kolzenburg

As tectonic plates pull apart, what drives the formation of rifts?

Rapid erosion of supermountains released large amounts of nutrients, which were eventually carried into the oceans. Photo: Peter Campbell

Supermountains controlled the evolution of life on Earth

Fault zone with broken rock inside stippled lines and faulting directions of each rock segment outlined by half arrows. Photo credit: Henrik Drake. Illustration: Mikael Tillberg.

How fault lines in a kitchen sink are changing what we...

Researchers used thermochronometric data from four North American locations to determine the cause of the “Great Unconformity”—a massive loss of rock about 700 million years ago. Credit: Kalin McDannell

New research strengthens link between glaciers and Earth’s ‘Great Unconformity’

The model offers new insights into how the plate subducted under Japan breaks into segments by bending and thereby crushing olivine grains on its underside. (Graphic: Taras Gerya / ETH Zurich)

Crushed resistance: Tectonic plate sinking into a subduction zone

Boudins of amphibolite layers (metamorphosed basalts) that were stretched within quartz schists (Norway). Photo credits © Haakon Fossen.

Fate of sinking tectonic plates is revealed

A map of the World Ocean Floor. Credit: Library of Congress, Geography and Map Division

Geologists take Earth’s inner temperature using erupted sea glass

The cliffs of the volcanic island of Santorini showing the layers of deposits from past volcanic eruptions. Credit: co-author Dr. Ralf Gertisser (Keele University).

Sea levels influence eruptions on volcanic island

A "Plume" in the Earth's mantle, i.e. a surge of hot material, caused the Indian Plate to spin off. (Graphic: Alisha Steinberger)

Supervolcano fed from Earth’s mantle caused crustal plates to rotate

Zircons studied by the research team, photographed using cathodoluminescence, a technique that allowed the team to visualize the interiors of the crystals using a specialized scanning electron microscope. Dark circles on the zircons are the cavities left by the laser that was used to analyze the age and chemistry of the zircons.Scientists led by Michael Ackerson, a research geologist at the Smithsonian's National Museum of Natural History, provide new evidence that modern plate tectonics, a defining feature of Earth and its unique ability to support life, emerged roughly 3.6 billion years ago. The study, published May 14 in the journal Geochemical Perspective Letters, uses zircons, the oldest minerals ever found on Earth, to peer back into the planet's ancient past.The team tested more than 3,500 zircons, each just a couple of human hairs wide, by blasting them with a laser and then measuring their chemical composition with a mass spectrometer. These tests revealed the age and underlying chemistry of each zircon. Of the thousands tested, about 200 were fit for study due to the ravages of the billions of years these minerals endured since their creation. Credit: Michael Ackerson, Smithsonian.

Earth’s oldest minerals date onset of plate tectonics to 3.6 billion...

Elements of a newly discovered process in plate tectonics include a mass (rock slab weight), a pulley (trench), a dashpot (microcontinent), and a string (oceanic plate) that connects these elements to each other. In the initial state, the microcontinent drifts towards the subduction zone (Figure a). The microcontinent then extends during its journey to the subduction trench owing to the tensional force applied by the pull of the rock slab pull across the subduction zone (Figure b). Finally, the microcontinent accretes to the overriding plate and resists subduction due to its low density, causing the down-going slab to break off (Figure c). Credit: Erkan Gün/University of Toronto

Discovery of new geologic process calls for changes to plate tectonic...

A close-up image of bladed barite crystals in the Mapepe Formation in the Barberton Greenstone Belt of South Africa. Credit: Desiree Roerdink

New research uncovers continental crust emerged 500 million years earlier than...

1...345...20Page 4 of 20

Related Articles

All