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plate tectonics

plate tectonics

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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.
plate tectonics

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

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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
plate tectonics

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

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

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

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Bathymetric chart of a part of the Red Sea. Source GEOMAR.
plate tectonics

Red Sea is no longer a baby ocean

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From left, University of Wyoming students Shane Scoggin, Adam Trzinski and Jessie Shields are part of new research investigating crustal melting in western North America. Here, they examine igneous rocks in the Snake Range of Nevada. Credit: Jay Chapman
plate tectonics

Scientists probe mysterious melting of Earth’s crust in western North America

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The Atlantis II fracture zone in the southwestern Indian Ocean with a zoom on the northern corner. The greater water depth in the transform valley is clearly visible. As the plates move, magmatism in the corners refills the deep transform valleys so that the adjacent fracture zones are shallower. Graphic: Christoph Kersten/GEOMAR according to Grevemeyer et al., 2021
plate tectonics

A new view on plate tectonics

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In this image, the warped amount of the surface is due to the opening of the Central American gateway that allowed hot material to flow through. (a) Before 8.5 million years ago, hot material was upwelling under the Galapagos from deep inside the Earth, but was blocked out of the Caribbean because of a curtain of subducting plate. (b) A gateway opened at 8.5 million years ago allowing the hot material to flow through. (c) Today, the hot material reaches midway between Central America and the Lesser Antilles, tilting up the bottom of the Caribbean sea by about 300 m (1,000 ft). Credit: University of Houston
plate tectonics

Geologists discover powerful ‘river of rocks’ below Caribbean

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Using a method to better locate the source of weak tremors from regions with complex geological features, researchers found that many tremors originate from the shear zone, an area of high fluid pressure, in the Nankai Trough, which is schematically shown here with structures of tectonic plates and fault lines.
plate tectonics

Making sense of commotion under the ocean to locate tremors near...

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The Middle America Trench, seen here as a dark blue strip off the Pacific coast of Central America, is a surface feature of a subduction zone extending from Mexico to Costa Rica. Credit: NOAA
plate tectonics

Subduction may recycle less water than thought

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Mylonite is a fine-grained, compact metamorphic rock produced by dynamic recrystallization of the constituent minerals resulting in a reduction of the grain size of the rock. Credit: Wikipedia
plate tectonics

Going with the grains to explain a fundamental tectonic force

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39 Ocean Bottom Seismometers where deployed on the ocean floor across the Mid-Atlantic Ridge as part of the PI-LAB experiment. Credit: University of Southampton
plate tectonics

Geological phenomenon widening the Atlantic Ocean

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Photo: © Christian S. Marien
plate tectonics

Slow start of plate tectonics despite a hot early Earth

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Looking at the Toaroha River, near New Zealand’s Alpine Fault. | GNS Science
plate tectonics

Seismic activity of New Zealand’s alpine fault more complex than suspected

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The quantitative model used in the study explains the enigmatic melt degrees and layered structures observed in most cratons on Earth.
plate tectonics

Continents prone to destruction in their infancy, study finds

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Distribution of snow and ice in winter and summer on Aurica (left) and Amasia. Credit: Way et al. 2020
plate tectonics

What will the climate be like when Earth’s next supercontinent forms?

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Schematic diagram showing the geometry of a typical subduction zone and the production of arc volcanoes. Credit: Xiaotao Yang
plate tectonics

Piecing together the Alaska coastline’s fractured volcanic activity

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A graphic showing the convective heat cycle (red arrows) that drives plate tectonic motion (black arrows) on Earth. Heat flows toward subduction zones through the uppermost mantle layer, the asthenosphere. A computer model from Rice University finds that the asthenosphere can locally drag plates along with it rather than acting exclusively as a brake on plate movements as had been widely believed. (Image courtesy of Surachit/Wikimedia Commons)
plate tectonics

Former piece of Pacific Ocean floor imaged deep beneath China

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Final model for the East African Rift System. Hashed lines indicate newly discovered broad deforming zone. Arrows represent predicted tectonic plate motions. ABFZ—Andrew Bain Fracture Zone; IFZ—Indomed Fracture Zone; RSZ—Ranotsara shear zone. Figure created by D.S. Stamps.
plate tectonics

East African Rift System is slowly breaking away, with Madagascar splitting...

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The journey of Hawaii's pancake from its creation at the mantle plume to where it slipped under the Pacific plate and sunk deep into the Earth's mantle. Credit: Michigan State University
plate tectonics

Researchers discover ‘missing’ piece of Hawaii’s formation

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Three-dimensional visualisation of partial melting at the base of tectonic plates. The orange iso-surfaces show the regions where, at a depth of between 100 and 300 km, the quantity of molten rock is greater than 0.2%. The white sphere in the centre of the globe represents the Earth’s core. Credit © Stéphanie Durand, Laboratoire de géologie de Lyon: Terre, planètes et environnement (CNRS/ENS de Lyon/Université Claude Bernard Lyon 1).
plate tectonics

Deep magma facilitates the movement of tectonic plates

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