back to top
27.8 C
New York
Tuesday, December 31, 2024
Home Tags Plate tectonics

Tag: plate tectonics

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...

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

Red Sea is no longer a baby ocean

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

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

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

A new view on plate tectonics

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

Geologists discover powerful ‘river of rocks’ below Caribbean

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.

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

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

Subduction may recycle less water than thought

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

Going with the grains to explain a fundamental tectonic force

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

Geological phenomenon widening the Atlantic Ocean

Photo: © Christian S. Marien

Slow start of plate tectonics despite a hot early Earth

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

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

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

Continents prone to destruction in their infancy, study finds

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

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

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

Piecing together the Alaska coastline’s fractured volcanic activity

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)

Former piece of Pacific Ocean floor imaged deep beneath China

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.

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

1...345...19Page 4 of 19

Related Articles

All
Facebook Instagram Linkedin TikTok Twitter Youtube
© © 2011-2024. All Rights Reserved.