Sunday, 25 October 2020

Geology: Tectonic plate ‘lost’ for 60M years found hiding under Pacific Ocean

 

Tectonic plate ‘lost’ for 60M years found hiding under Pacific Ocean


By Chris Ciaccia, Fox News, October 23, 2020

(l-r) Jonny Wu, assistant professor of geology in the UH Department of Earth and Atmospheric Sciences and Spencer Fuston, a third-year geology doctoral student, applied a technique developed by the UH Center for Tectonics and Tomography called slab unfolding to reconstruct what tectonic plates in the Pacific Ocean looked like during the early Cenozoic Era. University of Houston


A tectonic plate “lost” for 60 million years under the Pacific Ocean has been reconstructed by scientists at the University of Houston.

Known as Resurrection, the plate has been a controversial topic among geologists because many believe it never existed. Others believe it may have directly resulted in the volcanoes in the Pacific Ocean, known as the Ring of Fire.

“Volcanoes form at plate boundaries, and the more plates you have, the more volcanoes you have,” the study’s co-author, Jonny Wu, assistant professor of geology in the Department of Earth and Atmospheric Sciences, said in a statement. “Volcanoes also affect climate change. So, when you are trying to model the earth and understand how climate has changed since time, you really want to know how many volcanoes there have been on earth.”

Animated Maps: Tectonic Plate Movement, ESRI, Nov 20, 2019

This set of 41 paleo-elevation models (DEM) represents the changing paleogeography of the oceans and continents back to 540 million years ago (Cambrian-Precambrian Period). The snapshots of ancient elevation and bathymetry, based on the interpretation of the rock record, were estimated for time intervals 5 million years apart. The digital elevation model starts when Pangea split into the supercontinents of Laurasia (northern hemisphere) and Gondwana (southern hemisphere). These two continents subsequently subdivided to form the modern continents and ocean basins. India, which rifted from Gondwana ~100 million years ago collided with Asia to form the Himalaya mountains and Tibetan plateau 50 million years ago. The resolution of the data is 1 geographic degree.



The researchers used a computer model of the Earth’s crust to reconstruct the plates of the early Cenozoic era, which started 66 million years ago, not long before the mass extinction event that resulted in the death of the dinosaurs.

At the time, there were two tectonic plates in the Pacific Ocean, the Kula and the Farallon. These plates have long since slid underneath the Earth’s crust, a process known as subduction.

In 2013, a separate group of researchers found evidence that the Farallon is still present in central California and Mexico.

There is lots of magma in modern-day Alaska and Washington state that some geologists argue is the remnants of a long-lost tectonic plate and the subsequent volcanoes near the edge of the plate.

Tectonic plates are constantly moving around the Earth’s surface and bumping up against each other, either forming mountains or sliding under one another, forming subduction zones.

“We believe we have direct evidence that the Resurrection plate existed,” the study’s lead author, Spencer Fuston, added. “We are also trying to solve a debate and advocate for which side our data supports.”

The study has been published in the scientific journal GSA Bulletin.

This image shows plate tectonic reconstruction of western North America 60 million years ago showing subduction of three key tectonic plates, Kula, Farallon and Resurrection. Spencer Fuston and Jonny Wu/Univ

In 2019, Fox News reported that a tectonic plate that appears to be “peeling apart” on the seabed off the coast of Portugal may one day “shrink” the Atlantic Ocean.

In 2018, researchers learned the 8.2 magnitude earthquake that brought devastation and 98 deaths to southern Mexico in September 2017 split the tectonic plate responsible for the quake in half.

Every time them pesky woolly mammoths stampede I feel the earth move!
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