• Email Us: [email protected]
  • Contact Us: +1 718 874 1545
  • Skip to main content
  • Skip to primary sidebar

Medical Market Report

  • Home
  • All Reports
  • About Us
  • Contact Us

Earth’s Core May Be Surrounded By The Remains Of Ancient Oceanic Crusts

April 6, 2023 by Deborah Bloomfield

Seismic waves reveal thin but dense layers of material sitting between Earth’s core-mantle boundary in parts of the world. One team of geologists suspects it is composed of material that once formed the ocean floor, before being pushed down into the mantle by overriding continental plates.

Some parts of the continents date back most of the way to Earth’s beginnings, while more typical areas are still billions of years old. The ocean floor is a different matter, being produced constantly at mid-ocean ridges, it then gets returned to the mantle at subduction zones where the lighter continental plates ride over the top. Little has survived from more than 200 million years ago, frustrating the search for older impact craters. 

Advertisement

This discovery, a crucial part of the theory of tectonic plates, left open the question of what happens to the oceanic crust once it reaches the mantle, passing beyond our capacity to see it. A team led by Professor Samantha Hansen of the University of Alabama has revealed the likely answer in a new paper: at least some sinks to the bottom of the mantle and collects around Earth’s core.

Our knowledge of the interior structure of the planet depends on the way seismic waves produced by earthquakes bend and bounce when they encounter the boundaries between layers. In recent years our capacity to measure these waves has improved. 

“We are finding that this structure is vastly more complicated than once thought,” Hansen said in a statement. Co-author Dr Edward Garnero described finding “Mountains on the core, in some places up to five times taller than Mt. Everest.”

Hansen and co-authors investigated ultra-low velocity zones (ULVZs), which as its name suggests are regions at the bottom of the mantle where seismic waves slow down. Since their discovery, ULZVs have attracted the attention of geologists worldwide. Previous research revealed they are layered, with thin strata of varying compositions, but that doesn’t explain their origins. 

Advertisement

Hansen thinks that what we have learned about ULVZs fits with them being composed of oceanic crust deposited beneath subduction zones.

“Our research provides important connections between shallow and deep Earth structure and the overall processes driving our planet,” Hansen added.

The ULZVs are more than just the crust’s waste disposal service. Their presence or absence could shape where heat escapes from the Earth’s core. This in turn could influence the presence of hotspots, such as those that produced Hawaii and Iceland.

Seismic equipment is lowered into place at one of the Antarctic stations in 2012.

When scientists say they have to go to the ends of the Earth for their research, some mean it literally, such as this team lowering seismic detectors into the Antarctic ice. Image credit: Photo courtesy of Lindsey Kenyon.

 ULZVs are poorly understood because the waves suited to probing them are only produced by rare forms of earthquakes. When they do occur, the waves don’t always surface in the most convenient parts of the planet. Less than 20 percent of the boundary between the core and mantle has been surveyed for the presence of ULVZs. Hansen and her students had to repeatedly visit Antarctica to install the monitoring devices they needed. Even where surveys have taken place, existing methods are unable to detect ULVZs less than 5 kilometers (3 miles) thick, so areas considered ULVZ-free may just have a very thin layer.

Advertisement

The ULVZ the team focused on is not under any existing subduction zone, but given the way the continents move around it is plausible it was once and we have found the ancient remains. Indeed, modeling suggests it would take more than 100 million years for crustal material to descend through the 2,000-kilometer (1,200-mile) thick mantle.

The study is published in Science Advances.

Deborah Bloomfield
Deborah Bloomfield

Related posts:

  1. Pandemic-hit Qantas weighs new pay structure to keep key executives
  2. European stocks rise on AstraZeneca, ASM strength
  3. Looking To Boost Your Brand? You Need This Voice-Over Subscription
  4. Porcine Pacifists Help Break Up Fights Between Fellow Pigs

Source Link: Earth’s Core May Be Surrounded By The Remains Of Ancient Oceanic Crusts

Filed Under: News

Primary Sidebar

  • The First American To Fly Into Space Had To Pee In His Space Suit
  • The Biggest Chemical Cover-Up In History Was Kept Hidden For Years
  • Can You Hear Electricity?
  • Newest Member Of The Solar System Just Announced, Capuchins Have Started Stealing Baby Howler Monkeys, And Much More This Week
  • Capuchin Kidnappers, Spinosaurus Daddy, And A New Member Of The Solar System
  • Plastic Rocks Are A “New And Terrifying” Phenomenon Coming To A Shore Near You
  • “We Also Tried Remote Control Cars Dressed As Females”: How Scientists Took On Rare Kākāpō Artificial Insemination
  • “Missing Americans”: US Excess Deaths Still Above Pre-COVID Levels, Upwards Of 1 Million
  • Clever Hawk Spotted Using Pedestrian Crossing To Catch Prey In New Jersey
  • There’s A Bold And Controversial Theory That Jesus Was A Hallucinogenic Mushroom
  • You Don’t Have 5 Senses, You Have Way More Than That
  • Space Oddity: The Atmosphere Of Titan Spins In A Different Way From The Saturnian Moon
  • Hummingbirds Have Rapidly Evolved In California Over The Past Century
  • The Moon’s Mysterious Magnetic Rocks Might Have A Cataclysmic Explanation
  • The Earth’s Core Is Leaking. The Result: More Gold
  • Over 40 Percent Of Kids In A US Study Thought Bacon Was A Plant
  • Fossil Mystery Reveals New Species Of 85-Million-Year-Old Sea Monster, And It’s “Very Odd”
  • Can’t Handle The Heat? A Potential “Anti-Spice” Could Tame Spicy Food
  • We Now Know When Denisovans, Neanderthals, And Modern Humans Inhabited Denisova Cave
  • Tailless Alligator Shocks Passersby On Highway In Southern Louisiana
  • Business
  • Health
  • News
  • Science
  • Technology
  • +1 718 874 1545
  • +91 78878 22626
  • [email protected]
Office Address
Prudour Pvt. Ltd. 420 Lexington Avenue Suite 300 New York City, NY 10170.

Powered by Prudour Network

Copyrights © 2025 · Medical Market Report. All Rights Reserved.

Go to mobile version