Study: Recycling of Earth's Crust Started 3 Billion Years Ago
March 19, 2012 5:49 PM
comment(s) - last by
Researchers say the recycling began around the same time as the start of plate tectonics
A researcher from England has found that the Earth started recycling its crust approximately 3 billion years ago at the
start of plate tectonics
Bruno Dhuime, an isotope geochemist at the University of Bristol in England, explained that a surface of new continental crust covered much of the Earth 3 billion years ago until our planet began recycling it.
Dhuime and his team made this discovery after taking a closer look at zircon minerals found in sediments. These sediments were extracted from North America, Australia, South America and Eurasia.
The team particularly focused on the isotopes inside the sediments, which are atoms of the same element but with different numbers of neutrons. By looking at the oxygen isotope composition, they were able to tell if the sediments had come from new crust that wasn't affected by plate tectonics or recycled crust.
According to Dhuime, sediment in newly formed crust would have a narrow range of oxygen-18 to oxygen-16 ratios while
would have a much broader range of oxygen-18 to oxygen-16 ratios. Recycled crust has a broader range because of the influence of factors such as life.
They concluded that the Earth's first 1.5 billion years had an average net new crust growth rate of 0.7 cubic miles per year, which was high. However, this rate slowed 3 billion years ago by about a third. Dhuime said this decrease was due to "a change in the way the continental crust was generated." These changes occurred around the time of the start of plate tectonics, where oceanic and continental plates were finally solid enough to start running into each other.
"The new approach we developed based on the chemical information in the mineral zircon enables us to predict in a very accurate way the volume of continental crust that was present throughout Earth's evolution," said Dhuime. "Our next challenge is to determine which tectonic regime shaped the Earth's crust back before 3 billion years in the Archean and Hadean eons. The scarcity of rocks older than 3 billion years preserved on Earth's surface may, however, constitute an obstacle in future research."
This article is over a month old, voting and posting comments is disabled
RE: good luck...
3/20/2012 2:29:41 PM
Ok, here are some rocks for sale...
"I mean, if you wanna break down someone's door, why don't you start with AT&T, for God sakes? They make your amazing phone unusable as a phone!" -- Jon Stewart on Apple and the iPhone
Fossilized Plankton Provide Insight into Earth's Ancient Atmosphere
February 23, 2011, 4:40 PM
Pacific Northwest Should Prepare for "The Big One", Claims OSU
May 25, 2010, 10:33 AM
Creationists are Mad About Google Doodle Depicting Evolution
November 24, 2015, 8:48 PM
DHS and TSA: Whoops, We Missed That 73 Airport Employees May be Terrorists
November 19, 2015, 2:16 PM
Star Wars Spinoff Film "Rogue One", Theme Park Attractions Announced
August 17, 2015, 12:20 PM
SpaceX Falcon 9's Seventh Supply Mission to ISS Ends w/ Fiery Stage 1 Explosion
June 28, 2015, 1:10 PM
Cool Science Video: Glowing Millipede Prowls the Nevada Desert
May 18, 2015, 12:00 PM
Newly Discovered Costa Rican Glass Frog is Kermit's Doppelgänger
April 22, 2015, 11:26 AM
Latest Blog Posts
Sceptre Airs 27", 120 Hz. 1080p Monitor/HDTV w/ 5 ms Response Time for $220
Dec 3, 2014, 10:32 PM
Costco Gives Employees Thanksgiving Off; Wal-Mart Leads "Black Thursday" Charge
Oct 29, 2014, 9:57 PM
"Bear Selfies" Fad Could Turn Deadly, Warn Nevada Wildlife Officials
Oct 28, 2014, 12:00 PM
The Surface Mini That Was Never Released Gets "Hands On" Treatment
Sep 26, 2014, 8:22 AM
ISIS Imposes Ban on Teaching Evolution in Iraq
Sep 17, 2014, 5:22 PM
More Blog Posts
Copyright 2016 DailyTech LLC. -
Terms, Conditions & Privacy Information