Featured Research

from universities, journals, and other organizations

Key Component Of Earth's Crust Formed From Moving Molten Rock

Date:
March 9, 2008
Source:
Cornell University
Summary:
By studying what were once pockets of hot, melted rock 13 kilometers deep in the Earth's crust 55 million years ago, scientists are able to explain how granulite, a major component of continental crust, is formed.

Gabriela Depine, left, and Chris Andronicos in the Coast Mountains of British Columbia.
Credit: Gabriela Depine

Earth scientists are in the business of backing into history -- extrapolating what happened millions of years ago based on what they can observe now. Using this method, a team of Cornell researchers has created a mathematical computer model of the formation of granulite, a fine-grained metamorphic rock, in the Earth's crust.

By studying what were once pockets of hot, melted rock 13 kilometers (about 8 miles) deep in the Earth's crust 55 million years ago and calculating the period of cooling, the scientists were able to explain how granulite is formed as the molten rock migrates up through the crust.

Granulite, composed mainly of feldspars, has no residual water and is called metamorphic because it is formed in temperatures of greater than 800 degrees Celsius (1,472 degrees Fahrenheit). It is a major component of the continental crust.

Working in British Columbia in summer 2006, the researchers puzzled over the formation of granulite, which, unlike other rocks, forms under a wide range of depths but under a narrow range of temperatures. In many places on Earth, temperature is assumed to vary linearly with depth -- that is, the deeper the crust, the hotter the rock.

The researchers decided to mathematically recreate the formation of granulite at various depths, to see if they could come up a method that mirrors the natural formation of the rock.

They did so by looking at plutons, or pockets of hot, melted rock that were once as much as 13 kilometers below the Earth's surface but are now exposed. (Plutons that rise to the surface and erupt can become volcanoes.) The researchers found that as melted rock deep in the Earth becomes buoyant and migrates up through the crust, granulite can form at various depths but at similar temperatures.

The research is published in the March issue of the journal Nature by Gabriela V. Depine, a fourth-year graduate student in earth and atmospheric sciences (EAS); Christopher L. Andronicos, an EAS associate professor; and Jason Phipps-Morgan, professor of EAS.

Looking at the melting process is like looking at the process of the formation of continents, Andronicos explained.

"If you look over geologic time, not all the rocks are the same age, and the reason for that is they got formed at different times," he said. "So if you can get a handle on the temperature, which is what controls melting and metamorphism, then you have a better idea of some of the fundamental controls that lead to rock formation, and therefore continents."

The computer model, he said, will hopefully provide further insight into the energy balance of the Earth during crustal formation.

The research is funded by Cornell and by the National Science Foundation's Continental Dynamics program.

 


Story Source:

The above story is based on materials provided by Cornell University. Note: Materials may be edited for content and length.


Cite This Page:

Cornell University. "Key Component Of Earth's Crust Formed From Moving Molten Rock." ScienceDaily. ScienceDaily, 9 March 2008. <www.sciencedaily.com/releases/2008/03/080305144216.htm>.
Cornell University. (2008, March 9). Key Component Of Earth's Crust Formed From Moving Molten Rock. ScienceDaily. Retrieved April 23, 2014 from www.sciencedaily.com/releases/2008/03/080305144216.htm
Cornell University. "Key Component Of Earth's Crust Formed From Moving Molten Rock." ScienceDaily. www.sciencedaily.com/releases/2008/03/080305144216.htm (accessed April 23, 2014).

Share This



More Earth & Climate News

Wednesday, April 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

California Drought Is Good News for Gold Prospectors

California Drought Is Good News for Gold Prospectors

AFP (Apr. 22, 2014) — For months California has suffered from a historic drought. The lack of water is worrying for farmers and ranchers, but for gold diggers it’s a stroke of good fortune. With water levels low, normally inaccessible areas are exposed. Duration: 01:57 Video provided by AFP
Powered by NewsLook.com
Raw: MN Lakes Still Frozen Before Fishing Opener

Raw: MN Lakes Still Frozen Before Fishing Opener

AP (Apr. 22, 2014) — With only three weeks until Minnesota's fishing opener, many are wondering if the ice will be gone. Some of the Northland lakes are still covered by up to three feet of ice, causing concern that just like last year, the lakes won't be ready. (April 22) Video provided by AP
Powered by NewsLook.com
Is North Korea Planning Nuclear Test #4?

Is North Korea Planning Nuclear Test #4?

Newsy (Apr. 22, 2014) — South Korean officials say North Korea is preparing to conduct another nuclear test, but is Pyongyang just bluffing this time? Video provided by Newsy
Powered by NewsLook.com
Nasa Gives You An Excuse to Post a Selfie on Earth Day

Nasa Gives You An Excuse to Post a Selfie on Earth Day

TheStreet (Apr. 22, 2014) — NASA is inviting all social media users to take a selfie of themselves alongside nature and to post it to Twitter, Facebook, Flickr, Instagram, or Google Plus with the hashtag #globalselfie. NASA's goal is to crowd-source a collection of snapshots of the earth, ground-up, that will be used to create one "unique mosaic of the Blue Marble." This image will be available to all in May. Since this is probably one of the few times posting a selfie to Twitter won't be embarrassing, we suggest you give it a go for a good cause. Video provided by TheStreet
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins