Key component of Earth's crust formed from moving molten rock

March 05, 2008

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.

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

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.

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.
-end-


Cornell University

Related Computer Model Articles from Brightsurf:

Computer model explains altered decision making in schizophrenia
Scientists have built a computer 'brain circuit', or artificial neural network, that mirrors human decision-making processes and sheds light on how circuits might be altered in psychiatric diseases.

Computer model shows how COVID-19 could lead to runaway inflammation
New study addresses a mystery first raised in March: Why do some people with COVID-19 develop severe inflammation?

Computer model predicts how drugs affect heart rhythm
UC Davis Health researchers have developed a computer model to screen drugs for unintended cardiac side effects, especially arrhythmia risk.

Computer model described the dynamic instability of microtubules
Researchers of Sechenov University together with their colleagues from several Russian institutes studied the dynamics of microtubules that form the basis of the cytoskeleton and take part in the transfer of particles within a cell and its division.

Computer model helps make sense of human memory
Researchers at the Okinawa Institute of Science and Technology Graduate University (OIST) and the RIKEN Center for Brain Science have created an artificial network to simulate the brain, demonstrating that tinkering with inhibitory circuits leads to extended memory.

Computer model could help test new sickle cell drugs
A new computer model that captures the dynamics of the red blood cell sickling process could help in evaluating drugs for treating sickle cell disease.

Novel computer model supports cancer therapy
Researchers from the Life Sciences Research Unit (LSRU) of the University of Luxembourg have developed a computer model that simulates the metabolism of cancer cells.

Reverse-engineered computer model provides new insights into larval behavior
Scientists have developed a new approach to describe the behaviors of microscopic marine larvae, which will improve future predictions of how they disperse and distribute.

New computer-aided model may help predict sepsis
Can a computer-aided model predict life-threatening sepsis? A model developed in the UK that uses routinely collected data to identify early symptoms of sepsis, published in CMAJ, shows promise.

'NarcoLogic' computer model shows unintended consequences of cocaine interdiction
Efforts to curtail the flow of cocaine into the United States from South America have made drug trafficking operations more widespread and harder to eradicate.

Read More: Computer Model News and Computer Model Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.