Study Into Earth’s Crust Finds Heat Source That May Stabilise Continents

Related Articles

Related Articles

Rocks from the Rio Grande continental rift have provided a rare snapshot of active geology deep inside Earth’s crust, revealing new evidence for how continents remain stable over billions of years, according to a team of scientists.

“We tend to study rocks that are millions to billions of years old, but in this case we can show what’s happening in the deep crust, nearly 19 miles below the surface of the Earth, in what geologically speaking is the modern day,” said Jacob Cipar, a graduate student in geosciences at Penn State. “And we have linked what’s preserved in these rocks with tectonic processes happening today that may represent an important step in the development of stable continents.”

The team, led by Penn State scientists, found evidence that heat from the mantle is melting the lower crust at the rift, where tectonic forces are pulling apart and thinning the lithosphere, or the crust and upper mantle that make up the rigid outer layer of Earth.


Heating the continental crust is considered important to its development. But the process is often associated with crustal thickening, when continental plates collide and form mountains like the Himalayas, the scientists said.

“Our research suggests that these rocks that have been thought of as related to mountain building may have actually been cooked by a thinning lithosphere like what’s happening in the modern-day Rio Grande rift,” Cipar said. “And more broadly, thinning lithosphere may be more important than previously recognized for stabilizing continents and preventing them from sinking back into the mantle.”

The researchers recently reported their findings in the journal Nature Geoscience.

Earth’s continents feature a unique silicon-rich, buoyant crust that allows land to rise above sea level and host terrestrial life, the scientists said. The crust also contains heat-producing elements like uranium that could destabilize it over geological time.

Heating the crust creates molten rock that carries those elements toward the surface, resulting in a cooler and stronger lower crust that can protect continents from being absorbed into the mantle, the scientists said. But questions remain about the sources of that heat.

“We are suggesting that thinning of the lithosphere is really the removal of a barrier that keeps that heat away from the crust,” said Andrew Smye, assistant professor of geosciences at Penn State and Cipar’s adviser. “Removing or thinning that barrier at the Rio Grande rift appears to be what is generating the heat needed to initiate this process of stabilizing continental crust. And this has been overlooked in our understanding of how continents become so stable.”

The scientists tapped into rocks brought to the surface 20,000 years ago by volcanoes in New Mexico. The rocks are considered geologically young and are significant because they retain the context of the lower crust, the scientists said.

“In contrast, what we see in the rock record around the world is that oftentimes what it takes to get them up to the surface has disrupted their original relationship with the lower crust,” said Joshua Garber, a postdoctoral researcher at Penn State. “This makes it really challenging to use older rocks to try to understand tectonics, and it makes the Rio Grande probably the best place to do this research.”

The scientists used analytical techniques to link the age of minerals in the rocks to the pressure and temperature they faced as they made their way through the crust.

Similarities between the pressure and temperature path from the Rio Grande lower crust and rocks from other locations suggest that a thinning lithosphere is important for stabilizing Earth’s continents, the scientists said.

“The snapshots of data we do have from other locations really nicely aligns with what we found in the Rio Grande rift,” Garber said. “So that tells us this is not just happening now in the western United States. This shows the guts of continents have probably undergone this globally at least for the last billion years.”


Header Image Credit : Dicklyon – CC BY-SA 3.0

Download the HeritageDaily mobile application on iOS and Android

More on this topic


Tenochtitlan – The Aztec Capital

Tenochtitlan was the capital of the Aztec civilisation, situated on a raised islet in the western side of the shallow Lake Texcoco, which is now the historic part of present-day Mexico City.

Archipelago in Ancient Doggerland Survived Storegga Tsunami 8,000-Years-Ago

Doggerland, dubbed “Britain’s Atlantis” is a submerged landmass beneath what is now the North Sea, that once connected Britain to continental Europe.

Cereal, Olive & Vine Pollen Reveal Market Integration in Ancient Greece

In the field of economics, the concept of a market economy is largely considered a modern phenomenon.

The Annulment of Henry VIII to Catherine of Aragon at Dunstable Priory

The Priory Church of St Peter (Dunstable Priory) is the remaining nave of a former Augustinian priory church and monastery, that today is part of the Archdeaconry of Bedford, located within the Diocese of St Albans in the town of Dunstable, England.

Teōtīhuacān – Birthplace of the Gods

Teōtīhuacān, named by the Nahuatl-speaking Aztecs, and loosely translated as "birthplace of the gods" is an ancient Mesoamerican city located in the Teotihuacan Valley of the Free and Sovereign State of Mexico, in present-day Mexico.

Chetro Ketl – The Great House

Chetro Ketl is an archaeological site, and the ancient ruins of an Ancestral Puebloan settlement, located in the Chaco Culture National Historical Park, New Mexico, United States of America.

The Gila Cliff Dwellings

The Gila Cliff Dwellings is an archaeological site, and ancient settlement constructed by the pueblos Mimbres branch of the Mogollon, located in southwest New Mexico of the United States of America.

Rare Cretaceous-Age Fossil Opens New Chapter in Story of Bird Evolution

A Cretaceous-age, crow-sized bird from Madagascar would have sliced its way through the air wielding a large, blade-like beak and offers important new insights on the evolution of face and beak shape in the Mesozoic forerunners of modern birds.

Popular stories

Teōtīhuacān – Birthplace of the Gods

Teōtīhuacān, named by the Nahuatl-speaking Aztecs, and loosely translated as "birthplace of the gods" is an ancient Mesoamerican city located in the Teotihuacan Valley of the Free and Sovereign State of Mexico, in present-day Mexico.

Legio IX Hispana – The Lost Roman Legion

One of the most debated mysteries from the Roman period involves the disappearance of the Legio IX Hispana, a legion of the Imperial Roman Army that supposedly vanished sometime after AD 120.

The Secret Hellfire Club and the Hellfire Caves

The Hellfire Club was an exclusive membership-based organisation for high-society rakes, that was first founded in London in 1718, by Philip, Duke of Wharton, and several of society's elites.

Port Royal – The Sodom of the New World

Port Royal, originally named Cagway was an English harbour town and base of operations for buccaneers and privateers (pirates) until the great earthquake of 1692.