24/7 Space News
TECTONICS
A mineral produced by plate tectonics has a global cooling effect, study finds
MIT geologists have found that tectonic activity gives rise to smectite, a type of clay that can sequester a surprising amount of organic carbon within its microscopic folds (shown here), over millions of years. Credits:Credit: Photo courtesy of Anthony Priestas, Boston University
A mineral produced by plate tectonics has a global cooling effect, study finds
by Jennifer Chu | MIT News
Boston MA (SPX) Dec 01, 2023

MIT geologists have found that a clay mineral on the seafloor, called smectite, has a surprisingly powerful ability to sequester carbon over millions of years.

Under a microscope, a single grain of the clay resembles the folds of an accordion. These folds are known to be effective traps for organic carbon.

Now, the MIT team has shown that the carbon-trapping clays are a product of plate tectonics: When oceanic crust crushes against a continental plate, it can bring rocks to the surface that, over time, can weather into minerals including smectite. Eventually, the clay sediment settles back in the ocean, where the minerals trap bits of dead organisms in their microscopic folds. This keeps the organic carbon from being consumed by microbes and expelled back into the atmosphere as carbon dioxide.

Over millions of years, smectite can have a global effect, helping to cool the entire planet. Through a series of analyses, the researchers showed that smectite was likely produced after several major tectonic events over the last 500 million years. During each tectonic event, the clays trapped enough carbon to cool the Earth and induce the subsequent ice age.

The findings are the first to show that plate tectonics can trigger ice ages through the production of carbon-trapping smectite.

These clays can be found in certain tectonically active regions today, and the scientists believe that smectite continues to sequester carbon, providing a natural, albeit slow-acting, buffer against humans' climate-warming activities.

"The influence of these unassuming clay minerals has wide-ranging implications for the habitability of planets," says Joshua Murray, a graduate student in MIT's Department of Earth, Atmospheric, and Planetary Sciences. "There may even be a modern application for these clays in offsetting some of the carbon that humanity has placed into the atmosphere."

Murray and Oliver Jagoutz, professor of geology at MIT, have published their findings in Nature Geoscience.

A clear and present clay
The new study follows up on the team's previous work, which showed that each of the Earth's major ice ages was likely triggered by a tectonic event in the tropics. The researchers found that each of these tectonic events exposed ocean rocks called ophiolites to the atmosphere. They put forth the idea that, when a tectonic collision occurs in a tropical region, ophiolites can undergo certain weathering effects, such as exposure to wind, rain, and chemical interactions, that transform the rocks into various minerals, including clays.

"Those clay minerals, depending on the kinds you create, influence the climate in different ways," Murray explains.

At the time, it was unclear which minerals could come out of this weathering effect, and whether and how these minerals could directly contribute to cooling the planet. So, while it appeared there was a link between plate tectonics and ice ages, the exact mechanism by which one could trigger the other was still in question.

With the new study, the team looked to see whether their proposed tectonic tropical weathering process would produce carbon-trapping minerals, and in quantities that would be sufficient to trigger a global ice age.

The team first looked through the geologic literature and compiled data on the ways in which major magmatic minerals weather over time, and on the types of clay minerals this weathering can produce. They then worked these measurements into a weathering simulation of different rock types that are known to be exposed in tectonic collisions.

"Then we look at what happens to these rock types when they break down due to weathering and the influence of a tropical environment, and what minerals form as a result," Jagoutz says.

Next, they plugged each weathered, "end-product" mineral into a simulation of the Earth's carbon cycle to see what effect a given mineral might have, either in interacting with organic carbon, such as bits of dead organisms, or with inorganic, in the form of carbon dioxide in the atmosphere.

From these analyses, one mineral had a clear presence and effect: smectite. Not only was the clay a naturally weathered product of tropical tectonics, it was also highly effective at trapping organic carbon. In theory, smectite seemed like a solid connection between tectonics and ice ages.

But were enough of the clays actually present to trigger the previous four ice ages? Ideally, researchers should confirm this by finding smectite in ancient rock layers dating back to each global cooling period.

"Unfortunately, as clays are buried by other sediments, they get cooked a bit, so we can't measure them directly," Murray says. "But we can look for their fingerprints."

A slow build
The team reasoned that, as smectites are a product of ophiolites, these ocean rocks also bear characteristic elements such as nickel and chromium, which would be preserved in ancient sediments. If smectites were present in the past, nickel and chromium should be as well.

To test this idea, the team looked through a database containing thousands of oceanic sedimentary rocks that were deposited over the last 500 million years. Over this time period, the Earth experienced four separate ice ages. Looking at rocks around each of these periods, the researchers observed large spikes of nickel and chromium, and inferred from this that smectite must also have been present.

By their estimates, the clay mineral could have increased the preservation of organic carbon by less than one-tenth of a percent. In absolute terms, this is a miniscule amount. But over millions of years, they calculated that the clay's accumulated, sequestered carbon was enough to trigger each of the four major ice ages.

"We found that you really don't need much of this material to have a huge effect on the climate," Jagoutz says.

"These clays also have probably contributed some of the Earth's cooling in the last 3 to 5 million years, before humans got involved," Murray adds. "In the absence of humans, these clays are probably making a difference to the climate. It's just such a slow process."

"Jagoutz and Murray's work is a nice demonstration of how important it is to consider all biotic and physical components of the global carbon cycle," says Lee Kump, a professor of geosciences at Penn State University, who was not involved with the study. "Feedbacks among all these components control atmospheric greenhouse gas concentrations on all time scales, from the annual rise and fall of atmospheric carbon dioxide levels to the swings from icehouse to greenhouse over millions of years."

Could smectites be harnessed intentionally to further bring down the world's carbon emissions? Murray sees some potential, for instance to shore up carbon reservoirs such as regions of permafrost. Warming temperatures are predicted to melt permafrost and expose long-buried organic carbon. If smectites could be applied to these regions, the clays could prevent this exposed carbon from escaping into and further warming the atmosphere.

"If you want to understand how nature works, you have to understand it on the mineral and grain scale," Jagoutz says. "And this is also the way forward for us to find solutions for this climatic catastrophe. If you study these natural processes, there's a good chance you will stumble on something that will be actually useful."

Research Report:"Palaeozoic cooling modulated by ophiolite weathering through organic carbon preservation"

Related Links
Department of Earth, Atmospheric and Planetary Sciences
Tectonic Science and News

Subscribe Free To Our Daily Newsletters
Tweet

RELATED CONTENT
The following news reports may link to other Space Media Network websites.
TECTONICS
Dual hydration of oceanic lithosphere
Shenzhen, China (SPX) Nov 08, 2023
This study is led by Dr. Jian Lin (Southern University of Science and Technology) and Dr. Fan Zhang (South China Sea Institute of Oceanology, Chinese Academy of Sciences). "Water is crucial to processes of both Earth's surface and interior, facilitating plate tectonics and making the Earth a habitable planet. Seawater penetrates into oceanic lithosphere through fractures on seafloor and migrates along faults and pores. The distribution of water governs the style of convective flow and distinct tectonic ... read more

TECTONICS
NASA awards $2.3 million to study growing food in lunar dust

Earth bacteria could make lunar soil more habitable for plants

Big bang: Dutch firm eyes space baby

Cosmic currents: Preserving water quality for astronauts during space exploration

TECTONICS
UK Space Agency backs Orbit Fab's innovative refueling interface, GRASP

Ariane 6 Core Stage fires up for long-duration test

Report Forecasts Significant Growth in Hypersonic Flight Market by 2030

US 'strongly condemns' N. Korean space launch

TECTONICS
Perseverance's Parking Spot

NASA uses two worlds to test future Mars helicopter designs

California lawmakers ask NASA not to cut Mars budget

Spacecraft fall silent as Mars disappears behind the Sun

TECTONICS
Shanghai Sets Sights on Expanding Space Industry with Ambitious 2025 Goals

China's BeiDou and Fengyun Satellites Elevate Global Weather Forecasting Capabilities

New scientific experimental samples from China's space station return to Earth

Shenzhou XVI crew return after 'very cool journey'

TECTONICS
Embry-Riddle's Innovative Mission Control Lab prepares students for booming space sector

A major boost for space skills and research in North East England

GalaxySpace to boost mobile broadband with new-gen satellite technology

SpaceX launches more Starlink satellites from Cape Canaveral

TECTONICS
Six recycling innovations that could change fashion

Map highlights environmental and social costs of rare earths extraction

Canadian mining firm seeks to suspend 7,000 workers in Panama

Developing a superbase-comparable BaTiO3-xNy oxynitride catalyst

TECTONICS
Minimalist or maximalist? The life of a microbe a mile underground

Deformable Mirrors in Space: Key Technology to Directly Image Earth Twins

Hubble measures the size of the nearest transiting Earth-sized planet

Webb detects water vapor, sulfur dioxide and sand clouds in the atmosphere of a nearby exoplanet

TECTONICS
Juice burns hard towards first-ever Earth-Moon flyby

Fall into an ice giant's atmosphere

Juno finds Jupiter's winds penetrate in cylindrical layers

Salts and organics observed on Ganymede's surface by June

Subscribe Free To Our Daily Newsletters




The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.