Nav: Home

New study describes 200 million years of geological evolution

December 05, 2016

Tectonic plates, big sections of Earth's crust and blocks underneath them, are constantly moving. The areas where these sections meet and interact are called faults. They appear as scars on the outermost layer of the Earth. A lot is going on along the largest of faults: mountains can grow, volcanoes can erupt, continents can separate and earthquakes happen.

Also more discrete events are constantly happening close to faults: The emission of the greenhouse gas methane from ocean floor commonly occurs in gas hydrate provinces along tectonically active continental margins.

Active methane seepage happening frequently

This is what makes brittle faults particularly alluring for CAGE/NGU researcher Jochen Knies. He is one of the coauthors of a new study in Nature Communications that, for the first time, precisely dates the evolution of a brittle fault from its initial formation to its later reactivation.

Brittle faults may be important because they open up pathways along which methane, released from the reservoirs deep under the Earth's crust, can migrate to shallower depths or even into the ocean itself.

"Active methane leakage from the sea floor happens episodically, and frequently. Some seeps activate annually, others become active on a millennial scale. We need to better identify and characterize timing and duration of these leaks. It is critical for our understanding of the role the natural gas emissions play on global climate." says Jochen Knies, researcher at CAGE/NGU.

The story of the faults is the story of methane release

Methane is a very potent greenhouse gas. The impacts of the industrial and agricultural release of the gas are well known and mapped. But the effects and quantities of the natural release of the gas, especially from the ocean floor, are poorly understood. Recent studies show that this natural release has been heavily underestimated.

The Nature Communications study focuses on brittle faults and fractures onshore in western Norway. Up to now, applications for directly fingerprinting the age of brittle faulting and reactivation - and thus potentially the timing of gas emission through the crust - did not exist.

"We have managed to precisely date several episodes of faulting and reactivation of brittle faults onshore Norway. Our study unravels and dates a complex evolution of the local brittle deformation, which straddles a 200 million year timespan." says Giulio Viola, the lead-author of the study .

The onshore study gives scientists the necessary tools to understand the age of offshore faults, which are important for methane release from gas hydrate provinces.

Improving the models and estimates of methane release

The innovative method behind the study combines a twofold approach: the detailed structural analysis of faults, and the dating of their history by applying potassium/argon dating of the clay mineral illite. The faulting causes deformations in which illite can form, and just a few milligrams of the clay mineral are enough to do this type of dating.

"Testing this toolbox on fault and fracture systems below active sites of methane leakages, would potentially provide an innovative and unique possibility: By constraining the timing of offshore faulting episodes, we may ultimately be able to identify the events of increased methane emission to the ocean and atmosphere. These episodes are not something that is restricted to the past. They are happening now, and will be happening frequently in the future", concludes Knies.

The method and the findings may also improve current models that estimate the amounts of methane released from natural sources.
-end-


CAGE - Center for Arctic Gas Hydrate, Climate and Environment

Related Evolution Articles:

A timeline on the evolution of reptiles
A statistical analysis of that vast database is helping scientists better understand the evolution of these cold-blooded vertebrates by contradicting a widely held theory that major transitions in evolution always happened in big, quick (geologically speaking) bursts, triggered by major environmental shifts.
Looking at evolution's genealogy from home
Evolution leaves its traces in particular in genomes. A team headed by Dr.
How boundaries become bridges in evolution
The mechanisms that make organisms locally fit and those responsible for change are distinct and occur sequentially in evolution.
Genome evolution goes digital
Dr. Alan Herbert from InsideOutBio describes ground-breaking research in a paper published online by Royal Society Open Science.
Paleontology: Experiments in evolution
A new find from Patagonia sheds light on the evolution of large predatory dinosaurs.
A window into evolution
The C4 cycle supercharges photosynthesis and evolved independently more than 62 times.
Is evolution predictable?
An international team of scientists working with Heliconius butterflies at the Smithsonian Tropical Research Institute (STRI) in Panama was faced with a mystery: how do pairs of unrelated butterflies from Peru to Costa Rica evolve nearly the same wing-color patterns over and over again?
Predicting evolution
A new method of 're-barcoding' DNA allows scientists to track rapid evolution in yeast.
Insect evolution: Insect evolution
Scientists at Ludwig-Maximilians-Universitaet (LMU) in Munich have shown that the incidence of midge and fly larvae in amber is far higher than previously thought.
Evolution of aesthetic dentistry
One of the main goals of dental treatment is to mimic teeth and design smiles in the most natural and aesthetic manner, based on the individual and specific needs of the patient.
More Evolution News and Evolution Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: The Power Of Spaces
How do spaces shape the human experience? In what ways do our rooms, homes, and buildings give us meaning and purpose? This hour, TED speakers explore the power of the spaces we make and inhabit. Guests include architect Michael Murphy, musician David Byrne, artist Es Devlin, and architect Siamak Hariri.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

What If?
There's plenty of speculation about what Donald Trump might do in the wake of the election. Would he dispute the results if he loses? Would he simply refuse to leave office, or even try to use the military to maintain control? Last summer, Rosa Brooks got together a team of experts and political operatives from both sides of the aisle to ask a slightly different question. Rather than arguing about whether he'd do those things, they dug into what exactly would happen if he did. Part war game part choose your own adventure, Rosa's Transition Integrity Project doesn't give us any predictions, and it isn't a referendum on Trump. Instead, it's a deeply illuminating stress test on our laws, our institutions, and on the commitment to democracy written into the constitution. This episode was reported by Bethel Habte, with help from Tracie Hunte, and produced by Bethel Habte. Jeremy Bloom provided original music. Support Radiolab by becoming a member today at Radiolab.org/donate.     You can read The Transition Integrity Project's report here.