Aletho News

Origin of massive methane reservoir identified

Tall Bloke’s Talk Shop | August 21, 2019

As we already knew from elsewhere in the solar system, fossils are not essential for the production of methane aka natural gas. Only two ingredients are needed, one being water, as explained below.

New research from Woods Hole Oceanographic Institution (WHOI) published Aug. 19, 2019, in the Proceedings of the National Academy of Science provides evidence of the formation and abundance of abiotic methane—methane formed by chemical reactions that don’t involve organic matter—on Earth and shows how the gases could have a similar origin on other planets and moons, even those no longer home to liquid water.

Researchers had long noticed methane released from deep-sea vents, says Phys.org. But while the gas is plentiful in the atmosphere where it’s produced by living things, the source of methane at the seafloor was a mystery.

“Identifying an abiotic source of deep-sea methane has been a problem that we’ve been wrestling with for many years,” says Jeffrey Seewald a senior scientist at WHOI who studies geochemistry in hydrothermal systems and is one of the study’s authors.

Of 160 rock samples analyzed from across the world’s oceans, almost all contained pockets of methane. These oceanic deposits make up a reservoir exceeding the amount of methane in Earth’s atmosphere before industrialization, estimates Frieder Klein, a marine geologist at WHOI and lead author of the study.

“We were totally surprised to find this massive pool of abiotic methane in the oceanic crust and mantle,” Klein says.

The scientists analyzed rocks using Raman spectroscopy, a laser-based microscope that allows them to identify fluids and minerals in a thin slice of rock.

Nearly every sample contained an assemblage of minerals and gases that form when seawater, moving through the deep oceanic crust, is trapped in magma-hot olivine. As the mineral cools, the water trapped inside undergoes a chemical reaction, a process called serpentinization that forms hydrogen and methane.

The authors demonstrate that in otherwise inhospitable environments, just two ingredients—water and olivine—can form methane.

“Here’s a source of chemical energy that’s being created by geology,” says Seewald.

Full report here.
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Abstract of the paper:

Our findings highlight the ubiquitous occurrence of methane (CH4)-rich fluid inclusions in olivine-bearing rocks that, collectively, may constitute one of the largest reservoirs of abiotic CH4 on Earth. Because serpentinization in olivine-hosted fluid inclusions takes place in isolation from the surrounding rock, hydrogen (H2) and CH4 can form in any rock type containing olivine that hosts aqueous fluid inclusions, including those that do not undergo serpentinization on a macroscopic scale. Serpentinization and associated CH4 formation within olivine-hosted fluid inclusions has likely supplied microbial ecosystems with abiotic CH4 throughout most of Earth’s history and may be a source of H2 and CH4 on other planetary bodies in our solar system, even those where liquid water is no longer present.

August 21, 2019 - Posted by aletho | Phony Scarcity