TPU researchers: clay minerals 'preserve' natural methane and curb global warming

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TPU researchers: clay minerals "preserve" natural methane and curb global warming

For the first time, geologists from Tomsk Polytechnic University have studied how clay minerals in marine sediments change under the influence of natural methane emissions. It has been established that these minerals, due to their structural features, are able to accumulate methane, partially restraining its release into the atmosphere. This property makes clay minerals an indicator of possible oil and natural gas deposits, and also helps researchers to learn more about the evolution of the world ocean and global warming.

The research was supported by the Russian Science Foundation grant (No. 23-77-10002). The results of the research have been published in the journal Applied Clay Science (Q1, IF: 5,8).

Methane seeps - underwater emissions of natural gas, mainly methane, through marine and oceanic sediments - have a significant impact on the biogeochemical processes occurring in bottom sediments and waters. According to the scientific community, in some regions of the planet, primarily in the Arctic, natural methane emissions may be associated with the degradation of submarine permafrost. These processes are considered as a potential factor capable of influencing the Earth climate system.

"Our task was to select a widespread component of sedimentary rocks that is able to detect the effects of methane. Using such indicator, we can reconstruct the conditions and episodes of methane discharge and assess their impact on the development of sedimentary basins in the geological past. Clay minerals, which are widespread in sedimentary rocks, were chosen as such indicator," said Alexey Ruban, joint author of the study, associate professor of the Department of Geology at the Engineering School of Natural Resources.

Researchers from the TPU Engineering School of Natural Resources studied clay minerals from the bottom sediments of the Laptev Sea, selected during Arctic expeditions, to assess how active methane discharge affects their composition and properties.

When studying clay minerals using pyrolysis, we found that samples from methane seeps emit methane at high temperatures, while samples from background sites do not show such a reaction. Hence we can conclude that clay minerals actually "preserve" natural methane emissions, restraining its entry into the atmosphere. Moreover, this indicates that the effect of methane fluids leave a stable geochemical trace in bottom sediments, which can persist for a long time,

- says Maxim Rudmin, associate professor of the Department of Geology at the Engineering School of Natural Resources.

The results of the study are of fundamental importance. The identified specific features of the clay minerals in sedimentary deposits subject to methane seepage can serve as indicators for assessing the chronological aspects of this process, as well as for reconstructing the conditions of rock formation in various geological periods.

Besides, the knowledge gained may be applied. For example, areas where analysis of clay minerals showed the presence of methane may indicate possible deposits of oil and natural gas.