Research blows the lid on volcanic activity

Posted by ap507 at Dec 11, 2017 11:41 AM |
Study of ancient eruptions challenges hotly debated issues

Issued by University of Leicester on 11 December 2017

Geologists from the University of Leicester have been unravelling an age-old geological story.

Their research, relating to ancient volcanic activity in Mongolia and China, challenges existing knowledge about the processes involved.

It is published in Science Direct: http://www.sciencedirect.com/science/article/pii/S0024493717303997

Tom Sheldrick , from the University of Leicester’s School of Geography, Geology and the Environment, said: “This is exciting research which looks at the geochemical similarities of the Mesozoic volcanism in Mongolia with that in the North China Craton – a matter that is highly debated.

“To date, there has only ever been one other published article (Dash et al. 2015) on the Mongolian Mesozoic basaltic volcanism. This paper challenges many models and shows similar geological processes happened in Mongolia and China at a similar time.”

Key findings of the research include:

-          Much of the Mesozoic lavas in the Gobi Altai (southern Mongolia) are a similar age (124-117 Ma) to Mesozoic magmatism in the North China Craton (~135 – ~115 Ma) and have similar geochemical signatures

-          The geochemical evidence from our Gobi lavas suggest that the lithosphere (the uppermost solid part of Earth’s mantle) was stripped away. This is a similar story to what happened in the North China Craton

-          The team constrains that this Mesozoic lithosphere was completely removed by 107 Ma. This also happened under the North China Craton at a similar time interval; perhaps, further indicating a shared geological process for explaining the magmatism

-          The researchers demonstrate that asthenospheric upwelling occurred in east and southern Mongolia, and the North China Craton, at a very similar time interval (~107 Ma)

Tom said the rock samples under examination were collected by Tiffany Barry and Douwe van Hinsbergen  -  whilst they were studying at Leicester - during separate field excursions. Some of the geochemical data is 21 years old - collected by Tiffany Barry when she did her PhD at Leicester.

“When I started my PhD, I was given this data, and I have been using it to help unravel the Mesozoic geological story, “ said Tom.

He added: ”The geological processes responsible for producing large quantities of magmatism are often debated. In the case of this Central Asia Mesozoic magmatism this is particularly true, because typical models for producing magmatism, such as subducting tectonic plates, is not viable. In this particular case, it is fascinating that such wide-scale magmatism occurred (some of the volcanic fields in Mongolia, Russia and the North China Craton are >1500 km away from each other!). Yet, despite the spatial differences, the geochemical data suggest linked geological processes. “

Ends

You can contact Tom via: tcs3@le.ac.uk

Notes to editors

 

NERC (Natural Environment Research Council) is the UK's main agency for funding and managing research, training and knowledge exchange in the environmental sciences. Our work covers the full range of atmospheric, Earth, biological, terrestrial and aquatic science, from the deep oceans to the upper atmosphere and from the poles to the equator. We coordinate some of the world's most exciting research projects, tackling major issues such as climate change, environmental influences on human health, the genetic make-up of life on Earth, and much more. NERC is a non-departmental public body. We receive around £330 million of annual funding from the Department for Business, Energy & Industrial Strategy.

 

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