"The subduction of continental crust to this depth has never been reported in the Himalayas and is also extremely rare in the rest of world," said Dr Anju Pandey of the National Oceanography Centre in Southampton, who led the research.

Pandey and her colleagues used sophisticated analytical techniques to demonstrate the occurrence of relict majorite, a variety of mineral garnet, in rocks collected from the Himalayas.

Majorite is stable only under ultra-high pressure conditions, meaning that they must have been formed very deep down in the Earth's crust, before the subducted material was exhumed millions of years later.

"Our findings are significant because researchers have disagreed about the depth of subduction of the Indian plate beneath Asia," said Pandey.

In fact, the previous depth estimates conflicted with estimates based on computer models. The new results suggest that the leading edge of the Indian plate sank to a depth around double that of previous estimates.

"Our results are backed up by computer modelling and will radically improve our understanding of the subduction of the Indian continental crust beneath the Himalayas," said Pandey.

The new discovery is also set to modify several fundamental parameters of Himalayan tectonics, such as the rate of Himalayan uplift, angle, and subduction of the Indian plate.

The study was supported by the UK's Natural Environment research Council. The researchers are Anju Pandey and Andy Milton of the National Oceanography Centre, Southampton, Mary Leech of San Francisco State university), and Preeti Singh and Pramod Verma of the University of Delhi. 1 Pandey, A, Leech, M., Milton, A., Singh, P. and Verma, P. K. Evidence of former majoritic garnet in Himalayan eclogite points to 200-km-deep subduction of Indian continental crust. Geology 38, 399-402 (2010). doi: 10.1130/G30584.1

del.icio.us	Digg	Reddit
YahooMyWeb	Google	Facebook

Memory Foam Mattress Review

SPACE MEDIA NETWORK PROMOTIONS Solar Energy Solutions Tempur-Pedic Mattress Comparison ... Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

Peruvian Tectonic Plates Move By Earthquakes And Non-Seismic Slip
Livermore CA (SPX) May 11, 2010
Just a few years ago, Dan Farber happened to be doing field work in Peru with students when the 8.0 Pisco earthquake struck. As a scientist working in the active tectonics of the Peruvian Andes - funded through the Lawrence Livermore National Laboratory's Institute for Geophysics and Planetary Physics - Farber was asked by colleagues if he could participate in a rapid response team to map the da ... read more