Link between frontal collision and lateral plate extrusion: palaeomagnetic fingerprint in the Tethyan Himalaya

• Applicant: Professor Dr. Erwin Appel
• Subject Area: Geophysics
• Term: from 2005 to 2012
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5437468

The India-Asia collision is the Earth's most spectacular "natural laboratory" to study the geodynamic evolution of continental collision. The project deals with the link between frontal collision by the Indian indenter and the extrusion of the Tibetan Plateau. In the western part of the Himalaya oroclinal bending is well reflected by palaeomagnetic data. In contrast, data from the central part and a first result from the eastern part (Bhutan) indicate palaeomagnetic rotations, which are not compatible with an oroclinal bending model. It can be hypothesised that eastward extrusion of the Tibetan Plateau left its fingerprint in a long-term deformation of the Himalayan region forming a shear zone with strong clockwise block rotations and sinistral strike-slip faults between individual blocks. This model would match with present-day movements shown by GPS velocities. The proposed project aims at testing the hypothesis of a shear zone by analysing palaeomagnetic remanences in the eastern Tethyan Himalaya between ca. 83-89°E. West-east and south-north sections will be sampled to obtain a regional rotation pattern. Secondary pyrrhotite remanences will be used which proved to provide reliable results during former projects. Geological, geochronological and geothermometric work is involved in order to support the interpretation of the palaeomagnetic data. This multidisciplinary concept is based on a cooperation of scientists from Germany, Switzerland, Austria, Canada, China and Nepal.

• DFG Programme: Research Grants
• Participating Person: Dr. István Dunkl