 |
| Titel |
Crustal density structure from gravity modelling beneath Himalaya and Lhasa terranes, Tibet |
| VerfasserIn |
Zhongjie Zhang, Sufang Zhang, Carla Braitenberg |
| Konferenz |
EGU General Assembly 2011
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250047469
|
|
|
|
|
|
| Zusammenfassung |
| The Himalaya, Lhasa terranes are geologic units which constitute the south and central Tibetan plateau. They are the product of the deep-reaching process of mountain building due to the convergence and collision of the Indian and Eurasian plates. We define a 3D density model beneath these tectonic terranes constrained by a review of all available active seismic and passive seismological results on the velocity structure of crust and lower lithosphere in Tibet. From our final density model, we infer that the present subduction-angle of the Indian plate is small, but presents some variations along the west-east extension of the orogenic belt. The dip angle of the Moho interface is about 8-9°in the eastern and western part of the orogenic belt, and about 16°in the central part. Integrating crustal P-wave velocity distribution from wide-angle seismic profiling, geothermal data and our crustal density model, we infer a crustal composition model, which is composed of an upper crust with granite- granodiorite and granite gneiss beneath the Lhasa terrane; biotite gneiss and phyllite beneath the Himalaya, a middle crust with granulite facies and possible pelitic gneisses, and a lower crust with gabbro-norite-troctolite and mafic granulite beneath the Lhasa terrane. |
|
|
|
|
|
|