TITLE:
Variation of Moho Depth across Bangong-Nujiang Suture in Central Tibet—Results from Deep Seismic Reflection Data
AUTHORS:
Zhanwu Lu, Rui Gao, Hongqiang Li, Wenhui Li, Xiaosong Xiong
KEYWORDS:
Moho Depth, Deep Seismic Reflection, Bangong-Nujiang Suture, Tibet
JOURNAL NAME:
International Journal of Geosciences,
Vol.6 No.8,
August
7,
2015
ABSTRACT: There is a long-term
dispute at Moho depth across the Bangong-Nujiang suture (BNS). Due to the
complicated and changeable seismic geological condition, it is not easy to
acquire images of the reflective Moho in central Tibet. In the support of the
SinoProbe project, a series of deep seismic reflection profiles were conducted
to image Moho structure across the BNS and the Qiangtang terrane. These profiles
extend from the northern Lhasa terrane to the Qiangtang terrane crossing the
BNS. Both shot gathers and migration data show clear Moho images beneath the
BNS. The Moho depth varies from 75.1 km (~24 s TWT) beneath the northmost Lhasa
terrane to 68.9 km (~22 s TWT) beneath southmost Qiangtang terrane, and rises
smoothly to 62.6 km (~20 s TWT ) at ~28 km north of the BNS beneath the
Qiangtang terrane. We speculate that the Moho appears a 6.2 km sharp offset
across the BNS and becomes ~12.5 km shallower from the northmost Lhasa terrane
to the south Qiangtang terrane at ~28 km north of the BNS. The viewpoint of
Moho depth across the BNS based on deep seismic reflection data is inconsistent
with the previous 20 km offset.