Analysis of
Slip History on Strike-Slip Faults Using Sedimentary Basins: Examples from the
NE Tibetan Plateau
Ritts, Bradley1, Yongjun Yue2, Stephan Graham3 (1)
Indiana University, Bloomington, IN (2) Chevron North America Exploration and
Production Company, Bakersfield, CA (3) Stanford University, Stanford, CA
Sedimentary basins forming along active
strike-slip faults show progressive dislocation from potential sediment source terranes on the opposite wall of the fault and thus provide
the opportunity to reconstruct fault slip history through provenance analysis.
We have applied this technique, inspired by work of John Crowell in the Ridge
basin, to develop an understanding of the timing and distribution of slip on
the left-lateral Altyn Tagh
fault (ATF) and associated structures that bound the northern margin of the
Tibetan Plateau. Piercing points in the Xorkol basin,
on the central segment of the ATF, are supported by petrologic and geochronologic matches between sediments and sources and
show that the Oligocene Xorkol basin was aligned with
the North Qilian Shan, but by early Miocene the basin
had been translated to a position adjacent to the Central Qilian
Shan, and by the end of the early Miocene the Xorkol
basin was opposite the South Qilian-North Qaidam terrane. These offsets
indicate large (360±40 km) Oligocene and younger displacement and low (°Ü65 km)
post-early Miocene displacement. The small post-early Miocene offset is
confirmed by similar relationships in the Mangnai,
AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California