The sedimentary and structural record of the NW Tarim Basin, China, provides an
insight into the amalgamation of Central Asia and is an ideal area in which to examine
the impact of an inherited tectonostratigraphic framework on the evolution of
foreland fold-thrust belts. The NW Tarim Basin contains a thick (3-16 km)
sedimentary succession which was deposited from the Late Neoproterozoic onwards,
and has been exhumed by a foreland fold-thrust belt system associated with the South
Tien Shan mountains during the Middle to Late Cenozoic. The research presented in
this thesis combines satellite image interpretation and field investigations in order to
examine the tectonostratigraphic framework of the NW Tarim Basin and to ascertain
the causes of lateral structural variability and partitioning of the foreland fold-thrust
belt system.
The Upper Neoproterozoic to Lower Permian sedimentary succession records the
progressive evolution of the NW Tarim Basin as a rift, intracratonic and foreland
basin. Following a period of subaerial exposure throughout the Mesozoic, tectonic
subsidence from the Middle Cenozoic onwards was driven by flexural deflection
beneath the Pamirs and Tien Shan orogenic belts. This was coupled with the
development of a foreland fold-thrust belt system along the northwest margin of the
Tarim Basin. Lateral variations in the structural geometry, architecture and style of the
foreland fold-thrust belt system correspond to changes in the thickness of the
sedimentary succession and interaction with inherited, basement fault zones. An eastwest
transition from the wide, arcuate Keping Shan Thrust Belt into the narrow
Kashgar Fold Belt is ascribed to thickening of the Cenozoic (syn-tectonic) foreland
basin succession. In contrast, internal variations in the structural architecture of the
Keping Shan Thrust Belt are governed by lateral changes in the thickness of the
Palaeozoic (pre-tectonic) sedimentary succession. These changes occur abruptly across
inherited, Early Permian fault zones that have been reactivated as strike-slip faults in
order to accommodate these lateral variations in the structure of the fold-thrust belt.