Hairpin river loops and slip-sense inversion on southeast Asian strike-slip faults
Geology; vol 26; n°8; p 703-706; 1998.
Lacassin R., A. Replumaz et P. H. Leloup
Laboratoire de tectonique et mécanique de la lithosphère,
C.N.R.S., IPG-Paris, 4 place Jussieu 75252 Paris Cedex O5, France
Abstract:
In the Golden Triangle region of southeast Asia (northern Thailand,
Laos and Burma, southern Yunnan), the Mekong, Salween, and neigboring
rivers show hairpin geometries where they cross active strike-slip
faults. Restoration of young, left-lateral offsets of these rivers
leaves residual right-lateral bends of many kilometers. We interpret
these hairpins as evidence of late Cenozoic slip-sense inversion
on these faults, about 5 to 20 Ma. Near the Red River fault, stress
field and slip-sense inversion occured ca. 5 Ma. This implies
that the present course of these large rivers has existed for
at least several million years. Pliocene-Quaternary slip rates,
possibly on the order of 1mm/yr, are inferred on each of the strike-slip
faults of the Golden Triangle.
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Insigths from Tertiary deformation of SE Asia |