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Analogue and Seismic Modelling of the Kuche Fold and Thrust Belt (North Tarim, China)

Yiping, Xia 2; Guichong, Wang 2; Callot, Jean Paul 1; Letouzey, Jean 1; Moretti, Isabelle *1; Ligui, Xu 2; Yongxing, Gu 1; Wu, Shenguy 3
(1) IFPen, Rueil Malmaison, France.
(2) BGP, Kuche, China.
(3) CC Reservoir, Houston, TX.

The Kuqa foreland fold and thrust belt developed at the contact between the uplifted basement block of the Tien Shan and the Tarim basin in foreland setting, since early Oligocene. It is mainly controlled by two major decollement levels. Thin skin deformation and Mesozoic thrust sheet develop above the Triassic coal measures. The Paleogene and Neogene foreland synclines developed detached above the stacked thrust sheets through the Eocene salt layer. Analogue models are used to analyse the relative importance of the kinematic boundary conditions and the rheological behaviour of the main decollement levels. The experiments demonstrate that the geometry of the belt depends on the two decollement with a frictional behaviour at Triassic level and a thick viscous Eocene salt layer pinching to the South along the Qilitag fodl belt and to the North close to the Tien Shan boundary. The geometry of the salt layer plays an important role in the structural style, controlling the shape and propagation of the foreland synclines. The backstop geometry is the second major element, controlling the dip of the stacked thrust sheets. Inverted basement block associated to a basement short cut emplaced during the late stage of evolution are both needed to generate the overall geometry of the Mesozoic units. Based on the analogue models, the geometry of the thrust sheet and foreland syncline is used to perform a synthetic seismic experiment. The recovered seismic data demonstrate that the thrust sheet length is not imaged. These results shed a new light on the Kuqa fold and thrust belt exploration potential.


AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California