The Upper Jurassic–Lower Cretaceous alluvial-fan deposits of the Kalaza Formation (Central Asia): Tectonic pulse or increased aridity?

摘要: The topographical evolution of tectonic systems, as well the sedimentation pattern and depositional environments in associated basins, are controlled by both tectonics climate. In region Tien Shan (Central Asia), Jurassic–Lower Cretaceous period was marked complex, low-intensity deformation major climate changes from humid to arid conditions (Jurassic) semi-arid (Cretaceous). Using sediment record Junggar, Tarim Fergana basins describe area during Mesozoic thus requires differentiation between climatic influences on sedimentation. conglomerates Upper Kalaza Formation were commonly with renewed activity resulting docking Lhasa block along southern margin Asia. From sedimentology sequence stratigraphy analyses several sections we reassess main factors controlling deposition this formation. We show that, while some persisted throughout Jurassic–Cretaceous transition, switch sandy deposits Jurassic Qigu coarse is largely linked development an