CHARACTERISTICS AND TECTONIC EVOLUTION OF THE LANPING-SIMAO MESOZOIC BASIN

The Lanping-Simao Mesozoic Basin is a sedimentary basin which was developed based on the Paleo-Tethys multi-island ocean framework,and its formation and evolution are closely related to the tectonic evolution of the Tethys-Sanjiang orogenic belt.The prototype basin was formed during the Middle Triassic accompanying the open of the Mid-Tethys Ocean.The closing of the Mid-Tethys made the crust deformed and the Lower Jurassic missed universally during the end of the Late Triassic to the Early Jurassic.The Neo-Tethys opened during the Middle Jurassic.It made the basin subside again and accept the Middle Jurassic-Cretaceous deposit.Himalayan orogenic movement made the Neo-Tethys closed,and the crust uplifted large scale when the basin was deformed to form fractures,folds and characteristic ramp structures.Then the Cenozoic pull-apart basin superposed on the Mesozoic basin.The tectonic evolution controlled the subsidence,sedimentation,pyrogenesis and structure framework of the basin.