Indosinian orogeny structure in ban pong and ban hong quarries, chiang mai and lamphun provinces, northwestern thailand

Abstract

© EAGE 2020. Indosinian orogeny is the tectonic events related to the closing of Palaeothetys Ocean, which is a product of collision between Sibumasu and Indochina Blocks during the Latest Palaeozoic to Early Mesozoic. However, the kinematics of structures is still problematic in Thailand, which is particularly related to their timing and distributions. Remote sensing and geological field observation are the methodologies used in this research. Extensive quarries in Ban Pong and Ban Hong exposed prominent Indosinian orogeny structure in NW Thailand. In Ban Pong, thrust fault related folds have compressional direction NE-SW where occurred close to the detachment zone of Suthep metamorphic core complex. The detachment separated an underlying gneissic rock and an overlying of Palaeozoic sedimentary rocks. Furthermore, in this area, lozenges structure is well-developed associated with thrust and extensional where the latter show E-W direction. Different orientation of brittle and ductile shear zones supposed to be occurred in different timing of tectonic events. In Ban Hong, Palaeozoic sedimentary rocks comprise limestone, shale, sandstone, and marble. However, the Palaeozoic structures of duplex thrust fold belts have E-W orientation where it is significant different with Ban Pong. Regarding this, NW-Thailand comprise complex structure of Indosinian orogeny even in close distance.