Active tectonics in and around Kimin-Ziro area, Lower Subansiri District, Arunachal Pradesh, NE India

摘要

The paper presents neotectonically-evolved landforms along the foothills of Arunachal Himalaya as well as within the Outer and Lesser Himalayan domains, along the Kimin-Ziro valley section, where tectonic activity is dated to 22-14 ka by OSL technique. High-resolution satellite data suggest the presence of a highly mature, almost flat Brahma- putra floodplain evolved during the recent geological past, in which palaeochannels had a very high sinuosity. Subsequent events of uplift resulted in the formation of entrenched meanders due to incision of the valley floor. As the process of incision was unable to keep pace with the rate of uplift, after initial attempts to incise the major channels abandoned their sinuous courses mid instead followed a straight braided course from near the point of emergence of Himalayan Frontal Thrust (HFT). The data suggest that tectonic activity along the Main Boundary Thrust (MBT) and HFT during the Holocene have played significant role in geomorphic evolution.