Active tectonics of Dikrong Valley, northeast Himalaya, India: Insight into the differential uplift and fold propagation from river profile analysis

作者：Mishra Rajeeb Lochan^*; Jayangondaperumal R; Sahoo Hrushikesh

来源：Himalayan Geology, 2016, 37(2): 85-94.

• Differential rock uplift
• river profile
• steepness index
• lateral fold growth and propagation
• northeast Himalaya

The detachment-limited stream power model is a powerful proxy in active tectonics study for identifying the areas of variable rock uplift vis-a-vis bedrock incision. We made use of the channel steepness index (k(sm)) as a proxy for the detachment-limited model to estimate the differential uplift across the fold-thrust belt in the Dikrong river valley, northeast Himalaya by considering river profiles as a proxy for the local uplift. Though the model has earlier been applied in the northwest Himalaya, we validate its application in high monsoonal region like the northeast Himalaya. Based on field observations and analysis of drainage data from 30 m Digital Elevation Model, 147 channels traversing the major structural elements, viz., the Bomdila Thrust, Main Boundary Thrust, Tipi Thrust, Himalayan Frontal Thrust and the Simna Parvat Anticline have been considered for study. The k(sm) value for 147 channels varies from 22 to 199, with negligible lithological influence. k(sm) values between 22 and 53 for streams across the Bomdila and the Main Boundary Thrusts, and between 46 and 186 for streams across the Tipi and the Himalayan Frontal Thrusts suggest that the Bomdila and Main Boundary Thrusts are undergoing lesser degree of tectonic uplift than the Tipi and the Himalayan Frontal Thrusts. Higher k(sm) values (86-214) across the nose of the Simna Parvat Anticline suggest that this anticline is propagating towards ENE direction, resulting in the gradual shifting of the Dikrong river towards east and abandonment of paleochannels.

• 出版日期2016