| Abstract Submission No. | ABS-4.1-0185 |
| Title of Abstract | Exploring the role of rock strength vis-�-vis long-term tectonic-climatic feedback on the landscape evolution of the Indo-Burmese Range (IBR) |
| Authors | Arindom Gogoi*, Dr. Anand K. Pandey, Dr. Prabha Pandey |
| Organisation | CSIR-NGRI |
| Address | Extension Building CSIR-NGRI, Hyderabad, India Pincode: 500007 E-mail: ARINDOM.GOGOI9@GMAIL.COM |
| Country | India |
| Presentation | Poster |
| Abstract | The topographic expression of a landscape is considered an outcome of the long-term interplay between tectonic uplift and erosion processes by the fluvial regime, with minor contribution of hillslope processes, often ignoring the physical properties of lithologies. Indo-Burmese Range (IBR) is a north-south-trending exhumed accretionary range developed due to the hyper-oblique convergence of the Indian plate beneath the Burmese plate. We integrated the SRTM DEM-based stream power proxies, such as normalised steepness index (ksn), relief, Hypsometry Integral (HI), with the TRMM precipitation pattern and measured rock strength of different geologic units to explore the interplay of controlling factors in the landscape growth of IBR. The rebound hammer is used to measure the rock strength of diverse lithological units of different geological formations. The uniaxial compressive strength (UCS) values for different geological groups are measured, and they range for different geological units as follows: Tipam Group 16±7 MPa, Surma Group 27.33±12.8 MPa, Barail Group 40.84±18.3 MPa, Disang Group 33.86±17.1 MPa, and Ophiolite sequence 54.33±18.8 MPa. The corresponding stream power proxy (Ksn) ranges for different geological units are Tipam Group 10.71±6.01 m0.9, Surma Group 22.56±11.32 m0.9, Barail Group 55.84±25.7 m0.9, Disang Group 62.06±21.2 m0.9, and Ophiolite sequence 46.66±6.65 m0.9. We estimated normalised rock erodibility(K) of lithological units from the average ksn and rock strength, which show a strong positive correlation, except in shear zones and thinly bedded rocks, where structures have influenced the rock strength. The results are also analysed for spatial variation in the catchment area exchange proxies, which defines the competing headward growth of the catchments vis-a-vis tectonic forcing. The role of rock strength is included in the discussion on tectonic-climate coupling, which otherwise dominates the discourse of regional landscape growth. |
| Keywords | Indo-Burmese Range, fluvial geomorphology |