Quaternary alluvial fan dynamics of the Jaldhaka basin

Across the Himalayan foreland area, alluvial fans respond to fluvial depositional landforms created by active tectonics and are incorporated within hydro-sediment processes. Each tributary of the master stream has its water and sediment to discharge, which assists in initiating several meso-level fans in response to the active tectonics in Jaldhaka basin. Along the mountain front, active MBT (Main Boundary Thrust), MFT (Main Frontal Thrust) and lineaments (parallel and transverse to Himalaya) have governed the tectonically active Quaternary foreland area where numerous meso-level fans have developed. The study aims to estimate the tectonic activeness of each meso-fan using the morphotectonic indicators. The tributaries of the Jaldhaka River are permuted to the recent tectonism or neotectonics to form each meso fan with its basin displaying the varying degree of their activeness and aggradation system. Statistical methods like technique for order performance by similarity to ideal solution (TOPSIS) and VIKOR (Vlse Kriterijumska Optimizacija Kompromisno Resenje) that specify multicriteria optimization and compromise solution, in Serbian have ranked the Fan 2 as mostly active and Fan 4 is comparatively tectonically stable. The hydro-sediment characteristics reveal the topographic spatial dynamics of Fan 4 where lobe 3 has elevated from 1984-2014. The XRD analysis specifies the scientific key in response to the dominance of dolomite in the aggraded elevated bed sediments carried by the Rohtikhola River. The conceptual fan models of Fan 2 and 4 display the fan development phases through four stages. It has clearly defined the extension of the fan lobes of Fan 2 and 4. It is summarized that within a common climatic zone and similar neo-tectonic setting, meso-level fans have differential morphotectonic signatures with dynamic aggradation processes.

Automated summary

The study focused on medium-sized alluvial fans in the Himalayan foreland area, estimating their tectonic activeness using morphotectonic indicators and ranking them using statistical methods. It was found that within a common climatic zone and similar neo-tectonic setting, medium-sized fans exhibit differential morphotectonic signatures and dynamic aggradation processes.