Apatite Fission Track Thermochronology: fundamentals, technique and review study from the Garhwal-Kumaun region, NW-Himalaya

The aim of this paper is to enhance the awareness of the Fission Track (FT) analysis among the geosciences communities by describing the basic fundamentals, technique, and its geological applications. FT thermochronology has been widely used to constrain the exhumation and thermal histories of mountain belts. It is an ideal tool for reconstructing the thermal histories of a sedimentary basin, which provides detailed information on the exhumation of rocks, below about 110 +/- 10 degrees C for apatite, as typically found in the upper 3-4 km of the shallow crust. Apatite Fission Track (AFT) thermochronology is applied to study the provenance history of sedimentary basins, structural evolution, and long-term exhumation history of orogenic belts. Here, we have compiled the available AFT age data from the Garhwal-Kumaun region of the LHS, LHC, and HHC zones and made observations to understand the exhumation and tectonics evolution of this portion of the Himalaya. The plot of AFT ages versus the horizontal distance from the Main Boundary Thrust (MBT) to the South Tibetan Detachment System (STDS) mirrors the exhumation patterns as predicted in the out-of-sequence (O-O-S) model of the Mio-Pliocene evolution of the Himalayan orogen.