Rock Magnetism of Late Cretaceous to Middle Eocene Strata in the Lesser Himalaya, Western Nepal: Inferences Regarding the Paleoenvironment

The growth of the southern piedmont Himalayan boundary and its depositional setting has changed since uplift Himalaya due to continental Indian-Eurasian collision, which resulted in variation magnetic minerals marine- terrestrial-facies sediments. In this paper, we utilize rock magnetism data from late Cretaceous middle Eocene strata, including Amile Bhainskati formations Lesser (western Nepal), understand mechanism controlling susceptibility ( χ ). active tectonics strongly influenced saturation isothermal remanent magnetization (SIRM), HIRM, hysteresis loops, forming both low-coercivity sediments with low terrestrial facies (zones I, IIIA, V) high-coercivity high marine II, IIIB IV). Thermomagnetic κ-T curves frequency-dependent fd%) values show that carry magnetite coarse non-superparamagnetic (SP) grains hematite SP grains, respectively. Comparing lithologic, sedimentary environments, geomorphic features, sea level data, propose were mainly produced by an increase terrigenous detrital influx during regression period Tethys Sea, while formed sediments, prompted appearance ferromagnetic-antiferromagnetic paramagnetic transgression Sea.