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Abstract:
The foundation for examining the geomagnetic field changes over time is laid by paleomagnetic records from the sediments. To shed additional light on the global geomagnetic excursions, new paleomagnetic findings from Ramganga Paleolake, NW Himalaya, India, are discussed here. A 10 m thick profile of sediments from the Ramganga paleolake (Lat. 29°46′ 867′′; Long. 79°14′ 43′′; altitude 2803 m) in the Lesser Himalaya was subjected to palaeomagnetic and rock magnetic examinations. The present section yielded 330 oriented palaeomagnetic samples from 110 different sites. The entire section was likely deposited between 38 and 0.8 ka, according to the extrapolation of the optically stimulated luminescence date. The isothermal remanent magnetization demonstrates that low coercivity minerals and a considerable amount of the soft magnetic mineral, most likely magnetite, are responsible for carrying the remanence. Since hysteresis loops are identical to one another and display evidence of only one ferrimagnetic phase in magnetic minerals, magnetite may be the likely candidate. With a Curie temperature above or close to 560°C, significant phase can be seen on thermomagnetic curves for both heating and cooling suggesting that magnetite is the primary career. The reconstructed remanent magnetization throughout the sedimentary successions can be identified thanks to the paleomagnetic characteristics. Virtual Geomagnetic Pole latitudes were determined using mean declinations and inclinations and three geomagnetic excursions, which are closely related to the Ramganga excursion, were observed: the Mono Lake Event, ~28.4 kyr–25.8 kyr; Gulf of Mexico Event, ~12.5 and 17 Ka, and Bagwalipokar Excursion Event, ~16-14 ka/ 8-2.5 Ka.
