Provenance, tectonic setting and age of the sediments of the Upper Disang Formation in the Phek District, Nagaland

摘要: Abstract Integrated petrographic and geochemical studies of sandstones, shales turbidites from the Upper Disang Formation, Phek district, Nagaland have been carried out to determine their provenance, weathering conditions tectonic setting. Paleomagnetic were for magnetostratigraphic purposes. Studies indicate that most these sediments derived felsic mafic sources with minor contribution low medium grade metamorphic rocks. Most components transported distant as evidenced extensive reworking grains. The likely source rocks are granite/granite gneiss Karbi Anglong crystalline complex west study area. However, bulk contributed nearby basic ultrabasic sources. This would correspond fast rising Naga Ophiolite, which probably emerged above sea level during Mid-Eocene. Prevailing high temperatures humid climate caused intense chemical great distances by turbidity currents into an easterly deepening basin. Sediments east rapidly dumped on seafloor causing rapid mixing, leading textural immaturity. endorse published paleontological evidence Formation deposited Late Eocene. Deposition took place in a westward-migrating accretionary-prism active-margin setting at convergence Indian Burma plates. was rapidly-closing basin where anoxic prevailed. Towards end Eocene this closed completely destruction Tethyan Ocean.