Geochemistry and detrital zircon U–Pb dating of Lower Cretaceous volcaniclastics in the Babazhadong section, Northern Tethyan Himalaya: Implications for the breakup of Eastern Gondwana

Abstract

Lower Cretaceous volcaniclastic sandstones, widely distributed in the Tethyan Himalaya, provide insights into evolution of the Tethyan Himalaya and the continental breakup of Eastern Gondwana. Here we present the petrological, geochronological and geochemical data from the Lower Cretaceous volcaniclastic sandstones at the Babazhadong section, eastern Tethyan Himalaya. The geochronological data show that the youngest detrital zircons in the lowest volcaniclastic sandstones have U–Pb age of (134 ± 4 Ma), therefore were deposited post late Valanginian. The volcaniclastics are predominantly comprised by mafic detritus in the lower part, while felsic grains become more abundant up-section. The proportion of volcaniclastics in the sandstones also increases upwards. Geochemical data of mafic detritus indicate within-plate basalt affinity. Based on these observations, in combination with the stratigraphic correlation of coeval volcaniclastic sandstones deposited along the length of the Himalayas, we conclude that the volcaniclastics in the Babazhadong area are within-plate affinity, probably related to the opening of deep, crust cross-cutting fractures along the northern margin of Greater India.