Tracking provenance shift in the Cretaceous-Paleogene sedimentary succession of the Garhwal foreland basin, NW Himalaya using sediment geochemistry and U-Pb detrital zircon geochronology

• Published in: Journal of Asian earth sciences Vol. 264; p. 106067
• Main Authors: Ranjan Mishra, Shruti, Pratim Chakraborty, Partha, Das, Kaushik, Saha, Subhojit, Shibata, Tomoyuki, Mohanty, Sarada P., Chandra Tripathi, Satish
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.04.2024
• Subjects: Garhwal foreland basin; India-Asia collision; Subathu and Nilkanth Formations; Tectono- Sedimentation; Subathu and Nilkanth Formations; Garhwal foreland basin; Tectono- Sedimentation; India-Asia collision
• DOI: 10.1016/j.jseaes.2024.106067
• ISSN: 1367-9120

•From geochemical proxies, the present study deciphers the addition of a northern (ophiolitic) provenance during Subathu sedimentation as opposed to the sole cratonic input in the case of Nilkanth sedimentation in a passive margin basin setup. The Nilkanth sedimentation was terminated by Cenomanian.•The sediments of the Subathu Formation, particularly Subathu shales, with anomalous Ni (159 ppm) and Cr (301 ppm) concentrations substantiate the addition of an ophiolitic provenance from the north (the Kohistan-Dras Island arc including granitic plutons in the arc roots).•The detrital zircon age data from both Nilkanth and Subathu Formations justify the contention; whereas ∼100 and 120 Ma aged grains from the Nilkanth Formation suggest cratonic input from the south, documentation of ∼91 Ma zircon grain from the Subathu sandstone bear undoubted indication for an additional sediment source present in the north.•The evolution of the Subathu basin in the Garhwal foreland spanned over a period of ∼25 Ma. The fore-bulge created around 55 Ma with the collision between the Indian and Eurasian plates paved the way for foreland sedimentation. The present study involving the sediments of Nilkanth and Subathu formations from the Himalayan foreland basin in Garhwal region, NW-Himalaya, Uttarakhand, India focuses on the tectono-sedimentary evolution of the basin in relation to the India-Eurasia collision using sandstone petrography, sediment geochemistry and detrital zircon geochronology. Geochemical proxies including i) higher concentrations of MgO, Ni, Cr, ii) enriched LILE and LREE and iii) flat HREE in Subathu litho-succession as compared to the Nilkanth mixed clastic-carbonate succession, allowed proposing a northern arc-related supply (in addition to cratonic source) for the Subathu Formation as opposed to supply only from the cratonic side in case of Nilkanth Formation. The presence of ∼90 Ma youngest zircon grain in Subathu sandstone attests to the claim of detrital supply in the Subathu basin from the north. The idea also gets support from the chemical distinction between sandstone samples of the two formations and their tectonic set-ups inferred therefrom.Whereas the upper Cretaceous Nilkanth Formation, deposited in a passive margin set-up at the leading edge of the northward advancing Indian plate, between ∼125 and 100 Ma and receiveddetritus from the Indian peninsula, collision and forebulge formation resulted in the transgression that triggered Subathu sedimentation with the onset of detritus supply from the tectonically uplifted orogen in the north by Late Paleocene.