Episodic continental extension in eastern Gondwana during the mid-late mesozoic: insights from geochronology and geochemistry of mafic rocks in the Tethyan Himalaya

Mesozoic extension and rifting processes of the Gondwana continent are critical for understanding opening formation Indian Ocean. Here, we report petrological, geochemical, zircon U–Pb age, Lu–Hf isotopic data mafic dikes in central Tethyan Himalaya to reveal timing mechanism eastern rifting. These rocks exhibit two groups terms TiO2 MgO contents (Group I with < 2.0 wt.%, whereas Group II > wt.%), but (1) they have similar trace elements patterns enriched Light Rare Earth Element (LREE) without Eu anomalies (2) a wide range εHf(t) values. Both above geochemical characteristics those Oceanic Island Basalt (OIB). However, also show typical features continental crust input. Compared II, has higher MgO, Cr, Ni abundances (more primitive) more depleted Nb-Ta contents, which lower Dala rocks, suggesting that signature was mainly inherited from Greater India subcontinental lithospheric mantle (GI-SCLM). Therefore, here were derived hybrid source both OIB-like GI-SCLM. Furthermore, ages been identified: first group weight mean age 139.9 ± 0.2 Ma, second 163.2 0.9 Ma. The Middle Jurassic zircons intermediate acidic igneous setting, thus might record stage magmatism associated tectonic event passive margin. Early Cretaceous represent crystallization dikes, coeval most Himalaya. Based on these observations literature Himalaya, proposed Kerguelen plume incubating underneath at ca. 140 it not located triple junction among Antarctic, Australian plates. play synergistic role break-up Gondwana, had experienced least stages during Mid-Late Mesozoic.