Geochronology and geochemistry of late Paleozoic volcanic rocks from eastern Inner Mongolia, NE China: Implications for igneous petrogenesis, tectonic setting, and geodynamic evolution of the south-eastern Central Asian Orogenic Belt

Abstract Here we report new petrography, geochemistry, U Pb zircon geochronology, and Hf isotope results for volcanic rocks of the Dashizhai Formation in the Dashizhai area, Keerqin Right Wing Front Banner, Inner Mongolia. The volcanic rocks have mafic to felsic bulk-rock compositions and include basalt, rhyolite, basaltic andesite, andesite, dacite, and rhyolitic tuff. Two dacite and rhyolitic tuff samples yield laser ablation–inductively coupled plasma–mass spectrometry (LA–ICP–MS) 206Pb/238U zircon ages of 332 ± 1 Ma and 300 ± 1 Ma, respectively, suggesting that the timing of felsic volcanism ranged from the early to late Carboniferous. Mafic volcanic rock samples are enriched in large-ion lithophile elements (LILE) and light rare earth elements (LREE; La/Nb = 1.58–4.84), and are depleted in high-field-strength elements (HFSE; Th/Yb ratios