Closure of the Eastern Paleo-Asian Ocean: Constraints from the Age and Geochemistry of Early Permian Zhaojinggou Pluton in Inner Mongolia (North China)

The closing time of the Paleo-Asian Ocean and tectonic evolution northern margin North China Craton are still controversial. geochronology geochemistry Zhaojinggou monzogranite pluton provide new constraints on late Paleozoic closure in southern Central Asian Orogenic Belt (CAOB). yielded a zircon U-Pb age 286.7 ± 1.2 Ma. Due to characteristics low–moderate Mg# values (25.87–39.21), low Fe2O3T (1.13–1.72), A/CNK > 1, we show that is weak peraluminous, high potassium calc–alkaline series, displays feature S-type granite. total REE content low, distribution curve right dipping, LREE enriched; δEu average value 1.32 (1.11–1.54). granite presents relatively (87Sr/86Sr)i 0.712345–0.713723, εNd(t) −8.89–−8.21 (an −8.56), TDM2 1718–1773 Furthermore, situ Hf isotopic analysis shows 176Hf/177Hf ratios 0.282342 0.282614, εHf(t) −9.27–0.38 (mean −4.74), 1275–1887 Additionally, field strength elements such as Nb, Ta, Ti depleted, large ion lithophile elements, e.g., Rb, Ba, K, Sr, enriched. above features indicate was derived from Paleoproterozoic Mesoproterozoic lower crustal mafic materials. By discussing genesis implications massif, propose represents magmatic event caused by crustal–mantle interaction during southward subduction eastern Early Permian.