Response of the North China Craton to the Rodinia supercontinent breakup: New evidence from petrochemistry, chronology and Hf isotope of the gabbro in Xiaosongshan area of northern Helan Moun-tain

Zircon LA-ICP-MS U-Pb dating, petrochemistry and zircon Hf isotope study of the gabbros from Xiaoshongshan area of the North Helanshan show that the emplacement crystallization age is 835.5±5.3Ma, suggesting early Neoproterozoic. The gab-bros belong to intraplate tholeiite basalt series, and are slightly rich in LREE, rich in Rb, Ba, La, and slightly depleted in HFSE, Th, Nb, Ta, Zr and Hf; Hf isotopic data of the gabbros show high ε_Hf(t) values (5.83~7.87), the single stage model age t_DM1 is 1075~1155Ma, and the two stage model age t_DM2 is 1176~1289Ma. Comprehensive studies suggest that the magma of gabbros originated from an enriched mantle in the Mesoproterozoic, and was formed in an intraplate extension setting on the western margin of the North China continental blocks. The authors thus infer that this magma event was a response of the North China continental blocks to the breakup of the Rodinia supercontinent. Therefore, it was also a part of the supercontinent.