XIONG Guang-qiang1,2, ZHAO Hong-tao1, LIU Min1, ZHANG Da1, QIN Xiao-feng1, WANG Zhong3, TONG Li-hua4, HU Zhao-chu5
1. School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China;
2. Geophysical and Geochemical Exploration Panty, Jiangxi Bureau of Geology and Mineral Resources, Nanchang 330002, China;
3. Institute of Geological Survey of Inner Mongolia, Hohhot Inner Mongolia 010020, China;
4. Oil and Gas Survey, Center of the China Geological Survey, Beijing 100029, China;
5. State Key Laboratory of Geological Press and Mineral Resources, China University of Geosciencess, Wuhan 430074, China
Abstract: This paper carried out researches mainly about geochemistry, isotope chronology and Hf characteristics of the Goute pluton. The contents of SiO2 and Al2O3 respectively are 76.41%-78.36% and 11.72%-12.86%, and the A/CNK ratio is 1.40-1.43 indicated that the pluton is peraluminous; the contents of K2O and Na2O respectively are 4.8%-5.04% and 3.18%-3.47%, The values of K2O+Na2O and Na2O/K2O respectively are 7.99%-8.05% and 0.66-0.72, indicating the Goute granite is higher in potassium calc-alkaline; the values of σ and AR are 1.81-2.24 and 4.67-4.97, respectivley, also reflects that the Goute granite is calc-alkaline. The results of trace elements showed that the Goute granite enriches in LILEs and Pb, but strongly depletes in HFSEs. The ΣREE is between 115.84 ×10-6 to 153.56×10-6, LREE/HREE is 7.75-9.27, normalized La/Yb ratio is of 5.27-7.73 and δEu is 0.27-0.35. The intrusion is characterized remarkably by enriching LREE and depleting HREE. The zircon U-Pb age of the Goute granite is 134.1±1.0 Ma, belonging to the early Cretaceous; Hf isotope data suggested that the formation of its mantle source may be associated with early plate subduction. These characteristics indicated the Goute granite was a highly differentiated crust-mantle mixed S-type granite which was formed in the late of the Yanshan orogenic cycle.
Keywords: Inner Mongolia Goute pluton Early Cretaceous tectonic regime transformation
