地质通报2017，Vol.36Issue(5)：738-749,12.
桂北新寨强过铝质花岗岩的岩石成因及其构造意义——来自年代学、地球化学及Sr-Nd-Hf同位素的制约
Constraints of geochemistry, geochronology and Sr-Nd-Hf isotopes on the Xinzhai peralu? minous granite in northern Guangxi: implications for petrogenesis and tectonic significance
摘要
Abstract
LA-ICP-MS zircon U-Pb dating shows that the Xinzhai granites, emplaced in northern Guangxi, were generated in Mid?dle Ordovician (465±2Ma). These granites are characterized by uniform silicon content (SiO2=68.54%~4.57%), enrichment of alkali val?ues and considerable enrichment of K values (K2O+Na2O=7.61%~8.31%, K2O/Na2O=1.77~2.35), concentration of peraluminous (A/CNK=1.09~2.39) and high large ion lithophile elements (LILE) (e.g., Rb, K, Th) but relative depletion of high field-strength el?ements (HFSE) (e.g., Nb, Ta, P, Ti) and Sr. They belong to S-type granite. Granitic samples have homogeneous Sr-Nd isotope compositions (ISr=0.71137~0.71328,εNd(t)=-7.89~-7.26). Zircon Hf isotope compositions of the Xinzhai granites have relatively wide ranges (176Hf/177Hf=0.28232~0.28252,εHf(t)=-6.18~+0.61, TDM2=1.67~2.11Ga). The authors hold that the Xinzhai granites were likely generated by partial melting of Paleoproterozoic metapelite, with the addition of small amounts of mafic magma mantle-derived material. The Xinzhai S-type granites might have been the petrological response to the second activity of the Kwangsian orogen in northern Guangxi, which provided new evidence for the establishment of the Early Paleozoic tectonic-magma events in South China.关键词
中奥陶世/S型花岗岩/Sr-Nd-Hf同位素/广西运动/桂北Key words
Middle Ordovician/S-type granite/Sr-Nd-Hf isotope composition/Kwangsian orogen/northern Guangxi分类
天文与地球科学引用本文复制引用
贾小辉,王晓地,杨文强..桂北新寨强过铝质花岗岩的岩石成因及其构造意义——来自年代学、地球化学及Sr-Nd-Hf同位素的制约[J].地质通报,2017,36(5):738-749,12.基金项目
国家自然科学基金项目《粤北罗岗钾玄质侵入岩的岩石成因及其动力学意义》(批准号:41302046)、中国地质调查局项目《南岭关键地区区域地质调查》(编号:12120113063600)和《国家地质数据库建设与整合》(编号:1212011220512) （批准号:41302046）
