中国地质2018，Vol.45Issue(1)：95-109,15.DOI:10.12029/gc201808109
豫西崤山韩沟岩体锆石U-Pb定年、地球化学特征及地质意义
Zircon U-Pb dating and geochemical features of Hangou granitic body in Xiaoshan Mountain, western Henan Province, and its geologic implications
摘要
Abstract
Hangou monzonitic granite porphyry body lies in northern Xiaoshan Mountain,western Henan Province.Petrogenetic research on Hangou rock body is important for recognizing tectonic evolution in northern Xiaoshan Mountain area,and it is also significant for estimating mineralization potential.The zircon U-Pb dating method of LA-ICP-MS was used to confirm the age of biotite monzonitic granite porphyry sample named LLHG01 from Hangou rock body.The results of 20 zircon spots are consistent with 207Pb/235U-206Pb/238U trend line,with 206pb/238U ages being from 142 Ma to 147 Ma,and weighted average age being (145.1±0.7)Ma.Hangou rock body is characterized by higher SiO2 and alkali,enrichment of K2O,and lower MgO and CaO.Compositional spots of Hangou rock body fall into high-K calc-alkaline series in the SiO2-K2O diagram,and it belongs to K-rich calc-alkaline granite (KCG).In chondrite-normalized REE patterns,Hangou rock body samples have shown the characteristics of LREE-enrichment and HREE depletion with trivial Eu positive anomaly,whose (La/Yb)N ratios are from 10.41 to 11.51.Samples from Hangou rock body are enriched in large ion lithophile elements and depleted in high field-strength elements,which has formed troughs of Nb,Ta and Ti in spider diagram.Samples of Hangou rock body have higher Sr and lower Y and Yb,suggesting that Hangou rock body is adakite.According to the content of Na2O and K2O,Hangou rock body is C-type adakite.Hangou rock body originated from partial melting of the thickened lower crust,and its residual phases of partial melting source included garnet and rutile,with no plagioclase.North Xiaoshan Mountain area underwent the process of lithosphere delamination of different scales in ～145 Ma and ～130 Ma,and Hangou rock body is a product of smaller scale lithosphere delamination that occurred at ～145 Ma.The formation age of Hangou rock body falls into the time interval of～145 Ma stage of acid magmatism and endogenetic mineralization in western Henan Province.In the disaster process of lithosphere delamination in Hangou area,huge deep fluids were driven and discharged rapidly,suggesting that Hangou rock body and its concealed part have large mineralization potential.There are 11 Au deposits and Au mineralization spots around Hangou rock body,which constitute the best exploration evidence.关键词
韩沟岩体/LA-ICP-MS锆石定年/埃达克岩/岩石圈拆沉/成矿潜力/崤山Key words
Hougou monzonitic granite porphyry/LA-ICP-MS zircon dating/adakite/lithosphere delamination/mineralization potential/Xiaoshan Mountain分类
天文与地球科学引用本文复制引用
卢仁,梁涛..豫西崤山韩沟岩体锆石U-Pb定年、地球化学特征及地质意义[J].中国地质,2018,45(1):95-109,15.基金项目
国家自然科学基金项目(U1504405)、河南省基础与前沿技术研究计划(162300410065)、河南省国土资源厅科技攻关项目(2016-08,2014-06,2011-622-25,2011-622-36)资助. Supported by State Natural Science Foundation Program (No.U1504405),Henan Province Basic and Advanced Technology Research Project (No.162300410065),Henan Provincial Bureau of Land and Resources Science and Technology Key Project (No.2016-08,2014-06,2011-622-25,2011-622-36). （U1504405）
