地质与勘探2017，Vol.53Issue(6)：1090-1104,15.
广西岑溪地区糯垌A型花岗岩的厘定及其构造意义
Confirmation of the Nuodong A-Type Granite in Cenxi City of Guangxi and its Tectonic Significance
摘要
Abstract
The Nuodong pluton in Guangxi is located at the connection between the Cathaysia and Qinzhou-Hangzhou junction zone. The main rock type is biotite K-feldspar granite, and the LA-ICP-MS zircon U-Pb age of two zircons is (151. 1 ± 1. 9) Ma and (152. 6 ± 1. 2) Ma, respectively, indicating that it is the product of Late Jurassic magmatic activity in the early Yanshanian period. This pluton has characteristics of rich alkali, high potas-sium and iron and poor magnesium (alk=10. 29% ~10. 91%, FeOT =3. 60% ~5. 10%, FeOT/MgO=10. 33~11. 69). The granitoid is alkaline (δ43=4. 78~5. 38) and metaluminous series (A/CNK=0. 96~0. 98,A/NK=1. 21~1. 24). The rare earth elements have a right-type distribution pat-tern,with high content of rare earth elements(∑REE=(610.03~790.48)×10 -6) and strong negative europium anomaly(δEu=0.30~0.37).On the primitive mantle-normalized spider diagrams,the granites show positive Rb, Th, La, Ce, Zr, Hf and Y anomalies,negative Ba, Sr, P and Ti,and high 10000Ga/Al(3.03~3.31) and Zr+Nb+Ce+Y values((857.7~1244.4)×10 -6).The above geochemical characteristics indicate that the Nu-odong pluton is aluminum A-type granite,and its low incompatible element ratios ( Ce/Nb, Y/Nb, Yb/Ta) suggest it is a non-orogenic A1 type gran-ite. The Sr-Nd isotopes (εNd(t) = -2. 25~ -1. 52,εSr(t) =22. 34~37. 59,TDM =0. 86~1. 24 Ga) indicate that the Nuodong pluton is derived from the Meso-Neoproterozoic crust material and may be involved in mantle material. The Nuodong pluton was formed in an intraplate environment,which indi-cates the Cenxi area of Guangxi has undergo the Tethyan tectonic domain converted into the Pacific Ocean tectonic domain in the Late Jurassic and entered a non-orogenic tectonic environment.关键词
Sr-Nd同位素/A型花岗岩/非造山构造环境/糯垌岩体/岑溪地区/广西Key words
Sr-Nd isotope/A-type granite/non-orogenic tectonic setting/Nuodong granitoid/Cenxi area/Guangxi分类
天文与地球科学引用本文复制引用
李程,杨启军,秦亚..广西岑溪地区糯垌A型花岗岩的厘定及其构造意义[J].地质与勘探,2017,53(6):1090-1104,15.基金项目
广西"找矿突破战略行动"项目桂国土资函[2016]429号项目和广西高校科研项目(编号:KY2015YB127)资助. （编号:KY2015YB127）
