中扬子地区南华纪早期碎屑锆石U-Pb年龄及其对物源特征和古地理格局的约束  

U-Pb Age of Detrital Zircon and Its Restriction of Provenance & Paleogeographic Characteristics of Early Nanhua Period in Middle Yangtze

作　　者：宋芳[1] 牛志军[1,2] 何垚砚 杨文强[1,2] 

机构地区：[1]中国地质调查局武汉地质调查中心,武汉430205 [2]中国地质调查局古生物与生命-环境协同演化重点实验室,武汉430205 [3]中国地质大学(武汉),武汉430074

出　　处：《地质学报》2016年第10期2661-2680,共20页Acta Geologica Sinica

基　　金：中国地质调查局地质矿产调查评价专项(12120114039301;1212011120117;121201102000150012-19)项目资助的成果

摘　　要：南华纪早期中扬子地区以鄂中古陆为主体,在其周缘发育以莲沱组为代表、以河流相为主的沉积。本文通过对湖北通山、长阳以及湖南杨家坪3个地区代表性剖面的莲沱组及相应层位碎屑锆石年龄谱的研究,结合研究区已发表的相关成果,对中扬子地区不同地理位置南华纪早期物源特征及其对古地理格局的约束进行探讨。根据研究区碎屑锆石年龄谱~810Ma、~860Ma、~2000Ma及~2500Ma的年龄峰值,认为其物源为典型的亲扬子型,主要物源区为鄂中古陆的隆起剥蚀区;>3000Ma的崆岭杂岩物源只分布于宜昌莲沱、长阳以及随州大洪山地区,在该线南东方向应存在一个地势较低的区域。Ezhong Old Land was the main component of Middle Yangtze during Early Nanhua Period,fluvial deposition of Liantuo Formation and corresponding sedimentation developing in surrounding area.Considering published research achievement,through the U-Pb age of detrital zircon of Liantuo formation and corresponding sedimentation from sections of Tongshan, Changyang in Hubei Province and Yangjiaping in Hunan Province,we discuss provenance and paleogeographic characteristics of the research area.According to the age peaks of^810Ma,~860Ma,~2000Ma and ~2500Ma,provenance of the area is typically from Yangtze Block,denudation area in Ezhong Old Land being the main source.Meanwhile,provenance from Kongling Complex with the age peak of 3000Ma only could be found in Yichang,Changyang and Suizhou,implying a low-lying area to the south-east.

关 键 词：碎屑锆石 中扬子 南华纪 物源特征 古地理格局 

分 类 号：P597.3[天文地球—地球化学] P531[天文地球—地质学]