西大别红安岩群含磷岩系的形成时代及物源分析  

Sedimentary Age and Provenance of Phosphorous-containing Rocks in Hong'an Group in the Western Dabie Area

作　　者：刘浩 徐扬 张维峰 徐大良[1,3] 魏运许 邓新[1,3] 金鑫镖 彭练红[1] LIU Hao;XU Yang;ZHANG Wei-Feng;XU Da-Liang;WEI Yun-Xu;DENG Xin;JIN Xin-Biao;PENG Lian-Hong(Wuhan Center,China Geological Survey(Geosciences Innovation Center of Central South China),Wuhan 430205,Hubei,China;Hubei Key Laboratory of Paleontology and Geological Environmental Evolution,Wuhan 430205,Hubei,China;Research Center for Petrogenesis and Mineralization of Granitoid Rocks,China Geological Survey,Wuhan 430205,Hubei,China)

机构地区：[1]中国地质调查局武汉地质调查中心(中南地质科技创新中心),湖北武汉430205 [2]古生物与地质环境演化湖北省重点实验室,湖北武汉430205 [3]中国地质调查局花岗岩成岩成矿地质研究中心,湖北武汉430205

出　　处：《华南地质》2023年第2期278-291,共14页South China Geology

基　　金：古生物与地质环境演化湖北省重点实验室开放研究基金(PEL202113);中国地质调查局花岗岩成岩成矿地质研究中心开放基金(PM202307);中国商务部对外援助项目([2021]28)。

摘　　要：西大别红安岩群含磷岩系赋存有我国最大的磷灰石变质矿床,其时代约束可以为红安岩群层序划分、黄麦岭岩组与扬子陆块陡山沱组对比提供重要依据。通过岩石学及LA-ICP-MS锆石U-Pb同位素测年,在黄麦岭岩组中的浅粒岩和磷矿石中获得~640 Ma、~730 Ma、~760 Ma、~810 Ma、~2017 Ma五组较集中的碎屑锆石U-Pb年龄和零星的~2476 Ma和~2700 Ma年龄。碎屑锆石最小年龄616±13Ma约束了黄麦岭岩组的最大沉积年龄,表明黄麦岭岩组为红安岩群最晚期沉积,推测黄麦岭岩组沉积时代与陡山沱组相当或晚于后者。样品碎屑锆石磨圆度差,且年龄谱系与西大别地区的岩浆活动一致,推测西大别地区为黄麦岭岩组的物源区。The phosphorous-containing deposit in the western Dabie area is the largest metamorphic apatite deposit in China,deposit time of which is the key to reveal the sequence of Hong'an Group and the contrast between the Huangmailing Formation in Dabie and the Doushantuo Formation in the Yangtze block. Through petrology and LA-ICP-MS zircon U-Pb dating,the peak ages of ~640 Ma,~730 Ma,~760 Ma,~810 Ma,~2017 Ma and sporadic ages of ~2476 Ma and ~2700 Ma were obtained in the leptites and phosphate ores.The minimum age of clastic zircons is 616 ± 13Ma,which limits the maximum sedimentary age of the Huangmailing Formation. It is speculated that the Huangmailing Formation is equivalent or later than that of the Doushantuo Formation, and it is the latest deposit in the Hong'an Group. The age spectrum of the sample is consistent with the magma activities in the western Dabie along with the poor round shape of the zircons,which indicates that western Dabie area is the provenance area of these phosphrous rocks.

关 键 词：红安岩群 黄麦岭岩组 变质磷矿 时代及物源 西大别 

分 类 号：P597[天文地球—地球化学] P619.213[天文地球—地质学]