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引用本文:刘远栋,李翔,徐磊,陈美君,刘风龙,陈小友. 浙南龙泉地区晚侏罗世火山岩的厘定及成因探讨[J]. 中国地质, 2019, 46(6): 1530-1546.
LIU Yuandong,LI Xiang,XU Lei,CHEN Meijun,LIU Fenglong,CHEN Xiaoyou. Identification and genesis of the Late Jurassic volcanic rocks in Longquan area, southern Zhejiang Province[J]. Geology in China, 2019, 46(6): 1530-1546(in Chinese with English abstract).
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浙南龙泉地区晚侏罗世火山岩的厘定及成因探讨
刘远栋, 李翔, 徐磊, 陈美君, 刘风龙, 陈小友
浙江省地质调查院, 浙江 杭州 311203
摘要:
浙江晚中生代大规模火山活动始于晚侏罗世还是早白垩世,长期以来存在争议。本文对浙南龙泉地区火山岩进行了锆石U-Pb定年,获得一批高精度的年代学数据,其SHRIMP锆石U-Pb和LA-ICP-MS锆石U-Pb年龄集中于163~145 Ma,确认浙江晚中生代火山活动始于晚侏罗世。地球化学特征和Sr-Nd同位素特征表明这套晚侏罗世火山岩具有高硅、高钾、低磷、贫铁镁的特征,属于过铝质高钾钙碱性岩石系列。由于晚中生代太平洋板块的俯冲作用,导致了下部地壳物质(基底变质岩)广泛熔融,形成了本区晚侏罗世火山岩浆活动。为了便于表达、对比,笔者建议新建“晚侏罗世黄茅尖群”地层单位。
关键词:  锆石U-Pb  晚侏罗世  火山岩  浙南  黄茅尖群  地质调查工程
DOI:10.12029/gc20190618
分类号:P588.14
基金项目:中国地质调查局项目(12120114043101)、浙江省省基础性公益性战略性地质工作项目([省资]2018007,[省资]2018006)共同资助。
Identification and genesis of the Late Jurassic volcanic rocks in Longquan area, southern Zhejiang Province
LIU Yuandong, LI Xiang, XU Lei, CHEN Meijun, LIU Fenglong, CHEN Xiaoyou
Geological survey Institute of Zhejiang Province, Hangzhou 311203, Zhejiang, China
Abstract:
There has been controversy for a long time that the large-scale volcanic activity of Late Mesozioc in Zhejiang Province began with Late Jurassic or Early Cretaceous? Through zircon U-Pb geochronologic study of volcanic rocks in Longquan area of southern Zhejiang Province, a batch of high precision chronologic data were obtained. These zircon U-Pb ages are between 163 Ma to 145 Ma which were confirmed by SHRIMP and LA-ICP-MS. These data indicate that large-scale volcanic avtivity in Zhejiang Province began with Late Jurassic. According to geochemical characteristics and Sr-Nd isotope analysis, these Late Jurassic volcanic rocks belong to peraluminous and high potassium Ca-alkaline series characterized by high SiO2, K2O but low P2O5, FeOT and MgO. Due to the subduction of the Pacific plate in Late Mesozoic, the lower crust material (basement metamorphic rocks) was extensively melted and the late Jurassic volcanic-magmatic rocks in this area were formed. In addition, the authors propose defining a new rock-stratigraphic unit named" the Late Jurassic Huangmaojian Group"so as to better express and contrast.
Key words:  Zircon U-Pb geochronology  Late Jurassic  volcanic rocks  southern Southern Zhejiang  Huangmaojian Group  geological survey engineering