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华南大陆构造与铀矿省
引用本文:周维勋.华南大陆构造与铀矿省[J].铀矿地质,1996,12(1):1-10.
作者姓名:周维勋
作者单位:华东地质学院,中南地质局230研究所
摘    要:华南前震旦纪基底由江南、武夷、云开-南海和闽台等4个地块组成,它们自晚元古代起处在同一岩石图板块范围内。铅同位素研究揭示,该板块富铀、钍,从而为铀矿省的形成提供了必不可少的地质前提。元古代、加里东、印支和燕山等造山事件导致4个板块的融合及其最终与扬子克拉通连成一体,但运动发生在莫霍流变层垫托之上,属板内构造范畴;晚震旦一早寒武世、晚古生代含铀黑色岩系及中生代容矿花岗岩、火山岩分别产生在相应时代主造山隆起带的前陆地区。继三叠纪-早侏罗世地壳显著增厚和花岗岩基大规模侵位之后,构造体制从挤压松弛往侧向伸展方向发展,其间中始新世至渐新世发生过局部性挤压,但伸展仍居主导地位,绝大多数铀矿床正形成于这一准克拉通化过程中,即晚侏罗世至第三纪。华南地学断面显示,在福建大田、泉州一带壳下岩石圈出现薄化裂离而在湘中一带壳下岩石圈则呈现为漏斗状凹陷。据分析,前者起因于热地幔柱上涌,并可能是太平洋超级热幔柱的组成部分;后者则为冷地幔柱下降所在位置,处于亚洲超级冷幔柱范围内。文中突出强调花岗岩一火山区是寻找富大铀矿的主要目标区,后火山侵入体(富挥发份花岗质小岩体或斑岩体)控制富铀矿生成。

关 键 词:板内构造  铀矿省  铀矿床  华南地区  大陆构造

CONTINENTAL TECTONICS AND URANIUM PROVINCE OF SOUTH CHINA
Zhou Weixun.CONTINENTAL TECTONICS AND URANIUM PROVINCE OF SOUTH CHINA[J].Uranium Geology,1996,12(1):1-10.
Authors:Zhou Weixun
Abstract:The pre-Sinian metamorphic basement of South China consists of 4 blocks,namely the Jiangnan,the Wuyi,the Yunkai-South Sea and the Mintal which belong to the same lithospheric plate from late Proterozoic on. The plate is enriched in U and Th revealed by Pb-isotopic study,which plays an role of essential prerequisite for the formation of U province. The amalgamation of the 4 blocks and their final attachment to Yangtze craton were resulted from Proterozoic,Caledonian, Indosinian and Yangshanian orogenic events,driven by Moho-rheologic stratification so that uraniferous black rock sequences and U-hosting granites and volcanics in age from late Sinian to Jurassic were produced in the forelands of corresponding major orogenic uplifts. The change of tectonic regime from compression-relaxed to lateral tension happened after significant crust's thickening and large-scale emplacement of granitic batholiths during late Triassic and early Jurassic though lacal compression occurred from middle Eocene to Oligocene. Most of U deposits were just formed in association with this para-cratonization process from late Jurassic to Eogene. South China GGT shows that there exist the thinning and the break-up of undercrustal lithosphere at the Datian and the Quanzhou and funnel-shaped seg at middle Hunan. The former two are considered to be the product of up-migration of hot mantle plume and the latter to be the place of down-migration of cold mantle plume.
Keywords:Intraplatic tectonics  Intracontinental tectonics  Uranium province  Post-volcanic intrusion
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