扬子区寒武系底部含磷岩系沉积特征对比与成矿规律

扬子区寒武系底部含磷岩系主要蕴藏于梅树村期地层中，因沉积相类型多样，含磷岩系复杂，沉积厚度变化大，含大量磷矿资源而具有重要的研究价值.对研究区13条含磷岩系剖面进行野外勘查和大区域横纵向综合对比研究，结果表明：含磷岩系沉积层序自下而上显示颗粒由粗变细，层理类型由交错层理、波状层理及粒序状层理转为平行层理，生物屑减少至消失；自西向东沉积微相大致由浅水缓坡、深水缓坡过渡为大陆坡、深海；碳酸盐岩、硅质岩、磷块岩及部分粉砂质黏土岩过渡为硅质岩、碳质页岩、结核状磷块岩.沉积微相对磷块岩的形成具有一定的控制作用.云南梅树村组中谊村段下段、贵州织金戈仲伍组下段及贵州清镇桃子冲组下段含磷岩系为下矿层；梅树村组中谊村段上段、戈仲伍组上段及桃子冲组上段含磷岩系为上矿层；贵州金沙、习水、遵义、开阳、镇远等地牛蹄塘组，贵州天柱、铜仁的留茶坡组与江西上饶、浙江江山荷塘组及江苏南京幕府山组含磷岩系为顶部矿层.

SEDIMENTARY CHARACTERISTICS AND METALLOGENIC REGULARITY OF PHOSPHORIC ROCK SERIES AT THE BOTTOM OF CAMBRIAN STRATA IN YANGTZE REGION

The phosphoric rock series at the bottom of Cambrian in Yangtze region are mainly contained in the strata of Meishucunian Age.It is worth studying for the various sedimentary facies,complex phosphoric rock series,great variation of sedimentary thickness and large amount of phosphate resources.Through field survey and comparison study of 13 phosphoric rock series profiles in the area,the sedimentary sequence show that,from bottom to top,the grains change from coarse to fine,from cross bedding,wave bedding and graded bedding to parallel bedding,and the bioclasts decrease to disappear;From west to east,the sedimentary microfacies generally change from shallow gentle slope and deepwater gentle slope to continental slope and deep sea,which control the formation of phosphorites to a certain extent.The carbonate rocks,siliceous rock,phosphorites and some silty clay rock transform into siliceous rocks,carbonaceous shale and nodular phosphorites.The phosphoric rock series in the lower section of Zhongyicun Member of Meishucun Formation in Yunnan,the lower member of Gezhongwu Formation in Zhijin and lower member of Taozichong Formation in Qingzhen of Guizhou are the lower ore beds;while the phosphoric rock series in the upper section of Zhongyicun Member of Meishucun Formation,the upper member of Gezhongwu Formation and upper member of Taozichong Formation are the upper ore beds.The phosphoric rock series in the Niutitang Formation in Jinsha,Xishui,Zunyi,Kaiyang and Zhenyuan of Guizhou,the Liuchapo Formation in Tianzhu and Tongren of Guizhou,the Hetang Formation in Shangrao of Jiangxi and Jiangshan of Zhejiang,and the Mufushan Formation in Nanjing of Jiangsu are the top ore beds.