桂西南地区三叠系沉积型锰矿床成因研究

发布时间：2018-05-24 11:11

本文选题：桂西南地区 + 三叠系　；参考：《沉积学报》2017年06期

【摘要】：桂西南地区锰矿床资源富集并具有较好的找矿前景,然而目前有关该区三叠系主要沉积地层的地层格架划分尚较薄弱且鲜有探讨。利用桂西南地区东平锰矿区四口钻孔的自然伽马测井曲线进行去趋势、高通滤波处理以及累计残差计算等方法,对桂西南地区含锰岩系进行了旋回地层学研究。研究结果表明:含锰岩系下三叠统北泗组共可划分为四个海进—海退旋回层序,碳酸锰矿层发育的旋回层序位置主要出现于各旋回层序内海退沉积序列中,并位于旋回层序内海退—海侵界面附近,锰矿沉积主要发生在相对海平面由缓慢下降至逐渐上升的时期的转换时期。综合研究区锰矿形成的海平面变化、古地理条件、锰质来源、氧化还原条件等特征的基础上,笔者提出了研究区锰矿成因模式,即具有地理隔绝形式的、并由同生断裂控制的"局限海"台盆相碳酸锰矿沉积模式,碳酸锰矿的形成主要经历以下3个阶段:1)海平面下降—氧化锰矿物形成阶段;2)海平面上升—氧化锰矿物转化碳酸锰矿物阶段;3)最高海泛面—少量碳酸锰矿物发育阶段。该研究成果可为桂西南地区今后锰矿勘探工作中的地层分析、建立区域内高频层序单元格架及锰矿成因等研究提供一种新的方法和手段。
[Abstract]:The manganese deposit in southwest Guangxi is rich in resources and has a good prospect for prospecting. However, the stratigraphic framework division of the main sedimentary strata of Triassic in this area is still weak and rarely discussed. Based on the natural gamma logging curves of four boreholes in Dongping Manganese Mine area of southwest Guangxi, the cyclic stratigraphic study of manganese bearing rock series in southwest Guangxi is carried out by means of detrend, high pass filtering and calculation of accumulative residual. The results show that the lower Triassic Beisi formation in the manganese bearing series can be divided into four marine and regressive sequences, and the cyclic sequence positions of the manganese carbonate ore beds mainly occur in the internal marine regressive sedimentary sequences of each cyclic sequence. It is located near the regressive and transgressive interface within the cyclic sequence and the manganese deposit mainly occurs during the transition period from the slow decline of the relative sea level to the gradual rise of the sea level. On the basis of the characteristics of sea level change, paleogeographic condition, manganese source, redox condition and so on in the study area, the authors put forward the genetic model of manganese ore in the study area, that is, the manganese ore has the form of geographical isolation. And the sedimentary model of "limited sea" platform facies manganese carbonate controlled by syngenic faults. The formation of manganese carbonate ore mainly goes through the following three stages: 1) sea level drop-manganese oxide mineral formation stage (2) sea level rise-manganese oxide mineral transformation stage mn carbonate stage 3) the highest sea surface stage-a small amount of manganese carbonate mineral development stage. The results can provide a new method and means for the stratigraphic analysis of manganese ore exploration in southwest Guangxi and the establishment of high-frequency sequence cell frame and manganese ore genesis in the area.
【作者单位】：成都理工大学沉积地质研究院;中国石化中原油田分公司勘探开发研究院;成都理工大学油气藏地质及开发工程国家重点实验室;
【基金】：“十二五”国家科技支撑计划项目(2011BAB04B10) 国家自然科学基金项目(40972084) 高等学校博士点专项科研基金课题(20105122110012)~~
【分类号】：P618.32

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