闽中地区梅仙铅锌矿田赋矿变质岩系对比与深部找矿前景

发布时间：2018-01-27 02:23

本文关键词： 闽中梅仙铅锌矿田马面山群东岩组变质岩层序原岩恢复　出处：《南京大学》2015年硕士论文　论文类型：学位论文

【摘要】：梅仙铅锌矿田形成于闽中大陆裂谷环境中,铅锌矿体主要赋存于新元古界马面山群绿片岩相的变质岩系内,层位和岩性控制特征显著。矿田以尤溪河为界分为河西(以丁家山矿区为代表)和河东(以峰岩矿区为代表)两部分,然而,矿田内不同矿区之间在赋矿变质岩系的岩性定名、层位划分及矿体特征等方面存在明显差异,导致不同矿区之间层位难以对比,给找矿预测工作带来较大困难。本文在充分研究前人成果的基础上,通过对马面山群变质岩层序及地球化学特征的分析研究,对梅仙地区铅锌矿赋矿变质岩系的地层进行了划分对比:梅仙矿田新元古界马面山群变质岩系自老至新为龙北溪组、东岩组。龙北溪组为岩性主要为石英云母片岩、长石石英片岩、大理岩、石英岩等"浅色片岩"夹有少量薄层"绿片岩",根据其岩石化学与稀土元素特征,经原岩恢复,龙北溪组为下伏于东岩组的一套巨厚的海相硅质、钙镁质、半粘土质、泥砂质沉积变质岩系,间隙有小规模的基性-超基性岩浆喷发。该组在梅仙地区仅丁家山矿区有所揭露,且与上覆东岩组整合接触,表明丁家山矿区的赋矿岩系为东岩组的底部。东岩组由多组"浅色片岩"-"绿片岩"岩性旋回组成。"浅色片岩"主要为云母片岩、长石绿帘石石英片岩、大理岩、钠长变粒岩等;"绿片岩"主要为绿帘石、透辉石、绿泥石、阳起石等绿色矿物组成的岩石系列,为矿田内铅锌矿的主要赋矿层位。根据其岩石化学与稀土元素特征,经原岩恢复,东岩组为一套泥钙质沉积与少量基性-中酸性火山喷发的沉积旋回。①丁家山矿区目前揭露该组为2岩性段,为1组"浅-绿"变质岩系旋回,且为东岩组的底部岩层;②峰岩矿区目前揭露该组为4岩性段,分为2组"浅-绿"变质岩系旋回,尚未见底;且大致可与峰岩东矿区东岩组上部6、5、4、3段相对应;③峰岩东矿区目前揭露该组为6岩性段,分为3组"浅-绿"变质岩系旋回,尚未见底。因此,研究认为,丁家山矿区与峰岩矿区的赋矿变质岩系并非同一层位,而是下伏于其下的含矿岩层,峰岩矿区深部具备寻找丁家山式铅锌矿床的前景。
[Abstract]:The Meixian Pb-Zn ore field was formed in the central Fujian continental rift environment, and the Pb-Zn orebody mainly occurred in the metamorphic rock series of the greenschist facies of the Maofanshan Group in the Neoproterozoic. The ore field is divided into two parts: Hexi (represented by Dingjiashan mining area) and Hedong (represented by Fengyan mine). There are obvious differences in lithology designation, stratigraphic division and orebody characteristics among different mining areas in the ore-bearing metamorphic rock series, which leads to the difficulty to contrast the strata between different mining areas. In this paper, based on the study of previous achievements, the sequence and geochemical characteristics of metamorphic rocks in Mamianshan Group are analyzed and studied. The strata of ore-bearing metamorphic rock series of lead and zinc deposits in Meixian area are divided and compared: the metamorphic rock series of Mafanshan Group of Neoproterozoic in Meixian Orefield is from old to new Longbei Xi formation. Dongyan formation. The lithology of Longbei Xi formation is mainly composed of quartz mica schist, feldspar quartz schist, marble, quartzite and other "light color schist" with a small amount of thin layer "green schist", according to its petrochemistry and rare earth element characteristics. Through the restoration of the original rocks, the Longbei Xi formation is a set of extremely thick marine siliceous, calciumite, semi-clayey and muddy sedimentary metamorphic rock series which lies in the Dongyan formation. There is a small scale basic-ultrabasic magma eruption in the gap. Only the Dingjiashan mining area in Meixian area has been exposed and has integrated contact with the overlying Dongyan formation. The results show that the host rock series of the Dingjiashan mining area is the bottom of the eastern rock formation, which is composed of several groups of "light color schist" and "green schist" lithologic cycle. The "light color schist" is mainly mica schist, and the feldspar verdite quartz schist is mainly composed of "light color schist" and "green schist". Marble, sodium granulite, etc.; The "greenschist" is a series of green minerals such as verdant, diopside, chlorite and actinolite, which is the main ore-bearing bed of the lead-zinc deposit in the ore field, according to its petrochemistry and REE characteristics. The Dongyan formation is composed of a set of mud-calcareous deposits and a few basic-intermediate-acid volcanic eruptions. 1. At present, it is revealed that the formation is a 2 lithologic member, which is a "shallow-green" metamorphic rock series cycle. And it is the bottom rock of Dongyan formation; (2) at present, the Fengyan mining area reveals that the formation is a 4 lithologic member, which is divided into 2 groups of "shallow-green" metamorphic rock series cycles, but has not yet been bottomed out; And it can be roughly corresponding to the upper part of the Dongyan formation of Fengyandong Mining area, section 6, 5, 5, 4, and 3. At present, it is revealed that the formation is 6 lithologic member, divided into 3 groups of "shallow-green" metamorphic rock series cycle, not yet bottom. Therefore, the study believes that. The ore-bearing metamorphic rock series of Dingjiashan and Fengyan mining areas are not the same horizon, but the ore-bearing strata underlying them. The deep part of Fengyan mining area has the prospect of finding Dingjiashan type lead-zinc deposit.
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.4

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