本文關(guān)鍵詞： 構(gòu)造巖相 界面成礦 郭家?guī)X花崗閃長巖 大尹格莊金礦床 膠東西北部　出處：《中國地質(zhì)大學(xué)(北京)》2017年博士論文　論文類型：學(xué)位論文

【摘要】：膠東是我國最重要的黃金產(chǎn)區(qū)之一,金礦成礦受中生代花崗巖及斷裂構(gòu)造控制。本文圍繞膠西北郭家?guī)X花崗閃長巖構(gòu)造地質(zhì)特征與區(qū)域構(gòu)造背景的關(guān)系、構(gòu)造作用通過影響金礦成礦的物理化學(xué)條件并進(jìn)而影響成礦地球化學(xué)過程等問題,開展郭家?guī)X花崗閃長巖構(gòu)造地質(zhì)特征、區(qū)域及典型礦床構(gòu)造巖相控礦特征等研究,獲得以下認(rèn)識:(1)膠西北郭家?guī)X巖體及圍巖內(nèi)部似片麻理走向為NW~NNW向,接觸帶似片麻理走向與接觸帶走向近一致;巖體中鉀長石斑晶長軸走向為NW和NNE向,二者夾角110°~120°,巖體西南部斑晶密度較大、a軸長度較小,巖體東北部斑晶密度較小、a軸長度較大,斑晶密度和a軸長度等值線呈NW向展布;顯示郭家?guī)X巖體主動侵位特點,揭示巖體在強力擠壓狀態(tài)下侵入,最大主壓應(yīng)力方向為NE向。(2)郭家?guī)X巖體巖石顯微組構(gòu)分為巖漿-高溫固態(tài)流動組構(gòu)、中溫固態(tài)流動組構(gòu)和低溫固態(tài)流動組構(gòu),據(jù)此將巖體分為高溫、中溫和低溫構(gòu)造巖相帶,各帶呈NW向展布;石英C軸EBSD組構(gòu)特征顯示:高溫、中溫和低溫構(gòu)造巖相帶石英變形溫度為450~550℃、350~450℃和250~350℃,分別通過柱面(1010)0001、柱面(1010)1210和底面(0001)1120滑移系蠕變;鉀長石斑晶a軸長度較大區(qū)域位于高溫巖相帶,密度較大區(qū)域位于低溫巖相帶。(3)膠西北地區(qū)構(gòu)造蝕變圍繞控礦斷裂發(fā)育,構(gòu)造蝕變帶展布與斷裂帶基本一致,自斷裂帶向外構(gòu)造蝕變逐漸減弱,且斷裂下盤更發(fā)育,金礦一般賦存于黃鐵絹英巖帶。通常含礦區(qū)段蝕變帶較寬,蝕變帶較窄或無蝕變區(qū)段不含礦。(4)大尹格莊金礦床構(gòu)造蝕變帶流體包裹體完全均一溫度為148~310℃,鹽度為1.71%~12.71%;成礦流體富含CO2;陰陽離子主要為SO42-、F-、Ca2+、Na+,成礦流體為中低溫、低鹽度CO2-H2O-NaCl體系。氫氧同位素分析表明成礦流體主要來源于巖漿混合水。(5)大尹格莊金礦床構(gòu)造蝕變帶巖石應(yīng)力應(yīng)變分析表明:自斷裂帶向外黃鐵絹英巖、黃鐵絹英巖化花崗質(zhì)碎裂巖和鉀化花崗巖變形石英a/c軸比均值為2.495、2.8415和2.5323,ac面差應(yīng)力均值為283.54×105Pa、361.18×105Pa和276.68×105Pa,a/c軸比值和差應(yīng)力值均先升后降;在此基礎(chǔ)上測得構(gòu)造蝕變帶構(gòu)造附加靜水壓力為(821.90~1156.48)×105Pa;經(jīng)構(gòu)造校正測算獲得礦床成礦深度為-2775.4~-4164.5m。(6)建立了大尹格莊金礦床構(gòu)造巖相界面成礦模式。顯示構(gòu)造力集中和松弛部位分別對應(yīng)其他物理化學(xué)參量高值、低值區(qū),高低值轉(zhuǎn)變帶存在有利于成礦的構(gòu)造物理化學(xué)界面帶,成礦發(fā)育于構(gòu)造力松弛一側(cè)。
[Abstract]:Jiaodong is one of the most important gold-producing areas in China. Gold mineralization is controlled by Mesozoic granite and fault structure. This paper revolves around the relationship between tectonic geological characteristics and regional tectonic setting of Guojialing granodiorite in northwestern Jiao. Tectonism develops the tectonic geological characteristics of granodiorite in Guojialing by influencing the physical and chemical conditions of gold mineralization and further affecting the process of mineralization and geochemistry. Based on the study of tectonic facies and ore-controlling characteristics of regional and typical deposits, the following conclusions are obtained: (1) in Guojialing rock mass and surrounding rock mass in northwestern Jiao, the trend of NW~NNW is similar to that in the inner part of Guojialing rock mass. The contact zone is similar to that of the contact zone. In the rock mass, the long axis strike of potash feldspar porphyry is NW and NNE, the angle between them is 110 擄~ 120 擄, the length of porphyry axis is larger in the southwest part of the rock mass, and the porphyry density is smaller in the northeast part of the rock mass. The length of a axis is large, and the isopleth of porphyry density and a axis length is distributed in NW direction. It shows the characteristics of active emplacement of Guojialing rock mass, and reveals that the rock mass invades under the condition of strong compression, and the direction of the maximum principal compressive stress is NE. 2) the rock microstructure of the Guojialing rock body can be divided into magma and high temperature solid flow fabric. According to the medium temperature solid flow fabric and the low temperature solid flow fabric, the rock mass is divided into high temperature, moderate and low temperature tectonic facies belts, each of which is NW distributed; The EBSD fabric characteristics of quartz C-axis show that the deformation temperature of quartz in the tectonic facies belt of high temperature, moderate temperature and low temperature is 450 ~ 550 鈩，

本文編號：1464058