本文選題：銅多金屬礦床　切入點(diǎn)：礦床地球化學(xué)特征　出處：《東華理工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：格陵蘭是世界上重要的巨型多金屬成礦帶之一,Jameson Land盆地屬格陵蘭東部成礦帶。Jameson Land盆地位于格陵蘭島東部的火山裂谷邊緣,是形成于加里東期造山運(yùn)動(dòng)的拉張斷陷盆地,盆地基底為前寒武紀(jì)變質(zhì)巖,盆地蓋層形成始于中泥盆世,盆地內(nèi)各種沉積物堆積厚度達(dá)到17公里。經(jīng)研究發(fā)現(xiàn)區(qū)內(nèi)Cu、Pb、Zn等金屬地表礦化特征明顯、礦化強(qiáng)度大、分布范圍廣、厚度大,礦體形態(tài)呈層狀、似層狀,且礦化主要受地層層位控制,具備形成大型甚至超大型沉積巖容礦層狀銅礦床的條件,找礦前景巨大。但目前對(duì)該區(qū)科學(xué)研究幾乎為空白,所以有必要對(duì)該區(qū)進(jìn)一步開展關(guān)于礦床的成礦地質(zhì)和系統(tǒng)的地球化學(xué)研究工作,從而分析成礦物質(zhì)來源、成礦流體演化特征等礦床成因機(jī)制等科學(xué)問題。本文通過對(duì)Jameson Land盆地所在銅多金屬礦床區(qū)域的成礦地質(zhì)背景分析,綜合野外地質(zhì)調(diào)查工作和流體包裹體、C-O同位素、S同位素等地球化學(xué)的分析研究,取得了研究區(qū)的初步認(rèn)識(shí)有:1)通過對(duì)研究區(qū)礦石礦物顯微研究,發(fā)現(xiàn)金屬硫化物賦存形式多樣,既表現(xiàn)有同生沉積的特征,又有后期改造的特點(diǎn),認(rèn)為研究區(qū)銅多金屬礦床具有同生沉積-成巖-后期熱液改造的特點(diǎn)。2)通過與礦石礦物共生的脈石礦物(石英和重晶石)流體包裹體測(cè)溫得出均一溫度范圍113~387℃,平均值為185℃,溫度集中在120~220℃之間,顯示為中低溫成礦流體;鹽度范圍在0.4ωt%~13.4ωt%之間,平均為7.9ωt%,峰值出現(xiàn)在6.0ωt%~13.0ωt%之間,顯示流體為中低鹽度成礦流體;流體密度范圍在0.73~0.98g/cm3之間,平均值0.94g/cm3;均一溫度-鹽度典型熱液流體類型圖可以看出,成礦流體為大氣降水和與海水的混合。3)礦區(qū)方解石δ13CVPDB為-4.7‰~0.5‰,平均值-2.5‰,δ18OVPDB變化范圍為-26.0~-14.0‰,平均值-15.2‰,碳氧同位素圖解表明碳來源于海相碳酸鹽巖(即圍巖)的溶解,也說明流體與圍巖發(fā)生了水巖反應(yīng);金屬硫化物硫δ34S在-11.0~3.8‰之間,平均值-3.9‰;重晶石δ34S在13.4~15.2‰之間,平均值14.0‰。4)硫源來自三疊紀(jì)的蒸發(fā)巖和有機(jī)質(zhì)的還原作用,成礦金屬物質(zhì)來源于Ravnefjeld組頁巖、下伏中泥盆世磨拉石建造和圍巖。綜合以上研究得出Jameson Land盆地的銅多金屬礦床為典型的沉積-改造型礦床。
[Abstract]:Greenland is one of the most important giant polymetallic metallogenic belts in the world. The Jameson Land basin belongs to the eastern Greenland metallogenic belt. The Jameson Land basin is located on the edge of the volcanic rift in eastern Greenland and is formed in the Caledonian orogenic extensional fault basin. The basement of the basin is Precambrian metamorphic rock, the caprock formation of the basin began in the middle Devonian, and the thickness of various sediments in the basin reached 17 kilometers. The orebody is stratiform and layered in thickness, and mineralization is mainly controlled by stratigraphic strata. It has the conditions to form large or even super-large sedimentary rock ore bearing layered copper deposits, and the prospecting prospect is great. However, there is almost no scientific research in this area at present. Therefore, it is necessary to further study the ore-forming geology and systematic geochemistry of the deposits in this area, so as to analyze the source of the ore-forming materials. In this paper, the metallogenic geological background of the copper polymetallic deposit in the Jameson Land basin is analyzed by means of the metallogenic mechanism of ore deposits, such as the evolution characteristics of ore-forming fluids, and so on. Based on the field geological survey and the analysis of the geochemistry of fluid inclusions, such as C-O isotopes and S isotopes, a preliminary understanding of the study area has been obtained. Through the microscopic study of ore minerals in the study area, it is found that there are various forms of metallic sulphides. It not only shows the characteristics of syngenic deposition, but also has the characteristics of late transformation. It is considered that the copper polymetallic deposits in the study area have the characteristics of syngenic deposition-diagenesis and late hydrothermal transformation. 2) the homogeneous temperature range of 113 ~ 387 鈩，

本文編號(hào)：1583076