【摘要】：爭光金礦位于大興安嶺東北部地區(qū),是多寶山礦集區(qū)內(nèi)重要的金礦床。目前,金的儲量已達(dá)30噸以上,平均品位為3.49克/噸,達(dá)到大型金礦床的規(guī)模。由于爭光金礦目前研究程度非常低,所以本文從巖礦相學(xué)、元素地球化學(xué)、同位素以及年代學(xué)四方面對其進(jìn)行系統(tǒng)地研究,并進(jìn)一步建立礦床模型。主要的研究成果包括:(1)礦石中金的存在形式主要為銀金礦和含金碲銀礦,金礦物通常賦存在黃鐵礦的裂隙中,或者處于石英與方鉛礦的接觸面上。含金礦物通常與黃銅礦、閃鋅礦和方鉛礦共生在一起。除金之外,部分礦石中Cu、Pb、Zn也達(dá)邊界品位,可加以綜合利用。(2)發(fā)現(xiàn)了低硫型淺成低溫?zé)嵋盒偷V床標(biāo)志礦物冰長石和富鐵閃鋅礦。且礦石中石英和方解石具有典型的梳狀構(gòu)造,H-O同位素表明其流體組成具低硫型特征,多方面因素共同證實爭光為低硫型淺成低溫?zé)嵋盒偷V床。(3)H-O同位素(δ18O水=-3.2‰~-1.0‰,δD水=-113.5‰~-119.8‰)研究顯示成礦流體主要為大氣水,含有少量巖漿水的參與。C-O同位素(δ13CPDB=-4.06‰~-1.60‰,δ18OSMOW=6.30‰~14.65‰)研究表明成礦流體中的C源于巖漿,并具低溫蝕變的特征。Si-O同位素(δ30Si=-1.0‰~0.3‰,δ18O石英=10.9‰~13.6‰)顯示石英中Si為巖漿來源,并顯示其為熱液成因。S同位素(δ34S主要為-5.4‰~-1.5‰,另有兩個異常值-12.1‰和-8.9‰)顯示成礦流體S主要來源于巖漿。(4)奧陶紀(jì)的多寶山組和閃長巖類具有下地殼來源的特征,而侏羅紀(jì)閃長巖具有中上地殼來源的特征。Lu-Hf同位素分析顯示奧陶紀(jì)閃長巖類具有幔源特征(其εHf(t)=+11.94~+15.63),侏羅紀(jì)閃長巖類具有殼源特征并有少量幔源物質(zhì)的參與(εHf(t)=-11.76~-1.00)。而礦石的稀土和微量元素特征顯示多寶山組可能為主要的礦源層。(5)爭光金礦經(jīng)歷了三次成礦作用。屬于奧陶紀(jì)多寶山斑巖成礦系統(tǒng)的斑巖型和淺成低溫?zé)嵋盒统傻V作用(成礦年齡約460 Ma~480 Ma);侏羅紀(jì)早期古太平洋和蒙古-鄂霍茨克洋的俯沖造成了板內(nèi)伸展背景下的淺成低溫?zé)嵋盒统傻V作用(成礦年齡為184.6±2.6 Ma);以及侏羅紀(jì)晚期蒙古-鄂霍茨克洋閉合導(dǎo)致的伸展作用及巖石圈拆沉背景下的淺成低溫?zé)嵋盒统傻V作用(成礦年齡為150.67±0.77 Ma)。
[Abstract]:Zhengguang gold deposit is an important gold deposit in Dobaoshan ore concentration area, located in the northeast of Daxinganling. At present, the gold reserves have reached more than 30 tons and the average grade is 3.49 g / t, reaching the scale of large gold deposit. Due to the very low degree of study of Gengguang Gold Mine at present, this paper systematically studies the gold deposit from four aspects of petrology, elemental geochemistry, isotope and geochronology, and further establishes the ore deposit model. The main results are as follows: (1) the main forms of gold in ore are silver gold deposit and gold tellurium silver deposit, which usually occurs in the fissure of pyrite or on the contact surface between quartz and galena. Gold-bearing minerals are usually associated with chalcopyrite, sphalerite and galena. In addition to gold, Cu,Pb,Zn also reaches boundary grade in some ores, which can be comprehensively utilized. (2) the low sulfur epithermal hydrothermal type deposits have been found to mark the mineral ice feldspar and marmatite rich in sphalerite. Quartz and calcite in ore have typical comb-like structure, H-O isotopes show that their fluid composition is of low sulfur type. It is confirmed by many factors that Gengguang is a low-sulfur epithermal hydrothermal deposit. (3) the study of H-O isotope (未 18O water = -3.2 鈥，

本文編號：2268581