本文選題：礦床地球化學(xué) + 流體包裹體��； 參考：《中國(guó)地質(zhì)大學(xué)(北京)》2017年碩士論文

【摘要】：西藏岡底斯-喜馬拉雅造山系中的古堆地區(qū),位于藏南江孜-隆子金銻多金屬成礦帶上,成礦潛力巨大。該地區(qū)地質(zhì)工作程度不高,多金屬礦床的勘查程度偏低,對(duì)區(qū)內(nèi)典型多金屬礦床的地球化學(xué)特征及成礦流體進(jìn)行研究還十分薄弱,也缺乏區(qū)域成礦規(guī)律的總結(jié)與研究。研究區(qū)的多金屬礦床與三疊系涅如組二段、三段,侏羅系遮拉組聯(lián)系緊密,巖性都以泥質(zhì)成分為主,普遍含碳較高,并含有灰?guī)r、鐵硅結(jié)核,推斷沉積環(huán)境為差異升降下的水下扇沉積的進(jìn)積型地層對(duì)成礦較為有利。碰撞造山和拆離伸展兩個(gè)階段形成的壓扭、伸展作用疊加形成的近EW、NE和NW向斷裂構(gòu)造及次級(jí)斷裂交匯處,是有利的成礦控礦構(gòu)造。古近紀(jì)40Ma左右的花崗巖與金銻多金屬成礦關(guān)系密切,新近紀(jì)20Ma左右的花崗巖與銻鉛鋅關(guān)系密切。本文取得如下成果和認(rèn)識(shí):(1)流體包裹體類型主要有水溶液包裹體(W型)、CO2-H2O型包裹體(C型),少量氣液兩相包裹體,無(wú)含子礦物多相包裹體。三個(gè)典型礦床均一溫度為170-220℃,鹽度平均6.82%,成礦壓力為50-55MPa,成礦深度為1.5-2.5km,可判斷其屬于淺成低溫?zé)嵋盒偷V床;激光拉曼光譜分析得出成礦流體的氣體成分都以CO2為主,推斷古堆地區(qū)多金屬礦床流體都為中低溫低鹽度NaCl-H2O熱液體系。(2)氫、氧、硫、鉛同位素組成顯示,成礦流體主要為建造水,部分為變質(zhì)水與建造水的混合。硫具有深源巖漿硫的特征,鉛具有從造山帶向上地殼鉛演化的趨勢(shì),形成了與圍巖相同的鉛同位素組成。(3)分析了控礦因素,建立了研究區(qū)成礦模式圖,認(rèn)為達(dá)拉巖體巖漿活動(dòng)為成礦物質(zhì)提供了初始熱源及運(yùn)移動(dòng)力,地幔熱液的上涌及中酸性次火山巖侵入作用,產(chǎn)生動(dòng)力熱液變質(zhì)作用并汲取多種成礦元素,使之活化成含礦熱液,并且遷移、沉淀,在區(qū)內(nèi)一系列近EW向主斷裂與近SN向次級(jí)斷裂交匯處富集成礦。
[Abstract]:The Gudui area of the Gangdis Himalayan orogenic system in Tibet is located in the Jiangzi-Longzi gold-antimony polymetallic metallogenic belt in southern Tibet with great metallogenic potential. The degree of geological work in this area is not high and the degree of exploration of polymetallic deposits is on the low side. The geochemical characteristics and ore-forming fluids of typical polymetallic deposits in this area are still very weak, and the summary and study of regional metallogenic laws are also lacking. The polymetallic deposits in the study area are closely related to the second, third and Jurassic Chola formations of the Triassic, and their lithology is dominated by muddy compositions, generally with high carbon content, and with limestone and iron-silicon nodules. It is inferred that the precession of the subaqueous fan deposits in the depositional environment is favorable for metallogenesis. The compression and torsion formed in the two stages of collision orogeny and detachment extension, the superposition of extensional action to form near EWU NE and NW trending fault structures and the junction of secondary faults are favorable ore-controlling structures. The granites about 40 Ma in Paleogene are closely related to Au-SB polymetallic mineralization, while the granites of about 20 Ma in Neogene are closely related to antimony, lead and zinc. The main results of this paper are as follows: (1) the types of fluid inclusions are mainly aqueous inclusions (W type) and CO _ 2-H _ 2O inclusions (C type), a small amount of gas-liquid two-phase inclusions, and no multiphase inclusions containing sub-minerals. The homogenization temperature of the three typical deposits is 170-220 鈩，

本文編號(hào)：2069961