發(fā)布時間：2018-02-24 06:06

  本文關(guān)鍵詞： 大坪金礦床 礦化類型套疊 成礦流體特征 成礦物質(zhì)來源 成礦機制　出處：《中國地質(zhì)大學(北京)》2015年碩士論文　論文類型：學位論文

【摘要】：大坪金礦床是我國最重要的新生代金沙江—哀牢山金礦帶中的超大型礦床,研究表明該金礦床在主體造山型金礦化之上套疊了淺成低溫熱液金—多金屬礦化,其成礦作用獨具特色。為此,論文在對大坪金礦床地質(zhì)特征的進行系統(tǒng)調(diào)研基礎之上,通過成礦流體特征和同位素示蹤研究,重點剖析了淺成低溫熱液金—多金屬礦化與造山型金礦化疊套成礦的過程和機理,獲得如下主要認識:(1)大坪金礦床主體具有造山型金礦的典型地質(zhì)特征:受控于區(qū)域性深大斷裂帶及其次級斷裂帶;礦體呈左行雁列式產(chǎn)于高角度斷層中;脈狀礦化樣式發(fā)育;以Au礦化為主。(2)南部金河金礦廠礦段顯示出淺成低溫熱液金礦床的地質(zhì)特征:金礦體發(fā)育在緩傾的層間破碎帶;角礫狀、網(wǎng)脈狀和梳狀礦化樣式發(fā)育;大量Ag、Pb和Cu富集;出現(xiàn)冰長石—格子狀方解石蝕變礦物組合以及硅化、絹云母化、碳酸鹽化和青磐巖化的蝕變分帶特征。(3)流體包裹體類型主要分為3類,為H2O兩相包裹體、CO2包裹體、CO2-H2O三相包裹體,兩種礦化均以CO2-H2O三相包裹體為主。造山型礦化成礦溫度為250℃~290℃,淺成低溫熱液型礦化為250℃~330℃。兩種類型礦化流體均為中低鹽度,且流體主要成分相似,陽離子以Na+和K+為主,陰離子以Cl-和SO42-為主。造山型成礦流體COCl-、Na+的含量較高;淺成低溫熱液型成礦流體中K+、SO42-的較高。兩種礦化成礦流體表現(xiàn)出相似的特征,表現(xiàn)出成礦流體長期持續(xù)的關(guān)系。(4)兩種礦化類型同位素特征相似:δ18OV-SMOW為10.9‰~14.3‰,δD為-113‰~-40‰;δ34S為2‰~10‰;δ13CV-PDB為-7.6~-2.3‰,顯示了兩種類型礦化成礦流體的H2O、CO2、S主要來自于殼�；旌献饔�,并受變質(zhì)流體的影響。淺成低溫熱液礦化的Pb同位素特征介于煌斑巖和閃長巖之間,結(jié)合煌斑巖富集系數(shù)為181.44,而閃長巖富集系數(shù)為1.57,代表Pb可能來源于煌斑巖。(5)綜合礦床地質(zhì)、礦床地質(zhì)特征、成礦流體來源特征和大坪金礦床和區(qū)域演化背景,大坪金礦存在造山型礦化和淺成低溫熱液金—多金屬礦化的套疊組合,兩種類型礦化形成于從碰撞造山到造山后期伸展活動的長期過程中。
[Abstract]:The Daping gold deposit is one of the most important superlarge deposits in the Cenozoic Jinshajiang-Ailaoshan gold deposit in China. The study shows that the gold deposit overlay the main orogenic type gold deposit with epithermal hydrothermal gold-polymetallic mineralization. Therefore, based on the systematic investigation of the geological characteristics of the Daping gold deposit, the characteristics of ore-forming fluid and isotopic tracer are studied. The process and mechanism of superimposed mineralization of epithermal gold-polymetallic mineralization and orogenic gold mineralization are emphatically analyzed. The main conclusions are as follows: the main body of the Daping gold deposit has typical geological characteristics of orogenic gold deposit: controlled by regional deep fault zone and its secondary fault zone, the orebody occurs in high angle fault as Zuo Xing Yan series, and vein mineralization style develops; Au mineralization is dominant in au mineralization.) the southern Jin He gold mine shows the geological characteristics of the epithermal hydrothermal gold deposits: the gold body develops in the gently inclined interlayer fracture zone, the breccia, reticular vein and comb mineralization patterns develop, and a large amount of Ag Pb and Cu are enriched; The altered mineral assemblage of ice feldspar and lattice calcite and silicification, sericite, carbonization and denudation are mainly classified into three types of fluid inclusions, which are CO _ 2-H _ 2O and CO _ 2-H _ 2O three phase inclusions. The ore-forming temperature of orogenic type is 250 鈩，

本文編號：1529143