特征及成礦流體
(1. 中南大學(xué) 有色金屬成礦預(yù)測教育部重點實驗室，長沙 410083；
2. 中南大學(xué) 地球科學(xué)與信息物理學(xué)院，長沙 410083；3. 中國有色地質(zhì)調(diào)查中心，北京 100012)
摘 要: 卡爾卻卡多金屬礦床位于祁漫塔格成礦帶，礦區(qū)主要有斑巖型和矽卡巖型兩種礦化類型，均與印支期花崗閃長巖關(guān)系密切。流體包裹體研究表明，矽卡巖礦石中可見水溶液包裹體(Ⅰ型)；斑巖型礦化巖體中發(fā)育有水溶液包裹體(Ⅰ型)和含子礦物的包裹體(Ⅱ型)。斑巖型礦化巖體中的流體包裹體氣液均一溫度在274~495 ℃，鹽度介于5.9%~59.1%(質(zhì)量分數(shù)，NaCl equiv，下同)之間；矽卡巖礦石樣品的氣液均一溫度集中在137~322 ℃，鹽度介于0.7%~12.7%之間。研究顯示礦區(qū)成礦流體來源于富Na+及成礦物質(zhì)的高溫(達500 ℃)、高鹽度(達60%)的巖漿流體，具有超高壓特征。流體演化至290~320 ℃時由于圍巖碎裂減壓而發(fā)生沸騰現(xiàn)象，并和外來流體混合，改變流體的成分和物理化學(xué)性質(zhì)，有利于成礦物質(zhì)沉淀富集。
關(guān)鍵字: 斑巖型礦化；矽卡巖型礦化；流體包裹體；成礦流體；卡爾卻卡；青海省
（1. Key Laboratory of Metallogenic Prediction of Nonferrous Metals, Ministry of Education,
Central South University, Changsha 410083, China;
2. School of Geosciences and Info-Physics, Central South University, Changsha 410083, China;
3. China Nonferrous Metals Resource Geological Survey, Beijing 100012, China）
Abstract:There are two mineralization types in Kaerqueka copper polymetallic deposit in Qimantage area, Qinghai Province, which are skarn-type mineralization and porphyry-type mineralization. Both of the two mineralization types are closely related to Indosinian granodiorite. Fluid inclusions (FI) host in porphyry-type mineralization granodiorite and skarn-type ore, and the fluid inclusions in skarn-type ore typically are aqueous FI (type Ⅰ) while those in porphyry-type mineralization granodiorite are usually aqueous FI (typeⅠ) or daughter mineral-bearing FI (type Ⅱ) as well. The homogenization temperatures of the fluid inclusions in the skarn-type ore and the porphyry-type mineralized granodiorite vary from 137 ℃ to 322 ℃ and 274 ℃ to 495 ℃, respectively. The salinities of skarn-type ore range from 0.7% to 12.7% (mass fraction, NaClequiv); and those in porphyry-type mineralized granodiorite range from 5.9% to 59.1%. The study demonstrates that the ore-forming fluids originate from magma which is high-temperature (up to 500 ℃), hypersaline (up to 60%), rich in Na+ and metallogenic material, with the characteristics of ultrahigh pressure. Fluid-boiling occurs when the ore-forming temperatures are between 290 ℃ and 320 ℃ because of breaking of wall rocks. Then the composition and physicochemical properties of ore-forming fluids are changed by mixed extraneous fluids, leading to the precipitation and enrichment of metallogenic material.
Key words: skarn-type; porphyry-type; fluid inclusion; ore-forming fluid; Kaerqueka; Qinghai Province
