(1. 湖南省地質(zhì)調(diào)查院，長(zhǎng)沙 410116；
2. 中南大學(xué) 有色金屬成礦預(yù)測(cè)與地質(zhì)環(huán)境監(jiān)測(cè)教育部重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410083；
3. 湖南黃金集團(tuán)有限公司，長(zhǎng)沙 410129；
4. 國(guó)土資源評(píng)價(jià)與利用湖南省重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410116；
5. 昆明理工大學(xué) 國(guó)土資源工程學(xué)院，昆明 650093)
摘 要: 平灘白鎢礦床位于南嶺西段的苗兒山-越城嶺巖體西部，為一新發(fā)現(xiàn)的形成于加里東期的礦床。對(duì)平灘鎢礦床中的含鎢石英脈進(jìn)行了流體包裹體的研究，依據(jù)礦物共生組合以及石英脈的穿插關(guān)系將其成礦過(guò)程劃分為兩個(gè)階段：石英-白鎢礦階段(Ⅰ)和石英-硫化物階段(Ⅱ)。從第Ⅰ階段到第Ⅱ階段，均一溫度從260~380 ℃明顯降低到240~300 ℃，其鹽度也呈明顯下降趨勢(shì)(平均鹽度分別為11.26% NaCleqv和8.61% NaCleqv)。激光拉曼成分分析結(jié)果顯示，第Ⅰ階段的流體包裹體中含有CO2、CH4和N2等氣相成分，明顯區(qū)別于第Ⅱ階段。第Ⅰ階段中一定比例的含子晶流體包裹體以及各階段石英脈中金屬硫化物的δ34S組成為(-0.491×10-3~+2.065×10-3)，平均為+0.496×10-3，表明其成礦流體來(lái)自于巖漿水。引起鎢礦質(zhì)沉淀的主要原因?yàn)槌傻V流體的沸騰作用；平灘鎢礦主要為源自于地殼重熔的巖漿經(jīng)高度的分異演化后，富含鎢礦質(zhì)的巖漿熱液經(jīng)歷了沸騰作用所形成。
關(guān)鍵字: 平灘白鎢礦床；加里東期成礦；流體包裹體；S同位素；沸騰作用；成礦機(jī)制
（1. Hunan Institute of Geological Survey, Changsha 410116, China;
2. Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring, Ministry of Education, Central South University, Changsha 410083, China;
3. Hunan Gold Group Co., LTD., 410129;
4. Hunan Key Laboratory of Land Resources Evaluation and Utilization, Changsha 410007, China;
5. Faculty of Land Resource Engineering, Kunming University of Science and Technology, Kunming 650093, China）
Abstract:Pingtan deposit, situated in the northwest part of the Miao’ershan granite batholith (western Nanling Range), is a newly-discovered Caledonian W-(Mo) deposit. Its mineralization can be divided into two stages, namely quartz-scheelite stage (Ⅰ) and quartz-sulfide stage (Ⅱ). The homogenization temperatures (260-380 ℃ for Stage Ⅰ and 240-300 ℃ for Stage Ⅱ) and the average salinities (11.26% NaCleqv for Stage Ⅰ and 8.61% NaCleqv for Stage Ⅱ) show significant decreasing trends from early to late. Raman spectroscopy reveals that the fluid inclusions in stage Ⅰ contain CO2, CH4, and N2, whilst those in stage Ⅱ mainly contain H2O. A proportion of daughter mineral-bearing inclusions discovered in quartz veins of stage Ⅰ and the sulfur isotopes from sulfides (-0.49×10-3-+2.06×10-3, +0.50×10-3 for the average) imply that the ore-forming fluid is originated from magmatic fluids. Therefore it can be concluded that the ore-forming material in Pingtan deposit is derived from the partial melting of crustal which experiences highly fractionated, and the effective metallogenic mechanism of the deposits might be fluid boiling.
Key words: Pingtan scheelite deposit; Caledonian mineralization; fluid inclusions; S isotopes; fluid boiling; metallogenic mechanism
