【摘要】：白鑫灘銅鎳礦床是近幾年在東天山地區(qū)新發(fā)現(xiàn)的一個中型銅鎳礦床,位于覺羅塔格構(gòu)造巖漿帶中段,對其開展深入研究有利于下一步的礦床勘查。本文在前人研究成果基礎(chǔ)上,對白鑫灘礦床進(jìn)行了較系統(tǒng)的橄欖石、輝石、斜長石和鉻尖晶石礦物晶體化學(xué)和全巖Sr、Nd同位素的研究工作。結(jié)果表明白鑫灘礦床橄欖石Fo值為78.8~84.3,屬貴橄欖石,Ni含量為299×10~(-6)~2483×10~(-6)。斜方輝石En為79.1~83.9,屬古銅輝石;單斜輝石En為44.3~48.8,Wo為42.6~45.4,屬透輝石-頑透輝石。斜長石An為60~83.9,主要為拉長石和培長石;鉻尖晶石100Cr/(Cr+Al))為51~73.9。模擬計算表明白鑫灘礦床母巖漿MgO和FeO含量分別為9.30%和10.59%,Mg#值為0.61,是原始巖漿發(fā)生一定程度分離結(jié)晶的產(chǎn)物。母巖漿中橄欖石開始結(jié)晶溫度為1258℃,約發(fā)生了7%的橄欖石分離結(jié)晶,結(jié)晶出的橄欖石與熔離出的硫化物的質(zhì)量比介于50∶1~15∶1之間。斜方輝石開始結(jié)晶溫度為1183℃,單斜輝石開始結(jié)晶溫度為1143℃。白鑫灘礦床的(~(87)Sr/~(86)Sr)i=0.70278~0.70439,εNd(t)=+4.51~+5.92(t=278Ma),表明其源區(qū)為虧損地幔,但其富集程度略高于東天山地區(qū)其它典型礦床。Sr、Nd同位素模擬計算表明原生巖漿上升過程中經(jīng)歷了約5%~20%的地殼物質(zhì)同化混染,橄欖石的分離結(jié)晶和地殼物質(zhì)同化混染共同促進(jìn)了巖漿中硫化物的熔離。
[Abstract]:The Baixintan copper-nickel deposit is a newly discovered middle-sized copper-nickel deposit in the East Tianshan area in recent years. It is located in the middle section of the Guolotag tectonic magmatic belt. Further study on the deposit is beneficial to the further exploration of the deposit. Based on the previous research results, a systematic study of the crystal chemistry of olivine, pyroxene, plagioclase and chromium-spinel minerals and Sr,Nd isotopes of the whole rock has been carried out in the Baixintan deposit. The results show that the Fo value of olivine in Baixintan deposit is 78.8 ~ 84.3, belonging to olivine, and the Ni content of olivine is 299 脳 10 ~ (-6) ~ 2483 脳 10 ~ (-6). The En of clinopyroxene is 79.1 / 83.9, which belongs to palaeopyroxene, and the En of clinopyroxene is 44.3 / 48.8Wo / 42.6 / 45.4, belonging to diopyroxene / dienstatite. The An of plagioclase is 60 ~ 83.9, which mainly consists of elongated stone and feldspar, and the 100Cr/ (Cr Al) of chrome spinel is 51 ~ 73.9. The results show that the contents of MgO and FeO in the parent magma of Xintan deposit are 9.30% and 10.59mg #, respectively, which are the products of some degree of separation and crystallization of the primitive magma. The initial crystallization temperature of olivine in the mother magma is 1258 鈩，

本文編號：2324717