Petrology and Geochemistry of Gabbro and Magnetite-pyroxene Vein in the Haladala Mafic Complex, Southwestern Tianshan Mts., Xinjiang
详细信息
- 责任者：Huang QiuYue(Key Laboratory of Orogenic Belts and Crustal Evolution ; Ministry of Education ; School of Earth and Space Science ; Peking University ; Beijing 100871 ; China) ; Zhu YongFeng
- 刊名：Acta Petrologica Sinica
- 出版年：2012
- 卷期：28(7)
- 关键词：辉长岩 ; gabbros ; 磁铁矿 ; magnetite ; 天山 ; Tianshan Mountains
- 页码：p.2199-2208
- 图表：illus.,4 tables,19 refs.
- 分类号：0801
- issnNo：ISSN1000-0569
- isbnNo：CN11-1922/P
摘要
mal; ORPHANS: 2; FLOAT: none; LETTER-SPACING: normal; COLOR: rgb(0,0,0); WORD-SPACING: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px">The Haladala mafic pluton in the southwestern Tianshan Mountains mainly consists of troctolite, olivine gabbro and gabbro. After the fractional crystallization of olivine and plagioclase, the residual magma intruded and formed gabbro. The clinopyxene(Cpx-I)in gabbro has lower concentrations of rare earth elements(REE<51×10mal; FONT-STYLE: normal; TEXT-INDENT: 0px; FONT-FAMILY: ����,verdana; WHITE-SPACE: normal; ORPHANS: 2; LETTER-SPACING: normal; COLOR: rgb(0,0,0); FONT-WEIGHT: normal; WORD-SPACING: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px">-6mal; ORPHANS: 2; FLOAT: none; LETTER-SPACING: normal; COLOR: rgb(0,0,0); WORD-SPACING: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px">)with insignificant Eu negative anomalies. The concentrations of other trace elements(Sc, Cr etc. )in Cpx-I vary largely with a wide range of Mgmal; FONT-STYLE: normal; TEXT-INDENT: 0px; FONT-FAMILY: ����,verdana; WHITE-SPACE: normal; ORPHANS: 2; LETTER-SPACING: normal; COLOR: rgb(0,0,0); FONT-WEIGHT: normal; WORD-SPACING: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px">#mal; ORPHANS: 2; FLOAT: none; LETTER-SPACING: normal; COLOR: rgb(0,0,0); WORD-SPACING: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px">(80～95, diopside-augite). The magnetite-pyroxene vein intruded into gabbro. The composition of clinopyxene(Cpx-II)in the vein is homogeneous(diopside). Compared to Cpx-I, Cpx-II has higher concentrations of REE(>100×10mal; FONT-STYLE: normal; TEXT-INDENT: 0px; FONT-FAMILY: ����,verdana; WHITE-SPACE: normal; ORPHANS: 2; LETTER-SPACING: normal; COLOR: rgb(0,0,0); FONT-WEIGHT: normal; WORD-SPACING: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px">-6mal; ORPHANS: 2; FLOAT: none; LETTER-SPACING: normal; COLOR: rgb(0,0,0); WORD-SPACING: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px">)with obvious Eu negative anomalies. Distinct from the rapid intrusion of the later-stage Fe-rich mafic magma which formed the magnetite-pyroxene vein, the early-stage magma went through a complex evolution before its intrusion(gabbro). Besides, exsolution texture found in both Cpx-I and Cpx-II implies that the Haladala pluton underwent rapid uplift(or fast cooling)after magnetite-pyroxene vein. Gold-bearing calcite-magnetite vein, representing an episode of epithermal activity after magma process, cuts through both gabbro and magnetite-clinopyroxene vein. Further study focusing on the gold-bearing calcite-magnetite vein is of great significance to gold exploration in this region.
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