摘要
一种艳丽的蓝紫色矿物巨晶在我国新疆哈密地区红山铜-金矿床氧化带中、上部大量出现,经详实的野外地质观察和室内测试,如 X-射线单晶及粉晶衍射测定、湿法化学分析、热分析、穆斯堡尔谱和红外光谱测试等,确认其为一罕见硫酸盐矿物—副针绿矾(Paracoquimbite,Fe_2(SO_4)_3·9H_2O),是继智利丘基卡马塔巨型斑岩铜矿区1935年报道后,在世界上的又一次发现,在我国尚属首次。该矿物晶体如此之硕大(单晶粒度可达8cm~12cm),远大于智利首次发现的晶体(1.95cm),在国内外和自然界亦堪称首例,与副针绿矾密切共生者为针绿矾,二者呈多型关系。本文副针绿矾湿法化学分析结果为(wt%):SO_3 42.55,Fe_2O_3 28.19,H_2O 28.72,CaO 0.02,MgO 0.01,Al_2O_3 0.03,Na_2O 0.02,总计99.54,其 XRD 特征谱线为:4.61(100),8.89(83),3.38(67);针绿矾湿法化学分析结果为(wt%):SO_342.31,Fe_2O_3 28.61,H_2O 28.98,MgO 0.01,Al_2O_3 0.01,总计99.92,其 XRD 特征谱线为:8.27(100),5.46(76),2.77(76)。红外光谱分析判定了不同基团及同一种基团在不同结构环境下振动模式或频率的差别。穆斯堡尔谱分析确定了副针绿矾和针绿矾中铁的氧化态、配位数以及结构中存在共价键(π键),其穆斯堡尔谱共有特征是四极矩分裂值较小,均由单一吸收峰组成。各种实验分析数据完全吻合,保证了副针绿矾和针绿矾研究的准确性和可靠性。在同一标本上连续切片,通过连续系统的电子探针分析,对针绿矾与副针绿矾互为多型的成因机理做了初步探讨。红山矿区氧化带中除与该矿物副针绿矾共生者外,尚有其它多种硫酸盐矿物亦为我国首次发现。目前上述诸多矿物已作为湿法冶铜及制酸工业的新型资源,副针绿矾巨大晶体的发现兼有一定的实用价值和收藏价值。
A great number of tremendous glaucous crystals were found in middle-upper oxidization of Hongshan Cu-Au deposit, Kalatage district, eastern Tianshan, NW-China. The authors made systematic analysis such as XRD, TA and identified it is a rare kind of sulfate-Paracoquimbite[ Fe2 (SO4 )3 · 9H2O]. Paracoquimbite of Hongshan deposit was reported for the second in the world (first case reported at 1935 in Chile). And the Paracoquimbite megacryst (d = 8cm - 12cm) of Hongshan deposit are much bigger and more rare than that (d = 1.95cm) of Chuquicamata porphyry copper deposit, in Northern Chile. Paracoquimbite occurs with its polytype- eoquimbite. The chemical analysis results of Paraeoquimbite (wt%) are: SO3 42.55, Fe2O3 28.19, H2O 28.72, CaO 0. 02, MgO 0. 01, Al2O3 0.03, Na2O 0.02, total 99.54 ; and its characteristic data of XRD analysis are : 4.61 (100) , 8.89 ( 83 ), 3.38 (67). The chemical analysis results of Coquimbite (wt%) are: SO3 42.31, Fe2O3 28.61, H2O 28.98, MgO 0.01, Al2O3 0.01, total 99.92; and its characteristic data of XRD analysis are: 8.27 (100), 5.46 (76), 2.77 (76). The results of samples XRD and chemical analysis were furthermore confirmed through thermal, infrared spectrum and mossbauer spectrum analysis. Their thermal reaction and facies change mechanism were also explained. Systemetic EPMA analysis shows that Al impurity in crystal lattice, disfigurement of crystal are important to polytype formation of paracoquimbite and coquimbite besides stack fault. The oxidization zone lies on the upper part with a depth of 50km - 60m. It is composed of natural elements, chlorides, Fe-oxide and sulfates with various colors, in which sulfate minerals dominated. Besides paracoquimbite, five minerals were founded in China for first time. Now these sulfate minerals have been used as a new type of acid-resource for copper smelting. So the Paracoquimbite megacrysts may be practicality and collection value.
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2008年第5期1112-1122,共11页
Acta Petrologica Sinica
基金
国家自然科学基金项目(40672069)
中国科学院知识创新工程重要方向项目(KZCX2-YW-107)
国家“十一五”科技攻关新疆305项目铜镍矿课题(2006BAB07B03)资助
关键词
氧化带
副针绿矾巨晶
针绿矾
多型
红山铜-金矿床
东天山
Oxidization zone
Megacryst
Paracoquimbite
Coquimbite
Polytype
Hongshan HS-epithermal Cu-Au deposit
East Tianshan Mountains