投稿时间：2011-09-26
修订日期：2012-02-06
中文摘要:文章选取印尼苏拉威西岛Kolonodale红土型镍矿区为研究区,对201个浅井剖面共采取3 161件风化壳样品,进行了w(Ni)值的测试,以揭示超基性岩红土风化壳中Ni的表生富集规律及矿化结构特征。研究结果表明,在平面上,矿区内风化壳的w(Ni)平均值的高低与地形地貌关系密切。斜坡带、坡脚堆积带的风化壳为含镍高值区,其w(Ni)值为0.8%~1.8%;山顶平台区、山脊的风化壳为含镍低值区,其w(Ni)值为0.7%~1.4%。在垂向上,风化产物的w(Ni)值的高低与取样深度及样品属性密切相关。w(Ni)值随着红土带→腐岩带→基岩带的变化出现低值(0.85%~1.55%)→高值(1.15%~4.75%)→低值(≤0.55%)的波动变化规律。矿层的产状(分布、深度、厚度)与风化壳产状之间表现出明显的正相关关系。矿区内的低品位矿层〔1.5%≤w(Ni)≤2.0%〕和高品位矿层〔w(Ni)≥2.0%〕单独或组合发育,产出"正常型双层矿化"、"倒置型双层矿化"、"低品位单层矿化"、"高品位单层矿化"和"叠层矿化"等5种矿化结构类型。综合分析认为,富镁及中等程度蛇纹石化的超基性岩母岩、热带雨林气候环境是矿区内发育富镍红土风化壳的首要条件。吸附、离子交换以及次生沉淀等3种成矿作用的共同发育,导致了红土风化壳中Ni表生矿化的连续性、矿石类型的多样性及特高品位矿石的形成。矿床中矿化结构类型的多样化是区域构造背景、地形地貌、构造发育、水文条件等诸多因素耦合作用的结果。文章指出,在今后的红土型镍矿床的找矿勘查过程中,需要综合考虑各类内、外生控矿因素对矿床发育的影响,总结矿区尺度的矿化结构规律,可有效地指导矿床勘查工作。
Abstract:The Kolonodale ore deposit, located in Sulawesi Island of Indonesia, was chosen as the research target for the study of the Ni supergene enrichment and mineralization texture in the laterite weathering crust from ultrabasic rock. 3 161 samples collected from 201 shallow-well profiles were analyzed for Ni grade. The results show that the average Ni grade of laterite weathered crust has good relationship with topography and land form. On the gentle slope and at hill foot, the Ni value is commonly high (0.8%~1.8%), whereas in the ridge and platform of the highland, the Ni value is relatively low (0.7%~1.4%). The average Ni grade changes in order of low(0.85%~1.55%)→high(1.15%~4.75%)→low(≤0.55%) with the increasing depth from laterite layer through saprolite layer to base rock layer, suggesting that the Ni grade is related to the depth and petrological type of the sample. The modes of occurrence of ore beds, with w(Ni)≥1.5%, change greatly but have good positive correlation with laterite weathered crust in depth and thickness. Five types of mineralization textures were distinguished, namely "normal double-layer texture", "inverted double-layer texture", "high grade single-layer texture", "low grade single-layer texture" and "laminated-layer texture". A comprehensive analysis shows that the Ni supergene enrichment and mineralization in Kolonodale area are attributed to the weathering process of the outcropped ultrabasic rock body under the conditions of active plate tectonic movement and tropical rainforest climate. Various types of mineralization texture are closely related to regional factors, such as basement rock, landform, local structure, and drainage condition. The adsorption, ion exchange and secondary deposition are considered to be the main ore-forming processes. The authors hold that various controlling factors, no matter whether they are of geological origin or of geographical origin, must be considered comprehensively in the determination of the exploration direction, and the study and summarization of the mineralization texture of the ore deposit is beneficial to further mineral prospecting.
keywords:geology laterite nickel deposit ore grade change mineralization texture ore-forming process Southeast Asia
文章编号：
中图分类号：P618.63
文献标志码：
基金项目:本文为国家自然科学青年基金(41102051)、国家自然科学基金(40972220)与广西自然科学青年基金(桂科青0991083)联合资助的成果
引用文本：
付伟,牛虎杰,陈远荣,雷良奇,黄小荣,任小瑞.2012.超基性岩红土风化壳中镍的表生富集规律及矿化结构研究 ——以印尼苏拉威西岛Kolonodale矿区为例[J].矿床地质,31(2):229~240FU Wei,NIU HuJie,CHEN YuanRong,LEI LiangQi,HUANG XiaoRong,Ren XiaoRui.2012.Supergene enrichment and mineralization texture of nickel in laterite weathered crust from ultrabasic rocks: A case study of Kolonodale ore district in Sulawesi Island, Indonesia[J].Mineral Deposits31(2):229~240
图/表
