摘要
Mpanda地区Sangu碳酸岩位于坦桑尼亚克拉通西南缘的Ubendian造山带上,侵入于古元古界Ubende群斜长角闪岩和中元古界Ifume群砂砾岩之间,呈层状、似层状或岩墙状产出。由于研究程度较低,Sangu碳酸岩的地球化学特征和成因机制尚不明确,通过电感耦合等离子体质谱分析和便携式XRF分析仪检测获得碳酸岩的稀土元素含量和土壤地球化学含量,分析结果显示稀土元素呈现为轻稀土富集的右倾分布型式,轻、重稀土分异明显且无Eu异常,土壤地球化学Sr、Th含量高于全区岩石,而Rb含量相对较低,综合地质特征,发现Sangu碳酸岩以白云方解石碳酸岩和白云石碳酸岩为主,其次为铁碳酸岩,具有完整的演化过程,在晚阶段具备稀土矿成矿条件。地质及地球化学特征研究表明Sangu碳酸岩可能由地幔橄榄岩部分熔融形成碳酸质熔体,沿古断裂上侵形成,上升过程中使稀土、稀有、铜、金和铁等元素发生富集,形成稀土和金属矿床。
The Sangu carbonatite from Mpanda is located on the Ubendian Orogenic Belt in the southwest margin of Tanzania craton,they are layered,stratified or wall-like and intruded between the plagioclastic amphiboles of Ubende Group and the sand con⁃glomerate of Ifume Group.Due to lack of detailed geological studies,the geochemistry and genesis of Sangu carbonatite remain unclear.The rare earth elements and soil geochemistry of carbonatite by ICP-MS and portable X-ray fluorescence,the results show carbonatite have a right-handed distribution pattern of light rare enrichment,with obvious differentiation of light and heavy rare elements,The pe⁃dogeochemistry of Sr and Th content is higher than the whole rock,while the content of Rb is relatively low.Comprehensive geological characteristics,Sangu carbonatite are mainly dolomite-calcite carbonatite and dolomite carbonatite,followed by iron carbonatite,which have a complete evolutionary process,in the late stage,it has the metallogenic conditions of REE ore.Studies on geological and geo⁃chemical characteristics show that Sangu carbonate may be formed by partial melting of mantle peridotite to form carbonate melt along the paleofault.In the rising process,REE,rare element,copper,gold,iron and other elements are enriched to form rare earth and metal deposits.
作者
曾瑞垠
黄建业
田犁平
谭康雨
张毅
刘昭
詹勇
ZENG Ruiyin;HUANG Jianye;TIAN Liping;TAN Kangyu;ZHANG Yi;LIU Zhao;ZHAN Yong(Sinodrill Co.,Ltd.,Beijing 100012,China;Sinotech Minerals Exploration Co.,Ltd.,Beijing 100012,China;Geological Team 306 of Yunnan Non-ferrous Metals Geological Bureau,Kunming 650001,Yunnan,China)
出处
《矿产勘查》
2021年第1期116-123,共8页
Mineral Exploration
