Carbonatites in China:A review for genesis and mineralization

来源 :Geoscience Frontiers | 被引量 : 0次 | 上传用户:ling1945081
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
Carbonatites are commonly related to the accumulation of economically valuable substances such as REE.Cu,and P.The debate over the origin of carbonatites and their relationship to associated silicate rocks has been ongoing for about 45 years.Worldwide,the rocks characteristically display more geochemical enrichments in Ba,Sr and REE than sedimentary carbonate rocks.However,carbonatite’s geochemical features are disputed because of secondary mineral effects.Rock-forming carbonates from carbonatites at Qinling.Panxi region,and Bayan Obo in China show REE distribution patterns ranging from LREE enrichment to flat patterns.They are characterized by a Sr content more than 10 times higher than that of secondary carbonates.The coarse- and fine-grained dolomites from Bayan Obo H8 dolomite marbles also show similar high Sr abundance,indicating that they are of igneous origin.Some carbonates in Chinese carbonatites show REE(especially HREE) contents and distribution patterns similar to those of the whole rocks.These intrusive carbonatites display lower platinum group elements and stronger fractionation between Pt and Ir relative to high-Si extrusive carbonatite.This indicates that most intrusive carbonatites may be carbonate cumulates.Maoniuping and Daluxiang in Panxi region are large REE deposits.Hydrothermal fluorite ore veins occur outside of the carbonatite bodies and are emplaced in wallrock syenite.The fiuorite in Maoniuping has Sr and Nd isotopes similar to carbonatite.The Daluxiang fiuorite shows Sr and REE compositions different from those in Maoniuping.The difference is reflected by both the carbonatites and rock-forming carbonates,indicating that REE mineralization is related to carbonatites.The cumulate processes of carbonate minerals make fractionated fluids rich in volatiles and LREE as a result of low partition coefficients for REE between carbonate and carbonatite melt and an increase from LREE to HREE.The carbonatite-derived fluid has interacted with wallrock to form REE ore veins.The amount of carbonatite dykes occurring near the Bayan Obo orebodies may support the same mineralization model,i.e.that fluids evolved from the carbonatite dykes reacted with H8 dolomite marble,and thus the different REE and isotope compositions of coarse- and fine-grained dolomite may be related to reaction processes. Carbonatites are commonly related to the accumulation of economically valuable substances such as REE. Cu, and P. The debate over the origin of carbonatites and their relationship to associated silicate rocks has been ongoing for about 45 years. Worldwide, the rocks characteristically display more geochemical enrichments in Ba, Sr and REE than sedimentary carbonate rocks.However, carbonatite’s geochemical features are disputed because of secondary mineral effects. Rock-forming carbonates from carbonatites at Qinling. Panxi region, and Bayan Obo in China show REE distribution patterns ranging from LREE enrichment to flat patterns. They are characterized by a Sr content more than 10 times higher than that of a secondary carbonates. The coarse- and fine-grained dolomites from Bayan Obo H8 dolomite marbles also show similar similar Sr abundance, indicating that they are of igneous origin .Some carbonates in Chinese carbonatites show REE (especially HREE) contents and distribution patterns similar to those of the whole rocks.These intrusive carbonatites display lower platinum group elements and stronger fractionation between Pt and Ir relative to high-Si extrusive carbonatite. This indicates that most intrusive carbonatites may be carbonate cumulates. Maoniuping and Daluxiang in Panxi region are large REE deposits. Hydrothermal fluorite ore veins occurs outside of the carbonatite bodies and are emplaced in wallrock syenite. The fiuorite in Maoniuping has Sr and Nd isotopes similar to carbonatite. The Daluxiang fiuorite shows Sr and REE compositions different from those in Maoniuping. The difference is reflected by both the carbonatites and rock-forming carbonates, indicating that REE mineralization is related to carbonatites. The cumulate processes of carbonate minerals make fractionated fluids rich in volatiles and LREE as a result of low partition coefficients for REE between carbonate and carbonatite melt and an increase from LREE to HREE. The carbonatite-derived fluid has interacted with wallrockto form REE ore veins. The amount of carbonatite dykes occurring near the Bayan Obo orebodies may support the same mineralization model, iethat fluids evolved from the carbonatite dykes reacted with H8 dolomite marble, and thus the different REE and isotope compositions of coarse- and fine-grained dolomite may be related to reaction processes.
其他文献
本文主要吸取和借鉴国家国际竞争力和城市综合竞争力研究的经验和方法,针对区域经济的特点,将区域综合竞争力分解为核心竞争力、基础竞争力和辅助竞争力,并用三维模型对提高
2010年10月9—24日,由中国地质科学院地质研究所、北京离子探针中心和中国国际前寒武研究中心联合主办的“第五届SHRIMP国际工作会议暨高分辨二次离子质谱(HR-SIMS)及LA-ICP-
公路建设日益迅速,公路建设全过程的环境保护也越来越受到政府的重视。如何根据各地的自然环境、生态环境、社会经济环境等因地制宜地解决好公路建设的环境保护问题具有十分
结合宁通公路六合东至江都段旧水泥混凝土路面加铺SMA沥青罩面的工程实践,阐述了玻纤格栅的特性、防治反射裂缝的作用机理、施工方法、注意事项及经验体会。 The engineerin
本文介绍了国产船用低速柴油机泵体材料的研制过程。通过合理选择工艺路线和工艺参数,使国产高纯钢泵体的各项检查项目及力学性能达到了苏尔寿专利标准,满足了造机厂提高大型
去岁末的一个雪天,我在车站等车,身边有两位女士在唠新上演的电视连续剧《弘一大师》。她们饶有兴趣地唠着一个颇有传奇色彩的故事:一个叫李叔同的教书先生出家了,把一个日
利用不同时期遥感信息资源,结合实地调查测绘,编制不同时期果林类型图,经过叠合比较,建立动态分类系统,获得果林类型动态日,以此分析淳化县泥河沟流域1986~1995年果林面积的动态变化与综合效
近几年来,东津镇农村经济管理站切实加强农村财务管理,进一步规范各种管理制度,取得了明显成效。管理的农民负担资金及别的资金都非常规范,农民负担严格控制在上年人平纯收
用原子吸收分光光度计对1.5mol.L-1盐酸浸提木麻黄针叶中钠、钙、镁等矿质元素进行测定,具有快速简单、容易操作、减少污染等特点。实验结果表明:用该方法测定木麻黄针叶中钠、钙、镁等矿