北秦岭二郎坪群重晶石岩热水沉积地球化学证据及其成矿意义  

Geochemical characteristics of hydrothermal sediments for baritic rocks of Erlangping Group in northern Qinling Mountains and their significance for mineralization

作　　者：冯胜斌[1] 邢矿[2] 周洪瑞[3] 燕长海[4] 彭翼[4] 赵吉梅 胡绍斌 任建光[3] 

机构地区：[1]中石油长庆油田公司勘探开发研究院,西安710021 [2]华北水利水电学院,郑州450011 [3]中国地质大学地球科学与资源学院,北京100083 [4]河南省地质调查院,郑州450007 [5]青海省环境地质勘查局,西宁810007 [6]云南省地质调查院,昆明653100

出　　处：《世界地质》2007年第2期199-207,共9页World Geology

基　　金：中国地调局国土资源大调查项目(199910200227);中国地调局地质调查项目(200310200001-5)

摘　　要：北秦岭二郎坪群中存在与地层整合产出的层状重晶石岩和铜多金属矿床。重晶石岩贫Al2O3、TiO2组分含量;富集热液组分As、Sb、Ba、Ag和Hg;微量元素U/Th>1;低ΣREE(平均值27.78×10-6)、富集轻稀土(LREE)、亏损重稀土(HREE)、具明显Eu正异常、Ce负异常及与大西洋TAG热液区热液沉积物相似的球粒陨石标准化的稀土元素配分模式特征。这些特征揭示研究区重晶石岩是热水沉积成因型。热水沉积重晶石岩与铜多金属矿床的紧密联系说明,研究区铜金属矿床是海底热液喷流沉积成岩成矿作用的产物。There exist bedded baritic rocks and copper polymetallic deposits which are sandwiched con- formably in the Erlangpin Group of northern Qinling Mountains. The baritic rocks contain Al2O3 and TiO2 in lower contents, with concentration of thermal fluid compositions such as As, Sb, Ba, Ag and Hg. The ratio of trace elements U and Th is more than 1. The total REE is low （averaging 27.78×10^-6）, The EREE patterns display ∑LREE-rich but ∑HREE-depletion, with positive Eu anomaly and negative Ce anomaly, which is similarly to REE distribution pattern of chondrite within normalized typical hydrothermal deposits in TAG region,The results show the baritic rocks belonging to type of hot-water deposit. The paragenetic relationship of hydrothermal sedimentogenic baritic rocks and copper polymetalic deposits manifest that the copper polymetalic deposits are formed by the submarine hydrothermal exhalative lithogenesis and mineralization.

关 键 词：重晶石岩 热水沉积 成矿意义 二郎坪群 北秦岭 

分 类 号：P595[天文地球—地球化学]