中国东部地幔岩包体中的金含量及其成矿学意义  

Content of Mantle-derived Xenoliths in Eastern China and Its Metallogenic Significance

作　　者：赫英[1] 董振信[2] 岳可芬[1] 张战军[1] 陈金武 王新[1] 

机构地区：[1]西北大学大陆动力学重点实验室,西北大学地质系西安710069 [2]中国地质博物馆,北京100812 [3]国际地质实验测试中心,北京100037

出　　处：《地质论评》2004年第4期418-425,共8页Geological Review

基　　金：国家自然科学基金资助项目 (编号 40 3 72 0 5 2;49972 0 3 4);国家 973项目 (编号G19990 43 2 11)的成果。

摘　　要：笔者等分析了中国东部 91件地幔岩包体及其寄主玄武岩中的金含量并有重要发现。除河北万全和海南定安的一些高于 10× 10 - 9的异常样品外 ,包体及寄主岩中的金含量分别在 0 .5× 10 - 9～ 10 .0× 10 - 9和 0 .2×10 - 9～ 5 .3× 10 - 9之间。其中包体平均含金 4 .6× 10 - 9,玄武岩平均含金 2 .7× 10 - 9。地幔岩中包体一般比寄主玄武岩含金高 ,二者间相关性不明显。中国东部 91件地幔岩包体及其寄主玄武岩中的金含量在空间分布上有非均一性 ,它们以华北地台为中心 ,向北和向南 (向南更明显一些 )分别降低 ,这一趋势与中国金矿大多数集中于华北地台的两缘而向南北有减少和减小的趋势是基本一致的。高于地幔金丰度 5× 10 - 9的样品 ,除海南岛外主要集中在华北地台两缘(辽宁、河北、山西、山东 ) ,与冀北西部和山东的金矿集中区有对应关系。研究表明这种对应关系是岩石圈地幔和地壳间在形成时代、性质和成分上耦合性的反映 ,而富二氧化碳含金地幔流体对金活化、富集和转移直至成矿的作用是在先期岩石圈地幔的物质基础上发生的。地幔岩包体中金含量的高低 ,对地壳中金矿床和金矿集中区的分布有指示意义。海南岛 15个包体样品平均含金 11.4× 10 - 9,最高达 36 .0× 10 - 9。鉴于有不少研究反映海南岛?The gold content of 91 samples of mantle-derived xenoliths and their host basalts from eastern China were analyzed, and some significant phenomena were discovered. Except for some samples with gold content exceeding 10.0 ×10 -9 from Hebei and Hainan Provinces, the gold contents of the mantle-derived xenoliths and host basalts fall in ranges of 1.0×10 -9～8.2×10 -9 (averaging 3.8 ×10 -9) and 0.2×10 -9～5.3×10 -9 (averaging 2.7×10 -9) respectively. The mantle-derived xenoliths have a higher gold content than the host rocks, but their relativity is not very clear, suggesting that the genetic relationship between them is complex. The gold content is found to be inhomogeneous in space: having the highest values on the margins of the North China platform and decreasing towards the north and south. Except the samples from Hainan Province, the mantle-derived xenoliths in basalts with high gold content are distributed on the two margins of the North China platform, corresponding to districts with concentrated gold deposits in northwest Hebei Province and Shandong Province, showing the control of the old continental lithospheric mantle and the lower continental crust and the effect of auriferous CO 2 mantle fluids on the later activation, transportation, enrichment and mineralization of the gold. The gold content of the mantle-derived xenoliths from Hainan Province ranges from 1.4×10 -9 to 36.0×10 -9(averaging 10.0 ×10 -9), suggesting that some blocks of the lithospheric mantle in Hainan Province might be derived from ancient gold-rich lithospheric mantle of western Australia and that Hainan Province may be an important district for concentrated gold deposits. Therefore, the gold content of the mantle-derived xenoliths may be an indicator for such ore districts.

关 键 词：地幔岩包体 玄武岩 金含量 地幔成矿学 

分 类 号：P618.51[天文地球—矿床学]