中国东部华北克拉通南缘和华南地块地幔岩中的钼含量及其意义  

Molybdenum content of mantle-derived rocks from South China block and southern margin of North China craton in eastern China and its implications

作　　者：岳可芬[1] 赫英[1] 董振信[2] 张维平[1] 

机构地区：[1]西北大学大陆动力学国家重点实验室西北大学地质学系 [2]中国地质博物馆,北京100812

出　　处：《地球化学》2006年第4期388-394,共7页Geochimica

基　　金：国家自然科学基金(40372052);高等学校博士点基金(20040697003);陕西省自然科学基金(2004B27)

摘　　要：对中国东部华北克拉通南缘(山东临朐、昌乐、胶州和安徽明光)和华南地块(福建牛头山、广东英峰岭、海南定安和海南蓬莱)80件地幔岩包体及其寄主玄武岩石中的钼含量进行了分析。中国东部华北克拉通南缘和华南地块新生代地幔岩包体钼含量在0.10～0.41μg/g之间,平均含钼0.19μg/g;这些包体的寄主玄武岩中的钼含量明显高于其地幔岩包体中的钼含量。寄主玄武岩中钼含量在0.75～7.21μg/g之间,平均含钼3.17μg/g。其中安徽明光寄主玄武岩中钼含量最高,平均6.8μg/g;山东临朐、昌乐寄主玄武岩中钼含量平均为3.6μg/g;福建牛头山、海南定安和海南蓬莱寄主玄武岩中钼含量低,这三地平均为1.4μg/g,与世界基性岩钼的丰度1.4μg/g一致。中国东部华北克拉通南缘和华南地块地幔岩包体的寄主玄武岩中的钼含量在空间分布上明显表现为华北克拉通南缘高而华南地块低。结合我国大型钼矿集中于华北克拉通南缘以及成矿元素来源于下地壳的事实,说明寄主玄武岩中钼含量的高低对地壳中钼矿床和钼矿集中区的分布有指示意义。Molybdenum content of 80 samples of mantle-derived xenoliths and their host rocks from southern margin of North China craton （Linqu, Changle, Jiaozhou of Shandong Province and Mingguang of Anhui Province） and South China block （Niutoushan of Fujian Province, Yingfengling of Guangdong Province, Ding＇an and Penglai of Hainan Province） in eastern China was analyzed. The molybdenum content of the Cenozoic mantle-derived xenoliths is in the range of 0. 1 - 0.41 μg/g, averaging 0. 19 μg/g. The molybdenum content of the host rocks falls in the range of 0.75 - 7.21 μg/g, averaging 3.17 μg/g, which is far higher than the average molybdenum abundance （1.4 μg/g） of the basites in the world. The molybdenum content of the host rocks from Mingguang of Anhui Province is the highest, averaging 6. 8 μg/g, and that from Linqu, Changle of Shandong Province averages 3.6 μg/g; whereas the molybdenum content of the host rocks from Niutoushan of Fujian Province, Ding＇an and Penglai of Hainan Province is far lower, averaging 1.4μg/g. The host rocks have higher molybdenum content than the mantle-derived xenoliths, suggesting that molybdenum tends to be concentrated into the melt during the partial melting. The molybdenum content of mantle-derived xenoliths and their host rocks is found to have higher values on southern margin of North China craton and lower values on South China block in SE China, and especially the molybdenum content of the host basites, corresponding to the fact that the large-scale molybdenum deposits are concentrated in the two margins of the North China craton and the ore-forming materials are derived mainly from the lower continental crust. It is considered that the molybdenum content of the alkali basalts may be an indicator to the distribution of molybdenum deposits and concentrated districts.

关 键 词：地幔岩包体 玄武岩 钼含量 华北克拉通 华南地块 

分 类 号：P595[天文地球—地球化学]