内蒙古东部闹牛山—巨里河铜多金属矿带岩浆活动与成矿的关系

RELATIONSHIP BETWEEN METALLOGENESIS AND MAGMATIC ACTIVI-TIES IN THE NAONIUSHAN-JULIHE COPPER POLYMETALLIC ORE BELT, EASTERN INNER MONGOLIA

内蒙古东部闹牛山—巨里河铜多金属矿带的岩浆活动主要属华力西晚期和燕山早期的两大构造旋回 ,矿带上已发现的铜多金属矿床的成矿时代绝大部分为燕山早期 ,成矿与燕山早期中酸性浅成—超浅成的岩浆侵入活动关系密切。区内火山—次火山岩的稀土总量低 ,w(∑Ce) /w(∑Y)比值高 (2 7～ 14 1) ,具微弱铕亏损 ,表明岩浆岩为上地幔—下地壳的混合来源 ,成矿岩体具有基性程度高、来源深的特点 ,属钙碱性岩石系列 ,富Si、K而贫Fe、Mg。岩浆岩中Bi、W、Sn、Ag、Pb、Cu等成矿元素及伴生元素的丰度较高 ,为本区的成矿提供了物质来源。

Magmatic activities in the Naoniushan-Julihe copper polymetallic ore belt are mainly composed of two structural cycles, i.e. structural cycle in late Variscan period and early Yanshanian period. The ore-forming ages of the discovered copper polymetallic deposits are dominantly early Yanshanian period, and metallogenesis are related to intrusive rocks in early Yanshanian period, especially to hypabyssal-supper hypabyssal intermediate-acidic and acidic rocks. Total content of rare earth elements in volcanic-subvolcanic rocks in the area is low, and the ratio of ΣCe to ΣY is high(2.7 to 14.1),and Eu anomaly is little. These rocks, which originated from upper mantle to lower crust, belong to calcic-alkalic rock series that are rich in Si, K and poor in Fe, Mg. Ore-forming elements and associated elements, such as Bi, W, Sn, Ag, Pb, Cu are characterized by high abundance value, which provide ore-forming material sources for the copper polymetallic ore belt.