冀北水泉沟-后沟偏碱性侵入杂岩体的成矿特征

THE MINEROGENETIC FEATURES OF THE SHUIQUANGOU-HOUGOU SUBALKALIC INTRUSIVE COMPLEX BODY IN NORTH HEBEI

水泉沟 -后沟偏碱性侵入杂岩体地处河北省崇礼 -赤城地区 ,是我国唯一在碱性 -偏碱性侵入杂岩体内发现许多具有工业意义金矿床的地区 .偏碱性侵入杂岩体的展布受尚义 -崇礼 -赤城东西向深断裂控制 ,杂岩体主要由正长岩类、碱性正长岩类、二长岩类以及石英二长岩等岩石组成 .综合岩石和矿床的常量元素、微量元素、稀土元素及铅同位素等特征 ,表明偏碱性侵入杂岩体是深部壳幔混合作用形成的 ;且金矿床的形成与偏碱性侵入杂岩体是密切相关的 .成矿作用在偏碱性侵入杂岩体的东部与西部有所不同 ,西部多以石英脉、石英细脉、网脉型为主 ,围岩以正长岩、石英二长岩为主 ;东部则多为石英细网脉和破碎蚀变岩型 ,围岩主要是碱长正长岩、正长岩 .金矿床受控于尚义 -崇礼 -赤城东西向深断裂的次一级东西向构造和南北向构造 ,赋矿部位主要在两组构造的交汇部位 .

The Shuiquangou Hougou subalkalic intrusive complex body, situated in Chongli Chicheng district in Hebei Province, is the only subalkalic alkali intrusive complex body that is pregnant with many gold deposits in China. The distribution of the subalkalic intrusive complex body is controlled by the east west trend Shangyi Chongli Chicheng deep fault. The rock of the subalkalic intrusive complex body is composed of mainly diorite, syenite, alkalisyenite ,monzonite and quartz monzonite.The studies on constant element, trace element, REE and lead isotope indicate that the subalkalic intrusive complex body is formed by deep crust mantle migmatization. The gold deposits are closely related to the subalkalic intrusive complex body. Between east and west, the mineralization in subalkalic intrusive complex is different. In the west,the veins are chiefly quartz veins, quartz veinlets and network veins,the wall rocks are mainly syenite and quartz monzonite. In the east,the fine quartz network veins, altered kata rocks , alkali syenite and syenite are dominant. The gold deposits are under the control of the east west and south north trending secondary structures derived from the east west trend Shangyi Chongli Chicheng deep fault. The ore bodies occur in the intersecting positions of two structures.