沽源超级环形构造与中生代成矿大爆发  

Guyuan Super Circular Structures and Mesozoicera Mineralization big Explosion

作　　者：宫进忠 施兴 张亚东 楚福录 

机构地区：[1]河北省地球物理勘查院,河北廊坊065000

出　　处：《矿产与地质》2009年第5期399-405,共7页Mineral Resources and Geology

摘　　要：由火山喷发、岩浆侵入或陨石撞击作用所形成的环形构造，是地球物质活化迁移的重要场所，对区域成矿过程具有极大的制约意义。在河北省西北部坝上地区，围绕沽源县城一带，早白垩世岩浆岩、布格重力异常及水系沉积物地球化学异常均呈现明显的多级环带分布。这种现象并非尚义-崇礼-赤城深大断裂与乌龙沟-上黄旗岩浆岩带的简单复合叠置，而是以沽源为中心的火山机构的具体表现。该环形构造至少可划分为三个岩浆岩环带，分布着早白垩世（K—Ar100～123Ma）安山质火山-沉积岩和燕山旋回第四期（K—Ar100～138Ma）次粗面岩、次安山岩、二长斑岩、石英正长斑岩等浅成超浅成侵入岩体或岩株，它们的银、铅、锌、镉、铀、钍、钼、砷、锑等元素显著活化和富集。该环形构造控制着蔡家营铅锌矿、张麻井铀钼矿、彭家沟银矿、青羊沟铅锌矿、牛圈银金矿及北岔沟门铅锌银矿的时空定位。若干迹象表明，沽源环形构造可能是白垩纪时期一次陨击事件（因火星和木星之间两颗小行星的碰撞）的结果，这也许是中生代成矿大爆炸的根本诱发机制。The circular structures that formed by the volcanic eruption, magma intrusion or meteorite impacts, is important arenas of the Earth＇s material activation and migration, has great control significance to the regional mineralization process. In the northwest Hebei province region, around Guyuan county city area, Early Cretaceous epoch magmatic rocks, Bouguer gravity anomaly and stream sediment geochemical anomalies showed a clear multi-ring belt. This phenomenon is not Shangyi-Chongli-Chicheng deep fault and Wulonggou-Shanghuangqi magmatic rocks belt with a simple superposed composite, but specific manifestation of the volcanic mechanism that by Guyuan as center. The circular structure at least can be divided into three mgmatic rocks bands, it distributes the Early Cretaceous epoch（K-Ar 100-123Ma） andesitic volcanicsedimentary rocks and Yanshanian fourth stage（K-Ar 100-138Ma） hypabyssal-super hypabyssal intrusive bodies, sub-trachyte, sub-andesite, monzonitic-porphry, and quartz-syenite-porphry, their contain of silver, lead, zinc, cadmium, uranium, thorium, molybdenum, arsenic, antimony and other elements outstanding activates and accumulates. The circular structure controls time and space setting of Caijiaying, Zhangmajing, Pengjiagou, Qing yang gou, Niujuan and Beichagoumen and so on large-scale silver-lead-zinc mineral deposits. Some signs make clear, the circular structure may be a result of Cretaceous period meteorite impact event （caused by the collision of two little Planets in between Mars and Jupiter, 100-160Ma ago）, it may possibly be the inducement mechanism to Mesozoic mineralization big explosion.

关 键 词：环形构造 地球物理地球化学 成矿大爆发 陨击事件 河北沽源 

分 类 号：P588[天文地球—岩石学]