冀东变质核杂岩中银金矿床地质地球化学特征

The Geological and Geochemical Characteristics of Ag-Au Mineral Deposits Related to the Metamorphic Core Complexes in the Eastern Hebei

赋存于中元古宙长城系常州沟组的洞子沟银矿床和尖宝山金矿床是由密云—都山变质核杂岩构造体系所控制的一组矿床。其成因为中元古宙火山岩浆活动形成的沉积矿源 ,后经中生代的变质核杂岩构造岩浆体系叠加改造而成。洞子沟银矿床具有层控迭加改造的特点 ;尖宝山金矿床则具有破碎蚀变岩型矿床的特点。两矿床的围岩蚀变类型以及微量、稀土元素特征也表现一定的相似性。它们是中元古宙大红峪期和中生代印支、燕山等多期次的伸展构造环境下岩浆活动的产物。矿床在变质核杂岩中所处的构造部位及其矿体赋矿围岩性质的不同决定了它们不同的矿化特点。

Dongzigou Ag deposit and Jianbaoshan Au deposit are hosted in the sandstone of Middle\|Proterozoic suberathem,which are developed from the proterozoic sediment metal source\|rocks formed during the Meso\|proterozoic volcanism and reworked by the Mesozoic tectono\|magmatism during the formation of the metamorphic core complexes in Eastern Hebei.The Dongzigou Ag deposit has the characteristics of reformed strata\|bound origin,the Jianbaoshan Au deposit,located in the detachment fault,is the alterated rock type.Both deposits have the similar wall\|rock alteration,and show the same trace element behavior,and REE patterns.They are the results of the multi\|stage tectono\|magmatism in the environment of continental extension in Eastern Hebei region.Their mineralization depended on their wall rocks and relative location in metamorphic core complexs.