河北省赤城县金家庄金矿地质特征及找矿方向

海西期超基性岩侵入于太古界桑干群地层中。金矿化分布于超基性岩体内、外接触带的破碎带中。本文讨论了超基性岩体的地质特征,岩石学、岩石化学特征及含矿性;论述了金矿成矿地质条件、矿床地质特征,找矿标志和找矿方向。

GEOLOGICAL FEATURE AND THE EXPLORATION DIRECTION OF JIN JIAZHUANG Au-DEPOSIT CHICHENG COUNTY, HEBEI PROVINCE

Jin Jiazhuang Au-deposit, Chicheng County, Hebei province is a new type occuring in thefracture zone related to Xiao Zhangjia kou ultrabasic rock body. This ultrabasic rock body is thelargest one among those distributed aiong Shangyi-Chicheng deep fracture in the north Hebei province, extending in E-W direction. It emplaced in Archean metamorphic rock series. K-Ar agedating is 220 my. bolonging to Hercynian Period. Petrologically, the rock body is hornblend-pyroxenite-pyroxeniteseverely altered with serpentinization, carbonatization, silicification etc. Average Au-Abundance is 50 ppb. Au-concentration is closely related to the alteration. Ore bodies are mainly located in the upper and lower block of the north marginal faut by which the ultrabasic rock body contacts with the Archean rock occuring as en echelon with Au-grade of 6-18/t. Au-mineraliza-tion in the ultrabasic rock is marked by Fe Mn carbonatization silicification limonitization, pyritization and chloritization; in the migmatized-leuco-granulite, cataclasite gneiss bysilicification, hematization, sericitization, limoitiaztion and K-alteration. Geocemically-Au-mineralization is marked by superimposition of Cu, Pb, Zn, As and Au anomaly. Regionally,fracture zones (F₁, F₂and F₃) trending in E-W direction by which the ultrabasic body contact with the Archean rock on south and north side control Au-mineralization.