陕西省山阳县池沟地区斑岩成矿特征、成矿规律及找矿预测

Porphyry Metallogenic Regularity and Prospecting Direction in Chigou Region of Shanyang County,Shaanxi Province

池沟地区小斑岩体广泛发育,岩体多呈北东向展布的串珠状小岩株或岩枝产出,属燕山期高钾钙碱性系列I型花岗岩,具(似)斑状特征。区内出现有与燕山期岩浆活动有关的斑岩型铜矿、斑岩型钼矿、矽卡岩型铜矿、构造蚀变岩型金矿等4种类型金属矿化。蚀变、化探异常及矿化均围绕斑岩体呈(环)带状分布,由岩体往外依次出现钼、铜、金矿化的分带性,构成斑岩-矽卡岩-热液脉型铜钼金矿成矿系列,岩体成岩成矿同步,表现出明显的斑岩成矿规律。该区7个岩体群中Ⅰ号岩体是主岩,Ⅰ号岩体内及边部主要为钼矿化,向外则依次出现铜矿化、金矿化,且矿化分带与岩体岩性、围岩蚀变和成矿元素地球化学的分带完全一致。综合研究认为,Ⅰ号岩体西、南外围是另一处铜矿富集的部位,通过深部钻探控制,有望找到具一定工业价值的铜矿体。

There exist many small intrusions in Chigou region,Shanyang county,Shaanxi province.The magmatic rocks distribute to North-East direction in little rock plants or branches,belong to Yanshan epoch,high levels of potassium and calcium alkaline series I-typed granite,with porphyritic structure.There have porphyry copper deposit,porphyry molybdenum,skarn type copper,tectonic altered rock type gold deposit of four kinds of mineralization,which related to magmatic activity of Yanshan period in Chigou region.Alteration,geochemical anomalies and mineralized body show zonal distribution surrounding porphyry intrusion.It developed molybdenium,copper,and gold mineralization in turn from intrusion to outside,that composed of porphyry-typed,skarn-typed,and hydrothermal solution-typed copper,gold,and molybdenium metallogenic series,rock-forming and ore-forming happened simultaneously,and appears obvious regularity of porphyry metallogenesis.No.Ⅰrockbody among these 7 rockbody groups is the main intrusion,Inside and at the edge of the No.Ⅰrock mass is main position of molybdenum mineralization,outward emerges copper mineralization and the golden mineralization,meanwhile,the zoning of mineralization is the same as that of intrusion lithology,wallrock alteration,and metallogenic geochemistry.It concluded that the west and south periphery of No.Ⅰrockbody should be another place for copper enriching.Through deep drilling control,it is expected to find copper orebody with certain industrial value in the site.