冀北隆化小罗卜沟金银矿床特征及找矿意义

冀北隆化县小罗卜沟中型金银矿床的发现是该地区找矿的重大突破。勘查区位于1∶20万和1∶5万Au、Ag等多元素综合异常内,通过以钻探、硐探为主的探矿工程,基本查明了矿体赋存于早白垩世九佛堂组复成分角砾岩和义县组安山岩及安山质火山角砾岩的构造裂隙内。矿体受断裂带控制,与围岩界线明显,对围岩没有选择性,矿床属燕山期与岩体有关的浅成中低温热液矿床。矿区内共圈定17个矿体,矿体长28～788 m,斜深8～489 m,平均厚度0.80～3.96 m,Ag平均品位68.44×10~(-6)～447.50×10~(-6),共生Au平均品位1.16×10~(-6)～6.25×10~(-6);伴生Au平均品位0.20×10~(-6)～1.00×10~(-6),伴生S平均品位2.34%～11.10%。主要矿体Ⅳ-1银资源储量达中型。矿区内及外围仍存在寻找多金属矿床的潜力。该矿床的发现对寻找同类矿床具有重要指示意义。

Characteristics of the gold and silver deposit in Xiaoluobugou, northern Hebei Province and the significance for prospecting

The discovery of the medium-sized Xiaoluobogou gold and silver deposit in Longhua county of northern Hebei Province makes a major breakthrough of prospecting in this area. It is located in the 1:200,000 and 1:50,000 Au and Ag multi-element anomaly zones. Drilling and adit exploration show that the ore bodies are present in the structural fissures of breccia of Early Cretaceous Jiufotang Formation and andesite or andesite volcanic breccia of Yixian Formation. These ore bodies are controlled by the fault zones, with clear boundaries to surrounding rocks without any selectivity. The deposit belongs to the Yanshanian epithermal deposit related to rock mass. There are 17 ore bodies delineated in the ore district, which are 28~788m long and 8~489m obliquely deep. They have average thickness of 0.80~3.96m, average grade of Ag 68.44×10-6~447.50×10-6, average grade of symbiosis Au 1.16×10-6~6.25×10-6, average grade of associated Au 0.20×10-6~1.00×10-6, and average grade of associated S 2.34%~11.10%. The main ore body IV-1 reaches medium silver reserves. There is still potential for searching for multi-metallic deposits in the ore district and perimeter. The discovery of this deposit has an important instructive significance for prospecting similar deposits in this region.