Exploration for Kuroko mineralisation at the Okuzo prospect, Akita prefecture
Exploration for Kuroko mineralisation at the Okuzo prospect, Akita prefecture
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秋田县 Okuzo 矿区黑子矿化勘探
DOI：
10.11456/shigenchishitsu1992.51.7
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
Yoshitaka Hosoi
中科院分区：
文献类型：
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作者：
Nobuaki Ishikawa;H. Kubota;E. Arai;Yoshitaka Hosoi
Okuzo勘探区位于秋田县大庭市东南20公里处。日本金属矿业厅（MMAJ）在对该地区进行区域地质调查时，发现了伴随铅、锌、金和银的黑古式矿化。Okuzo勘探区位于北黑陆盆地东南缘，根据地质和重力资料，该盆地沿gachimaeda断裂至Gattsu盆地南缘边界的一条线闭合。根据地质调查结果，在火山碎屑岩的露头中发现了直径为15厘米的黑子矿碎片；分析结果为0.75 g/t Au, 160g/t Ag, 0.2% Cu, 5.2% Pb， 23.0% Zn和39.5% BaSO4。通过感应极化和钻孔测量，确定了具有黑罗科矿化作用的南岭湾和土特湾安克劳石岩的趾部特征分别为斜长石和绿泥石绢云母。认为黑岩矿化后中新世中期火山活动持续，形成了喷口角砾岩。
The Okuzo prospect is located 20 km southeast of Odate city, Akita prefecture. The Metal Mining Agency of Japan (MMAJ) discovered Kuroko-style mineralisation accompanying lead, zinc, gold and silver during a regional geological survey of the area.The Okuzo prospect is located on the southeastern rim of the Hokuroku Kuroko Basin, which is closed along a line extending from the Gacchimaeda fault to the boundary of the southern rim of the Gattsu basin based on geological and gravity data. As a result of the geological survey by the MMAJ, a fragment of Kuroko ore with a diameter of 15cm was discovered in an outcrop of volcaniclastic rock; analysis returned 0.75 g/t Au, 160g/t Ag, 0.2% Cu, 5.2% Pb, 23.0% Zn and 39.5% BaSO4. Based on induction polarization and drilling surveys, toe cnaractenstics or nanging-wan and toot-wan ancrauun assucraicu with Kuroko mineralisation were identified as the presence plagioclase and chlorite-sericite, respectively. It is proposed that volcanic activity had been continuous at the middle Miocene after the Kuroko mineralisation and resulted in the formation of vent breccia.