Timing of Au-Ag mineralization and related volcanism at Otoge, Yamagata Prefecture, Northeast Japan
Timing of Au-Ag mineralization and related volcanism at Otoge, Yamagata Prefecture, Northeast Japan
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日本东北部山形县 Otoge 的金银矿化和相关火山活动的时间
DOI：
10.2465/ganko.91.297
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
T. Itaya
中科院分区：
文献类型：
--
作者：
Nanshi Zeng;E. Izawa;Koichiro Watanabe;T. Itaya
测得奥托格存款金银矿化和热液蚀变的K-Ar年龄分别为3.93±0.15、3.99±0.10、4.10±0.10和4.15±0.10 Ma，证明深部含金银石英脉与现今地表粘土存款的绢云母带是同期形成的。年龄也接近的Au-Ag-Pb-Zn矿化在Yatani存款，3公里的Otoge存款，这表明在这两个地区的成矿作用发生在一系列的热液系统。测得乙下组上部熔结凝灰岩的喷发年龄为4.85± 0.13Ma（黑云母，K-Ar法）和4.60± 0.30Ma（锆石，裂变径迹法），早于成矿作用。
K-Ar ages of Au-Ag mineralization and hydrothermal alteration at the Otoge deposit were determined to be 3.93±0.15, 3.99±0.10, 4.10±0.10 and 4.15±0.10 Ma for four sericite separates, proving that the Au-Ag bearing quartz veins at deep level and the sericite zone of the clay deposit at the surface of present level were formed contemporaneously. The ages are also close to those of Au-Ag-Pb-Zn mineralization at the Yatani deposit, 3 km northeast of the Otoge deposit, suggesting that mineralization in both areas occurred within a series of hydrothermal systems. The eruption ages for welded tuff of the upper part of the Otoge Formation were determined to be 4.85±0.13 Ma (biotite, K-Ar age) and 4.60±0.30 Ma (zircon, fission track age), predating the mineralization.