论文部分内容阅读
沿朱诺金矿带分布的中温热液含金石英脉于早第三纪在200—325℃温度和超过1—1.5kbar的压力下,由富含H_2O—CO_2 (±N_2,H_2S,CH_4)、低盐度流体析出形成。所具有+8‰到+12‰的δ~(18)O值以及-20‰到-30‰的δD值同位素的含重金属成矿热液表明为深部矿源。这些资料同阿拉斯加南部大陆边缘俯冲处物质由变质而挥发生成的成矿热液模式一致。变质流体向上渗透到因机械作用增强渗透率的构造带,这些带与海岸山脉巨型区域断裂构造有关,并在较高处的消减壳层的脆性地层中形成含金脉。金的沉积伴有数种作用机理,包括沸腾、热液-围岩交代及热液的压力和温度的降低。
The gold-bearing quartz veins of mid-temperature hydrothermal gold distributed along the Juno gold belt were characterized by the presence of H_2O-CO_2 (± N_2, H_2S, CH_4) at temperatures of 200-325 ℃ and pressure of more than 1-1.5kbar in the early Tertiary. ), Low salinity fluid precipitation formation. The δ 18 O values from + 8 ‰ to + 12 ‰ and δ D isotopes containing heavy metals from -20 ‰ to -30 ‰ were identified as deep source minerals. These data are consistent with the ore-forming hydrothermal patterns resulting from metamorphism and volatilization of the subducted material at the margin of the southern continental margin of Alaska. Metamorphic fluids penetrate upwards into the tectonic belts where mechanical permeability enhances, and these belts are associated with the fault zone in the gigantic zone of the Coastal Mountains and form gold-bearing veins in the brittle strata of the descending crust at higher altitudes. Gold deposition is accompanied by several mechanisms of action, including boiling, hydrothermal-metasomatism, and reduction of hydrothermal pressure and temperature.