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东太平洋海底扩张中心7个多金属硫化物矿床中的48个热液沉淀物样品的化学全分析表明,金的富集具有明显不同的模式。发现两个硫化物矿床样品中含金量高,即轴向海山和勘探者海岭南部。采自轴向海山矿床顶部的一个重达160kg的样品由二氧化硅、重晶石和闪锌矿组成。该样含金达6700ppb,平均为4900ppb。勘探者海岭南部的样品含金达1500ppb,平均660ppb。对这两个地区所采多种样品进行的详细矿物学研究及化学全分析表明,金的沉淀受元素伴生和共生次序的控制。浓度约为200ppb的金与高含量的铜(>1wt％)和钼(达470ppm)伴生;浓度高于800ppb的金与高含量锌(>10wt％)、钡(>3wt％)和二氧化硅(>20wt％)伴生;浓度高于1200ppb的金则与高含量的铅(>0.1wt％)、银(>100ppm)、砷(>300ppm)和锑(50—100ppm)伴生。两地所采的含金量最高的样品,均在非晶质二氧化硅基质中含有晚期泉华状低温铅、砷、锑、银和硫的硫盐。这些硫盐可能是金的贮集场所。 采于其他玄武岩型海底矿床(北纬21度地区、加拉帕戈斯裂谷、胡安德富卡海岭南部因代沃海岭)的贫金样品(<200ppbAu),与轴向海山和勘探者海岭南部样品相比,从发表的数据看,其金属和硫的含量高,但SiO_2含量低。瓜伊马斯盆地热液矿床下伏的沉积物,较洋中脊玄武岩富Au,但这些矿床中所采的样
Full chemical analysis of 48 hydrothermal sediment samples from seven polymetallic sulphide deposits at the Eastern Pacific Seabed Expansion Center shows that gold enrichment has significantly different patterns. Two samples of sulphide deposits were found to contain high levels of gold, namely axial seamounts and south of the explorer’s ridge. A sample taken from the top of an axial seamount deposit weighing 160 kg consisted of silica, barite and sphalerite. The gold content of 6700ppb, with an average of 4900ppb. The southern sampler of the Prospector Ridge contains 1500 ppb gold, an average of 660 ppb. Detailed mineralogical and chemical analyzes of various samples taken in these two regions show that the precipitation of gold is controlled by elemental and symbiotic sequences. Gold at concentrations up to about 200 ppb are associated with high levels of copper (> 1 wt%) and molybdenum (up to 470 ppm); gold with concentrations above 800 ppb is associated with high levels of zinc (> 10 wt%), barium (> 20 wt%); gold concentrations above 1200 ppb are associated with high levels of lead (> 0.1 wt%), silver (> 100 ppm), arsenic (> 300 ppm) and antimony (50-100 ppm). Both gold and gold samples collected from the two places contain late-spring-like low-temperature lead, arsenic, antimony, silver and sulfur in the amorphous silica matrix. These sulfur salts may be gold deposits. Gold-depleted samples (<200 ppb Au) from other basaltic seabed deposits (latitude 21 degrees, Galapagos Rift, Indevo Ridge in southern Juan de Fuca Ridge) Compared to the sample, the published data show that the content of metal and sulfur is high but the content of SiO 2 is low. The sediments underlying the hydrothermal deposits in the Guaymas Basin are more Au-rich than the mid-oceanic basalts, but the samples taken from these deposits