Silver Enrichment and Mineralization of Seafloor Hydrothermal Sediment from the Jade Hydrothermal Field in the Middle Okinawa Trough

JIANG Fu qing; ZHAI Shi kui; LI An chun

The hydrothermal sediments from Jade hydrothermal field are mainly composed of massive sulfide ore and massive sulfate ore. The massive sulfide ore is characterized as the richness of Pb and Ag. According to electron microprobe analysis and neutron activation analysis, silver is mainly rich in the coarse grained sulfide and fine grained sulfide aggregate as dispersion regime in the massive sulfide ore. Silver enrichment mineralization occurs in the early and late period of hydrothermal activity. In the massive sulfate ores mainly composed of anhydrite, silver is rich in the fine grained sulfide aggregate at dispersion regime. Silver is rich at above 150 degree centigrade in the middle late period of hydrothermal activity. Natural silver is found in sulfate ores mainly composed of barite for the first time, which is the major regime of concentration for silver. Silver enrichment mineralization occurs at below 160 degree centigrade in the late period of hydrothermal activity.

1. Institute of Oceanology, Chinese Academy of Scineces, Qingdao,Shandong 266071;

2. Ocean University of China, Qingdao,Shandong 266003

Received Date: 2003-12-03

Rev Recd Date: 2004-04-12

Publish Date: 2004-12-10

Key words:

Abstract: The hydrothermal sediments from Jade hydrothermal field are mainly composed of massive sulfide ore and massive sulfate ore. The massive sulfide ore is characterized as the richness of Pb and Ag. According to electron microprobe analysis and neutron activation analysis, silver is mainly rich in the coarse grained sulfide and fine grained sulfide aggregate as dispersion regime in the massive sulfide ore. Silver enrichment mineralization occurs in the early and late period of hydrothermal activity. In the massive sulfate ores mainly composed of anhydrite, silver is rich in the fine grained sulfide aggregate at dispersion regime. Silver is rich at above 150 degree centigrade in the middle late period of hydrothermal activity. Natural silver is found in sulfate ores mainly composed of barite for the first time, which is the major regime of concentration for silver. Silver enrichment mineralization occurs at below 160 degree centigrade in the late period of hydrothermal activity.

HTML

Reference (13)

[1]	Letouzey J, Kimura M. Okinawa Trough genesis: structure and evolution of a back-arc basin developed in a continent. Marine and Petroleum Geology, 1985, 2:111～130
[2]	Sibuet J C, Letouzey J, Barbier F, et al. Back-arc extension in the Okinawa Trough. Journal of Geophysics Research, 1987, 92:14041～14063
[3]	Halbach P, Nakamura K, et al. Probable modern analogue of Kuroko-type massive sulphide deposits in the Okinawa Trough back-arc basin. Nature, 1989, 338:496～499
[4]	Halbach P, Pracejus B, et al. Geology and Mineralogy of Massive Sulfide Ores from the Central Okinawa Trough, Japan. Economy Geology, 1993, 88:2210～2225
[5]	侯增谦, 浦边撤郎.古代与现代海底黑矿型块状硫化物矿床矿石地球化学比较研究.地球化学,1996,25(3):228～241[Hou Zengqian,T Urabe. A comparative study on geochemistry of sulfide ores from the Kuroko-type deposits on ancient and modern seafloor. Geochimica, 1996,25(3): 228～241]
[6]	侯增谦, 张琦玲. 冲绳海槽海底热水区CO2-烃类流体:流体包裹体证据. 中国科学[D辑], 1998, 18(2):142～148[Hou Zengqian Zhang Qiling.CO2-hydrocarbon fluids of the Jade hydrothermal field in the Okinawa Trough:fluid inclusion evidence. Science in China(D), 1998, 18(2):142～148]
[7]	Halbach P, et al. Whole-rock and sulfide lead-isotope data from the hydrothermal Jade field in the Okinawa back-arc trough. Mineralium Deposita, 1997, 32:70～78
[8]	曾志刚, 蒋富清,翟世奎,等. 冲绳海槽Jade热液活动区块状硫化物的铅同位素组成及其地质意义. 地球化学, 2000, 29(3):239～245[Zeng Zhigang,Jiang Fuqing,Zhai Shikui, et al. Lead isotopic compositions of massive sulfides from the Jade hydrothermal field in the Okinawa Trough and its geological implications. Geochimica, 2000,29(3): 239～245]
[9]	曾志刚,蒋富清,翟世奎,等. 冲绳海槽中部Jade热液活动区中海底热液沉积物的硫同位素组成及其地质意义.海洋学报,2000,22(4):74～82[Zeng Zhigang,Jiang Fuqing, Zhai Shikui, et al. Sulfur isotopic composition of seafloor hydrothermal sediment from the Jade hydrothermal field in the central Okinawa Trough and its geological significance. Acta Oceanologica Sinica,2000,22(4):74～82]
[10]	Herzig P M & Hannington M D. Polymetallic massive sulfides at the modern seafloor : A review. Ore Geology Reviews. 1995, 10:95～115
[11]	Bischoff J L and Seyfried W E. Hydrothermal chemistry of seawater from 25℃ to 350℃. American Journal Sciences, 1978, 278:838～860
[12]	Janecky D R and Seyfried Jr W E. The solubility of magnesium-hydroxide-sulfate-hydrate in seawater at elevated temperatures and pressures. American Journal Sciences,1983, 3:831～860
[13]	Haymon R M, Growth history of hydrothermal black smoker chimneys. Nature, 1983, 301:695～698

Silver Enrichment and Mineralization of Seafloor Hydrothermal Sediment from the Jade Hydrothermal Field in the Middle Okinawa Trough

Abstract

References

Proportional views

通讯作者: 陈斌, bchen63@163.com

Article Metrics

Proportional views

Related