DOI: 10.1038/ngeo2661
论文题名: Gold enrichment in active geothermal systems by accumulating colloidal suspensions
作者: Hannington M. ; Hardardóttir V. ; Garbe-Schönberg D. ; Brown K.L.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2016
卷: 9, 期: 4 起始页码: 299
结束页码: 302
语种: 英语
Scopus关键词: black smoker
; colloid
; concentration (composition)
; geothermal system
; gold
; island arc
; mid-ocean ridge
; ore deposit
; reservoir
; Iceland
英文摘要: The origins of high-grade hydrothermal ore deposits are debated, but active geothermal systems provide important clues to their formation. The highest concentrations of gold are found in geothermal systems with direct links to island arc magmatism. Yet, similar concentrations have also been found in the absence of any input from arc magmas, for example, in the Reykjanes geothermal field, Iceland. Here we analyse brine samples taken from deep wells at Reykjanes and find that gold concentrations in the reservoir zone have increased over the past seven years from an average of 3 ppb to 14 ppb. The metal concentrations greatly exceed the maximum solubility of gold in the reservoir under saturated conditions and are now nearly two orders of magnitude higher than in mid-ocean ridge black smoker fluids - the direct analogues of Reykjanes deep liquids. We suggest that ongoing extraction of brine, the resulting pressure drop, and increased boiling have caused gold to drop out of solution and become trapped in the reservoir as a colloidal suspension. This process may explain how the stock of metal in the reservoirs of fossil geothermal systems could have increased over time and thus become available for the formation of gold-rich ore deposits. © 2016 Macmillan Publishers Limited. All rights reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/106027
Appears in Collections: 气候减缓与适应 科学计划与规划
There are no files associated with this item.
作者单位: GEOMAR, Helmholtz Centre for Ocean Research Kiel, Wischhofstraße 1-3, Kiel, Germany; Earth and Environmental Sciences, University of Ottawa, 25 Templeton, Ottawa, Canada; ÍSOR, Iceland Geosurvey, Orkugardur, Grensásvegi 9, Reykjavík, Iceland; Institute of Geosciences, Kiel University, Ludewig-Meyn-Strasse 10, Kiel, Germany; GEOKEM, PO Box 30-125, Barrington, Christchurch, New Zealand
Recommended Citation:
Hannington M.,Hardardóttir V.,Garbe-Schönberg D.,et al. Gold enrichment in active geothermal systems by accumulating colloidal suspensions[J]. Nature Geoscience,2016-01-01,9(4)