DOI: 10.1007/s00531-012-0844-6
Scopus记录号: 2-s2.0-84875402849
论文题名: Constraints regarding gold deposition in episyenites: The Permian episyenites associated with the Villalcampo Shear Zone, central western Spain
作者: López-Moro F.J. ; Moro M.C. ; Timón S.M. ; Cembranos M.L. ; Cózar J.
刊名: International Journal of Earth Sciences
ISSN: 14373254
出版年: 2013
卷: 102, 期: 3 起始页码: 721
结束页码: 744
语种: 英语
英文关键词: Chemical uraninite age
; Fluid inclusions
; Gold-bearing episyenites
; Stable isotopes
; Sulphide deposition
; Villalcampo Shear Zone
Scopus关键词: deposition
; fluid inclusion
; gold
; leaching
; mass transfer
; ore body
; Permian
; quartz
; shear zone
; stable isotope
; sulfide
; syenite
; Spain
英文摘要: The Villalcampo Shear Zone (around 307 Ma) shows second-order shear zones (420-390 °C) with gold ore bodies hosted by episyenites, which consist of albite episyenites (albitites) and albite-Kfs episyenites, both types with different contents in sulphides and gold. Mass transfer modelling supports higher fluid/rock ratios in albitites than in albite-Kfs episyenites. The study of worldwide barren and gold-bearing episyenites reveals abundant sulphides in the latter as a distinguishing feature. The electrochemical processes at the surface of sulphide would have enhanced gold precipitation, sulphides working as a gold trap. A complex fluid history occurred in gold ore bodies hosted by episyenites, although in essence, it was similar to quartz-sealed faults hosting late Variscan gold deposits: (a) an early fluid equilibrated with the metamorphic pile with sulphides or with a metamorphic fingerprint, resulted in a sulphide deposition and (b) a shallower fluid reservoir of meteoric origin provided gold deposition. In contrast to earlier claims regarding episyenite fluid flow, a down temperature and probably an upwards fluid flow are proposed for the episyenitization process, also in keeping with the early stages of fluid flow in quartz-sealed faults. Fluid inclusions in albite confirm that the striking coupled quartz leaching albitization processes occurred around 400 °C and 60 MPa, crosscutting the retrograde solubility field of silica and yielding a vuggy rock. Initially, albite, and later quartz and sulphide, filled the vugs from the same or a very similar fluid. Uraninites deposited during the albitization and probably the onset of the sulphide deposition afforded the same age (270 ± 12 Ma) as other Spanish episyenites, confirming a synchronous and a regional-scale process and ruling out a relationship with the granite cooling history (324 ± 11 Ma). © 2012 Springer-Verlag Berlin Heidelberg. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84875402849&doi=10.1007%2fs00531-012-0844-6&partnerID=40&md5=913e96bfe98170f7618ba26ec3ba2ccf
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/70593
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
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作者单位: Departamento de Geología, Facultad de Ciencias, Universidad de Salamanca, Plaza de los Caídos s/n, 37008 Salamanca, Spain; CIEMAT, Avd. Complutense 22, 28004 Madrid, Spain; Dpto. de Investigación en Recursos Geológicos, Instituto Geológico y Minero de España, Unidad de Salamanca, C/Azafranal 48, 1 A, 37001 Salamanca, Spain
Recommended Citation:
López-Moro F.J.,Moro M.C.,Timón S.M.,et al. Constraints regarding gold deposition in episyenites: The Permian episyenites associated with the Villalcampo Shear Zone, central western Spain[J]. International Journal of Earth Sciences,2013-01-01,102(3)