DOI: 10.1007/s00531-012-0785-0
论文题名: Zincian dolomite related to supergene alteration in the Iglesias mining district (SW Sardinia)
作者: Boni M. ; Mondillo N. ; Balassone G. ; Joachimski M. ; Colella A.
刊名: International Journal of Earth Sciences
出版年: 2013
卷: 102, 期: 1 起始页码: 61
结束页码: 71
语种: 英语
英文关键词: Nonsulfides
; Supergene
; SW Sardinia
; Zn dolomite
Scopus关键词: dolomite
; geochemistry
; hydrothermal alteration
; hydrothermal fluid
; lattice dynamics
; meteoric water
; ore deposit
; scanning electron microscopy
; supergene process
; temperature
; X-ray spectroscopy
; Italy
; Sardinia
英文摘要: One of the main effects of supergene alteration of ore-bearing hydrothermal dolomite in areas surrounding secondary zinc orebodies (Calamine-type nonsulfides) in southwestern Sardinia (Italy) is the formation of a broad halo of Zn dolomite. The characteristics of supergene Zn dolomite have been investigated using scanning electron microscopy and qualitative energy-dispersive X-ray spectroscopy, thermodifferential analysis, and stable isotope geochemistry. The supergene Zn dolomite is characterized by variable amounts of Zn, and low contents of Pb and Cd in the crystal lattice. It is generally depleted in Fe and Mn relative to precursor hydrothermal dolomite (Dolomia Geodica), which occurs in two phases (stoichiometric dolomite followed by Fe-Mn-Zn-rich dolomite), well distinct in geochemistry. Mg-rich smithsonite is commonly associated to Zn dolomite. Characterization of Zn-bearing dolomite using differential thermal analysis shows a drop in temperature of the first endothermic reaction of dolomite decomposition with increasing Zn contents in dolomite. The supergene Zn dolomites have higher δ18O but lower δ13C values than hydrothermal dolomite. In comparison with smithsonite-hydrozincite, the supergene Zn dolomites have higher δ18O, but comparable δ13C values. Formation of Zn dolomite from meteoric waters is indicated by low δ13C values, suggesting the influence of soil-gas CO2 in near-surface environments. The replacement of the dolomite host by supergene Zn dolomite is interpreted as part of a multistep process, starting with a progressive "zincitization" of the dolomite crystals, followed by a patchy dedolomitization s. s. and potentially concluded by the complete replacement of dolomite by smithsonite. © 2012 Springer-Verlag. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84872358553&doi=10.1007%2fs00531-012-0785-0&partnerID=40&md5=a99c95ca91dab151d8bf81f143ffea5e
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/70609
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: Dipartimento di Scienze della Terra, Università di Napoli, Via Mezzocannone 8, 80134 Naples, Italy; GeoZentrum Nordbayern University of Erlangen-Nuremberg, Schlossgarten 5, 91054 Erlangen, Germany
Recommended Citation:
Boni M.,Mondillo N.,Balassone G.,et al. Zincian dolomite related to supergene alteration in the Iglesias mining district (SW Sardinia)[J]. International Journal of Earth Sciences,2013-01-01,102(1)