Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
Hydrothermal alteration of felsic volcanic rocks associated with massive sulphide deposition in the northern Iberian Pyrite Belt (SW Spain)
Autore:
Sanchez-Espana, J; Velasco, F; Yusta, I;
Indirizzi:
Univ Pais Vasco, Dept Mineral & Petrol, E-48080 Bilbao, Spain Univ Pais Vasco Bilbao Spain E-48080 ral & Petrol, E-48080 Bilbao, Spain
Titolo Testata:
APPLIED GEOCHEMISTRY
fascicolo: 9, volume: 15, anno: 2000,
pagine: 1265 - 1290
SICI:
0883-2927(200010)15:9<1265:HAOFVR>2.0.ZU;2-1
Fonte:
ISI
Lingua:
ENG
Soggetto:
SULFIDE DEPOSITS; IMMOBILE ELEMENTS; RIO-TINTO; NEW-BRUNSWICK; GEOCHEMISTRY; CONSTRAINTS; GENESIS; CANADA; MINERALIZATION; TEMPERATURE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
85
Recensione:
Indirizzi per estratti:
Indirizzo: Sanchez-Espana, J Univ Pais Vasco, Dept Mineral & Petrol, Apdo 644, E-48080 Bilbao, Spain Univ Pais Vasco Apdo 644 Bilbao Spain E-48080 ao, Spain
Citazione:
J. Sanchez-Espana et al., "Hydrothermal alteration of felsic volcanic rocks associated with massive sulphide deposition in the northern Iberian Pyrite Belt (SW Spain)", APPL GEOCH, 15(9), 2000, pp. 1265-1290

Abstract

Massive sulphide deposits of the northern Iberian Pyrite Belt (IPB) are mainly hosted by felsic volcanic rocks of rhyolitic to dacitic composition. Beneath most of the massive ores of this area (e.g., Concepeion, San Miguel,Aguas Tenidas Este or San Telmo deposits) there is usually a wide hydrothermal alteration halo associated with stockwork-type mineralization. Within these alteration envelopes there are two principal rock types: (1) chlorite-rich rocks, linked to the inner and more intensely altered zones and dominantly comprising chlorite + pyrite + quartz + sericite (+ carbonate + rutile + zircon + chalcopyrite), and (2) sericite-rich rocks, more common in theperipheral zones and showing a dominant paragenesis of sericite + quartz pyrite + chlorite (+ carbonate + rutile + zircon + sphalerite). Mass-balance calculations comparing altered and least-altered felsic volcanic rocks suggest that sericitization was accompanied by moderate enrichment in Mg, Feand H2O, with depiction in Si, Na and K, and a slight net mass loss of about 3%. Chloritization shows an overall pattern which is similar to that of the sericitic alteration, but with large gains in Fe, Mg and H2O land minorenrichment in Si, S and Mn), and a significant loss of Na and K and a minor loss of Ca and Rb. However, chloritization has involved a much larger netmass change (mass gain of about 28%). Only a few elements such as Nb, Y, Zr, Ti, P and LREE appear to have remained inert during hydrothermal alteration, whilst Ti and Al have undergone very minor mobilization. The results point to the severity of the physico-chemical conditions that prevailed during the waxing stage of the ore-forming hydrothermal systems. Further, mineralogical and geochemical studies of the altered footwall rocks in the studied deposits indicate that hydrothermal ore-bearing fluids reacted with hostrocks in a multi-stage process which produced a succession of mineralogical and chemical changes as the temperature increased. (C) 2000 Elsevier Science Ltd. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 16/07/20 alle ore 19:29:25