Chilean strata-bound Cu- (Ag) deposits: An Overview
Victor Maksaev, Departamento de Geología, Universidad de Chile, Santiago, Chile, Marcos Zentilli, Department of Earth Sciences, Dalhousie University Halifax, Nova Scotia, Canada.

in - Porter, T.M. (Ed), 2002 - Hydrothermal Iron Oxide Copper-Gold and Related Deposits: A Global Perspective, PGC        Publishing, Adelaide, v. 2, pp 185-205.

< Previous Abstract | Monograph Index Page | Next Abstract >


Strata-bound Cu- (Ag) deposits, long known as 'Chilean manto-type', occur along the Coastal Cordillera of northern Chile hosted by Jurassic and Lower Cretaceous volcanic and volcano-sedimentary rocks. These deposits are typical of the first stage of Andean evolution characterized by an extensional setting of the arc magmatism along the active margin of South America. Strata-bound Cu- (Ag) deposits were formed during two metallogenic epochs in the Late Jurassic and uppermost Early Cretaceous. The mineralization took place at the time of structurally controlled emplacement of batholiths within the Mesozoic volcanic and sedimentary strata. The volcanic-hosted strata-bound Cu- (Ag) deposits invariably occur distal, but peripheral to coeval batholiths emplaced within tilted Mesozoic strata. The prevalent view that these deposits have an inherent genetic relationship with hydrothermal fluid derivation from subvolcanic stocks and dikes is contended here, because these minor intrusions are largely barren and this hypothesis does not fit well with Sr, Os and Pb isotopic data that call for crustal contribution of these elements. The strata-bound Cu- (Ag) mineralization appears to be produced by fluids of mixed origin that were mobilized within permeable levels and structural weakness zones of the Mesozoic arc-related volcano-sedimentary sequence during the emplacement of shallow granodioritic batholiths under transtensional regimes. These hydrothermal fluids deposited copper and subordinate silver when reacted with organic matter, pyrite and/or cooled away from their heat sources. Although strata-bound Cu- (Ag) mineralization took place during the same Cretaceous metallogenic event that formed the magnetite-apatite bodies, and Fe-oxide-Cu-Au deposits along the present Coastal Cordillera, the conceivable relationships with these other types of deposits are hampered by the inconclusive debate about the origin of the Chilean Fe-oxide deposits. However, the available data strongly suggest that the Fe oxide-rich deposits are metasomatic in origin and genetically related to contact zones of Lower Cretaceous dioritic batholiths, whereas the iron-poor volcanic-hosted Cu-(Ag) stratabound deposits constitute distal mineralization peripheral to Upper Jurassic of Lower Cretaceous granodioritic batholiths.

Buy Top   |   PGC Publishing     |   PGC Home

This book is NOW AVAILABLE FOR ORDER via the web by selecting the BUY button above.

This abstract was printed from the PGC Publishing website

PGC Logo
Porter GeoConsultancy Pty Ltd
 International Study Tours
     Tour photo albums
 Ore deposit database
PGC Publishing
 Our books  &  bookshop
     Iron oxide copper-gold series
     Super-porphyry series
     Porhyry & Hydrothermal Cu-Au
 Ore deposit literature
 What's new
 Site map