Provenance and geochemistry of sedimentary components in the Volcano-Sedimentary Complex, Iberian Pyrite Belt: discrimination between the sill–sediment-complex and volcanic-pile models

C.A. Boulter, Laurence Hopkinson, M.G. Ineson, J.S. Brockwell

Research output: Contribution to journalArticle

Abstract

Two highly contrasting models have been proposed for the palaeovolcanological setting of the massive sulphide deposits in the Iberian Pyrite Belt. The long-standing view of the host rocks is that they are a pile of effusive and pyroclastic rocks but this position has now been challenged by the proposal that high-level peperitic sills predominate. Discrimination between the volcanic-pile and sill–sediment-complex models is important because they lead to very different conclusions about such key metallogenic features as the timing of mineralization, the nature of the ore-forming convective system and the source of the metals. Sedimentary geochemistry, particularly REE and Ti/Nb, shows that there is no correspondence between the chemistries of mafic igneous sheets and intercalated stratified-volcaniclastic rocks that range from andesite to rhyodacite in composition. Therefore none of the mafic sheets supplied detritus to the sedimentary environment. Sedimentary rocks of continental provenance persist throughout the host-rock sequence, especially in mineralized regions, implying confinement of the majority of primary volcanic facies in the form of high-level intrusions. Some andesitic and felsic intrusions created a minor, stratified volcaniclastic component via hydrovolcanic eruptions. The volcanic-pile model is invalidated because the expected provenance patterns for this volcanic style are not present and the sill–sediment-complex setting of the sulphide deposits is confirmed.
Original languageEnglish
Pages (from-to)103-115
Number of pages13
JournalJournal of the Geological Society
Volume161
Issue number1
Publication statusPublished - 2004

Fingerprint Dive into the research topics of 'Provenance and geochemistry of sedimentary components in the Volcano-Sedimentary Complex, Iberian Pyrite Belt: discrimination between the sill–sediment-complex and volcanic-pile models'. Together they form a unique fingerprint.

  • Cite this