Volcanic architecture in the Odiel river area and the volcanic environment in the Riotinto-Nerva Unit, Iberian Pyrite Belt, Spain

In order to assess the volcanic architecture of the VSC in the Iberian Pyrite Belt, Spain, a study of the volcanic and sedimentary lithofacies has been undertaken on a section up to 1000 m thick in the Odiel river, considered to be also representative of other areas of the Riotinto-Nerva Unit. Among other mineral deposits, this unit includes the world-class volcanic-hosted massive sulfide deposits of the Riotinto mining district. Several conclusions have been obtained: a) a complex, thick volcanic succession, as well as mafic and felsic sills and thin sedimentary intervals, predated the genesis of the sulfide deposits, which did not form in a dominantly sedimentary environment; b) two successive, felsic volcanic sequences can be distinguished, showing textural and chemical variations from bottom to top; c) mafic lithofacies decrease upwards in the sequence, and d) volcanic structures, eruption style and internal organization suggest a deep subaqueous depositional environment, which agrees with the depositional setting for massive sulfide deposits. (C) 2011 Elsevier B.V. All rights reserved.