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Geology of the Tapo and Acobamba pre-andean ultramafites, Tarma, Cordillera Oriental, Perú

dc.contributor.authorCastroviejo, Ricardo
dc.contributor.authorFeliciano Rodrigues, José
dc.contributor.authorAcosta, Jorge
dc.contributor.authorPereira, Eurico
dc.contributor.authorRomero, Darwin
dc.contributor.authorQuispe, Jorge
dc.contributor.authorEspí, José Antonio
dc.date.accessioned2014-04-25T10:26:12Z
dc.date.available2014-04-25T10:26:12Z
dc.date.issued2009
dc.identifier.urihttp://hdl.handle.net/10272/8046
dc.description.abstractUltramafic rocks occur scattered along a 300 km long NNW-SSE trending belt, parallel to the central Peruvian Andes in the Cordillera Oriental, from Tarma (Junín Dept.) to Huancapallac and Tingo María (Huánuco Dept.). The Tarma occurrences (Tapo and Acobamba) are dealt with here, as the first step of a broader research. The Tapo massif comprises strongly tectonised serpentinites with scarce peridotitic relics, amphibolites and podiform chromitites. It was overthrust on early Carboniferous metasedimentary rocks of the Andean basement (Ambo Group), and it shows evidences of a pre-Andean deformational history, not observed in the Ambo Group; the basal thrust plane is folded by the Andean tectonics. The two smaller Acobamba occurrences are also allochtonous and show similar tectonic features. Major and trace element composition of amphibolites point to a tholeiitic basalt (to picrobasalt) protolith, compatible with an ocean-ridge or ocean-island environment. Small podiform chromitite lenses and chromite disseminations also occur; they are strongly deformed, metamorphosed and overprinted by hydrothermal alteration related to deformation, and were the subject of small scale mining. The ores comprise mainly chromite, ferritchromite, spinel, magnetite, ilmenite and scarce sulphides, as well as the secondary minerals stichtite and nimite. Results of this work exclude current interpretations of the Tarma ultramafites as autochtonous igneous intrusives, and point to a new interpretation for their emplacementen_US
dc.language.isospaen_US
dc.rightsAtribución-NoComercial-SinDerivadas 3.0 España
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/3.0/es/
dc.subject.otherTapo ultramafic massifen_US
dc.subject.otherAmphiboliteen_US
dc.subject.otherCordillera Oriental Andesen_US
dc.subject.otherChromiteen_US
dc.subject.otherPodiformen_US
dc.titleGeología de las ultramafitas pre-andinas de Tapo y Acobamba, Tarma, Cordillera Oriental del Perúen_US
dc.titleGeology of the Tapo and Acobamba pre-andean ultramafites, Tarma, Cordillera Oriental, Perúeng
dc.typeinfo:eu-repo/semantics/articleen_US
dc.rights.accessRightsinfo:eu-repo/semantics/openAccess


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