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The stratigraphy of a proximal late hercynian pyroclastic sequence - the vilancos region of the pyrenees

Gilbert, Jennifer (1991) The stratigraphy of a proximal late hercynian pyroclastic sequence - the vilancos region of the pyrenees. Geological magazine, 128 (2). pp. 111-128. ISSN 0016-7568

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Abstract

Volcanic activity, the result of crustal differentiation during the Hercynian orogeny, generated eight explosive eruptions in the Vilancos region of the Spanish Pyrenees. The volcanic products comprise the Erill Castell Volcanic Formation of Stephanian age, which crops out as a 20 km long, WNW-trending strip < 2 km wide dipping steeply to the south. The Vilancos region represents a small fragment of an originally extensive regional terrain of silicic centres. The explosive eruptions mainly generated strongly peraluminous and phenocrystal garnet-bearing subaerial ignimbrite facies. Proximal intra-formational breccias represent a substantial volume of the preserved erupted product and one phreatoplinian deposit is exposed. Mass-flow deposits are common, and small-volume basalt, andesite and rhyolite lava flows, minor tuffs and palaesols also occur. Electron microprobe data show that each garnet-bearing member of the Vilancos region has a distinct garnet composition. This is used as geochemical fingerprinting tool to aid mapping and correlation between proximal intra-formational breccias and ignimbrite of the same eruption. Within one debris-flow deposit (the Vilancos Breccia Member) at least three garnet populations occur. Two of these are derived from pyroclastic members within the mapped region, the other comes from an unexposed rhyolite lava source.

Item Type: Article
Journal or Publication Title: Geological magazine
Uncontrolled Keywords: IGNIMBRITE ; BRECCIA ; FLOW ; METAMORPHISM ; EVOLUTION ; SANTORINI ; GREECE ; EUROPE
Subjects:
Departments: Faculty of Science and Technology > Lancaster Environment Centre
ID Code: 53480
Deposited By: ep_importer_pure
Deposited On: 13 Apr 2012 09:55
Refereed?: Yes
Published?: Published
Last Modified: 09 Apr 2014 23:17
Identification Number:
URI: http://eprints.lancs.ac.uk/id/eprint/53480

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