Evidencias de hidrotermalismo diagenético en la formación Oiartzun (Cretácico Superior), margen NE de la Cuenca Vasco-Cantábrica
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1
Universidad del País Vasco/Euskal Herriko Unibertsitatea
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Universidad del País Vasco/Euskal Herriko Unibertsitatea
Lejona, España
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2
Universidad de Burgos
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ISSN: 1576-5172
Argitalpen urtea: 2021
Zenbakien izenburua: X Congreso Geológico de España
Zenbakia: 18
Orrialdeak: 160
Mota: Artikulua
Beste argitalpen batzuk: Geotemas (Madrid)
Laburpena
The upper Albian-lower Cenomanian braidplain delta system of the Oiartzun Formation expands alongside the NW Bortziriak Massif border (NE margin of the Basque Cantabrian Basin). Shallow marine carbonate patches are embedded between terri- genous delta-front sediments, probably linked to the halokinetic forced-fold anticlines developed during that time (Bodego et al, 2018a), which show altered diagenetic products. The objective of this study is to characterize and interpret the processes responsible for such diagenetic modifications from the Oiartzun Fm. in Txoritokieta area (Donostia). Diagenetic processes and their evolution have been defined based on cross-cutting relationships from both field outcrop and thin section observa- tions (petrological study through staining, cathodoluminescence and SEM), as well as geochemistry and structural analysis. Pigmentary iron inflow, recrystallization/neomorphism of the micritic matrix, several fracture systems and either dolomite precipitation or mineral replacement (siliceous and carbonaceous), are some features resulting from possible hydrothermal activity in relation to extensive tectonic episodes (Bodego et al, 2018b).