Fluid flow related to thrusts and folds affecting Middle and Upper Eocene syn-tectonic sediments at the Pyrenean Belt.

• Autores: Francesc Calvet Rovira, Anna Travé Herrero, Josep Anton Muñoz i de la Fuente, M. Acero
• Localización: Geotemas (Madrid), ISSN 1576-5172, Nº. 3, 1, 2001 (Ejemplar dedicado a: XIV Congreso Nacional de Sedimentología, IV Congreso del Cretácico de España), págs. 113-116
• Idioma: español
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• Resumen

  • The studied area is part of the south-Pyrenean fold-and-thrust belt. Tectonic activity in the area is represented by pre-orogenic extensive fractures, syn-orogenic thrust faults, early post-orogenic sinistra! faults and late post-orogenic extensive fractures, affecting Eocene deposits. A meteoric fluid, with relatively low Fe, low Sr and high Mg content, circulated through the thrust fractures as well as through the pre-thrust fractures synchronously to thrust development precipitating calcite cement with SwO ranging from -8.8 to -8.3 °/Q() PDB, S13C ranging from -3.1 to -2.1 °/Q0 PDB, and 87Sr/36Sr ranging from 0.708 1 6 to 0.70819. A fluid with a formation water composition with relatively high Fe content, circulated synchronously to sinistral fault development, probably early after thrust emplacement during relatively deep burial and precipitated calcite cement with 8180 ranging from -9.5 to -9.2 °/00 PDB, 813C ranging from -0.6 to -0.5 °/00 PDB and 87SrA6Sr of 0.70857. Finally, a hot meteoric fluid, with relatively low Mg and Fe and relatively high Sr content, circulated through the NW-SE fractures and precipitated calcite cement with 8lsO ranging from -14.4 to - 12.6 °/0() PDB and the 813C ranging from -4.0 to -3.1 °/00 PDB and 87Sr/66Sr of 0.70847 during a hydrothermal event associated to a Neogene extensive phase.