From hydroplastic to brittle deformation: Controls on fluid flow in fold and thrust belts. Insights from the Lower Pedraforca thrust sheet (SE Pyrenees)

Autor: David Cruset, Jaume Vergés, Cédric M. John, Richard Albert, Antonio Benedicto, Irene Cantarero, Axel Gerdes, Anna Travé
Přispěvatelé: Ministerio de Ciencia, Innovación y Universidades (España), Dirección General de Investigación Científica y Técnica, DGICT (España), Vergés, Jaume, Univ Barcelona, Dept Mineral Petrol & Geol Aplicada, Facultat Ciencies Terra, Marti i Franques S-N, E-08028 Barcelona, Spain, Géosciences Paris Saclay (GEOPS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Department of Earth Science and Technology [Imperial College London], Imperial College London, Institute of Earth Sciences Jaume Almera, Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Department of Geosciences, Goethe-University Frankfurt, 60438, Frankfurt am Main, Germany, Frankfurt Isotope and Element Research Center (FIERCE), Goethe-University Frankfurt, Frankfurt am Main, Germany, Institut für Geowissenschaften, Goethe-Universität Frankfurt am Main, Univ Barcelona, Dept Mineral Petrol & Geol Aplicada, Facultat Ciencies Terra, Marti i Franques S-N, E-08028 Barcelona, Spain., Vergés, Jaume [0000-0002-4467-5291]
Rok vydání: 2020
Předmět:
Zdroj: Dipòsit Digital de la UB
Universidad de Barcelona
Marine and Petroleum Geology
Marine and Petroleum Geology, Elsevier, 2020, 120, pp.104517. ⟨10.1016/j.marpetgeo.2020.104517⟩
Digital.CSIC. Repositorio Institucional del CSIC
instname
ISSN: 0264-8172
DOI: 10.1016/j.marpetgeo.2020.104517⟩
Popis: We present a multidisciplinary study to decipher the controls of deformation on fluid flow regime in fold and thrust belts using the Lower Pedraforca thrust sheet in the SE Pyrenees as an example. We integrate field-based and petrographic observations and geochemical and geochronological data to differentiate seven types of fractures, eight types of calcite cement (Cc1 to Cc8) and two sets of stylolites during the deformation stretching the studied thrust sheet. During syn-sedimentary hydroplastic normal faulting affecting poorly consolidated Upper Cretaceous and Eocene syn-orogenic sediments, calcite cement did not precipitate. During burial, bed-parallel stylolites formed and Cc1 and Cc2 precipitated from formation waters in a closed palaeohydrological system. During the layer-parallel shortening, Cc3 precipitated from formation waters (~+5.4‰ VSMOW) with 87Sr/86Sr ratios of 0.707922 and at ~70 °C. Cc4 precipitated from formation waters recording different burial conditions, as the up to 4‰ dispersion in δ18O of this cement suggests. Contrarily, during folding and thrusting, Cc5 to Cc7 precipitated in an open palaeohydrological system. Cc6 precipitated from formation waters (~+5‰ VSMOW), with 87Sr/86Sr ratios of 0.707817 and at ~75 °C. These fluids carried hydrocarbons and probably interacted with Upper Triassic evaporites. An 87Sr/86Sr ratio of 0.708230 for Cc5 indicates that formation waters also interacted with clays within continental deposits. During this period, stylolites formed in relation to faulting, and previous hydroplastic normal faults reactivated as reverse and strike-slip faults allowing fluid flow. Cc7 precipitated after Cc6, also from fluids in isotopic disequilibrium with their adjacent host rock. The fluid system continued open during the Oligocene, when Cc8 precipitated in normal faults affecting syn-orogenic conglomerates deposited during the reactivation of the Lower Pedraforca thrust sheet. The influence of deformation on fluid flow observed in the Lower Pedraforca thrust sheet is similar to that observed in other fractured areas worldwide.
This research was performed within the framework of DGICYT Spanish Project PGC2018-093903-B-C22 Ministerio de Ciencia, Innovación y Universidades/Agencia Estatal de Investigación/Fondo Europeo de Desarrollo Regional, Unión Europea, Alpimed (PIE-CSIC-201530E082), Subtetis project (PIE-CSIC-201830E039), and Grup Consolidats de Recerca “Geologia Sedimentària” (2017SGR-824) and “Geodinàmica Interna” (2017SGR–847).
Databáze: OpenAIRE
Externí odkaz: