Abstract
Structural, petrological and geochemical (δ13C, δ18O, clumped isotopes, 87Sr/86Sr and ICP-MS) analyses of fracture-related calcite cements and host rocks are used to establish a fluid-flow evolution model for the frontal part of the Bóixols thrust sheet (Southern Pyrenees). Five fracture events associated with the growth of the thrust-related Bóixols anticline and Coll de Nargó syncline during the Alpine orogeny are distinguished. These fractures were cemented with four generations of calcite cements, revealing that such structures allowed the migration of different marine and meteoric fluids through time. During the early contraction stage, Lower Cretaceous seawater circulated and precipitated calcite cement Cc1, whereas during the main folding stage, the system opened to meteoric waters, which mixed with the connate seawater and precipitated calcite cement Cc2. Afterwards, during the post-folding stages, connate evaporated marine fluids circulated through newly formed NW-SE and NE-SW conjugate fractures and later through strike-slip faults and precipitated calcite cements Cc3 and Cc4. The overall paragenetic sequence reveals the progressive dewatering of Cretaceous marine host sediments during progressive burial, deformation and fold tightening and the input of meteoric waters only during the main folding stage. This study illustrates the changes of fracture systems and the associated fluid-flow regimes during the evolution of fault-associated folds during orogenic growth.
Original language | English |
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Article number | 117 |
Pages (from-to) | 117 |
Number of pages | 29 |
Journal | Minerals |
Volume | 9 |
Issue number | 2 |
DOIs | |
Publication status | Published - 16 Feb 2019 |
Bibliographical note
Funding: This research was carried out within the framework of DGICYT Spanish Project CGL2015-66335-C2-1-R and the Grup Consolidat de Recerca “Geologia Sedimentària” (2017-SGR- 824).Acknowledgments: We thank three anonymous referees for their constructive reviews, which helped to improve the quality of the manuscript, together with the editorial guidance of Hairuo Qing. Carbon and oxygen isotopic analyses were performed at “Centre Científics I Tecnològics” of the Universitat de Barcelona. Strontium analyses were carried out at the “CAI de Geocronología y Geoquímica Isotópica (UCM-CEI)” of the Universidad Complutense de Madrid. The clumpled isotope analyses were done in the Qatar Stable isotope Laboratory of Imperial College of London. Elemental and REE composition analyses were performed at the Geochemistry Facility of labGEOTOP of the Institute of Earth Sciences Jaume Almera (ICTJA-CSIC), a cofounded structure by FEDER-UE (Ref. CSIC08-4E-001). EGR acknowledges the support of the Beatriu de Pinós programme of the Government of Catalonia’s Secretariat for Universities and Research of the Department of Economy and Knowledge (2016 BP 00208).
Keywords
- geochemistry of calcite cements
- meteoric and marine fluids
- fractures
- Bóixols thrust sheet
- southern Pyrenees
- Boixols thrust sheet
- FORELAND BASIN
- FLOW
- JABAL QUSAYBAH ANTICLINE
- CLUMPED ISOTOPE
- GROWTH
- RARE-EARTH-ELEMENTS
- BELT ALBANIA
- SYSTEMS
- FAULT
- PORE WATERS