Past hot fluid flows in limestones detected by Δ47–(U-Pb) and not recorded by other geothermometers - CNRS - Centre national de la recherche scientifique Accéder directement au contenu
Article Dans Une Revue Geology Année : 2020

Past hot fluid flows in limestones detected by Δ47–(U-Pb) and not recorded by other geothermometers

Benjamin Brigaud
Magali Bonifacie
Thomas Blaise
Damien Calmels
Frédéric Haurine

Résumé

Geothermometers are commonly used to reconstruct the diagenetic and thermal history of rocks. However, characterizing the timing, origin, and temperature of paleofluid flow remains challenging because it must be assessed indirectly through the analysis of microscopic cements that precipitate and fill intergranular spaces during fluid circulation. Here, we measure both the clumped isotope (Δ47) temperature and in situ U-Pb age of individual diagenetic calcite cements within a sedimentary section of the Paris Basin (France), whose thermal history has been previously inferred to be <60 °C. We show that cementation occurred during two stages associated with major events at the western European lithospheric scale: (1) the Bay of Biscay rifting (Late Jurassic–Early Cretaceous), and (2) north-south Pyrenean compression (Eocene) followed by east-west extension during the European Cenozoic rift system event (Oligocene). Related to both events, we report unexpectedly hot fluids, up to 110 °C, contrasting with the lower temperatures inferred from other geothermometers (e.g., fluid inclusions, clay minerals, apatite fission tracks, maturity of organic matter by Rock-Eval pyrolysis, or vitrinite reflectance). These high temperatures (>70 °C) have been measured for calcite cements containing single-phase aqueous fluid inclusions, challenging the commonly accepted assertion that the absence of nucleation of a vapor phase indicates crystallization at low temperature (∼<70 °C). We suggest that the kinetics of mineralization events prevented the recording of short-lived hot fluid flows by other
Fichier non déposé

Dates et versions

Identifiants

Citer

Benjamin Brigaud, Magali Bonifacie, Maurice Pagel, Thomas Blaise, Damien Calmels, et al.. Past hot fluid flows in limestones detected by Δ47–(U-Pb) and not recorded by other geothermometers. Geology, 2020, 48 (9), pp.851-856 (IF 4,768). ⟨10.1130/G47358.1⟩. ⟨hal-02925929⟩
44 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More