Groundwater silicification as a proxy of paleo-permafrost depth and a constraint for a fluid flow and geothermal modelling

• Published in: Climate of the Past
• Main Authors: Jost, Anne, Thiry, Médard, Rivière, Agnès, Violette, Sophie, Gonçalvès, Julio
• Other Authors: Structure et fonctionnement des systèmes hydriques continentaux (SISYPHE), Université Pierre et Marie Curie - Paris 6 (UPMC)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Mines Paris - PSL (École nationale supérieure des mines de Paris), Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Centre de Géosciences (GEOSCIENCES), Mines Paris - PSL (École nationale supérieure des mines de Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2014
• Subjects: silicification; permafrost; groudwater; modelling; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Ice
• Online Access: https://minesparis-psl.hal.science/hal-01087856; https://minesparis-psl.hal.science/hal-01087856/document; https://minesparis-psl.hal.science/hal-01087856/file/Jost%26al_2014_EUCOP4_model_Fbleau_poster.pdf; https://doi.org/10.5194/cp-8-1821-2012

International audience Tthe Fontainebleau Sand often contains calcite crystallarias, the dating of which shows formation during the past two cold periods of the Quaternary, around 300 kyr and 50-30 kyr. They would be equivalent to the cryocalcites related to frozen karst cavities, but would have developed in the sand aquifer. They are sometimes included in the quartzite, suggesting that sand silicification also has to be related to Quaternary cold periods. In this context, we run a set of transient simulations on a typical 2-D hydrogeologic section of the Beauce Plateau using a fully coupled groundwater flow and heat transfer model with integrated freezing and thawing processes. The code takes into account latent heat effects and modifications of hydraulic and thermal properties due to ice formation. Our model calculations allow us to investigate the temperature and pressure conditions associated with permafrost propogation that could have prevailed in the valleys at the groundwater outlet.