Guilhem Hoareau

Responsabilities

Head of L2 SDT (2nd year Bachelor in Earth science)

Vice-head of the Commission d'experts 35-36

Elected member of the UFR Sciences et Techniques

Skills

- Field work (mapping, sedimentology, structural)

- Microscopy / Petrography (optical, CL, SEM)

- Mineralogy (DRX)

- Elemental geochemistry (XRF, ICP-AES, EMPA)

- Isotope geochemistry (C, O, S, Sr)

- U-Pb dating of calcite by LA-ICPMS

- Fluid inclusions (petrography, microthermometry)

Research interests

I try to understand the conditions of formation of the main cements observed in sedimentary basins, based mostly on field observations, petrographic, geochemical and isotopic tools. The implications of such research are obvious, on the one hand because diagenesis controls the formation of hydrocarbons (source rocks) and of several minerals of economic interest (sulphides, U) and on the other hand because the formation or dissolution of diagenetic cements strongly influence the quality of reservoir rocks (porosity / permeability). Understanding how these minerals are formed and evolved enable (i) to target efficiently the formations that may contain oil or gas and which are easily exploitable, or (ii) to target rocks which are sufficiently permeable for storage. Petrography and geochemistry are therefore complementary to the structural and petrophysical methods commonly used for estimating reservoir properties.

Supervision

PhD students:

- 01/2017 - : Geoffrey Motte (funding Total): "Dolomitization related to magmatic and mantle fluids in hyperextended margins: the case of the Chaînons Béarnais (Pyrenees, France)". Dirs : Jean-Paul Callot (UPPA), Guilhem Hoareau, Eric Gaucher (Total)

- 04/2014 - 04/2017: Alexandre Pichat  (funding Total): "Dynamics of the evaporitic systems of a foreland salt basin, and diagenetic processes associated with the halokinetic context: example of the Sivas Basin (Turkey). Dirs: Jean-Paul Callot (UPPA), Guilhem Hoareau, Jean-Claude Ringenbach (Total)

- 10/2013 - 12/2016: Nemo Crognier (funding MESR) : "Thermal evolution, fluid circulation and fracturing associated with the structuration of the south pyrenean foreland basin" Dirs: Charles Aubourg (UPPA), Guilhem Hoareau (UPPA)

- 01/2013 - 11/2016: Kaveh Merkhian (financement Total) : "Microfracturing of quartz grain as a measurement of effective stress in sandstone reservoirs". Dirs: Charles Aubourg (UPPA), Jean-Pierre Girard (Total), Guilhem Hoareau (UPPA).

Post-docs : 

- 05/2017 - : Eider Hernandez Bilbao (financement Total) : "Chemostratigraphic caracterization of the Vaca Muerta Formation (Argentina)". With Alain Lejay (Total).

- 11/2012 - 12/2013: Brahimsamba Bomou (financement CNRS) : "Impact of Neo-Tethys closure on Eocene warming" With D. Marquer (Université de Besançon) and Y. Donnadieu (LSCE, Gif-sur-Yvette).

Projects

Main Current Projects

U-Pb carbonate dating (funding UPPA, Total). This project aims to establish a protocol for direct dating of the carbonate precipitation (calcite, dolomite) by geochronological methods (U-Pb system), using a femtosecond laser ablation coupled to a high resolution mass spectrometer (fsLA- ICPMS).

Dolomitization in the Béarnais Channels (funding Total), as part of Total's FLUIDS action (thesis G. Motte). We aim to understand the conditions of dolomitization and brecciation of the Jurassic and Cretaceous carbonates of the Chaînons, and the role played possibly by mantle-derived fluids and magmatic intrusions associated with the Cretaceous (Aptian-Albian) rifting.

Thermal and structural evolution of the French Pyrenees (funding INSU, LFCR, Total, Margin Actions, E2S) (post-doc E. Izquierdo, ATER A. Menant, Masters). We try to decipher the role of salt tectonics on the evolution of the French Pyrenees, in particular on the development of folding developed before pyrenean shortening, on the thermal evolution and on the circulation of fluids.

Fracturing, thermal regime and circulation of fluids in the context of active foreland: the Jaca basin (funding MESR, LFCR, Total, Isifor). This project focuses on the evolution of the south pyrenean foreland paleo-basin (Jaca basin) (theses N. Crognier, PA Grignard). The aims are to characterize the paleohydrology of the basin, the conditions of fracturing of the sedimentary rocks, the thermal evolution of the basin and the modalities of deposition of the tardi-orogenic clastics.

Project Sivas (Turkey) (funding Total): the project (A. Pichat thesis) aims at (i) constraining the age and environment of deposition of the evaporites at the origin of the development of salt tectonics in the Sivas basin, (ii) to demonstrate and understand the processes of recycling of the initial evaporites and (iii) to study the impact of evaporites on the diagenesis of the sandstone filling the mini-basins.

Publications

Pichat, A., Hoareau, G., Callot, J.-P., Legeay, E., Kavak, K.S., Révillon, S., Parat, C., Ringenbach, J.-C, 2017. Evidence of multiple evaporite recycling processes in a salt-tectonic context, Sivas Basin, Turkey. Terra Nova, accepted.

Crognier, N., Hoareau, G., Aubourg, C., Dubois, M., Lacroix, B., Branellec, M., Callot, J.-P.,  Venneman, T., 2017. Syn-orogenic fluid flow in the Jaca basin (South Pyrenean Fold and Thrust Belt) from fracture and vein analyses. Basin Research, in press.

Bastianini, L., Caline, B., Hoareau, G., Bonnel, C., Martinez, M., Lézin, C., Baudin, F., Brasier, AT., Guy, L., 2017. Caractérisation sédimentaire de la formation roche mère carbonatée Parnac du Kimméridgien supérieur du Bassin d’Aquitaine (Quercy). Bulletin de la Société Géologique de France, in press.

Krim, N., Bonnel, C., Tribovillard, N., Riboulleau, A., Imbert, P., Bout-Roumazeilles, V., Fasentieux, B., Hoareau, G., Aubourg, C, 2017. Paleoenvironmental evolution of the southern Neuquén Basin (Argentina) during Tithonian-Berriasian times (Vaca Muerta and Picún Leufú Formations): a multi-proxy approach. Bulletin de la Société Géologique de France, in press.

Pichat, A., Hoareau, G., Callot, J.-P., Ringenbach, J.-C., 2016. Diagenesis of Oligocene continental sandstones in salt-walled mini-basins - Sivas Basin, Turkey. Sedimentary Geology, 339, 13-31.

Hoareau, G., Odonne, F., Garcia, D., Debroas, E.-J., Monnin, C., Dubois, M., Potdevin, J.-L., 2015. Burial diagenesis of the Eocene Sobrarbe delta (Ainsa basin, Spain) inferred from dolomitic concretions. Journal of Sedimentary Research, 5, 1037–1057

Hoareau, G., B. Bomou, D. J. J. van Hinsbergen, N. Carry, D. Marquer, Y. Donnadieu, G. Le Hir, B. Vrielynck, and A.-V. Walter-Simonnet, 2015. Did high neo-tethys subduction rates contribute to early Cenozoic warming ? Climate of the Past, 11, 1751–1767

Hoareau, G., B. Bomou, D. J. J. van Hinsbergen, N. Carry, D. Marquer, Y. Donnadieu, G. Le Hir, B. Vrielynck, and A.-V. Walter-Simonnet, 2015. Did high neo-tethys subduction rates contribute to early Cenozoic warming ? Climate of the Past Discussions, 11(4), 2847-2888.

Chavagnac, V., C. Monnin, G. Ceuleneer, C. Boulart, and Hoareau, G., 2013. Characterization of hyperalkaline fluids produced by low-temperature serpentinization of mantle peridotites in the Oman and Ligurian ophiolites, Geochemistry, Geophysics, Geosystems, 14, 2496-2522.

Chavagnac V., G. Ceuleneer, C. Monnin, B. Lansac, Hoareau, G., and C. Boulart, 2013. Mineralogical assemblages formingat hyperalkaline warm springs hosted on ultramafic rocks : A case study of Oman and Ligurian ophiolites, Geochemistry, Geophysics, Geosystems, 14, 2474-2495.

Hoareau, G., Monnin, C., Odonne, F., 2011. The stability of gypsum in marine sediments from the ODP/IODP porewater composition data base. Marine Geology, 279, 87-97.

Odonne, F., Callot, P., Debroas, E.-J., Sempéré, T., Hoareau, G., Maillard, A., 2011. Soft sediment deformation resulting from submarine sliding, favourable conditions and triggering mechanisms in examples from Eocene Sobrarbe delta (Ainsa, Spanish Pyrenees) and Cretaceous Ayabacas formation (Andes of Peru). Sedimentary Geology, 235, 234-248.

Monnin, C., Hoareau, G., 2010. Chemical equilibrium between aqueous fluids and minerals in the marine environment. EMU Notes in Mineralogy, 10, chapter 6, 227-258.

Hoareau, G., Monnin, C., Odonne, F., 2010. A study of celestine equilibrium in marine sediment porewaters from the entire ODP/IODP data base. Geochimica et Cosmochimica Acta, 74, 3925-3937.

Hoareau, G., Odonne, F., Debroas, E.-J., Maillard, A., Monnin, C., Callot, P., 2009. Dolomite concretions in the Eocene Sobrabe delta : fluid circulation above a submarine slide scar infilling. Marine and Petroleum Geology, 26, 724-737.

Callot, P., Odonne, F., Debroas, E.-J., Maillard, A., Dhont, D., Basile, C., Hoareau, G., 2009. Three dimensional architecture of submarine slide surfaces and associated soft- sediment deformation in the Lutetian Sobrarbe deltaic complex (Ainsa, Spanish Pyrenees). Sedimentology, 56, 1226-1249.