Ecole de Terrain L3STE 2017

Ecole de terrain de fin d’année pour les Licences 3eme année en sciences de la Terre de l’Université de Dijon (Jura-Maconnais-Bourgogne). Au programme : études géomorphologiques, environnementales, sédimentologiques et tectoniques.

Publicités

Publication : Marine and Petroleum Geology

Sortie du papier portant sur l’étude micro à macro-échelle des réseaux de injectite dans le bassin vocontien (France) et des implications pour l’écoulement des fluide

Ravier 2015 marine and petroleum geology

E. Ravier, M. Guiraud, A. Guillien, E. Vennin, E. Portier, JF. Buoncristiani. 2015. Micro- to Macroscale internal structures, diagenesis and petrophysical evolution of injectite networks in the Vocontian Basin (France): implications for fluid flows. Marine and petroleum geology 64, 125-151 doi:10.1016/j.marpetgeo.2015.02.040

Publication : Palaeogeography, Palaeoclimatology, Palaeoecology

Publication de l’article sur l’origine des vallées tunnel

Does porewater or meltwater control tunnel valley genesis? Case studies from the Hirnantian of Morocco

ravier et al 2015 pal pal pal

Highlights

  • •We compared processes involved in the formation of two Upper Ordovician tunnel valleys.
  • •Models of tunnel valley formation are driven by porewater pressures or meltwater flows.
  • •The distribution of ice streams controls tunnel valley formations and morphologies

Abstract :

Several Ordovician tunnel valleys are exposed in the Moroccan Anti-Atlas Mountains, including the Alnif and the Foum Larjamme tunnel valleys, located 150 km away from each other. Sedimentological and deformational analyses of these two glacial troughs reveal that differing processes lead to their formations.

The Alnif tunnel valley contains numerous deformation structures within sediments both below and above the main glacial erosion contact surface. Ball-structures and clastic dykes occur within preglacial sediments down to 35 m below glacial incisions while overlying glacial sediments contain fluted surfaces, clastic dykes, dewatering structures, folds and radial step normal faults. The characteristics of the Alnif tunnel valley can be explained by a porewater pressure-driven model of formation where the localized increase of basal shear stress and porewater pressure underneath subglacial deforming zones lead to the development of a dense hydrofracture network in the preglacial bed. These processes of hydraulic brecciation promoted subglacial remobilization of the preglacial material and contributed to the formation of the tunnel valley.

The Foum Larjamme tunnel valley displays undisturbed preglacial sediments and few dewatering structures at the base of the glacial sedimentary infill which suggests relatively low porewater pressures within the tunnel valley during formation. This second type of tunnel valley where porewater pressure remained relatively low appears to have been formed by meltwater erosion. The undulating base of the Foum Larjamme tunnel valley implies progressive erosion by a stable subglacial braided network of Nye-channels, or alternatively by channels migrating laterally during episodic minor subglacial outbursts.

These two tunnel valleys highlight the regional variability of processes involved in the formation of tunnel valleys. The distribution of palaeo-ice streams in North Africa illustrate that morphologies and processes involved in the formation of tunnel valleys vary between ice stream and inter-ice stream zones due to variations in meltwater availability, the topography and bed lithological properties.

L3STE 2014 – Ecole de terrain de sédimentologie

Octobre 2014 – Ecole de terrain de sédimentologie pour les Licences 3eme année en sciences de la Terre de Dijon. Au programme sédimentologie de faciès dans différents environnements : fluviatiles, glaciaire, marins entre la Côte d’Or et le Jura.

Publication: Sedimentology

Sortie du papier portant sur les critères de différenciation entre le dépôts sous-glaciaires et les dépôts proglaciaires.

article sedimentology

Ravier, E., Buoncristiani, JF., Clerc, S., Guiraud, M., Menzies, J., Portier, E. (2014), Sedimentological and deformational criteria for discriminating subglaciofluvial deposits from subaqueous ice-contact fan deposits: A Pleistocene example (Ireland). Sedimentology. doi: 10.1111/sed.12111

 

 

Publication : sedimentary Geology

Sortie du papier sur le creusement des vallée tunnel durant l’Ordovicien

en tete papier sed geol maroc edouard

Edouard Ravier, Jean-François Buoncristiani, Michel Guiraud , John Menzies , Sylvain Clerc , Bastien Goupy , Eric Portier 2014. Porewater pressure control on subglacial soft sediment remobilization and tunnel valley formation : A case study from the Alnif tunnel valley (Morocco). Sedimentary Geology 304, 71-95.

Mission : études d’analogues terrain de méga injectites en Californie

Etude sur le terrain de deux complexes d’injection sableuse à l’échelle du réservoir :

  • Panoche et Tumey Hills (Paléocène inférieur) situé le long de la bordure ouest de la vallée de San Joaquin.
  • Santa Cruz (Miocène à Pliocène) situé dans la baie de Monterey.

logo BP

Recherche : et parfois, au milieu, coule du pétrole…