Pierre Dietrich

Chargé de recherche CNRS

Equipe Paléoenvironnement
P. Dietrich
Organisation:
Géosciences Rennes
Address:

Bât.15 campus Beaulieu

Université de Rennes 1

Localité:

Rennes 35042

France

Adresse courriel : pierre [dot] dietrich [at] univ-rennes [dot] fr

Numéro de bureau : Bât.15, P207/1

Research interests

Pierre Dietrich is a sedimentologist, stratigrapher and geomorphologist excited about the use of glaciogenic morphosedimentary systems to reconstruct the time-space extent of ice sheets that once occupied the surface of our planet, in recent (Quaternary) and ancient (Paleozoic) times. He conducted his Phd at the University of Strasbourg, France (2012-2015) dedicated to the study of glaciogenic sedimentary series recording the recession of the Laurentide Ice Sheet over eastern Canada (Quebec). He then moved to South Africa as postdoctoral fellow at the University of Johannesburg (2016-2018) where he investigated the morphosedimentary imprints of ice masses that occupied Western Gondwana some 300 Myr ago. During his stay, he conducted (and enjoyed!) many field campaigns throughout southern Africa. Coming back to France in 2019, at the University of Rennes, he has ever since tackled the legacy of past ice sheets on the landscape of Southern Africa; many modern, desertic landscapes that characterize the high-standing South African plateau were carved by flowing ice sheets that have long (hundreds of millions of years!) disappeared.

The Gomatum valley of NW Namibia is a 300 Myr-old fossil fjord. These sediments on the North Shore of the St. Lawrence Estuary (Québec, Canada) record the melting of the Laurentide Ice Sheet some 10.000 years ago and the ensuing glacio-isostating adjustment

 

 The desertic Gomatum valley of the Kaokoland of Northern Namibia has a typical U-shaped cross-profile and its flanks display evidence of flowing glaciers such a striae, grooves and coarse-grained sediments interpreted as lateral moraines. This valley as it exists today was carved by glaciers that 300 Myr ago flowed from central Africa to Brazil as the Atlantic Ocean were not yet opened. After the ice melting, the sea invaded the valley that turned into a fjord in which icebergs were floating, detached from the main retreating ice mass, as indicated by marine sediments with scattered ice-rafted debris. The valley had then been filled and buried with sediments over tens of millions of years and later exhumed as these sediments were progressively eroded away. Today, what we see is the original shape of the glacial valley; the desertic Gomatum valley is a fossil fjord (Dietrich et al., 2021 in Geology https://doi.org/10.1130/G49067.1 and NASA Earth Observatory https://earthobservatory.nasa.gov/images/148822/fossil-fjords-in-namibia; Credit: P. Dietrich).

Deltaic sediments 100 m-thick on the North Shore of the St. Lawrence Estuary (Quebec, Canada) recording the recession and melting of the Laurentide Ice Sheet that occurred some 10.000 years ago. These sediments fed from the melting ice sheet were originally deposited subaqueously and emerged owing to the effect of the glacio-isostatic adjustment -a rise of the land- that followed the retreat of the ice sheet (Dietrich et al., 2017 in Sedimentology, https://doi.org/10.1111/sed.12340; Dietrich et al., 2020 https://doi.org/10.1007/978-3-030-35137-3_10; Credit: J.-F. Ghienne).

Curriculum vitæ

2023-... : Chargé de Recherche CNRS (Research Scientist)

2022-2023: Postdoctoral Research Fellow (part time), Institute for Geological Sciences, Universität Bern, Switzerland

2019-2023: Postdoctoral Research Fellow, Géosciences Rennes, Université de Rennes, France

2016-2018: Postdoctoral Research Fellow, Department of Geology, University of Johannesburg, South Africa

2012-2015: Phd - Institut de Physique du Globe de Strasbourg, Université de Strasbourg, France Sedimentary and stratigraphic analysis of glacial and postglacial deposits tied to the Wisconsinan deglaciation (Pleistocene-Holocene) of the St. Lawrence Estuary, Quebec, Canada. Advisor: J.-F. Ghienne

Publications

Peer-reviewed articles

  • Le Heron, D.P., Busfield, M.E., Chen, X., Corkeron, M., Davies, B.J., Dietrich, P., Ghienne, J.-F., Kettler, C., Scharfenberg, L., Vandyk, T., & Wohlschlägel, R., New perspectives on glacial geomorphology in Earth’s deep time record, in Vesely, F.F., Isbell, J.L., & Busfield, M.E., (eds.) Diamictite and beyond: Understanding sedimentary proxies of glaciation and their paleoclimatic implications. Frontiers in Earth Sciences, Systems and Society, Special Publication. https://doi.org/10.3389/feart.2022.870359
  • Kalifi, A., Ribes, C. Dietrich, P., Dujoncquoy, E., Munoz, J.-A., Calot, J.-P., & Ringenbach, J.-C., 2023, Facies distribution along salt walls: the Upper Cretaceous mixed sliciclastic-carbonate deposits of the Cotiella mini-basins (Southern Pyrenees, Spain). Marine and Petroleum Geology, 147, https://doi.org/10.1016/j.marpetgeo.2022.105989
  • Normandeau, A., Lajeunesse, P., Ghienne, J.-F., & Dietrich, P., 2022, Repeat high-resolution autonomous underwater vehicle imagery of turbidity current system reveals complex flow/bedform interaction. Geophysical Research Letters. https://doi.org/10.1029/2021GL097389
  • Dietrich, P., Griffis, N.P., Le Heron, D.P., Montañez, I.P., Kettler, C. & Guillocheau, F., 2021, Fjord network in Namibia: A snapshot into the dynamic of the Late Paleozoic Glaciation. Geology. https://doi.org/10.1130/G49067.1
  • Le Heron, D.P., Kettler, C., Griffis, N.P., Dietrich, P., Montañez, I.A., Osleger, D.A., Hofmann, A., & Douillet, G.A., 2021, The Late Paleozoic Ice Age unconformity in southern Namibia viewed as a patchwork mozaic. The Depositional Record. https://doi.org/10.1002/dep2.163
  • Griffis, N.P., Montañez, I., Mundil, R., Le Heron, D.P., Dietrich, P., Kettler, L., Linol, B., Mottin, T., Vesely, F. & Iannuzzi, R., 2021, High-latitude ice and climate control on sediment supply across the late Carboniferous and early Permian of SW Gondwana, Geological Society of America Bulletin. https://doi.org/10.1130/B35852.1
  • Ghienne, J.-F., Normandeau, A., Dietrich, P., Bouysson, M., Schuster, L. & Lajeunesse, P., 2020, Stratal architecture, sedimentary facies and bedforms morphologies of cyclic-step related deposits: insights from both modern and Holocene glaciofluvial delta slopes. Sedimentology (Special Issue, Supercritical flow processes and products; Slootman, A., Cartigny, M., Normandeau, A. Ventra, D. & Hubbard, S. eds). https://doi.org/10.1111/sed.12806
  • Dietrich, P. & Hofmann, A., 2019, Ice-margin fluctuation sequences and grounding zone wedges: The record of the Late Paleozoic ice Age in the eastern Karoo Basin (Dwyka Group, South Africa). The Depositional Record. https://doi.org/10.1002/dep2.74
  • Dietrich, P., Franchi, F., Sethlabi, L., Prevec, R. & Bamford, M., 2019, The non-glacial diamictite of Toutswemogala Hill (Lower Karoo Supergroup, Central Botswana): implications on the extent of the Late Paleozoic Ice Age in the Kalahari-Karoo Basin. Journal of Sedimentary Research. https://doi.org/10.2110/jsr.2019.48
  • Le Heron, D., Dietrich, P., Busfield, M., Kettler, C., Bermanschläger, S. & Grasemann, B. 2019, Scratching the surface: Footprint of a late Carboniferous ice Sheet. Geology. https://doi.org/10.1130/G46590.1
  • Normandeau, A., Dietrich, P., Hughes Clarke, J., Van Wychen, W., Burgess, D., Lajeunesse, P. & Ghienne, J.-F., 2019, Retreat pattern of glaciers controls the occurrence of turbidity currents on high-latitude fjord deltas (Eastern Baffin Island). Journal of Geophysical Research: Earth Surface. https://doi.org/10.1029/2018JF004970
  • Dietrich, P., Ghienne, J.-F., Lajeunesse, P., Normandeau, A., Deschamps, R. & Razin, P., 2018, Deglacial sequences glacio-isostatic adjustment: Quaternary compared with Ordovician glaciations, in Le Heron, D.P., Hogan, K.A., Phillips, E.R., Huuse, M., Busfield, M.E. & Graham, A.G.C. (eds.) Glaciated Margins: The Sedimentary and Geophysical Archives, Geological Society, London, Special Publication, 475. https://doi.org/10.1144/SP475.9
  • Lajeunesse, P., Dietrich, P. & Ghienne, J.-F., 2018, Late-Wisconsinan grounding zones of the Laurentide Ice Sheet margin of the Québec North Shore (NW Gulf of St. Lawrence), in Le Heron, D.P., Hogan, K.A., Phillips, E.R., Huuse, M., Busfield, M.E. & Graham, A.G.C. (eds.) Glaciated Margins: The Sedimentary and Geophysical Archives, Geological Society, London, Special Publication, 475. https://doi.org/10.1144/SP475.10
  • Dietrich, P., Normandeau, A., Ghienne, J.-F. & Lajeunesse, P., 2017, Reconstructing ice margin retreat using delta morphostratigraphy. Scientific Reports. https://doi.org/10.1038/s41598-017-16763-x
  • Dietrich, P., Ghienne, J.-F., Schuster, M., Lajeunesse, P., Nutz, A., Deschamps, R., Roquin, C. & Duringer, P., 2017, From outwash to coastal systems in the Portneuf-Forestville deltaic complex (Québec North Shore): Anatomy of a forced regressive deglacial sequence. Sedimentology. https://doi.org/10.1111/sed.12340
  • Normandeau, A., Dietrich, P., Lajeunesse, P., Ghienne, J.-F., St-Onge, G. & Francus, P., 2017, Timing and controls on the delivery of coarse sediments to deltas and submarine fans on a formerly glaciated coast and shelf. Geological Society of America Bulletin. https://doi.org/10.1130/B31678.1
  • Dietrich, P., Ghienne, J.-F., Normandeau, A. & Lajeunesse, P., 2016, Upslope-migrating bedforms in a proglacial sandur delta: Cyclic steps from river-derived underflows? Journal of Sedimentary Research. https://doi.org/10.2110/jsr.2016.4
  • Nutz, A., Ghienne, J.F., Schuster, M., Dietrich, P., Roquin, C., Murray, B.H., Bouchette, F. & Cousineau, P., 2015, Forced-regressive deposits of a deglaciation sequence: example from the Late Quaternary succession in the Lake St-Jean basin (Québec, Canada). Sedimentology. https://doi.org/10.1111/sed.12196

Book chapters

  • Griffis, N.P., Mundil, R., Montañez, I.P., Le Heron, D.P., Dietrich, P., & Iannuzzi, R., A Carboniferous Apex for the late Paleozoic Icehouse. in: DiMichelle, W. et al., (eds.) Ice ages, climate dynamics and biotic events: The late Pennsylvanian World, Geological Society, London, Special Publication https://doi.org/10.1144/SP535-2022-256
  • Dietrich, P., Normandeau, A., Lajeunesse, P., Ghienne, J.-F., Schuster, M. & Nutz, A., 2020, Deltaic complexes of the Québec North-Shore, in Catto, N. & Slaymaker, O. (eds.) Landscapes and Landforms of Eastern Canada, Springer. https://doi.org/10.1007/978-3-030-35137-3_10
  • Nutz, A., Lajeunesse, P., Ghienne, J.-F., Schuster, M., Dietrich, P., Bouchette, F., Brouard, E. & Cousineau, P.A., 2020, Deglacial to paraglacial history of the Lake Saint-Jean lowlands: a geomorphological perspective, in Catto, N. & Slaymaker, O. (eds.) Landscapes and Landforms of Eastern Canada, Springer. https://doi.org/10.1007/978-3-030-35137-3_5

Scientific outreach - Other contributions

  • Fossil fjords in Namibia
  • Normandeau, A. & Dietrich, P., Poster (Geological Survey of Canada – Open File 8512), Distribution of potentially active turbidity currents in Eastern Baffin Island Fjords, link.
  • Busfield, M., Le Heron, D.P. & Dietrich, P., Leaflet, Oorlogskloof Gletservloer (Glacial Pavement) – Outstanding world-class exposure of grooves and furrows ploughed by ice 300 million years ago, link.