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Sébastien

LENARD

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Étudiant en thèse / PhD candidate

Tel : (33) 3 83 59 42 11 ; Fax : (33) 3 83 51 17 98

Sébastien Lénard


Recherche/Research Interests

Thesis subject/ Sujet de thèse : Evolution de l’Himalaya du Miocene à nos jours à partir de l’histoire de son érosion. Direction : Jérôme LAVÉ et Christian FRANCE-LANORD

My goal in this phD is to obtain a reliable record of Himalayan erosion and its evolution over the last million years. It has been advanced that Quaternary climate cooling was linked to a worldwide increase of erosion, but published records do not converge towards this assertion and can be either uncomplete or unprecise, and in some cases poorly time-constrained and biased.

The originality of my approach is to focus on a well-studied mid-latitude mountain range, the Himalaya, which is one of the largest sedimentary contributors on the Earth in modern times. I apply classic geochemical quantification to new marine and continental sedimentary series. The marine series integrate erosion of possibly 2/3 of the Himalaya, from the Ganga-Brahmaputra catchment, and were cored during IODP Expedition 354 and 355 in the turbiditic Bengal Fan (2015). In complement, I sampled the continental fluvial series from a new Siwalik section, in North India, which integrate erosion from the large Gandak-Narayani catchment.

I extract terrestrial 10Be from detrital quartz and bulk silicate 87Sr/86Sr and 143Nd/144Nd, and process to quantification using mass spectrometry. 10Be is a cosmogenic nuclide and its concentration in minerals are a proxy for erosion integrated on short time scales. 87Sr/86Sr and eNd are used to follow the provenance of sediments.

Publications

Publications CRPG

Papers in preparation for this phD :
- Late Cenozoic Himalayan denudation revealed by Bengal fan 10Be - 87Sr/86Sr - eNd, S. J.P. Lenard, J. Lavé, C. France-Lanord
- Narayani-Gandak past erosion investigated by 10Be applied on the Valmiki Siwalik series, S. J.P. Lenard, J. Lavé, C. France-Lanord, J. Charreau

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Autres publications

Enseignement/Teaching

I tought undergraduate classes for practical and tutorial work at the Université de Lorraine in 2016, 2017 and 2018 (128 h)

Portfolio

Valmiki Maloni Naha section Marine and continental sedimentary sites

Documents joints

Late Cenozoic 10Be paleo-erosion rates measured in the Siwaliks of the Central Himalayan range

13 mars 2018
Document : PDF
2.1 Mo

S. J.P. Lenard, J. Lavé, J. Charreau, C. France-Lanord, R. Pik, presented in HKT 2016, Aussois, France


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