Université de Neuchâtel

Rock-Eval pyrolysis discriminates soil macro-aggregates formed by plants and earthworms

Schomburg, Andreas ; Verrecchia, Eric P ; Guenat, Claire ; Brunner, Philip ; Sebag, David ; Le Bayon, Renée Claire

In: Soil Biology & Biochemistry, 2018, vol. 117, p. 117-124

Plants and earthworms, as soil ecosystem engineers, play a crucial role during stabilisation of organic matter in soil through its incorporation into soil aggregates. It is therefore essential to better understand the mechanisms and interactions of soil engineering organisms regarding soil organic matter stabilisation. Several methods have already been successfully applied to differentiate soil...

Université de Neuchâtel

Tidal rhythmites of the Marais Vernier Seine estuary, France and their implications for relative sea-level

Frouin, Millena ; Sebag, David ; Laignel, Benoit ; Ogier, Sylvie ; Verrecchia, Eric P. ; Durand, Alain

In: Marine Geology, 2006, vol. 235, no. 1-4, p. 165-175

The Marais Vernier, located in the upper reaches of the Seine River Estuary (northern France), preserves a thick Holocene succession of laminated detrital deposits and peats. The spectral analysis of one laminated deposit suggests that tidal processes were largely responsible for supplying sediments to this system. Two periods (16 and 32 laminae per cycle) were identified. These cycles can be...

Université de Neuchâtel

Monitoring organic matter dynamics in soil profiles by 'Rock-Eval pyrolysis' : bulk characterization and quantification of degradation

Sebag, D. ; Disnar, J. R. ; Guillet, B. ; Di Giovanni, C. ; Verrecchia, Eric P. ; Durand, A.

In: European Journal of Soil Science, 2005, vol. 57, no. 3, p. 334-355

Rock-Eval pyrolysis was designed for petroleum exploration to determine the type and quality of organic matter in rock samples. Nevertheless, this technique can be used for bulk characterization of the immature organic matter in soil samples and recent sediments. We studied 76 samples from seven soil classes and showed that their pyrograms can be described by a combination of four elementary...

Université de Neuchâtel

The natural hydrous sodium silicates from the northern bank of Lake Chad : occurrence, petrology and genesis

Sebag, D. ; Verrecchia, Eric P. ; Lee, Seong-Joo ; Durand, A.

In: Sedimentary Geology, 2001, vol. 139, p. 15-31

Hydrous sodium silicates sometimes associated with zeolites, form in an alkaline environment, in which there is a high concentration of dissolved silica. Such an environment existed during the Holocene in N'Guigmi interdunal depressions (Lake Chad), which led to the precipitation of various types of hydrous sodium silicates, including magadiite, kenyaite, and zeolites. Scanning electron and...

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2 Sebag, David