Woods Hole Oceanographic Institution

Valier Galy

»C residence time in the Ganges-Brahmaputra system - Nature Geoscience 2011
»Chemical composition of Ganges-Brahmaputra River sediments - JGR 2011
»Plant biomarkers in Ganges-Brahmaputra sediments - EPSL 2011
»Petrogenic carbon in the Amazon basin - Geology 2010
»Stable erosion regime in Himalaya - EPSL 2010
»Geological stabilization of C in the crust - Science 2008
»Paleovegetation LGM to present - QSR 2008
»Loading and fate of particulate organic carbon - GCA 2008
»Efficient organic carbon burial in the Bengal fan - Nature 2007
»Determination of TOC and 13C/12C - GGR 2007
»PhD Thesis

Valier Galy, Julien Bouchez and Christian France-Lanord , Determination of Total Organic Carbon Content and δ13C in Carbonate-Rich Detrital Sediments , Geostandards and Geonalytical Research, 2007

The determination of total organic carbon content and composition in detrital sediments requires careful removal of their carbonate minerals. In detrital sediments containing large amounts of carbonates, including dolomite, this can only be achieved by liquid acid leaching that may solubilize a significant proportion of the organic carbon. For a set of detrital sediments from Himalayan system and Amazon river as well as five geo-references, we determined the proportion of organic carbon (Corg) solubilized during acid leaching. It is significant for all analysed sediments and generally tends to increase with the organic carbon content. Compared to other types of sediments analysed, clay fractions extracted from river sediments and bed sediments with very low organic carbon content respectively have high and low proportions of acid soluble Corg. In Himalayan and Amazon river sediments the proportion of Corg solubilized during acid leaching is rather constant with respectively average values of 14 and 19 %. This allows one to correct the Corg content measured after decarbonation for the solubilized organic carbon content. Our data show that Corg solubilization during liquid acid leaching must be taken into account. After careful calibration, the method presented here should therefore be applied to any carbonate rich detrital sediments.

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