Preliminary assessment of biomarkers in sediments from the Transkei Basin (IODP Site U1581)

Gabriele.Uenzelmann-Neben [ at ]


A series of organic-rich sedimentary sequences that span the Paleocene through the Campanian was recovered from the Transkei Basin during IODP Expedition 392. Preliminary analyses of their organic geochemistry reveals suites of biomarkers that reflect diverse contributions of organic matter from both marine and terrestrial sources. The characteristics of the organic matter (OM) for a range of samples have been determined by shipboard and shore-based analyses that include evaluation of OM type and maturity by Rock-Eval pyrolysis, isotopic compositions of OM and the distributions of biomarkers including GDGTs. Samples from both the Paleocene and Campanian contain series of C37 to C40 diunsaturated alkenones, including the earliest record of C38 alkadien-2-ones and C39 alkadien-3-ones [1]. A sequence of Campanian samples also reveal an abundance of C28 sterenes and steryl ethers potentially indicative of upwelling conditions [2]. Polyaromatic hydrocarbons, including coronene, are present throughout the sequence likely reflecting inputs of OM associated with paleofires [3]. Variations in the abundance of organosulfur compounds [4,5] may afford evidence for temporal changes in redox conditions within the Transkei Basin during the Campanian. These initial results provide evidence that biomarker profiling will facilitate determination of the sources of OM throughout Late Cretaceous and Paleocene and the paleoenvironmental conditions of its deposition. [1] Brassell, 2014; [2] Brassell, 2009; [3] Finkelstein et al., 2005; [4] Valisolalao et al., 1984; [5] Brassell et al., 1986

Item Type
Conference (Poster)
Primary Division
Primary Topic
Helmholtz Cross Cutting Activity (2021-2027)
Publication Status
Event Details
AGU Fall meeting, 12 Dec 2022 - 16 Dec 2022, Chicago, USA.
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Cite as
Doiron, K. E. , Wagner, T. , Bijl, P. K. , Herrle, J. O. , Uenzelmann-Neben, G. , Bohaty, S. M. , Childress, L. B. and Brassel, S. , IODP Expedition 392 Science Party (2022): Preliminary assessment of biomarkers in sediments from the Transkei Basin (IODP Site U1581) , AGU Fall meeting, Chicago, USA, 12 December 2022 - 16 December 2022 .


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