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The Use of Organic Matter Study for the Reconstitution of Basin Paleogeography and the Record of Global Climate Change
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 4th EAGE North African/Mediterranean Petroleum and Geosciences Conference and Exhibition Tunis 2009, Mar 2009, cp-120-00044
- ISBN: 978-90-73781-99-3
Abstract
Fourteen cores have been executed across the southern part of the lake of Tunis, to trace the physico-chemical evolution of the sedimentary environment. The vertical distribution of TOC along cores, attests the existence from bottom to top, of a positive organic sequence illustrating a progressive enrichment of the sedimentary column in organic matter. From the marine stage up to the present lagoon stage, the lake of Tunis, acted as an organic matter trap. The maximum organic matter accumulation is recorded in the upper black sediments due to the development of highly anoxic conditions amplified by a marked anthropic influence. The paleo-morphology of the lagoon deduced from the organic evolution profiles interpretation of the sediment cores, indicates the existence, of two relatively deep anoxic marine areas (one at the West and one at the East) separated by a shallow marine less anoxic central area which remained constantly under the influence of strong hydrodynamic activity. The distribution of S2 (pyrolysable organic matter) is quasi-similar to that of the TOC contents. Such result clearly indicates that the organic matter associated with these sediments is homogeneous and exhibit the same origin (Tissot et Welte, 1984; Bélayouni, 1990; Disnar, 2003).