Pore water geochemistry as a tool for identifying and dating recent mass-transport deposits


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Susann.Henkel [ at ] awi.de

Abstract

Several previous studies have shown that submarine mass-movements can profoundly impact the shape of pore water profiles. Therefore, pore water geochemistry and diffusion models were proposed as tools for identifying and dating recent (max. several thousands of years old) mass-transport deposits (MTDs). In particular, sulfate (SO42−) profiles evidentially indicate transient pore water conditions generated by submarine landslides. After mass-movements thatresult in the deposition of sediment packages with distinct pore water signatures,the SO42− profiles can be kink-shaped and evolve into the concave and linear shape with time due to molecular diffusion. Here we present data from the RV METEOR cruise M78/3 along the continental margin off Uruguay and Argentina. SO42− profiles of 15 gravity cores are compared with the respective acoustic facies recorded by a sediment echosounder system. Our results show that in this very dynamic depositional setting, non-steady state profiles occur often, but are not exclusively associated with mass-movements. Three sites that show acoustic indications for recent MTDs are presented in detail. Where recent MTDs are identified,a geochemical transport/reaction model is used to estimate the time that has elapsed since the perturbation of the pore water system and, thus, the timing of the MTD emplacement. We conclude that geochemical analyses are a powerful complementary tool in the identification of recent MTDs and provide a simple and accurate way of dating such deposits.



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Peer-reviewed
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Published
Eprint ID
23868
DOI 10.1007/978-94-007-2162-3_8

Cite as
Henkel, S. , Schwenk, T. , Hanebuth, T. J. J. , Strasser, M. , Riedinger, N. , Formolo, M. , Tomasini, J. , Krastel, S. and Kasten, S. (2012): Pore water geochemistry as a tool for identifying and dating recent mass-transport deposits / Y. Yamada , K. Kawamura , K. Ikehara , Y. Ogawa , R. Urgeles , D. Mosher , J. Chaytor and M. Strasser (editors) , In: Advances in Natural and Technological Hazards Research 31, Submarine Mass Movements and Their Consequences, 4th edition, Y. Ogawa (ed.), Springer., Springer Science+Business Media B.V., 11 p. . doi: 10.1007/978-94-007-2162-3_8


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