Seismic Stratigraphy of Y O Unger Dryas Ice-Marginal Deposits in Western Norwegia·N Fjords
Seismic stratigraphy of Yo unger Dryas ice-marginal deposits in western Norwegia·n fjords INGE AARSETH, PER KRISTIAN AUSTBØ & HARALD RISNES Aarseth, 1., Austbø, P. K. & Risnes, H.: Seismic stratigraphy of Younger Dryas ice-marginal deposits in western Norwegian fjords. Norsk Geologisk Tidsskrift, Vol. 77, pp. 65-85. Oslo 1997. ISSN 0029-196X. The submarine portions of ice-marginal moraines and their distal sediments have been studied in the fjords between Stavanger and Åndalsnes, western Norway (59°-62°30'N). Echosounder, sparker, and high-resolution seismic profiles are used to record the thickness, morphology and structure of the deposits, which are divided into four main seismostratigraphic sequences describing the different phases of sedimentation. Evidence of several ice-push events is observed in some of the fjords, and models of glacial dynamics are presented for deep water and shallow water environments. Volumes of the different sedimentary fa cies have been estimated for some of the fjords. Coarse sediments (mainly glacioftuvial foreset beds) represent less than 10% of the Younger Dryas sequence. Dating of the moraines is accomplished through morphological correlation to the established chronostratigraphy of terrestrial sections. Inge Aarseth, Department of Geo/ogy, University of Bergen, A/legt. 41, N-5007 Bergen, Norway; Per Kristian Austbø, Fylkesmannen i Rogaland, Miljøvernavdelingen, Postboks 0059, N-4001 Stavanger, Norway; Harald Risnes, Petro-Data AS, P.O. Box 585, Madla, N-4040 HafrsfJord, Norway. Introduction & Molnia 1989; Syvitski 1989), and several models for such environments are put forward (Powell 1981, 1984; The mapping of Younger Dryas end moraines in western Elverhøi, Lønne & Seland 1983; Syvitski, Burrel & Skei Norway has shown that the ice margin crossed many 1987).
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