ALBERT

Description: This paper describes (i) the Recent distribution pattern of various types of carbonate sediments in Troms county (northern Norway), and (ii) the onset of carbonate sedimentation after the final deglaciation of the Fennoscandian ice-shield. The distribution of major facies belts is strongly dependent on hydrographic and topographic constraints. The main bulk of carbonate deposits is derived from maerl-producing coralline algal biotopes that are restricted to the photic zone of waveprotected areas and influenced by tidal currents. Furthermore, extended mollusc and echinoderm-rich arenites are present in the area investigated. In deeper subtidal areas, terrigenous sediments of Late Weichselian to Early Holocene age are preserved. However, these are strongly influenced by later winnowing processes, generating a coquina lag deposit that serves as a secondary hardground for a diverse fouling community. The Holocene facies successions can be seen in several raised outcrops, containing the transition from glacigenic to Recent non-glacigenic depositional conditions. Autochthonous radiocarbon dated rhodolith banks, which mark the onset of carbonate sedimentation, yielded surprisingly young ages of 5,500 YBP. Around 5,500 YBP, present-day oceanographic and climatic conditions had already been firmly established. This time-lag can be explained with the behaviour of postglacial sea level fluctuations in the area. From 10,000 their cooperation in this project. We address our sincere thanks specifically to Prof. T.O. Vorren, Dr. M. Hald, Dr. B. Gulliksen, Dr. J. Hansen, Dr. J.J. Møller, Dr. E. Thomsen, and Dr. G. Corner for their dedicate help in organizing our field trips in Troms and for extensive scientific discussions. Special thanks to capitain K. Bendiksen for his patience and professional skill while operating the vessel ‘OTTAR’ in the skerry area even under bad weather conditions. S. Rasmussen and G. Ellingsen assisted during the cruises and very kindly introduced us to the Norwegian way of life. Special thanks to the two reviewers (Prof. Dr. W.-Ch. Dullo and anonymus) for their critical but constructive remarks. J. Welling and Dr. M. Kaminski improved the language of the final version of the manuscript. This project is part of the German Science Foundation’s main research program ‘Globale und regionale Steuerungsprozesse biogener Sedimentation”. Financial support was kindly provided by the Deutsche Forschungs-gemeinschaft (He 1671/1-1, 2).

Description: By the nuclear bomb tests during the 1950s and early 1960s, the radiocarbon content of the atmospheric CO, on the Southern Hemisphere rose within a few years from 98 to 162% of the standard recent value and then dropped to 122% (at the end of 1984). This rapid fluctuation was used to determine the lifetime of five species of lichens collected in the beginning of 1985 in the maritime Antarctic. Under the assumption that Lichens assimilate each year carbon at the same rate and that carbon once fixed at least in main branches never will be exchanged later on. The age of mature thalli of Caioplaco regalis, Ramalino tetebrata and Ustiea antarctica was determined to 32 years, while U, aurantiaco-atra and Himantormia lugubris gave an age of ca. 38 years and ca. 60 years, respectively.