Rodney L. Stevens¹, Olof Larsson²

(1) Göteborg University, Göteborg, Sweden
(2) Göteborg University

ABSTRACT: Marine Stratigraphy in the Göteborg Archipelago, Sweden: Holocene Developments Related to Sea Level, Sediment Supply, Environmental Setting and Anthropogenic Influences

The dynamics of this archipelago setting, including alternate periods of rapid deposition and extensive erosion, can be largely related to the sediment-supply and drainage patterns during deglaciation. Wave exposure and erosion may have generally increased with land uplift, which has generally dominated over isostatic sea level rise. More recently, island sheltering has favored renewed deposition in many areas, also influenced by the anthropogenically-induced eutrophication and increased sediment supply. Although the archipelago setting is peculiar in its combination of parameters, it allows several hypotheses that cannot be easily tested within the stratigraphy of other coasts, such as the accumulation during a forced regression or an increase in sedimentation rate during a transgression. The geological record is characterized by a strong variation between sediment sources: glacial meltwaters, river and shoreline erosion, and agricultural and urban runoff. Also interesting in this setting, changes in water-column stratification and geographical salinity differences seem to have considerable influence upon archipelago circulation, and have not often been considered in sequence stratigraphic evaluations. Shipping and dredging activities are increasingly important factors. Considering the environmental risks associated with the natural or anthropogenic reworking of the contaminated recent sediments, the geological record needs to be scrutinized in order to best evaluate the factors concerning the future stability of these deposits.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado