The Ancient Shorelines of the Uppsala Esker Around Uppsala and the Shore Displacement

ABSTRACT

The Uppsala esker between Arnöhuvud and Valsgärde, i.e. from c. 16 km SSW to c. 7 km N of Uppsala, was mapped around 1940 by Uppsala geography students. On most of the maps, ancient shorelines are indicated and can be stratified to contour intervals of 2 m. It was found that the ancient shorelines appear more concentrated in some vertical intervals than others. Comparison with a preliminary shore displacement curve for the area indicates some correspondence between halts or transgressions in shore-displacement and accumulation of ancient shorelines. On the other hand, during phases of rapid regression of the shore few shorelines were developed. Thus, the idea of G. De Geer (1932 and 1940) that the shorelines of the Mälar valley were developed during occasional strong storm surges from the west must, on the whole, be abandoned. However, eustatic transgressions due to melting glaciers might also be correlated to times of high cyclonic activity with frequent storm surges that could encourage shoreline development. It is also suggested that a transgression of sea level might erase shorelines earlier formed.