Die Datierung von Baltischen Ancylus-Lagern Unter der Höchsten Ancylus-Grenze Auf Gotland und Öland

Abstract

Abstract Limnic molluscs, including Ancylus fluviatilis, Limnaea peregra f. ovata, and Gyraulus sp., were found in shore deposits approximately 20 m below the maximum limit of the Ancylus transgression on northern Oland (Konigsson 1964 a). Three new localities on Gotland with limnic faunas in comparable positions are described. A pollen diagram shows that the deposits at two localities, Roes on southern Gotland and Lilla Mafrids on middle Gotland, occurred before the rational limit of the Alnus pollen curve. This limit is connected with the middle part of the Ancylus transgression, the deposition thus having taken place in a regressive period during the transgression or, more likely, in the transition between the Yoldia and the Ancylus periods. In the deposits at Nyby on Oland and Tajnungs on northern Gotland Alnus pollen grains have been found. However, a Hystrix curve (marine organisms) in this limnic environment affords evidence of a secondary fossil deposition. The presence of Alnus in the two analyse...