Geoidal-eustatic changes induced by the deglaciation of fennoscandia

Abstract

Relative sea level changes in Fennoscandia have long been known to be a result of processes connected to the last glaciation. The post-glacial sea level changes have commonly been thought of as a result of global variations of the ocean water volume and isostatic movements (connected to the deglaciation). However, changes of the ice loads bring about gravimetric changes, and resulting eustatic changes will vary significantly over the globe. The importance of the geoid changes related to the deglaciation in Fennoscandia is illustrated by theoretical simulations, which show that the resulting sea level movements differ significantly over the globe. During a fast deglaciation there is not a worldwide rise in sea level due to increased volume of ocean water, but in the region near the former glacier there may actually be a fall in sea level. By simulations of the deglaciation history it is also shown that the associated sea level history varies even within a small area, and may differ by up to 20–30 m from the Barents Sea to central Scandinavia. This is really a significant difference, compared to the overall pattern of sea level change of 100 m for the last 15 ka. Thus no eustatic curve is valid globally.