Description
The product is a model of the beach shift and land uplift after the last ice age. It is based on a large number of shore displacement curves that have been established across different parts of the country combined with a model for land uplift and a digital elevation model with 50 m resolution (Påsse & Daniels 2015).
The ice sheets that covered northern Europe and North America during the Ice Age affected the underlying crust. The result was a dynamic interaction between land uplift, water level and inland ice (see Peterson Becher 2022 and references therein).
During the last ice age, the Earth's crust was pressed down by the weight of the ice sheet. When the ice melted, the pressure eased and the Earth's crust began to move upwards to regain previous levels, a process that is still active and is called land uplift in Sweden. At the same time, global sea level fluctuated, largely due to the amount of water bound in the inland ice sheets. This led to variations in the relationship between water and land (so-called shore displacement). This is what SGU's shore displacement model shows.
Because different parts of the landscape have been pushed down to different degrees, depending on the strength of the inland ice, the earth's crust is not raised uniformly. It was most pressed down in the central parts where the inland ice was most powerful. This also tilts the landscape, which means that the course of watercourses and the extent of lakes partly change over time. For example, differences in land elevation mean that Vättern's level rises in the southern part while it falls in the northern part.
SGU's shore displacement model shows an overall picture of the ancient distribution between sea and land, as well as changes in the extent of lakes. The beach displacement model is not intended for detailed studies but to show a general course of events. More detailed studies require caution and in-depth understanding of the uncertainties inherent in the various methods underlying the model. The map viewer provides shore displacement in 100-year intervals. This does not mean that the model has such a high accuracy, but the short intervals only provide an opportunity to see regional changes, ie not for accurate age determination.
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