Other Geological Features

Small ponds and gloes

The gloes were created as part of the flad-gloe succession that occurred along with the land uplift after the last glaciation. As a result of the descending sea level and advancing shoreline, water basins develop in the depressions of the soil. In some areas, De Geer moraine ridges act as natural water retaining sills and isthmuses. During the early stages of this development, the exchange of water between the sea and the basin is fairly free. Later the water's change rate weakens and the salinity of the water in the basin decreases.

Often, organic gyttja becomes stratified at the bottom of the flads and gloes. With the paludification and as a result of the drop in the ground water level as the land rises, mires may develop in some of the basins. The most typical paludifying process in the shore uplift zone is the paludification of water basins.

Flads and gloes can be found, for example, on the Björkö-Panike trail at points 7, 8 and 21.

Erratics

The erratics separated from the bedrock when the ice sheet flowed over the ground, breaking bits of it loose. Congelifraction, the formation of meltwaters and pressure fluctuations caused by the ice are major mechanisms contributing to the fragmentation of the bedrock. The erratics represent the local bedrock or they may have travelled long distances with the ice sheet or ice floes.

Erratics can be found along many of the Kvarken area’s nature and hiking trails, for example, on the Björkö-Panike trail at points 27, 32, 35 and 36.

Giant´s KettlesGiant´s Kettles

 Giant´s kettles, or also known as giant´s cauldron or potholes, have formed when flowing water has forced stones to rotate at the same place, and hence formed cavities in the rock. Usually Giant´s kettles occur along ridges that have been formed by glacial rivers.

 Giant´s kettles can be observed at Sommarö and on Öjberget in Sundom.

StriationsStriations

 Striations, or rock scratchings, show the direction of the ice´s movement. In the Kvarken archipelago hundreds of striations have been observed. These striations show that the older ice moved from the northeast to the southwest, while the younger moved from the northwest to the southeast.

Boulder Fields Near the Coast

The boulder fields close to the coast were created relatively recently as the land became uncovered by the sea. The waves hitting the shore have shifted and rounded the stones on the ground, simultaneously washing away the finer materials. The coarse-grained shore sediments may be as much as several metres thick and storms particularly may mould them into beach ridges several metres above sea level.

For example, point 1 at Kikanberget offers a fine example of such boulder fields.

Adapted from Jaakko Auri’s original text