Strömsholmsåsen - Esker - Malmköping, Södermanland - Places of Geologic Significance on Waymarking.com

Strömsholmsåsen
Strömsholmsåsen is an esker in Sweden. It was formed for over 10 000 years ago during the quaternary ice age. It was formed by stones and gravel which was carried away by the inland ices melted water. It goes from the lake Båvern in southern Södermanland to Åmänningen outside Fagersta, Västmanland. From Hällby to Tumbo the esker is rather flat because of the water which has leveled the esker there. You can find traces of Litorinahavet (a stadium of the Baltic sea) and the hight of the ocean reached at most 60 meters above sea level. No part of the esker is higher than 70-80 meters, which means that traces of Ancylussjön (a stadium of the Baltic sea) cant be found.

Esker
An esker is a long, winding ridge of stratified sand and gravel, examples of which occur in glaciated and formerly glaciated regions of Europe and North America. Eskers are frequently several kilometres long and, because of their peculiar uniform shape, are somewhat like railway embankments.

Most eskers are argued to have formed within ice-walled tunnels by streams which flowed within and under glaciers. They tended to form around the time of the glacial maximum when the glacier was slow and sluggish. After the retaining ice walls melted away, stream deposits remained as long winding ridges. Water can flow uphill if it is under pressure in an enclosed pipe, such as a natural tunnel in ice.

Eskers may also form above glaciers by accumulation of sediment in supraglacial channels, in crevasses, in linear zones between stagnant blocks, or in narrow embayments at glacier margins. Eskers form near the terminal zone of glaciers, where the ice is not moving as fast and is relatively thin.

Esker in Sims Corner Eskers and Kames National Natural Landmark, Washington, USA. Note trees at the edge of the esker and the single lane road crossing the esker to the right of the photo which provide scale.
Plastic flow and melting of the basal ice determines the size and shape of the subglacial tunnel. This in turn determines the shape, composition and structure of an esker. Eskers may exist as a single channel, or may be part of a branching system with tributary eskers. They are not often found as continuous ridges, but have gaps that separate the winding segments. The ridge crests of eskers are not usually level for very long, and are generally knobby. Eskers may be broad-crested or sharp-crested with steep sides.[2] They can reach hundreds of kilometers in length and are generally 20–30 metres in height.

The path of an esker is governed by its water pressure in relation to the overlying ice. Generally the pressure of the ice was at such a point that it would allow eskers to run in the direction of glacial flow, but force them into the lowest possible points such as valleys or river beds, which may deviate from the direct path of the glacier. This process is what produces the wide eskers upon which roads and highways can be built. Less pressure, occurring in areas closer to the glacial maximum, can cause ice to melt over the stream flow and create steep-walled, sharply-arched tunnels.

The concentration of rock debris in the ice and the rate at which sediment is delivered to the tunnel by melting and from upstream transport determines the amount of sediment in an esker. The sediment generally consists of coarse-grained, water-laid sand and gravel, although gravelly loam may be found where the rock debris is rich in clay. This sediment is stratified and sorted, and usually consists of pebble/cobble-sized material with occasional boulders. Bedding may be irregular but is almost always present, and cross-bedding is common.

Malma domäns nature reserve
The esker can be found in Malma domäns nature reserve, which the above coordinates point to. The reserve lies on a small part of Strömsholmsåsen, an esker which goes through Sparreholm and Malmköping, where it forms Malma hed. The esker was created for over 10 000 years ago by stones and gravel which was carried away by the melted ice from the inland ice, during the latest ice age. The inland ice was at most 3 000 meters thick. By the foot of the southern part of the reserve there is a very clear kettle which was formed by an ice block which losened from the inland ice and left a mark after it had melted away.

Waymark is confirmed to be publicly accessible: yes Parking Coordinates: N 59° 08.460 W 016° 43.125 Access fee (In local currency): .00 Requires a high clearance vehicle to visit.: no Requires 4x4 vehicle to visit.: no Public Transport available: yes Website reference: Not listed

Visit Instructions:
No specific requirements, just have fun visiting the waymark.

Recent Visits/Logs:

Date Logged Log User Rating   10/13/2018 repsac16 visited it 05/12/2017 suha002 visited it 08/15/2015 JorgoBoss visited it 04/15/2015 Tyfting visited it

View all visits/logs