Radiographs of sediment cores from the Swedish fjord Byfjorden
Partly overlapping radiographs of the upper part of core 961 from a depth (1983-08-11) of 28 m in Byfjorden. Several sediment layers in this core may be used as time markers, since they consist of dredged material from known dredging operations.
The given dredging periods are based on informations received from Johan Söderström.
Annual accumulation of solids at station 961 in Byfjorden.
For the period 1954-1983 the calculated mean and median value of annual sedimentation rate at this coring station amounted to 135 and 100 mg of solids/cm2, corresponding to a varve thickness of 6.9 and 5.0 mm respectively. For location, see the map further down.
Part of core 1290 from a depth of 35 m in Byfjorden. The lead letter B marks corresponding levels on the partly overlapping radiographs. Date of coring: 1988-07-17.
Annual accumulation of solids at station 1290 in Byfjorden.
For the 200-year period 1788-1988 the calculated mean and median value of annual sedimentation rate at this coring station amounted to 105 and 91 mg of solids/cm2, corresponding to a varve thickness of 4.0 and 3.0 mm respectively.
Radiographic comparison between annual varves and marker layers in cores 961 and 1290. The curve showing the downcore variation in dry bulk density is based on recorded variations in film density along the centre line of the left radiograph. Depth in core 1290 = 16 - 37 cm. From Axelsson 2002 (Geo-Marine Letters 21/4).
The dated marker layers consisted mainly of redeposited dredged material and were used in the core-to-core correlation. They also served as datum levels for checking the time scale based on varve counting.
Locations of 19 X-rayed sediment cores from Byfjorden.
Core no.------------------Date of coring
619-622-----------------1980-06-25
957-965-----------------1983-08-11
1288-1293--------------1988-07-17
A larger file in Swedish.
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