THE HIGHEST POSTGLACIAL SHORE LEVELS AND GLACIO‐ISOSTATIC UPLIFT PATTERN IN NORTHERN SWEDEN |
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| Authors: | MIKAEL BERGLUND |
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| Institution: | Department of Natural Sciences, Engineering and Mathematics, Mid Sweden University, H?rn?sand, Sweden |
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| Abstract: | The detailed clay varve chronology and an extensive knowledge of the highest postglacial shore level elevation (HS) in northern Sweden, along the Bothnian western coast, provides opportunities for determining the pattern of isostatic rise and centre of uplift from the early Holocene. The shore level of c. 10 100 cal yr bp (10 ka) for this area is determined by subtracting, from the metachronous HS elevations, the fall in relative sea level between local deglaciation time and the chosen reference time. The area of highest uplift since 10 ka is situated somewhat north of the location with the world‐record HS (Skuleberget in Ångermanland), but south of the area with most rapid current rise. Wave erosion marks in the studied area are seen to be more consistent indicators of HS than glaciofluvial delta levels. The gradients of shore marks at 10 ka are generally small within the investigation area. The regional 10 ka shore level pattern shows considerable irregularity compared to the current uplift. Central Sweden and western Finland show 10 ka gradients that indicate isostatic response to late (13–10 ka bp ) glacial unloading. Indications of a secondary uplift centre west of the present investigation area are reported in previous work; this also suggests rapid isostatic response to unloading. Finally, the possibility of identifying errors in the varve‐dated deglaciation chronology via the 10 ka shore level pattern is illustrated. |
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| Keywords: | early Holocene deglaciation glacio‐isostatic uplift highest postglacial shore level northern Sweden |
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