Open AccessHolocene shore displacement and deglaciation chronology in Norrbotten, Sweden
Author(s) -
LINDÉN MATTIAS,
MÖLLER PER,
BJÖRCK SVANTE,
SANDGREN PER
Publication year - 2006
Publication title -
boreas
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.95
H-Index - 74
eISSN - 1502-3885
pISSN - 0300-9483
DOI - 10.1111/j.1502-3885.2006.tb01109.x
Subject(s) - geology , holocene , deglaciation , shore , marine transgression , radiocarbon dating , chronology , oceanography , physical geography , tectonic uplift , paleontology , geomorphology , structural basin , geography
The coastal zone of Norrbotten, northern Sweden, was gradually inundated by the Ancylus Lake following the retreating ice margin and forming a highest coastline approximately 210 m above the present sea level. The succeeding shore displacement is reconstructed based on lithological investigations and radiocarbon datings of identified isolation sequences from 12 cored lake basins. The highest lake basins, along with two basins above the highest shoreline, suggest ice‐free conditions already at 10 500cal. yr BP This is at least 500 years earlier than previously thought and implies rapid ice‐sheet break‐up in the Gulf of Bothnia. The shore displacement (RSL) curve represents a forced regression of successively decreasing rate through the Holocene, from 9m/100yr to 0.8 m/100yr. During the first 1000–1200 years, the isostatic uplift is exponentially declining, followed by a constant uplift rate from c. 9500 cal. yr BP to 5500–5000 cal. yr BP. The last 5000 years seem to be characterized by a low but constant rebound rate. The development of the Ancylus Lake stage of the Baltic may also be discerned in the Norrbotten RSL curve, suggesting that the chronology of the Ancylus Lake stages may have to be revised. The Littorina transgression is also reflected by the RSL curve shape. In addition, a series of early to mid‐Holocene beach terraces were OSL‐dated to allow for comparison with the 14 C‐dated shore displacement curve. Interpretations of these ages and their relation to former sea levels were clearly more problematic than the dating of the lake basin isolations.