TY - JOUR
T1 - An attempt to resolve the partly conflicting data and ideas on the Ancylyus-Littorina transition
AU - Björck, Svante
AU - Andrén, Thomas
AU - Jensen, Jørn Bo
PY - 2008
Y1 - 2008
N2 - The transition phase between the Ancylus and Littorina stages of the Baltic Sea is an old controversial topic. With the newest data available we try to reach a compromise between the "dramatic" model, including a sudden and large drainage of the Ancylus Lake, and the idea of a non-existing Ancylus drainage through Denmark. This new model includes a minor, perhaps 5 m, sudden erosion and forced regression slightly before 10000 cal. yrs BP. This was followed by a 200-300 yr long period when the outlet through Denmark and Great Belt (Dana River) was characterized by a variable fluvial environment creating fluvial, levée and lacustrine deposits. During this period of rapidly rising sea level, we postulate that the gradient between the Ancylus Lake and sea level gradually decreased from some 5 in until sea level had reached the Ancylus and Darss Sill level. After this point in time occasional pulses of marine water could easier enter into the Baltic basin, which is seen as brackish pulses as early as 9800 cal. yrs BP in records from the Bornholm and Gotland basins, but also from Blekinge. It would, however, take another c. 15 00 years before the Öresund threshold was flooded by the rising sea level, causing a significant rise in salinity sometime between 8500-8000 cal. yrs BP, and marking the true onset of the Littorina Sea.
AB - The transition phase between the Ancylus and Littorina stages of the Baltic Sea is an old controversial topic. With the newest data available we try to reach a compromise between the "dramatic" model, including a sudden and large drainage of the Ancylus Lake, and the idea of a non-existing Ancylus drainage through Denmark. This new model includes a minor, perhaps 5 m, sudden erosion and forced regression slightly before 10000 cal. yrs BP. This was followed by a 200-300 yr long period when the outlet through Denmark and Great Belt (Dana River) was characterized by a variable fluvial environment creating fluvial, levée and lacustrine deposits. During this period of rapidly rising sea level, we postulate that the gradient between the Ancylus Lake and sea level gradually decreased from some 5 in until sea level had reached the Ancylus and Darss Sill level. After this point in time occasional pulses of marine water could easier enter into the Baltic basin, which is seen as brackish pulses as early as 9800 cal. yrs BP in records from the Bornholm and Gotland basins, but also from Blekinge. It would, however, take another c. 15 00 years before the Öresund threshold was flooded by the rising sea level, causing a significant rise in salinity sometime between 8500-8000 cal. yrs BP, and marking the true onset of the Littorina Sea.
KW - Ancylus lake
KW - Baltic sea
KW - Littorina sea
KW - Sea level
KW - palaeoenvironmental reconstruction
UR - http://www.scopus.com/inward/record.url?scp=42949103503&partnerID=8YFLogxK
U2 - https://www.pgi.gov.pl/en/dokumenty-przegladarka/publikacje-2/special-papers/23/1551-sp23-bjorck/file.html
DO - https://www.pgi.gov.pl/en/dokumenty-przegladarka/publikacje-2/special-papers/23/1551-sp23-bjorck/file.html
M3 - Article
AN - SCOPUS:42949103503
VL - 23
SP - 21
EP - 26
JO - Polish Geological Institute Special Papers
JF - Polish Geological Institute Special Papers
SN - 1507-9791
ER -