Geoscience Reference
In-Depth Information
Chapter 5
Late Quaternary Climate Variations Reflected
in Baltic Sea Sediments
Jan Harff, Rudolf Endler, Emel Emelyanov, Sergey Kotov, Thomas Leipe,
Matthias Moros, Ricardo Olea, Michal Tomczak, and Andrzej Witkowski
Abstract
Late Pleistocene to Holocene climate change of the Atlantic and the
northern European realm is reflected by the facies of sediments in the Baltic
Sea. The sedimentary sequence have been subdivided into zones reflecting the
main postglacial stages of the Baltic Sea basin development according to sediment
echosounder profiling and investigating sediment cores from the central Baltic. The
changes in the environment of Baltic Sea bottom water is displayed by sediment
physical, geochemical, and microfossil proxies. These proxies mark the main shift
in the sedimentary facies of the Baltic Basin at 8.14 cal. years BP, from a freshwa-
ter to a brackish/marine environment due to the Littorina transgression of marine
water masses from the North Sea. The downhole physical facies variation from the
Eastern Gotland can be correlated basinwide. Thickness maps of the freshwater and
the brackish sediments ascribe the general change in the hydrographic circulation
from a coast-to-basin to a basin-to-basin system along with the Littorina transgres-
sion. Variations in the salinity of the brackish Littorina Baltic Basin are attributed
to changes in the North Atlantic Oscillation (NAO) ascribing the wind forces driv-
ing the inflow of marine water into the Baltic Basin. Time series analysis of facies
variation reveals distinct periodicities of 900 and 1,500 years. These periods can be
compared with data from North Atlantic marine sediments and Greenland ice cores
identifying global climate change effects in Baltic Basin sediments.
Keywords
Eastern Gotland Basin
·
Holocene
·
Physico stratigraphical zona
