Late Quaternary Climate Variations Reflected in Baltic Sea Sediments - The Baltic Sea Basin - page 116

Fig. 5.10 Thickness (in m) of A zone sediments (Baltic Ice Lake to Ancylus Lake) and B zone
sediments (Littorina to LIA)
through the Stolpe Channel. This is due to the opening of the entrance to the Baltic
8,000 cal. year (Harff et al. 2005 ) , and with the Littorina transgressions the general
basin-to-basin current system of the Baltic Sea (Fig. 5.4 ) controlled the particle
dynamics. As a result the SW-NE trending sediment body of the Stolpe Foredelta
accumulated and this structure can be identified in map B of Fig. 5.10 .
5.5.4 Downhole Facies Variation at the Central Eastern Gotland
Basin as Indicator for Holocene Environmental Change
In a previous work, Harff et al. ( 2001a ) have mentioned that the change in the
abundance of lamination in central Eastern Gotland Basin cores can be used to
reconstruct the oxygen supply to the bottom water during deposition. Changes in
lamination are reflected well in the acoustic MSCL p-wave velocity. An acoustic
index as detrended (0, 1) standardized p-wave velocity turned out to show values
close to 1.0 in laminated sediments, reflecting anoxic environment of deposition,
whereas homogeneous sediments deposited under oxic conditions of bottom water
show an acoustic index near 0 (Harff et al. 2001a ) . This implies that the acoustic
index can be used as a qualitative proxy variable indicating the ventilation of near-
bottom water during sediment deposition. Looking at the p-wave velocity curve