Palaeogeographic Model for the SW Estonian Coastal Zone of the Baltic Sea - The Baltic Sea Basin - page 167

water-level surfaces will be combined with shore displacement curve data from the
Pärnu region in SWEstonia. Previous palaeo-environmental and shore displacement
data are summarized in this chapter in order to reconstruct the curve (Raukas et al.
1999 , Heinsalu et al. 1999 , Veski et al. 2005 , Kriiska and Lõugas 2009 ) . The water-
level change model will be applied together with DTM to reconstruct the coastline
change in SW Estonia and to examine the relationships between coastline change
and the displacement of early human settlements in the area.

8.2 Study Area

The study area was chosen to meet certain requirements: first of all slow postglacial
isostatic rebound with present-day apparent (relative to the mean sea level) uplift
rates of around 1 mm/year (Fig. 8.1 ) . The region is relatively flat, rising to ca. 30 m
above present-day sea level. As a result, even small increases in sea level can eas-
ily lead to the flooding of substantial areas. A complex deglaciation history of the
Baltic Sea area, with up-dammed lakes and early phases of postglacial seas, has
periodically caused SW Estonia to be submerged by the waters of the Baltic Sea
basin and to emerge in other periods as terrestrial land. Thus, deposits of water-laid
sediments formed during the transgression of the Ancylus Lake or the Littorina Sea
have led to repeated soil burials and to peat and/or gyttja formations, often associ-
ated with the cultural layers of Stone Age settlement sites. Our study area in SW
Estonia is rich in sites from different prehistoric periods. Coastal habitation is char-
acteristic of the Stone Age. The Pulli, Sindi-Lodja I and II and Jõekalda settlement
sites in the lower reaches of the Pärnu River and the Malda, Lemmetsa I and II set-
tlement sites in the lower reaches of the Audru River are important in this context
(Fig. 8.2 ; Kriiska 2001 , Kriiska et al. 2002 , 2003 , Kriiska and Saluäär 2000 , Kriiska
and Lõugas 2009 ) .

8.3 Modelling of Water-Level Change and Palaeocoastlines

8.3.1 Reconstruction of Water-Level Surfaces

The interpolated surfaces of water levels were derived using the late glacial (Saarse
et al. 2007 ) and Holocene Baltic Sea shoreline databases (Saarse et al. 2003 ) . In
this study we used six interpolated surfaces of water levels for different Baltic
stages: the Baltic Ice Lake (stages A 1 , BI, BIII) around 13,300, 12,300 12,100

and 11,700 cal. years BP (Saarse et al. 2007 ) ; Ancylus Lake transgression maxi-
mum around 10,200 cal. years BP (Saarse et al. 2003 ) , Littorina Sea transgression
maximum around 7,300 cal. years BP (Veski et al. 2005 ) and the modern Baltic
Sea over the period of last 100 years. The interpolated water-level surface for the
modern Baltic Sea is based on sea-level measurements complemented with geodetic
data (Ekman 1996 ) .

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