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Table 3. Lithostratigraphy of the studied sediment cores. lagoon with a connection to the open sea. EO OOO ee In the interval between 365-350 cm, cosmopolite salinity-indifferent Fragilaria spp. predominate after the disappearance of the brackish- water diatom assemblage. Small-sized fragilarioid taxa are considered to be the pioneer diatoms that have an advantage in a rapidly changing environment (Yu et al., 2004) and thus the peak of Fragilaria spp. is regarded as the marker of the transition to the final isolation of the Klooga basin. A dominance of periphytic freshwater diatoms, such as Cymbella- faba diluviana, Sellaphora vitabunda and Achnan- thidium minutissimum from the core-depth of 345 cm indicates the isolation from the sea and suggests a shallow hard-water lake environment. An AMS “C age of 411060 cal yr BP corresponds to the time shortly following the isolation and the modelled age of isolation is 4180+50 cal yr BP (hereafter 4200 cal yr BP). T .1. 7 2.L¢*. Vek 2 2.22. 2c? 2 LL. Uf 11... LL] have an advantage in a rapidly changing environment

Table 3 Lithostratigraphy of the studied sediment cores. lagoon with a connection to the open sea. EO OOO ee In the interval between 365-350 cm, cosmopolite salinity-indifferent Fragilaria spp. predominate after the disappearance of the brackish- water diatom assemblage. Small-sized fragilarioid taxa are considered to be the pioneer diatoms that have an advantage in a rapidly changing environment (Yu et al., 2004) and thus the peak of Fragilaria spp. is regarded as the marker of the transition to the final isolation of the Klooga basin. A dominance of periphytic freshwater diatoms, such as Cymbella- faba diluviana, Sellaphora vitabunda and Achnan- thidium minutissimum from the core-depth of 345 cm indicates the isolation from the sea and suggests a shallow hard-water lake environment. An AMS “C age of 411060 cal yr BP corresponds to the time shortly following the isolation and the modelled age of isolation is 4180+50 cal yr BP (hereafter 4200 cal yr BP). T .1. 7 2.L¢*. Vek 2 2.22. 2c? 2 LL. Uf 11... LL] have an advantage in a rapidly changing environment

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Figure 2. A — Overview map of the study area, brown lines show apparent uplift in mm yr! (Ekman 1996). Digital terrain model of: B — the northern and northwestern Estonia, C — the Island of Hitumaa, D — the coastal area of southern coast of the Gulf of Riga. Additional sites mentioned in discussion: 1 — Babelitis; 2 — Sand deposits ‘Vecdaugava’; 3 — Kanieris; 4 — Babites; 5 —- Daugava; 6 — Priedaine; 7 — Slepere.
Figure 2. A — Overview map of the study area, brown lines show apparent uplift in mm yr! (Ekman 1996). Digital terrain model of: B — the northern and northwestern Estonia, C — the Island of Hitumaa, D — the coastal area of southern coast of the Gulf of Riga. Additional sites mentioned in discussion: 1 — Babelitis; 2 — Sand deposits ‘Vecdaugava’; 3 — Kanieris; 4 — Babites; 5 —- Daugava; 6 — Priedaine; 7 — Slepere.
Table 1. The description of study sites in the north and northwestern Estonia. 4.1.2. Island of Hiitumaa
Table 1. The description of study sites in the north and northwestern Estonia. 4.1.2. Island of Hiitumaa
Table 2. The description of study sites on the Island of Hiiumaa. 4.1.3. Southern coast of Gulf of Riga aPpPpedl lille Ui INOUE ssOM Cl dl. (i770) AMG OddI sl Ol dl. (LUUU) WETY dGard, K6ivasoo, an ancient LitS lagoon on the K6pu Peninsula, is a small raised bog that lies near the LitS limit between two series of scarps at 27.6 and 23.8 ma.s.l. It contains lagoonal, limnic, and terrestrial deposits (Saarse et al. 2000). Loopsoo is an ancient, overgrown lagoon included in the large swamp area in the central part of Hiiumaa. It is surrounded by bow-shaped beach ridges, a thin woody rim, and field patches. Orru (1995) studied the thickness, distribution, and properties of the Loopsoo peat. Lake Tihu Keskmine, hereafter referred to as Tihu, is a small, elongated, shallow, semidystrophic lake in the western part of Hiiumaa. This area is characteristic with brownish till with erratic clasts and widely distributed marine sand, and the topography is broken by many beach ridges, spits, and fan-like bars (Ratas 1976; Eltermann 1993b). The lake shores are overgrown and are flanked by ridges and dunes; the catchment is paludified and is mostly forested by pines. Lake Prassi is a small lake in southern part of Hiiumaa that is mainly overgrown by reeds and surrounded by forested mire. The area studied in the central part of Latvia covers the Rigavas sandy plain, which is part of the coastal lowland along the southern coast of the Gulf of Riga. In total, eight lakes were cored (Fig. 2D; Table 3). Lakes Lilaste, Dunu, and Pulkstenu are located in the northeastern Rigavas Plain; lakes Ataru, Linu, Laveru, and Jugu are in the central part of the plain located between two large rivers, Gauja and Daugava; and Lake Slokas is distant from other sites, at the southeastern margin of the Rigavas Plain (Fig. 2D). The coastal lowland is an abrasional and accumulation plain originating from
Table 2. The description of study sites on the Island of Hiiumaa. 4.1.3. Southern coast of Gulf of Riga aPpPpedl lille Ui INOUE ssOM Cl dl. (i770) AMG OddI sl Ol dl. (LUUU) WETY dGard, K6ivasoo, an ancient LitS lagoon on the K6pu Peninsula, is a small raised bog that lies near the LitS limit between two series of scarps at 27.6 and 23.8 ma.s.l. It contains lagoonal, limnic, and terrestrial deposits (Saarse et al. 2000). Loopsoo is an ancient, overgrown lagoon included in the large swamp area in the central part of Hiiumaa. It is surrounded by bow-shaped beach ridges, a thin woody rim, and field patches. Orru (1995) studied the thickness, distribution, and properties of the Loopsoo peat. Lake Tihu Keskmine, hereafter referred to as Tihu, is a small, elongated, shallow, semidystrophic lake in the western part of Hiiumaa. This area is characteristic with brownish till with erratic clasts and widely distributed marine sand, and the topography is broken by many beach ridges, spits, and fan-like bars (Ratas 1976; Eltermann 1993b). The lake shores are overgrown and are flanked by ridges and dunes; the catchment is paludified and is mostly forested by pines. Lake Prassi is a small lake in southern part of Hiiumaa that is mainly overgrown by reeds and surrounded by forested mire. The area studied in the central part of Latvia covers the Rigavas sandy plain, which is part of the coastal lowland along the southern coast of the Gulf of Riga. In total, eight lakes were cored (Fig. 2D; Table 3). Lakes Lilaste, Dunu, and Pulkstenu are located in the northeastern Rigavas Plain; lakes Ataru, Linu, Laveru, and Jugu are in the central part of the plain located between two large rivers, Gauja and Daugava; and Lake Slokas is distant from other sites, at the southeastern margin of the Rigavas Plain (Fig. 2D). The coastal lowland is an abrasional and accumulation plain originating from
Table 3. The description of study sites in the Rigavas Plain, the southern coast of the Gulf of Riga. Lake Slokas is a large, shallow coastal lake situated in Kemeru National Park. The lake shores are overgrown by reeds, however some parts of the shores are devoid of vegetation. The bottom of the lake is situated on Devonian dolomite bedrock. This area is well known for its sulphur springs, which are formed by organic, rich bog water seepage through the Upper Devonian gypsum, which forms hydrogen sulphide—calcium sulphate brines.
Table 3. The description of study sites in the Rigavas Plain, the southern coast of the Gulf of Riga. Lake Slokas is a large, shallow coastal lake situated in Kemeru National Park. The lake shores are overgrown by reeds, however some parts of the shores are devoid of vegetation. The bottom of the lake is situated on Devonian dolomite bedrock. This area is well known for its sulphur springs, which are formed by organic, rich bog water seepage through the Upper Devonian gypsum, which forms hydrogen sulphide—calcium sulphate brines.
Figure 3. Sediment organic matter, carbonates and mineral matter content estimated by loss-on-ignition (% of dry weight), magnetic susceptibility (MS) and diatom summary diagram (% of total). M/B — marine/brackish taxa; HAL — halophilous taxa; IND — indifferent taxa; BWA — small-sized fragilarioid taxa with brackish water affinity; SMF — small-sized fragilarioid taxa; FW — freshwater taxa.
Figure 3. Sediment organic matter, carbonates and mineral matter content estimated by loss-on-ignition (% of dry weight), magnetic susceptibility (MS) and diatom summary diagram (% of total). M/B — marine/brackish taxa; HAL — halophilous taxa; IND — indifferent taxa; BWA — small-sized fragilarioid taxa with brackish water affinity; SMF — small-sized fragilarioid taxa; FW — freshwater taxa.
the current rate of land uplift (Torim 2004), which also shows a decreasing trend. In general, the reconstructed RSL curves show a linear trend of sea-level decrease that is in agreement with the curves recently reconstructed around the Gulf of Finland (Hyvarinen 1982; Seppa et al. 2000; Miettinen 2002, 2004; Rosentau et al. 2011; Saarnisto 2012) and the Gulf of Bothnia (Linden et al. 2006; Widerlund & Andersson 2011). Changes in sea level over the last 5000 years have been reported from various regions of the world (Morhange et al. 2001; Gehrels et al. 2006; Murray-Wallace 2007), including the Baltic coast (Lampe 2005). If a rapid rise in the ocean level does not occur, the decreasing trend of the sea level and apparent uplift in northern Estonia will continue.
the current rate of land uplift (Torim 2004), which also shows a decreasing trend. In general, the reconstructed RSL curves show a linear trend of sea-level decrease that is in agreement with the curves recently reconstructed around the Gulf of Finland (Hyvarinen 1982; Seppa et al. 2000; Miettinen 2002, 2004; Rosentau et al. 2011; Saarnisto 2012) and the Gulf of Bothnia (Linden et al. 2006; Widerlund & Andersson 2011). Changes in sea level over the last 5000 years have been reported from various regions of the world (Morhange et al. 2001; Gehrels et al. 2006; Murray-Wallace 2007), including the Baltic coast (Lampe 2005). If a rapid rise in the ocean level does not occur, the decreasing trend of the sea level and apparent uplift in northern Estonia will continue.
The reconstructed water-level curves display a time-transgressive LitS highstand peak occurring earlier in the K6ivasoo area and later in the Prassi area as a result of differences in the rate of land uplift. The calculated land uplift rate at 10 300 cal BP was 4.4 mm yr' at Kéivasoo and decreased to 2.5 mm yr’ in recent time (Torim 2004). These results complement observations in northern Estonia (Paper I, IT) as well as other studies from the Estonian coastal area (Veski et al. 2005; Saarse et al. 2010; Rosentau et al. 2013). The reconstructed water-level curves of the southern coast of the Gulf of Rigg show changes in RSL (Fig. 11) over the Holocene. The surrounding areas of Rigg were deglaciated and flooded by BIL at ca 14 000 cal BP (Vassiljev & Saarse 2013). Modelling results (Vassiljev & Saarse 2013) suggest that the water level reached up to 14-16 ma.s.l. just prior to the Billingen drainage at 11 700 cal BP (Figs. 11, 12). Considering that the water level after the rapid drainage of BIL was lowered by approximately 25 m to the ocean level, the YS maximum wate! level in the Gulf of Riga was approximately 9-11 m b.s.l. The land uplift in the Riga area most likely exceeded the ESL rise, resulting in YS regression. In earliet studies, Berzin (1967) and Kovalenko and Juskevics (1987) suggested that the YS minimum level was at least 29 m b.s.1. and 15 mb.s.1, respectively. Modelling results (Saarse et al. 2003) show that the water level in the Gulf of Riga during the AL transgression at 10 300 cal BP was about 12-17 m b.s.1; thus, it can be concluded that the YS regression minimum was lower than that value (Fig. 11).
The reconstructed water-level curves display a time-transgressive LitS highstand peak occurring earlier in the K6ivasoo area and later in the Prassi area as a result of differences in the rate of land uplift. The calculated land uplift rate at 10 300 cal BP was 4.4 mm yr' at Kéivasoo and decreased to 2.5 mm yr’ in recent time (Torim 2004). These results complement observations in northern Estonia (Paper I, IT) as well as other studies from the Estonian coastal area (Veski et al. 2005; Saarse et al. 2010; Rosentau et al. 2013). The reconstructed water-level curves of the southern coast of the Gulf of Rigg show changes in RSL (Fig. 11) over the Holocene. The surrounding areas of Rigg were deglaciated and flooded by BIL at ca 14 000 cal BP (Vassiljev & Saarse 2013). Modelling results (Vassiljev & Saarse 2013) suggest that the water level reached up to 14-16 ma.s.l. just prior to the Billingen drainage at 11 700 cal BP (Figs. 11, 12). Considering that the water level after the rapid drainage of BIL was lowered by approximately 25 m to the ocean level, the YS maximum wate! level in the Gulf of Riga was approximately 9-11 m b.s.l. The land uplift in the Riga area most likely exceeded the ESL rise, resulting in YS regression. In earliet studies, Berzin (1967) and Kovalenko and Juskevics (1987) suggested that the YS minimum level was at least 29 m b.s.1. and 15 mb.s.1, respectively. Modelling results (Saarse et al. 2003) show that the water level in the Gulf of Riga during the AL transgression at 10 300 cal BP was about 12-17 m b.s.1; thus, it can be concluded that the YS regression minimum was lower than that value (Fig. 11).
Figure 11. Water-level curves for the southern coast of Gulf of Riga, based on different proxies. Water level for Lake Lilaste is shown with +1 m error bar, for lakes Ataru, Laveru and Slokas mean modelled water level is shown. Eustatic sea level data are based on Lambeck et al. (2014).
Figure 11. Water-level curves for the southern coast of Gulf of Riga, based on different proxies. Water level for Lake Lilaste is shown with +1 m error bar, for lakes Ataru, Laveru and Slokas mean modelled water level is shown. Eustatic sea level data are based on Lambeck et al. (2014).
Figure 13. Schematic illustration of area flooded by rivers Daugava and Gauja during the Litorina Sea (6000-5000 cal BP).
Figure 13. Schematic illustration of area flooded by rivers Daugava and Gauja during the Litorina Sea (6000-5000 cal BP).
Language competence/skills (fluent, average, basic skills) Professional Employment Main scientific interests: diatom analysis, Quaternary geology, palaeoecology, palaeolimnology
Language competence/skills (fluent, average, basic skills) Professional Employment Main scientific interests: diatom analysis, Quaternary geology, palaeoecology, palaeolimnology
Fig. 1. Location of the study area, marked by a square. Estonian Journal of Earth Sciences, 2012, 61, 4, 307-316
Fig. 1. Location of the study area, marked by a square. Estonian Journal of Earth Sciences, 2012, 61, 4, 307-316
Table 1. AMS radiocarbon dates. The ages have been calibrated according to Reimer et al. (2009) change occurs in between 375 and 365 cm, where the OM content apparently rises and stabilizes afterwards. confidence level, using the Calib Rev 6.0.1 software (Reimer et al. 2009). Alternative chronology was created with an OxCal deposition model (Bronk Ramsey 2008, 2009), where AMS dates were combined with lithological boundaries. Both chronologies differ only slightly and therefore we present here Calib soft- ware results. Calibrated ages before present (cal yr BP; 0 =AD 1950) were applied in the present study. Due to the low level of salinity in the Gulf of Finland (Eronen et al. 2001; Miettinen et al. 2007), the marine calibration set was not considered.
Table 1. AMS radiocarbon dates. The ages have been calibrated according to Reimer et al. (2009) change occurs in between 375 and 365 cm, where the OM content apparently rises and stabilizes afterwards. confidence level, using the Calib Rev 6.0.1 software (Reimer et al. 2009). Alternative chronology was created with an OxCal deposition model (Bronk Ramsey 2008, 2009), where AMS dates were combined with lithological boundaries. Both chronologies differ only slightly and therefore we present here Calib soft- ware results. Calibrated ages before present (cal yr BP; 0 =AD 1950) were applied in the present study. Due to the low level of salinity in the Gulf of Finland (Eronen et al. 2001; Miettinen et al. 2007), the marine calibration set was not considered.
Fig. 2. Loss-on-ignition and magnetic susceptibility of Lake Lohja (A) and Lake Kasmu (B). The thick black line in the magnetic susceptibility graph is 5-sample moving average.
Fig. 2. Loss-on-ignition and magnetic susceptibility of Lake Lohja (A) and Lake Kasmu (B). The thick black line in the magnetic susceptibility graph is 5-sample moving average.
Fig. 4. Palaeogeographic maps for time windows 4000, 3000, 2300 and 1800 cal yr BP. Modelled water level surface isobases are indicated by brown lines together with altitudes in metres a.s.1. The shoreline location is shown together with a possible modelling error in the range of +1 m (black line +1 m, red line —1 m); the blue line corresponds to the modelled water depth of 5 m. The reconstructions are overlaid by LIDAR elevation data (Estonian Land Board) to visualize the location of the present-day land (greenish) and sea (blue). Lake Lohja is shown by a red square, Lake Kasmu by a blue square. Reconstruction by J. Vassiljev.
Fig. 4. Palaeogeographic maps for time windows 4000, 3000, 2300 and 1800 cal yr BP. Modelled water level surface isobases are indicated by brown lines together with altitudes in metres a.s.1. The shoreline location is shown together with a possible modelling error in the range of +1 m (black line +1 m, red line —1 m); the blue line corresponds to the modelled water depth of 5 m. The reconstructions are overlaid by LIDAR elevation data (Estonian Land Board) to visualize the location of the present-day land (greenish) and sea (blue). Lake Lohja is shown by a red square, Lake Kasmu by a blue square. Reconstruction by J. Vassiljev.
Fig. 5. Shoreline displacement curve for the study area. For the Lohja site blue lines mark the modelled possible minimum anc maximum water level changes and for the Kasmu site, the grey area (shown only from the Litorina Sea transgression up to today marks the modelled possible range of the water level. The reconstruction considers errors in both, modelled water levels (+1 m and ages. The blue and grey boxes show the possible isolation age according to modelled water level against the isolation ag according to the AMS MC dates (black circles with error bars).
Fig. 5. Shoreline displacement curve for the study area. For the Lohja site blue lines mark the modelled possible minimum anc maximum water level changes and for the Kasmu site, the grey area (shown only from the Litorina Sea transgression up to today marks the modelled possible range of the water level. The reconstruction considers errors in both, modelled water levels (+1 m and ages. The blue and grey boxes show the possible isolation age according to modelled water level against the isolation ag according to the AMS MC dates (black circles with error bars).
Table 1. Morphometric characteristics of the studied lakes.
Table 1. Morphometric characteristics of the studied lakes.
Fig. 1. Location of the studied lakes in northern Estonia, showing the positions of the palaeogeographic maps in Figs. 4-6. The studied lakes Tanavjarv, Klooga, Lohja and Kasmu are located in northern and northwestern Estonia (Fig. 1), on the terraces of the Litorina and Limnea Sea at 18.4 and 3.9 m above the present sea level (a.s.1.), respectively (Table 1). The glacial Limnea Sea at 18.4 and 3.9 m above the present sea
Fig. 1. Location of the studied lakes in northern Estonia, showing the positions of the palaeogeographic maps in Figs. 4-6. The studied lakes Tanavjarv, Klooga, Lohja and Kasmu are located in northern and northwestern Estonia (Fig. 1), on the terraces of the Litorina and Limnea Sea at 18.4 and 3.9 m above the present sea level (a.s.1.), respectively (Table 1). The glacial Limnea Sea at 18.4 and 3.9 m above the present sea
Table 2. Radiocarbon dates considered for the reconstruction of the relative sea level curve. fl a t a t oristic heterogeneity, mixed occurrence of marine nd brackish-water species with relatively frequent freshwater forms (Fig. 3A). The dominant part of he assemblage, however, consists of periphytic saline water tolerant species, while euplanktonic forms are bsent. Periphytic brackish/marine diatoms, namely Diploneis didyma, Cocconeis scutellum, Hyalodiscus scoticus and Campylodiscus clypeus are the diatoms hat are most abundant in the silt layer, accounting for 60-80 % of the assemblage (Fig. 3A). This
Table 2. Radiocarbon dates considered for the reconstruction of the relative sea level curve. fl a t a t oristic heterogeneity, mixed occurrence of marine nd brackish-water species with relatively frequent freshwater forms (Fig. 3A). The dominant part of he assemblage, however, consists of periphytic saline water tolerant species, while euplanktonic forms are bsent. Periphytic brackish/marine diatoms, namely Diploneis didyma, Cocconeis scutellum, Hyalodiscus scoticus and Campylodiscus clypeus are the diatoms hat are most abundant in the silt layer, accounting for 60-80 % of the assemblage (Fig. 3A). This
Fig. 2. Sediment organic matter, carbonates and mineral matter content estimated by loss-on-ignition (% of dry weight) and magnetic susceptibility (MS) of Lake Tanavjarv (A), Lake Klooga (B), Lake Lohja (C) and Lake Kasmu (D). The red line in the MS curve is 5-sample moving average.
Fig. 2. Sediment organic matter, carbonates and mineral matter content estimated by loss-on-ignition (% of dry weight) and magnetic susceptibility (MS) of Lake Tanavjarv (A), Lake Klooga (B), Lake Lohja (C) and Lake Kasmu (D). The red line in the MS curve is 5-sample moving average.
Fig. 4. Palaeogeographic maps of the Tanavjarv area for the time windows of 6500 (A), 6000 (B) and 5400 (C) cal yr BP. Modelled water level surface isobases are indicated by brown lines together with altitudes in meters a.s.|. The shoreline is shown with deviation +1 m (black line +1 m, brown line -1 m). Blue line corresponds to the 5 m water depth. The reconstructions are compiled with LIDAR elevation data (Estonian Land Board) to visualize the present day land (yellow) and sea (blue) area.
Fig. 4. Palaeogeographic maps of the Tanavjarv area for the time windows of 6500 (A), 6000 (B) and 5400 (C) cal yr BP. Modelled water level surface isobases are indicated by brown lines together with altitudes in meters a.s.|. The shoreline is shown with deviation +1 m (black line +1 m, brown line -1 m). Blue line corresponds to the 5 m water depth. The reconstructions are compiled with LIDAR elevation data (Estonian Land Board) to visualize the present day land (yellow) and sea (blue) area.
Fig. 5. Palaeogeographic maps of the Klooga area for the time windows of 7800 (A), 4500 (B) and 4000 (C) cal yr BP. For legend explanations see Fig. 4.
Fig. 5. Palaeogeographic maps of the Klooga area for the time windows of 7800 (A), 4500 (B) and 4000 (C) cal yr BP. For legend explanations see Fig. 4.
Fig. 6. Palaeogeographic maps of the Lohja and Kasmu area for the time windows of 7800 (A), 2200 (B) and 1800 cal yr BP (C). For legend explanations see Fig. 4. Lake Lohja is shown by a red square and Lake Kasmu by a blue square.
Fig. 6. Palaeogeographic maps of the Lohja and Kasmu area for the time windows of 7800 (A), 2200 (B) and 1800 cal yr BP (C). For legend explanations see Fig. 4. Lake Lohja is shown by a red square and Lake Kasmu by a blue square.
Fig. 7. The relative sea level curves for study areas. Lines mark the modelled possible minimum and maximum wate level (green for Lake Klooga, blue for Lake Lohja) and areas mark the modelled possible range of the water level (orange for Lake Tanavjarv and grey for Lake Kasmu). Reconstruction considers errors both in the modelled water levels +1 n and in the ages. Boxes in different colours show the isolation age range according to modelled water level. Black circles with error bars indicate the radiocarbon-dated age of the isolation. Despite several studies conducted in northern and western Estonia, the relative sea level curves that are based on both bio- and chronostratigraphica data have not been constructed until only recently The relative sea level curves for the Tanavjarv Klooga, Lohja and Kasmu area were compiled, considering the diatom evidence, lithostratigraphy 4C dates and geomorphological markers. The presented relative sea level curves are regular from the onset of the Litorina Sea regression (Fig. 7), showing smoothly falling sea level from 22 m a.s.l down to the present level. The isolation horizon provides regular upwards-younger radiocarbon ages and biostratigraphic proxies do not show evidence of transgression after 6000 cal yr BP. The smoothly falling relative sea level does not rule out changes in local water level during heavy storms that have been rather frequent over the last century and have causec remarkable damages on the coast (Orviku et al. 2009). In general, the reconstructed sea level curve: show a linear trend of sea level lowering that is simila to the reconstructed curves around the Gulf of Botnia (Lindén et al., 2006; Widerlund & Andres-
Fig. 7. The relative sea level curves for study areas. Lines mark the modelled possible minimum and maximum wate level (green for Lake Klooga, blue for Lake Lohja) and areas mark the modelled possible range of the water level (orange for Lake Tanavjarv and grey for Lake Kasmu). Reconstruction considers errors both in the modelled water levels +1 n and in the ages. Boxes in different colours show the isolation age range according to modelled water level. Black circles with error bars indicate the radiocarbon-dated age of the isolation. Despite several studies conducted in northern and western Estonia, the relative sea level curves that are based on both bio- and chronostratigraphica data have not been constructed until only recently The relative sea level curves for the Tanavjarv Klooga, Lohja and Kasmu area were compiled, considering the diatom evidence, lithostratigraphy 4C dates and geomorphological markers. The presented relative sea level curves are regular from the onset of the Litorina Sea regression (Fig. 7), showing smoothly falling sea level from 22 m a.s.l down to the present level. The isolation horizon provides regular upwards-younger radiocarbon ages and biostratigraphic proxies do not show evidence of transgression after 6000 cal yr BP. The smoothly falling relative sea level does not rule out changes in local water level during heavy storms that have been rather frequent over the last century and have causec remarkable damages on the coast (Orviku et al. 2009). In general, the reconstructed sea level curve: show a linear trend of sea level lowering that is simila to the reconstructed curves around the Gulf of Botnia (Lindén et al., 2006; Widerlund & Andres-
Lake Harku (59°25’N, 24°37’E) on the western border of Tallinn (Fig. 1A) became isolated rather late in the Holocene and offers a possibility to ex- amine the development and environmental changes in the lake over the past 2000 years. It is a medium size, shallow hypereutrophic lake at 1.2 m above mean sea level (a.s.1.) with an area of 163.3x104 m?
Lake Harku (59°25’N, 24°37’E) on the western border of Tallinn (Fig. 1A) became isolated rather late in the Holocene and offers a possibility to ex- amine the development and environmental changes in the lake over the past 2000 years. It is a medium size, shallow hypereutrophic lake at 1.2 m above mean sea level (a.s.1.) with an area of 163.3x104 m?
Table 1 Lithology of Lake Harku core Some drops of the remaining residue were spread over the cover slip, dried overnight and mounted permanently onto microscope slides with Naphrax medium. Between 500 and 600 valves were counted from each sub-sample under Zeiss Axio Imager Al microscope at 1000 magnification and identified to species level in order to estimate the percentage abundance of taxa.
Table 1 Lithology of Lake Harku core Some drops of the remaining residue were spread over the cover slip, dried overnight and mounted permanently onto microscope slides with Naphrax medium. Between 500 and 600 valves were counted from each sub-sample under Zeiss Axio Imager Al microscope at 1000 magnification and identified to species level in order to estimate the percentage abundance of taxa.
Fig. 2 Loss-on-ignition and magnetic susceptibility from Lake Harku core.
Fig. 2 Loss-on-ignition and magnetic susceptibility from Lake Harku core.
Fig. 3 Age-depth model considering lithological boundaries with respect to loss-on-ignition (see Fig. 2). The black line is weighted average of radiocarbon dates with error bars (blue lines) at one-sigma.
Fig. 3 Age-depth model considering lithological boundaries with respect to loss-on-ignition (see Fig. 2). The black line is weighted average of radiocarbon dates with error bars (blue lines) at one-sigma.
Fig. 4 Percentage diagram of selected diatom taxa from Lake Harku. In the transition zone (265—225 cm), the most sig- nificant feature of the diatom flora is the sharp increase in planktonic freshwater taxon Stephanodiscus parvus (up to 32%) and halophilous Cyclotella meneghiniana (up to 11%), indicating nutrient enrichment (Ander- A lithostratigraphic transect along the lake reveals that the thickness and composition of sediments in Lake Harku is quite similar (Saarse 1994). A com- parison of the LOI results of earlier studied cores (Saarse 1994) with the master cores obtained in 2005 and 2012 shows relatively good consistency. The sediment composition changes gradually from silt (Ha-1) to silty gyttja (Ha-2), algal gyttja (Ha-3) and calcareous gyttja (Ha-4; Fig. 2). Silt (core depth of 470-340 cm) contains about 5% OM, in silty gyttja (340-300 cm) the level of OM increases to 20% and in algal gyttja to 40% (Fig. 2). According to the age- depth model (Fig. 3), the silt was deposited between 2030 and 1480 cal BP, silty gyttja between 1480 and 1230 cal BP, algal gyttja from 1230 cal BP to AD 1956, and calcareous gyttja between AD 1956 and 2011. The maximum OM values measured along the 250-200 cm core interval correspond to 950—70 ca BP. The low content of CaCO, is typical of other fore-klint lakes (Saarse 1994), except for the topmost gyttja where it rapidly increased to 20%, due to the liming of soils in the lake catchment and by the estab-
Fig. 4 Percentage diagram of selected diatom taxa from Lake Harku. In the transition zone (265—225 cm), the most sig- nificant feature of the diatom flora is the sharp increase in planktonic freshwater taxon Stephanodiscus parvus (up to 32%) and halophilous Cyclotella meneghiniana (up to 11%), indicating nutrient enrichment (Ander- A lithostratigraphic transect along the lake reveals that the thickness and composition of sediments in Lake Harku is quite similar (Saarse 1994). A com- parison of the LOI results of earlier studied cores (Saarse 1994) with the master cores obtained in 2005 and 2012 shows relatively good consistency. The sediment composition changes gradually from silt (Ha-1) to silty gyttja (Ha-2), algal gyttja (Ha-3) and calcareous gyttja (Ha-4; Fig. 2). Silt (core depth of 470-340 cm) contains about 5% OM, in silty gyttja (340-300 cm) the level of OM increases to 20% and in algal gyttja to 40% (Fig. 2). According to the age- depth model (Fig. 3), the silt was deposited between 2030 and 1480 cal BP, silty gyttja between 1480 and 1230 cal BP, algal gyttja from 1230 cal BP to AD 1956, and calcareous gyttja between AD 1956 and 2011. The maximum OM values measured along the 250-200 cm core interval correspond to 950—70 ca BP. The low content of CaCO, is typical of other fore-klint lakes (Saarse 1994), except for the topmost gyttja where it rapidly increased to 20%, due to the liming of soils in the lake catchment and by the estab-
Fig. 5 Palaeogeographic maps of 2000 (A), 1500 (B), 1000 (C) and 800 cal yr BP (D) time windows. Red lines are th water level surface isobases.
Fig. 5 Palaeogeographic maps of 2000 (A), 1500 (B), 1000 (C) and 800 cal yr BP (D) time windows. Red lines are th water level surface isobases.
K6ivasoo is a small raised bog, an ancient Litorina Sea la- goon on the Képu Peninsula at 27.5 m a.s.l. (Fig. 1B), sur- rounded by wide spectrum of sandy beach formations. It has a narrow threshold in the south at an elevation of 27 m a.s.l., which was deepened by ditching the bog. Pollen and diatom re- cords of Kdivasoo deposits, taken from the central part (58°54’32”N; 22°11'56”E), were published earlier (Sarv, 1981; Sarv et al., 1982; K6nigsson et al., 1998; Saarse et al., 2000).
K6ivasoo is a small raised bog, an ancient Litorina Sea la- goon on the Képu Peninsula at 27.5 m a.s.l. (Fig. 1B), sur- rounded by wide spectrum of sandy beach formations. It has a narrow threshold in the south at an elevation of 27 m a.s.l., which was deepened by ditching the bog. Pollen and diatom re- cords of Kdivasoo deposits, taken from the central part (58°54’32”N; 22°11'56”E), were published earlier (Sarv, 1981; Sarv et al., 1982; K6nigsson et al., 1998; Saarse et al., 2000).
Sediment description of studied sites
Sediment description of studied sites
Radiocarbon dates calibrated at 95.4% probability from the Hiiumaa Island sequences Dates marked by asterisk have not been considered in the age-depth model
Radiocarbon dates calibrated at 95.4% probability from the Hiiumaa Island sequences Dates marked by asterisk have not been considered in the age-depth model
Fig. 2. Loss-on-ignition, magnetic susceptibility results and the lithological units of Loopsoo (A), Tihu (B) and Prassi (C)
Fig. 2. Loss-on-ignition, magnetic susceptibility results and the lithological units of Loopsoo (A), Tihu (B) and Prassi (C)
shore area, 1:10,000, 1:25,000 and 1:50,000 scale topographic maps were used. The peat deposits were removed from the DTM according to the1:10,000 scale soil maps (Estonian Land Survey) and unpublished reports from the Estonian Geological Survey. GIS-based water level surfaces for the Ancylus Lake (10,300 cal. yr BP) and the Litorina Sea (7800 cal. yr BP) were derived from the Estonian coastal formation database (Saarse et al., 2003, 2006). The water level surfaces were created with +1 metre residual, so that the reconstructed mean water level can fluctuate about 2 metres. In the current paper, the Litorina Sea water level surface (7800 cal. yr BP) was modified accord- ing to the assumption that the relative sea level has regressed evenly due to a linear land uplift (Morner, 1979; Lindén et al., 2006) and new water level surfaces for 8500, 7100, 6800, 5100, 4800, 4400, 2700 and 2200 cal. yr BP were interpolated.
shore area, 1:10,000, 1:25,000 and 1:50,000 scale topographic maps were used. The peat deposits were removed from the DTM according to the1:10,000 scale soil maps (Estonian Land Survey) and unpublished reports from the Estonian Geological Survey. GIS-based water level surfaces for the Ancylus Lake (10,300 cal. yr BP) and the Litorina Sea (7800 cal. yr BP) were derived from the Estonian coastal formation database (Saarse et al., 2003, 2006). The water level surfaces were created with +1 metre residual, so that the reconstructed mean water level can fluctuate about 2 metres. In the current paper, the Litorina Sea water level surface (7800 cal. yr BP) was modified accord- ing to the assumption that the relative sea level has regressed evenly due to a linear land uplift (Morner, 1979; Lindén et al., 2006) and new water level surfaces for 8500, 7100, 6800, 5100, 4800, 4400, 2700 and 2200 cal. yr BP were interpolated.
gloia elliptica, M. smithii and M. smithii var. lacustris) ata depth of 325 cm refers to the Early Litorina Sea sub-stage and the for- mation of a freshwater lagoon. Between core depths of 230 and 265 cm, large-lake diatoms disappear and the proportion of Mastogloia taxa decreases, being replaced by Cymbella ehrenbergii, C. laevis, Navicula radiosa and other shallow-wa- ter small-lake taxa. plant remains and mollusc shells (240-265 cm), coarse detritus gyttja (197-240 cm) and peat from 197 cm upwards (Sarv et al., 1982; Saarse et al., 2000; Table 1). Unlike the other studied sites, silt is highly calcareous and contains over 50% of carbon- ates. The boundary between calcareous silt and coarse detritus gyttja is richly paved with mollusc shells.
gloia elliptica, M. smithii and M. smithii var. lacustris) ata depth of 325 cm refers to the Early Litorina Sea sub-stage and the for- mation of a freshwater lagoon. Between core depths of 230 and 265 cm, large-lake diatoms disappear and the proportion of Mastogloia taxa decreases, being replaced by Cymbella ehrenbergii, C. laevis, Navicula radiosa and other shallow-wa- ter small-lake taxa. plant remains and mollusc shells (240-265 cm), coarse detritus gyttja (197-240 cm) and peat from 197 cm upwards (Sarv et al., 1982; Saarse et al., 2000; Table 1). Unlike the other studied sites, silt is highly calcareous and contains over 50% of carbon- ates. The boundary between calcareous silt and coarse detritus gyttja is richly paved with mollusc shells.
Fig. 4. Water-level curves for the Hiiumaa region, based on different proxies
Fig. 4. Water-level curves for the Hiiumaa region, based on different proxies
Fig. 5. 3D reconstruction at 8500 cal yr BP at K6ivasoo “ ‘Before the isolation, Loopsoo underwent a lagoonal (transi- tional) phase being strongly affected by the sea, as it was lo- cated on the small island in an open sea (Fig. 7A). Between
Fig. 5. 3D reconstruction at 8500 cal yr BP at K6ivasoo “ ‘Before the isolation, Loopsoo underwent a lagoonal (transi- tional) phase being strongly affected by the sea, as it was lo- cated on the small island in an open sea (Fig. 7A). Between
Fig. 6. 3D reconstructions of Hiiumaa Island at 7800 cal yr BP (A) and 4400 cal yr BP (B)
Fig. 6. 3D reconstructions of Hiiumaa Island at 7800 cal yr BP (A) and 4400 cal yr BP (B)
Fig. 7. 3D reconstructions at 7100 and 6800 cal yr BP in the surroundings of Loopsoo (A, B) and at 5100 and 4800 cal yr BP in the vicinity of Tihu (C, D)
Fig. 7. 3D reconstructions at 7100 and 6800 cal yr BP in the surroundings of Loopsoo (A, B) and at 5100 and 4800 cal yr BP in the vicinity of Tihu (C, D)
Table 1 Radiocarbon '*C dates from the Lake Lilaste sequence
Table 1 Radiocarbon '*C dates from the Lake Lilaste sequence
organic matter, MM-—mineral matter
organic matter, MM-—mineral matter
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