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Fossil diatoms and litho-stratigraphic changes in the Guern El Louläilet depressions, NW of the Great Western Erg, Algeria, were analysed to infer paleoenvironmental changes in the northern Algerian Sahara during the Early and Middle Holocene. Analysis was based on calcareous diatomite collected from four outcrops within the depressions. The diatom flora consists of brackish and epiphytic taxa, such as Epithemia argus, with percentages of some freshwater and planktonic species, mainly Cyclotella distinguenda. Results provide evidence for two Holocene lacustrine episodes related to the African Humid Period. The first episode (Early to Middle Holocene) was characterized by abrupt development of shallow-water conditions, with extensive littoral zones and evaporative periods that coincided with high salt concentrations in warm, alkaline water (swampy conditions). A second episode (Middle to Late Holocene?), with brackish water and alkaline conditions, coincided with a decline in lake water level that is attributed to drier conditions. Our findings are consistent with those of other studies from the area and demonstrate similar environmental changes occurred after 9300 cal yr BP at sites within the region. The main drivers of the African Humid Period were the northward shift of the Intertropical Convergence Zone (ITCZ) and expansion of summer monsoonal rains. Our study sites were located in the northern Sahara, where variations in the position of the Intertropical Convergence Zone (ITCZ) did not affect rainfall. Early and Middle Holocene climate fluctuations detected in this study may have been caused by intensification of winter precipitation in the south-central Mediterranean and its penetration southward.

An overview of the diatom flora of the last interglacial (Eemian) lacustrine gyttja deposit at Sokli, northeastern Finland is presented together with descriptions including photomicrographs of resting spores similar to the Aulacoseira islandica-skvortzowii group, not found in recent material from Europe. Comparisons are made with literature data on similar taxa. The morphology of the resting spores (e.g., the number of striae and areolae in 10 mu m) links them to the A. islandica-skvortzowii group, but the lack of vegetative cells in the Sokli record makes the determination of true synonymy difficult. The presence of spores similar/related to the A. islandica-skvortzowii group in the Sokli Eemian palaeolake may reflect a more widespread distribution of this group in the past.

Using diatoms, pollen, and geochemistry, we explore human habitation around Lina myr, Gotland, in relation to shore displacement. Archeological evidence has shown that Lina myr was an important area for its prehistoric human inhabitants. We investigate if and when Lina myr was connected to the sea and could therefore have been part of an inland water system useful for transport. A chronology was based on C-14 AMS dating of terrestrial macrofossils and bulk sediments with dates ranging between 9100 and 2360 cal. yr BP. The initiation of the Littorina transgression was dated to 8500 cal. yr BP. A twofold pattern for the maximum sub-phase of the Littorina Sea is suggested from 8100 to 7500 cal. yr BP and from 6500 to 6000 cal. yr BP. The onset of cultivation and grazing was indicated by the presence of Hordeum and Plantago lanceolata in the pollen record during the Late Neolithic, at about 4580 cal. yr BP. During this time sea level was relatively higher than today and the Lina myr basin was connected with the Littorina Sea, which it continued to be until isostatic uplift caused it to become isolated at about 3820 cal. yr BP. After about 3000 cal. yr BP, human-made landscape changes intensified, grasslands increased, and shrublands decreased.

In conjunction with the extensive archaeological projects conducted at the current outlet of Sweden’s second largest lake, Lake Vättern, macrofossil, pollen and diatom records have been studied from 14C-dated lake and river sediments from River Motala Ström in Motala and Lake Boren. These investigations have revealed sedimentary evidence of the Yoldia Sea regression, the Ancient Lake Vättern transgression, and the following stepwise river formation process. Around 9000 cal BC, two small kettlehole basins at Strandvägen and Kanaljorden became isolated from the Baltic basin. As the ice sheet retreated further north, the isostatic uplift isolated the Vättern basin from the Baltic basin. Due to the uneven isostatic uplift, the basin tilted toward the south, and the Ancient Lake Vättern transgression started in Motala. The threshold in Motala at 92.5 m a.s.l. was reached around 7200 cal BC, and River Motala Ström was formed. 14C-dated diatom records from Lake Boren, and shoreline deposits in Motala, confirm this event. The water level in Lake Vättern initially fell around 1.5 m, and around 5800 cal BC, a second erosional event cut down the threshold to modern day level. At this time, the Late Mesolithic settlements in Motala were established and expanded.

Holocene relative shore level (RSL) changes and Stone Age palaeogeography of Hiiumaa Island are reconstructed using airborne LiDARelevation data, sedimentological and archaeological proxies as well asGIS-based landscape modelling. Altogether, 38RSLindex and limiting points are used in modelling and presented in the current paper. The highest raised shorelines of the Ancylus Lake and Litorina Sea, mapped at the elevations of 47 and 26 m a.s.l., formed around 10.3 and 7.4 cal. kaBP, respectively. The reconstructedRSLcurve reveals a 20-m drainage of Ancylus Lake followed by a land-uplift-driven 3-m regression during the Initial Litorina Sea period.RSLrise during the Litorina Sea transgression remained below 4 m and its maximum was reached later than proposed previously, discarding therefore the idea of highly diachronous Litorina culmination in the eastern Baltic Sea. During the period 7.4-6.0 cal. kaBP,RSLfall was about 4.3 mm a(-1), and afterwards in average at about 1 mm(-1)less suggesting deceleration in isostatic rebound. suggesting deceleration in isostatic rebound. Palaeogeographical reconstructions show that during its earliest occupation at about 7.6 cal. kaBPless than 1% of the terrain of Hiiumaa was above the sea level and that wind-protectedSEexposed shores were the most preferred campsite locations of Late Mesolithic and Neolithic settlers. These campsites are located successively at lower elevations following the shoreline retreat and show repeated use of this coastal area between 7.6 and 4.6 cal. kaBP. Due to the spread of the Corded Ware culture around 4.8-4.0 cal. kaBPthe settlements of Hiiumaa Island and many other coastal areas of the eastern Baltic moved from the coast to more suitable places for agriculture and animal husbandry.

The shore displacement and palaeogeography of the Pärnu Bay area, eastern Baltic Sea, during the Stone Age, were reconstructed using sedimentological and archaeological proxies and GIS-based landscape modelling. We discovered and studied buried palaeochannel sediments on the coastal lowland and in the shallow offshore of the Pärnu Bay and interpreted these data together with previously published shore displacement evidence. The reconstructed relative shore-level (RSL) curve is based on 78 radiocarbon dates from sediment sequences and archaeological sites in the Pärnu Bay area and reported here using the HOLSEA sea-level database format. The new RSL curve displays regressive water levels at -5.5 and -4 m a.s.l. before the Ancylus Lake and Litorina Sea transgressions, respectively. According to the curve, the total water-level rise during the Ancylus Lake transgression (10.7-10.2 cal. ka BP) was around 18 m, with the average rate of rise about 35 mm per annum, while during the Litorina Sea transgression (8.5-7.3 cal. ka BP), the water level rose around 14 m, with average rate of 12 mm per annum. During the short period around 7.8-7.6 cal. ka BP, the RSL rose in Pärnu, but probably also in Samsø (Denmark), Blekinge (Sweden) and Narva-Luga (NE Estonia-NW Russia), faster than the concurrent eustatic sea level calculated from the far-field sites. The palaeogeographic reconstructions show the settlement patterns of the coastal landscape since the Mesolithic and provide new perspective for looking Mesolithic hunter-fisher-gatherer settlement sites on the banks of the submerged ca. 9000 years old river channel in the bottom of the present-day Pärnu Bay.