Holocene relative shore-level changes and Stone Age palaeogeography of the Pärnu Bay area, eastern Baltic Sea

Abstract

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.

Holocene relative shore level changes and Stone Age hunter‐gatherers in Hiiumaa Island, eastern Baltic Sea

“…2018a; Nirgi et al . 2020). During this period the water level rose in the Kõivasoo area up to elevations of 46.6–47.7 m a.s.l.…”

“…ka BP (Nirgi et al . 2020). This suggests that the previously proposed diachronous Litorina culmination in the eastern Baltic, in the range of ˜ 1000 years, is not likely.…”

A new formal subdivision of the Holocene Series/Epoch in Estonia

“…Terrestrial sedi ments of the Yoldia Sea are rare in Estonia due to the following transgressive Ancylus Lake. Recent findings (Nirgi et al 2020) in the Pärnu area, SW Estonia, report the lowest Yoldia Sea waterlevel at an altitude of ca -5.5 m, while in northern Estonia, due to uneven land uplift, the Yoldia Sea lowstand waterlevel remained below 24 m a.s.l. (Heinsalu & Veski 2007).…”

“…Therefore, traditionally stratigraphic studies in Estonia have concentrated on supraaquatic coastal sediments and the corresponding landforms that emerged as a result of glacioisostatic rebound. Due to moderate land uplift, the terrestrial landscapes and associated coastal sediments have been periodically inundated in connection with the Ancylus Lake (10 700-10 200 cal yr BP) and/or Litorina Sea (8500-7300 cal yr BP) transgressions and occur both below (Nirgi et al 2020) and above (Veski et al 2005;Rosentau et al 2013;Habicht et al 2016) the presentday sea level. The main focus in those studies has been relative sealevel (RSL) change, including the timing and ampli tude of fluctuations and resulting shoreline displacement.…”

Using Radiocarbon Dates and Tool Design Principles to Assess the Role of Composite Slotted Bone Tool Technology at the Intersection of Adaptation and Culture-History

“…It is probable that the finds from Pärnu River derive from several Stone Age sites originally located on the banks of the River Pärnu but inundated and buried under marine sediments by the rising transgressive Littorina Sea around 7500-7300 cal BP (Nirgi et al, 2019;Rosentau et al, 2011). On the basis of reported human bones (Glück, 1906, 275), a cemetery may also have been buried under the sediments (Tõrv, 2018, 242).…”