No abstract

Glacio–isostatic rebound is one of the most important landscape processes affecting the northern and northeastern coast of Canada and, therefore, reconstruction of postglacial rebound rates is critical for a better understanding of landscape evolution in this region. Yet, studies reconstructing coastal palaeogeography in Northern Canadaare constrained by the limitation of shell–based radiocarbon chronologies used in dating shoreline displacementand palaeo–sea levels. This study proposes an alternative methodology for the reconstruction and dating of palaeo–sea levels, which uses testate amoeba microfossils from coastal sediments as palaeoecological markers of coastal water table shifts linked to sea level change. Our results indicate that testate amoeba–inferred water table reconstruction is a good indicator of water table drawdown due to isostatic uplift on affected coastlines. Furthermore, radiocarbon dating of distinct plant macrofossils within the transitional marine/freshwater stratigraphy avoids the inherent reservoir effect issues associated with dating of marine shells.

This study proposes a local paleo–landscape reconstruction of the Danube floodplain based on a stratigraphic sequence retrieved from Brateș Lake which, by its emplacement near the confluence of Danube – Prut rivers, was fully receptive to changes associated to hydrological, geomorphological or anthropogenic driven events. Due to its intermediate position within the Lower Danube valley Brateș Lake is a proxy for the evolution of Cotul Dunării area (the region of Danube valley turning from S–N to W–E direction) and provide valuable information about the timing of Danube river advancement to the Black Sea after its reconnection to World Ocean. The sediments were analysed to get the history of their deposition by means of accelerator mass spectrometry (AMS) 14C dating, grain–size parameters, organic matter and carbonate content, magnetic susceptibility together with paleo–fauna and pollen content which altogether led to the identification of main stages: i) delta front advance into Danube estuary (before 8000 BP), ii) shoreline foreshore deposits which describe shoreline position (8000–7900 yrs BP), iii) river floodplain development (7900–5300/5000 yrs BP), iv) lake formation (5300/5000 yrs BP – present).