Palaeoenvironmental reconstructions during the Meso- to Neolithic transition (9.2–5.3 cal. ka BP) in Northwestern France: Palynological evidences

Abstract

Sedimentological, palynological, and micropalaeontological studies carried out throughout the first half of the Holocene, during the Mesolithic/Neolithic transition in the Bay of Brest (i.e. 9200-9000 and 6600-5300 cal. BP) and in the Bay of Douarnenez (i.e. 9200-8400 cal. BP), allowed characterizing coastal environmental changes under the increasing influence of the relative sea-level rise. The gradual flooding of the two studied sites implied a transition from river valleys to oceanic bays as revealed by the gradual retreat of salt marsh environments, as detected through palynological analysis. In addition, these high-resolution studies highlight the regional imprint of the North Atlantic millennial climate variability in northwestern coastal environments. Two cold climate events are indeed suggested to have been locally marked by a moisture increase, mainly detected by increases in Lingulodinium machaerophorum, Corylus, and Alnus percentages at 8550 cal. BP in the Bay of Douarnenez and at 6250 cal. BP in the Bay of Brest. Moreover, regarding the Neolithic transition timing in the Bay of Douarnenez, large pollen grains of Poaceae (i.e. Cerealia-type pollen grains) have been detected at around 8600 cal. BP, that is, 1500 years before the general accepted cereal cropping appearance in Western France. These results, consistent with other palynological studies conducted in the French Atlantic coast, could underline a Mesolithic 'proto-agriculture' in Brittany.

Striking forest revival at the end of the Roman Period in north-western Europe

“…2G). Tree percentages exceed even those values recorded close to the studied area during the Mesolithic at around 9000 years BP 25 (~ 80%; dotted line on Fig. 2G), which is a period characterized by few or no major human-forced environmental changes.…”

“…Reservoir age can, however, vary spatially and temporally. The local deviation from the oceanic mean (ΔR) is estimated at − 40 ± 23 years off the Brittany peninsula 46 , as confirmed by a reservoir age test in the BB 25 . We applied this additional correction to all dating obtained on marine carbonate material.…”

Oceanic versus continental influences over the last 7 kyrs from a mid-shelf record in the northern Bay of Biscay (NE Atlantic)

“…Nonetheless, there remains a need to better understand the paleohydrological signature of this complex group along onshore-offshore gradients and in the specific case of sediments from stratified, frontal and mixed-water regions (Marret et al, 2004). In order to discuss ecological changes within a marine as opposed to a continental context, we compared dinocyst data from three sediment cores strategically located along a marine (distal or offshore) to coastal (proximal or onshore) transect across the BoBy (Figure 5): i) the full-oceanic MD95-2002 core (2,174 m water depth; Zumaque et al, 2017;Figure 1b) was directly influenced by the North Atlantic Circulation (Frew et al, 2000); ii) the shelf CBT-CS11 core (73 m water depth; this study; Figure 1b) was under mixed oceanic and winter fluvial influences; iii) the coastal "A" core, collected within the Bay of Brest, comes from a shallow macro-estuarine environment (8 m water depth; Lambert et al, 2019;Figure 1b). By including different bathymetric ranges from the same temperate latitudes, we accounted for potential changes in hydrographical and/or stratification conditions that may have resulted from the Holocene relative sea level (RSL) rise under variable climate and/or anthropogenic forcings.…”

“…b) Map illustrating the general surface circulation of the Bay of Biscay (Koutsikopoulos and Le Cann, 1996) and the extent of the Loire and Gironde catchment areas. Are indicated the locations of the CBT-CS11 core (studied site) and of the other cited cores in the text: VK03-58bis core (Naughton et al, 2007); A core (Lambert et al, 2019); MD95-2002 core (Zumaque et al, 2017). Map performed using the online EMODnet Portal for Bathymetry (http://www.emodnet-bathymetry.eu/) and adapted from Mojtahid et al (2019).…”

Holocene vegetation, fire and land use dynamics at Lake Svityaz, an agriculturally marginal site in northwestern Ukraine

“…Moreover, local domestication or cultivation efforts may have started already during the Mesolithic, before the full Neolithisation material package was introduced (e.g. Tinner et al 2007 ; Miras et al 2010 ; Lambert et al 2019 ).…”