Holocene paleoenvironmental reconstructions in western Brittany (Bay of Brest) with a focus on the Neolithic-Bronze transition

The Bay of Brest (BB, western Brittany, NW France) is a semi-enclosed basin of 180 km² subject to macro-tidal dynamics and to the fluvial influences of the rivers Aulne and Elorn, which combined drain watersheds of 2,600 km². This coastal environment is subject to natural climate oscillations overlaid on the long-term landscape transformations inherited from the post-glacial sea level rise and increasing anthropogenic forcing since the Neolithic (6.9 ka BP), and especially from the Bronze Age (4.2 ka BP) onwards. The BB therefore appears suitable for reconstruction of the interactions between climate, environment and human dynamics across the Holocene. In this study, a palynological stack was created based on eight cores, allowing us to discuss the BB paleolandscape evolution over the last 7 kyrs. Since the Neolithic period, the forest cover of this areas has decreased in favour of open and agro-pastoral landscapes. This trend is not uniform, however: forest cover first declined slowly around 4 ka BP, then strongly decreased at the end of the Iron Age, before experiencing a revival of about 5 centuries at the end of the Roman period (1.7–1.2 ka BP). Finally, a drastic fall of tree pollen taxa is recorded at the start of the Middle Ages, related to the population dynamics around Brest Harbour and to intensive agro-pastoral practices. This study is the first on long-term Holocene trends in the BB paleolandscapes that allows discussion of both climatic and anthropogenic forcing over the last 7 kyrs BP at an unprecedent study resolution of 35 years. We also place this local evolution in a wider regional context so as to detail interactions between natural and anthropic forcings over time.

Disciplines

Cross-discipline, Human activities, Environment, Marine geology

Keywords

Holocene, Bay of Brest, Palynology, Precipitation regimes, Anthropization, Neolithic, Bronze Age

Location

48.425853N, 48.256767S, -4.170587E, -4.705842W

Devices

Cores Location Lat/Long Depth (m) Length (cm) Project/Cruise Publication

A

Bay of Roscanvel 48°19.207'N 4°31.771'W 8.2 418 project "Défi Golfe de Gascogne" - cruise Ifremer VIBARMOR Lambert et al., 2019
SRQ3-KS24 Bay of Roscanvel 48°19.330'N 4°31.369'W 26 181.5 cruise Ifremer SERABEQ-03 Lambert et al., 2019
PALM-KS05 Brest harbour 48°22.880'N 4°26.911'W 6 176 cruise Ifremer PALMIRA Ehrhold et al., 2021
PALM-KS06 Brest harbour 48°22.879'N 4°26.91'W 7.1 344 cruise Ifremer PALMIRA New in this study
G Rozegat 48°19.241'N 4°23.082'W 7.4 358 project "Défi Golfe de Gascogne" - cruise Ifremer VIBARMOR Lambert et al., 2020
ESSCALICO-KS02 Rozegat 48°18.767'N 4°24.456'W 8 253.5 cruise Ifremer EssCALICO Lambert et al., 2020
F Aulne mouth 48°18.236'N 4°17.519'W 21 345 project "Défi Golfe de Gascogne" - cruise Ifremer VIBARMOR New in this study
SRQ3-KS22 Aulne mouth 48°18.359'N 4°17.902'W 9.4 110 cruise Ifremer SERABEQ-03 Lambert, 2017
PM1 Porsmilin (coastal peat) 48°21′18.67″N 4°40′45.10″W - 0.5 NGF 430 project ANR COCORISCO Fernane et al., 2014
PM3 Porsmilin (coastal peat) 48°21′24.88″N 4°40′44.41″W + 6.5 NGF 370 project ANR COCORISCO Fernane et al., 2014

- interface cores : see Lambert et al., 2017

 

Data

FileSizeFormatProcessingAccess
Bay of Roscanvel sector (Cores A and SRQ3-KS24) - model age and palynological data
184 KoXLS, XLSXRaw data
Brest harbour sector (Cores PALM-KS05 and PALM-KS06) - model age, sedimentology and palynological data
1 MoXLS, XLSXRaw data
Mouth of Aulne sector (Cores SRQ3-KS22 and F) - model age, sedimentology and palynological data
106 KoXLS, XLSXRaw data
Plougastel peninsula sector (Cores ESSCALICO-KS02 and G) - model age and palynological data
158 KoXLS, XLSXRaw data
Porsmilin coastal peat (Cores PM1 and PM3) - model age and palynological data
224 KoXLS, XLSXRaw data
Bay of Brest interfaces (41 modern interface cores) - palynological data
2 MoXLS, XLSXRaw data
How to cite
Valero Clara, Penaud Aurélie, Lambert Clément, Vidal Muriel, David Ophélie, Leroux Estelle, Pailler Yvan, Nicolas Clément, Poncin Olivier, Stephan Pierre, Siano Raffaele, Ehrhold Axel (2024). Holocene paleoenvironmental reconstructions in western Brittany (Bay of Brest) with a focus on the Neolithic-Bronze transition. SEANOE. https://doi.org/10.17882/99422

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