Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8868268 | Palaeogeography, Palaeoclimatology, Palaeoecology | 2018 | 16 Pages |
Abstract
A 14-m long sedimentary sequence (core PAV12) was collected in the deepest part of Lake Pavin, a maar lake located in the French Massif Central. The PAV12 sedimentary sequence documents the lake's environmental evolution since its formation 7000â¯years ago. The relationships between the catchment's vegetation cover, erosion processes and changes in trophic status were shown using a multi-proxy characterization of mineral and organic fractions supported by palynological data. The record shows a succession of lithological units starting at the base with volcanoclastic material corresponding to the early stage of Lake Pavin. The deposition of organic-rich and diatomaceous sedimentary units above volcanoclastic material indicates an evolution toward a pristine lacustrine state. The Late Holocene environmental history of this lake is marked by two tipping points reflecting major environmental disturbances at ca. 4000â¯calâ¯BP and after the deposition of erosive mass-wasting deposits (MWDs) at 1350â¯calâ¯BP (AD 600) and 650â¯calâ¯BP (AD 1300). The upper unit of core PAV12, which corresponds to the past 700â¯years, indicates that one of these MWDs was likely the driving force behind a major limnological change marked by a shift in redox-sensitive elements (i.e., current meromictic lacustrine state). The palynological diagram indicates a forested catchment where woodland clearances and agro-pastoral activities have remained limited except over the last 700â¯years. These findings suggest restricted human impact within the watershed compared to other regional archives. The reconstruction of the Lake Pavin erosion record determined from titanium and red amorphous particle fluxes highlights phases of enhanced erosion at ca. 6.5-5.5, 4.1-3.8, 3.5, 2.8-2.6, 1.6-1.4â¯calâ¯kyrâ¯BP and during the Little Ice Age (LIA). A comparison between this erosion record, palaeoenvironmental archives from Western Europe and palaeoclimatic data supports an Atlantic signal driving precipitation patterns over Lake Pavin at centennial to millennial timescales. The influence of local human activities, even on a small scale, cannot be completely discounted as their impact on erosional processes may be amplified in a steep catchment such as that found in Lake Pavin.
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Earth-Surface Processes
Authors
Léo Chassiot, Yannick Miras, Emmanuel Chapron, Anne-Lise Develle, Fabien Arnaud, Mikaël Motelica-Heino, Christian Di Giovanni,