Evolution of the alpine Critical Zone since the Last Glacial Period using Li isotopes from lake sediments

Xu Zhang*, Manon Bajard, Julien Bouchez, Pierre Sabatier, Jérôme Poulenard, Fabien Arnaud, Christian Crouzet, Marie Kuessner, Mathieu Dellinger, Jérôme Gaillardet

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Comprehending and predicting the way humans affect the Earth's Critical Zone remains a challenge. An understanding of the past changes resulting from human and non-human influences in the dynamics of the Critical Zone is crucial. Here, we use a retrospective approach to address this question based on a new lithium (Li) isotope record from the Late Glacial Period to the present from a pre-Alpine lake sediment sequence (Lake La Thuile, France). Coupled with the lake sediment archive, the investigation of present-day soils in the lake catchment suggests that lake sediments are not necessarily recording the erosoin of topsoil in the catchment. Our findings indicate that soil particles can be sorted during transportation to the lake, with finer particles being preferentially mobilized, highlighting the influence of fine particle transport on the Li isotope signature of soils and lake sediments. Characterized by low Li isotope signatures, changes in weathering signatures in lake sediments can be amplified by the combined effect of soil development and selective transport. In the La Thuile catchment, soil development was limited during the Late Glacial Period, whereas it became a dominant process during the Holocene climatic optimum together with enhanced selective transport of fine particles. Human activities since 3,000–4,000 yr cal BP induced a strong perturbation hindering both soil formation and selective transport by reinforcing erosion rates. After a period of topsoil destruction caused by intense deforestation and agriculture, lake Li isotopes record the evolution of soil profiles associated with changes in agricultural practices.
Original languageEnglish
Article number118463
JournalEarth and Planetary Science Letters
Volume624
DOIs
Publication statusPublished - 15 Dec 2023

Keywords

  • Anthropocene
  • Critical Zone
  • Fine particle transport
  • Lake sediments
  • Lithium isotopes

Fingerprint

Dive into the research topics of 'Evolution of the alpine Critical Zone since the Last Glacial Period using Li isotopes from lake sediments'. Together they form a unique fingerprint.

Cite this