Lakes as Recorders of Earth Surface Dynamics From Yearly to Plurimillennial Time-Scales

Arnaud, Fabien; Sabatier, Pierre

doi:10.1016/b978-0-12-819166-8.00125-0

Cited by 4 publications

(2 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…sequence and processed at the litho-preparation facilities of the EDYTEM laboratory (Arnaud and Sabatier, 2022). Microscopic observations were obtained on a Leica DM4 P at the Geoazur Laboratory at 25x and 1000x magnification using plane-polarized (PPL), crossed-polarized (XPL) and oblique incident (OIL) lights.…”

Section: Sedimentological Analysesmentioning

confidence: 99%

“…The main objective of this study is to quantify variations of long-term Awash solid sedimentary discharges to establish regional flood activity and to reconstitute the hydrological regime of the Awash River. Moreover, human activities can also play a key role in sediment availability, which is a function of soil erodibility and transport processes (Arnaud et al, 2016;Arnaud and Sabatier, 2022;Bajard et al, 2017Bajard et al, , 2016Syvitski et al, 2022). We aim first to identify the hydro-sedimentary processes in the Afambo and Gemeri Lake basins (Central Afar Region, Ethiopia) under human and hydroclimate/meteorological forcing over the longterm.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Fifty-year seasonal variability of East African droughts and floods recorded in Central Afar lake sediments (Ethiopia) and their connections with ENSO

Mologni,

Revel,

Chaumillon

et al. 2024

Preprint

View full text Add to dashboard Cite

Abstract. Understanding past and present hydro-system feedbacks to global ocean-atmospheric interactions represents one of the main challenges to preventing droughts, extreme events and related human catastrophes in the face of global warming, especially in arid and semiarid environments. In eastern Africa, the El Niño-Southern Oscillation (ENSO) was identified as one of the primary drivers of precipitation variability affecting water availability. However, the northern East African Rift System (EARS) still suffers from ENSO climate teleconnection and the underrepresentation of predictive models because of the scarcity of local-to-regional historical or palaeo-data. In this paper, we provide a 50-year seasonal flood/drought chronicle of the Awash River catchment from the study of laminated sediment from Gemeri and Afambo lakes (Central Afar region, Ethiopia), with the aim of reconstructing the magnitude of regional hydro-climatic events. Pluri-centimetric micro-laminated lithogenic facies alternating with pluri-millimetric carbonate-enriched facies are investigated in both lakes. We couple dating methods including radiocarbon, short-lived radionuclides, palaeomagnetic field variations and varve counting on both lake deposits to build a high-resolution age model and to discuss the regional hydro-sedimentary dynamics of the Awash River over the last ~700 years, with a focus on the last fifty years. Using a multiproxy approach, we observe that following a multi-centennial enhanced hydrological period, the two lakes experienced a gradual decrease in river load inflow since 1979 CE, attaining extreme drought and high evaporative conditions between 1991 and 1997 CE. In 2014, the construction of a dam and the improvement of agricultural hydraulic management in the lower Awash River plain impacted the erodibility of local soils and the hydro-sedimentary balance of the lake basins, as evidenced by a disproportionate sediment accumulation rate. Comparison of our quantitative reconstruction with i) lake water surface evolution expressed in Km2, ii) the interannual Awash River flow rates expressed in mm/yr, and iii) the El Niño 3.4 model highlights the intermittent connections between ENSO SST anomalies, regional droughts and hydrological conditions in the northern EARS.

show abstract

Section: Sedimentological Analysesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fifty-year seasonal variability of East African droughts and floods recorded in Central Afar lake sediments (Ethiopia) and their connections with ENSO

Mologni,

Revel,

Chaumillon

et al. 2024

Preprint

View full text Add to dashboard Cite

show abstract

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

Zhang,

Bajard,

Bouchez

et al. 2023

Earth and Planetary Science Letters

View full text Add to dashboard Cite

Half of the soil erosion in the Alps during the Holocene is explained by transient erosion crises as a consequence of rapid human land clearing

Mazure,

Saulnier,

Giguet-Covex

et al. 2024

The Holocene

View full text Add to dashboard Cite

Human land use changes have altered soil erosion for millennia with extensive consequences on terrestrial and aquatic ecosystems as well as on biogeochemical cycles along the land-ocean continuum. Despite their great importance, past erosion trends have high uncertainties limiting quantitative estimates of long-term erosion dynamics. Here, we applied a new approach combining well-dated paleo-records of soil erosion from lake sediments and a spatially distributed semi-empirical model to simulate annual soil erosion in six lake watershed systems in the Northwestern Alps during the Holocene. Progressive and abrupt changes in soil erosion are detected in the six watersheds. Progressive erosion explains most of the soil exports observed during the Early to Mid-Holocene period (from 11,700 to 3000 cal. yr. BP), while transient erosion crises (i.e., periods of abrupt increase in the erosion rates spanning approximately 1000 ± 500 years) led to massive soil losses during the Late-Holocene period (from 3000 to 1000 cal. yr. BP). Our coupled approach of proxy-model reconstruction shows that the transient erosion crises represent the half of the total soil erosion exports during the Holocene. These estimates defy current representations of large-scale soil erosion during the Holocene that do not consider transient erosion crises, hence potentially underestimating the anthropogenic perturbation of lateral fluxes and fate along the land-ocean continuum. Our results further suggest that erosion and/or land cover proxies need to be consistently integrated into model approaches when attempting to estimate past variations in mass exports from terrestrial to aquatic ecosystems over centennial to millennial timescales.

show abstract

Lakes as Recorders of Earth Surface Dynamics From Yearly to Plurimillennial Time-Scales

Cited by 4 publications

References 43 publications

Fifty-year seasonal variability of East African droughts and floods recorded in Central Afar lake sediments (Ethiopia) and their connections with ENSO

Fifty-year seasonal variability of East African droughts and floods recorded in Central Afar lake sediments (Ethiopia) and their connections with ENSO

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

Half of the soil erosion in the Alps during the Holocene is explained by transient erosion crises as a consequence of rapid human land clearing

Contact Info

Product

Resources

About