Characterization of Saharan and Sahelian dust sources based on geochemical and radiogenic isotope signatures

Guinoiseau, Damien; Singh, Satinder Pal; Galer, S. J. G.; Abouchami, W.; Bhattacharyya, R.; Kandler, Konrad; Bristow, Charlie S.

doi:10.1016/j.quascirev.2022.107729

Cited by 9 publications

(7 citation statements)

References 98 publications

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“…These findings exclude the Bodélé Depression as a likely source, which showed high levels of AOT near its source region, according to MODIS satellite imagery shown in Figure 2. Consistent with previous studies [25,44], this work demonstrates that established western Saharan PSAs must be geographically refined to accurately account for dust emissions in the tropical Atlantic.…”

Section: Source Region Quantificationsupporting

confidence: 86%

“…By identifying source-specific elemental markers in desert outflows, a basis for model and satellite validation of regional desert aerosol flux and its Atlantic Ocean deposition can be achieved. Elemental isotope markers in downwind dust aerosol samples can characterize regional precursors of Saharan dust emission activity, advancing the prediction of dustclimate feedback effects [24,25]. This technique can also distinguish anthropogenic sources of dust emissions related to mining, industrial, agricultural, and other land-usage practices, shown to be chemically detectable at SAL receptor sites [26,27].…”

Section: Introductionmentioning

confidence: 99%

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Distinguishing Saharan Dust Plume Sources in the Tropical Atlantic Using Elemental Indicators

Yeager,

Morris

2024

Atmosphere

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The Sahara Desert is the largest contributor of global atmospheric dust aerosols impacting regional climate, health, and ecosystems. The climate effects of these dust aerosols remain uncertain due, in part, to climate model uncertainty of Saharan source region contributions and aerosol microphysical properties. This study distinguishes source region elemental signatures of Saharan dust aerosols sampled during the 2015 Aerosols Ocean Sciences Expedition (AEROSE) in the tropical Atlantic. During the 4-week campaign, cascade impactors size-dependently collected airborne Saharan dust particulate upon glass microfiber filters. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analysis differentiated metal isotope concentrations within filter samples from various AEROSE dust sampling periods. Back-trajectory analysis and NOAA satellite aerosol optical depth retrievals confirmed source regions of AEROSE ’15 dust samples. Pearson correlational statistics of source region activity and dust isotope concentrations distinguished the elemental signatures of North African potential source areas (PSAs). This study confirmed that elemental indicators of these PSAs remain detectable within dust samples collected far into the marine boundary layer of the tropical Atlantic. Changes detected in dust elemental indicators occurred on sub-weekly timescales across relatively small sampling distances along the 23W parallel of the tropical Atlantic. PSA-2 emissions, covering the western coast of the Sahara, were very strongly correlated (R2 > 0.79) with Ca-44 isotope ratios in AEROSE dust samples; PSA-2.5 emissions, covering eastern Mauritania and western Mali, were very strongly correlated with K-39 ratios; PSA-3 emissions, spanning southwestern Algeria and eastern Mali, were very strongly correlated with Fe-57 and Ti-48 ratios. The abundance of Ca isotopes from PSA-2 was attributed to calcite minerals from dry lakebeds and phosphorous mining activities in Western Sahara, based on source region analysis. The correlation between K isotope ratios and PSA-2.5 was a likely indicator of illite minerals near the El Djouf Desert region, according to corroboration with mineral mapping studies. Fe and Ti ratio correlations with PSA-3 observed in this study were likely indicators of iron and titanium oxides from Sahelian sources still detectable in Atlantic Ocean observations. The rapid changes in isotope chemistry found in AEROSE dust samples provide a unique marker of Saharan source regions and their relative contributions to desert outflows in the Atlantic. These elemental indicators provide source region apportionments of Sahara Desert aerosol flux and deposition into the Atlantic Ocean, as well as a basis for model and satellite validation of Saharan dust emissions for regional climate assessments.

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Section: Source Region Quantificationsupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Distinguishing Saharan Dust Plume Sources in the Tropical Atlantic Using Elemental Indicators

Yeager,

Morris

2024

Atmosphere

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“…S3 ). In addition, we used the oxide concentration dataset from soil and airborne dust aerosol measurements in or from western North Africa (e.g., Algeria, Mali, Mauritania, Morocco, and Senegal) to represent Saharan dust (Supplementary Table S1 ) because Saharan dust that travels to Greenland across the Atlantic Ocean originates primarily from this region 81 .…”

Section: Methodsmentioning

confidence: 99%

Millennial-scale variability of Greenland dust provenance during the last glacial maximum as determined by single particle analysis

Ro,

Park,

Yoo

et al. 2024

Sci Rep

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Greenland ice core records exhibited 100-fold higher dust concentrations during the Last Glacial Maximum (LGM) than during the Holocene, and dust input temporal variability corresponded to different climate states in the LGM. While East Asian deserts, the Sahara, and European loess have been suggested as the potential source areas (PSAs) for Greenland LGM dust, millennial-scale variability in their relative contributions within the LGM remains poorly constrained. Here, we present the morphological, mineralogical, and geochemical characteristics of insoluble microparticles to constrain the provenance of dust in Greenland NEEM ice core samples covering cold Greenland Stadials (GS)-2.1a to GS-3 (~ 14.7 to 27.1 kyr ago) in the LGM. The analysis was conducted on individual particles in microdroplet samples by scanning electron microscopy with energy dispersive X-ray spectroscopy and Raman microspectroscopy. We found that the kaolinite-to-chlorite (K/C) ratios and chemical index of alteration (CIA) values were substantially higher (K/C: 1.4 ± 0.7, CIA: 74.7 ± 2.9) during GS-2.1a to 2.1c than during GS-3 (K/C: 0.5 ± 0.1, CIA: 65.8 ± 2.8). Our records revealed a significant increase in Saharan dust contributions from GS-2.1a to GS-2.1c and that the Gobi Desert and/or European loess were potential source(s) during GS-3. This conclusion is further supported by distinctly different carbon contents in particles corresponding to GS-2.1 and GS-3. These results are consistent with previous estimates of proportional dust source contributions obtained using a mixing model based on Pb and Sr isotopic compositions in NEEM LGM ice and indicate millennial-scale changes in Greenland dust provenance that are probably linked to large-scale atmospheric circulation variabilities during the LGM.

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“…Both major dust sources identified were considered to be driven mainly by natural factors since they appear to be little affected by anthropogenic activities. This is based on several lithogenic tracers (geochemical and radiogenic Sr-Nd-Pb isotope proxies) as well as on the geological subdivision of North African geological provinces, Guinoiseau et al (2022) have defined six potential source areas (PSA), viz. : Libya-Algeria-Mali (PSALAM), Libya-Egypt (PSALE), Bodélé Depression (PSABD), Mali Center (PSAMC), West African Coast (PSAWAC) and Mauritania (PSAMa), providing a unique chemical and isotope fingerprint for each PSA.…”

Section: Location Of Source Areasmentioning

confidence: 99%

“…Though some plumes head northwards towards Europe, others travel eastwards across the Mediterranean to the Middle East (Kandler et al, 2007;Kubilay et al, 2000;Rodríguez et al, 2001). The Bodélé Depression in Chad and the El Djouf Desert in Western Sahara, are currently thought to be the two largest dust-emitting sources in North Africa (Guinoiseau et al, 2022;Prospero et al, 2002). Saltation and auto-abrasion processes are the principal causes of dust suspension from these source regions (Bristow and Moller, 2018).…”

Section: Propagation Dynamics Of Saharan Dust Stormsmentioning

confidence: 99%

The Saharan dust plume: Current knowledge on the impact on health, human activities, and the ecosystem, with comments on research gaps

Olarewaju

Fajinmi

Davies

et al. 2023

Preprint

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A massive amount of dust estimated at a million tons is released from the Sahara Desert each year into the atmosphere and travels over the North Atlantic Ocean, commonly referred to as the Saharan dust plume (SDP). With its ability to travel over very long distances across the sea, the SDP is of enormous global importance, affecting climatic processes, and playing a significant role in nutrient cycles, sedimentary cycles, and soil development. On the other hand, from an environmental health perspective, the SDP degrades air quality, posing serious health threats to humans, especially to people with lung conditions. Recent literature documents health issues, including respiratory and cardiovascular diseases and even death in extreme cases. Despite this knowledge, large uncertainties exist in our ability to predict future trends in Saharan dust emissions and model-projected atmospheric circulation patterns. Employing a comprehensive search of the recent literature, this study reviews present knowledge of the sources, composition and propagation dynamics of the SDP and the impact of its contained atmospheric particulates on health, ecosystems, and human activities to be able to formulate credible mitigation measures and unveil areas where further research is needed for improving on these formulations. A comprehensive list of the more recent references (mainly post-dating 2010) is assembled to aid the search process of those wanting to contribute to filling these important knowledge gaps.

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Characterization of Saharan and Sahelian dust sources based on geochemical and radiogenic isotope signatures

Cited by 9 publications

References 98 publications

Distinguishing Saharan Dust Plume Sources in the Tropical Atlantic Using Elemental Indicators

Distinguishing Saharan Dust Plume Sources in the Tropical Atlantic Using Elemental Indicators

Millennial-scale variability of Greenland dust provenance during the last glacial maximum as determined by single particle analysis

The Saharan dust plume: Current knowledge on the impact on health, human activities, and the ecosystem, with comments on research gaps

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