A three-year time series of mineral dust deposits on the West African margin: Sedimentological and geochemical signatures and implications for interpretation of marine paleo-dust records

Skonieczny, Charlotte; Bory, A.; Bout-Roumazeilles, V.; Abouchami, W.; Galer, S. J. G.; Crosta, Xavier; Diallo, Aboubacry; Ndiaye, T.

doi:10.1016/j.epsl.2012.12.039

Cited by 70 publications

(78 citation statements)

References 57 publications

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“…The observed occurrence of the minerals quartz, feldspar, mica, chlorite and calcite has also been described for the bulk size fraction of soil samples and dust samples collected in Mauritania (Schütz and Sebert, 1987). Palygorskite, mica and chlorite have also been detected by Skonieczny et al (2013) in the PM 30 size fraction of a 3-year time series of dust deposition at M'Bour, Senegal, more than 500 km south of Iwik, Mauritania. Smectite and kaolinite, which were absent in the Iwik samples, were the dominant minerals of the dust sampled at M'Bour (Skonieczny et al, 2013).…”

Section: Dust Mineralogical Compositionmentioning

confidence: 91%

“…The particle size correlated to local surface wind speed suggesting the contribution of local dust (Kandler et al, 2009). In contrast, in coastal Senegal, dust is sourced from the Sahel during winter as shown by low illite / kaolinite (I / K) ratios and lower palygorskite contents as opposed to the summer samples, which were suggested to originate from the Sahara (Skonieczny et al, 2013). Further, the I / K ratio in dust sampled on the Cape Verde Islands showed that dust was derived from strongly varying sources: northwestern Sahara, central and southern Sahara, and the Sahel (Caquineau et al, 2002).…”

Section: Introductionmentioning

confidence: 97%

“…Four-day back trajectories at altitudes of 10 (following Stuut et al, 2005), 100, 3000, 4500 (following Skonieczny et al, 2013) and 5500 m were calculated ending at the dust collector site Iwik (19 • 52 N, 16 • 17 W) and at the proximal marine trap site CBi (20 • 46 , 18 • 44 W) using the Hybrid Single Particle Langrangian Integrated Trajectory (HYSPLIT) model (Stein et al, 2015) and the reanalysis dataset (2.5 • spatial resolution) on the NOAA website (http://ready.arl. noaa.gov).…”

Section: Mapping With Arcmapmentioning

confidence: 99%

“…The source regions of Saharan dust have been studied frequently by analysing the mineralogical composition of dust collected at continental sites (e.g. Skonieczny et al, 2013Skonieczny et al, , 2011Schütz and Sebert, 1987;Kandler et al, 2009;Khiri et al, 2004), during aircraft flights (e.g. Formenti et al, 2008), on research ships (Chester et al, 1971(Chester et al, , 1972Stuut et al, 2005;Aston et al, 1973;Chester and Johnson, 1971a, b) and with gravity cores off NW Africa (Biscaye, 1964(Biscaye, , 1965Lange, 1982;Rateev et al, 1969;Griffin et al, 1968;Diester-Haass and Chamley, 1978;Meyer et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

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Seasonal provenance changes of present-day Saharan dust collected on- and offshore Mauritania

Friese¹,

Hateren²,

Vogt³

et al. 2017

Preprint

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Abstract. Saharan dust has a crucial influence on the earth climate system and its emission, transport and deposition are intimately related to, e.g., wind speed, precipitation, temperature and vegetation cover. The alteration in the physical and chemical properties of Saharan dust due to environmental changes is often used to reconstruct the climate of the past. However, to better interpret possible climate changes the dust source regions need to be known. By analysing the mineralogical composition of transported or deposited dust, potential dust source areas can be inferred. Summer dust transport off northwest Africa occurs in the Saharan air layer (SAL). In continental dust source areas, dust is also transported in the SAL; however, the predominant dust input occurs from nearby dust sources with the low-level trade winds. Hence, the source regions and related mineralogical tracers differ with season and sampling location. To test this, dust collected in traps onshore and in oceanic sediment traps off Mauritania during 2013 to 2015 was analysed. Meteorological data, particle-size distributions, back-trajectory and mineralogical analyses were compared to derive the dust provenance and dispersal. For the onshore dust samples, the source regions varied according to the seasonal changes in trade-wind direction. Gibbsite and dolomite indicated a Western Saharan and local source during summer, while chlorite, serpentine and rutile indicated a source in Mauritania and Mali during winter. In contrast, for the samples that were collected offshore, dust sources varied according to the seasonal change in the dust transporting air layer. In summer, dust was transported in the SAL from Mauritania, Mali and Libya as indicated by ferroglaucophane and zeolite. In winter, dust was transported with the trades from Western Sahara as indicated by, e.g., fluellite.

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Section: Dust Mineralogical Compositionmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 97%

Section: Mapping With Arcmapmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Seasonal provenance changes of present-day Saharan dust collected on- and offshore Mauritania

Friese¹,

Hateren²,

Vogt³

et al. 2017

Preprint

View full text Add to dashboard Cite

show abstract

“…Although part of the carbonate fraction might also have a terrestrial provenance as transported, for instance, with Saharan dust (Chester et al, 1977;Correggiari et al, 1989;Rutten et al, 2000), this does not seem to be the case with the investigated samples. Like other aeolian particles, aeolian carbonates are typically better sorted than those formed in situ, as shown by a well-sorted unimodal distribution due to gravitational settling during atmospheric transport (Skonieczny et al, 2013). The predominance of very poorly sorted grain size distributions within the bulk sediment samples (Fig.…”

Section: Lithogenics and Carbonatementioning

confidence: 98%

Composition and sources of sedimentary organic matter in the deep eastern Mediterranean Sea

et al. 2015

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Abstract. Surface sediments collected from deep slopes and basins (1018-4087 m depth) of the oligotrophic eastern Mediterranean Sea have been analysed for bulk elemental and isotopic composition of organic carbon, total nitrogen and selected lipid biomarkers, jointly with grain size distribution and other geochemical proxies. The distribution and sources of sedimentary organic matter (OM) have been subsequently assessed and general environmental variables, such as water column depth and physical circulation patterns, have been examined as causative factors of deep-sea sediment characteristics. Lithogenic and biogenic carbonates are the dominant sedimentary fractions, accounting for up to 85.4 and 66.5 % of the total weight respectively. The low OC and TN contents in the surface sediments of the study area, which ranged from 0.15 to 1.15 % and 0.06 to 0.11 % respectively, reflect the oligotrophic character of the eastern Mediterranean Sea. Both bulk and molecular organic tracers reflect a mixed contribution from autochthonous and allochthonous sources for the sedimentary OM, as indicated by relatively degraded marine OM, terrestrial plant waxes and anthropogenic OM (e.g. degraded petroleum by-products) respectively. Wide regional variations have been observed amongst the studied proxies, which reflect the multiple factors controlling sedimentation in the deep eastern Mediterranean Sea. Our findings highlight the role of deep eastern Mediterranean basins as depocentres of organic-rich finegrained sediments (mean 5.4 ± 2.4µm), with OM accumulation and burial being attributed to aggregation mechanisms and hydrodynamic sorting. A multi-proxy approach is applied aiming to investigate the biogeochemical composition of sediment samples, which sheds new light on the sources and transport mechanisms along with the impact of preservation vs. diagenetic processes on the composition of sedimentary OM in the deep basins of the oligotrophic eastern Mediterranean Sea.

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Holocene dust records from the West African Sahel and their implications for changes in climate and land surface conditions

et al. 2014

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We reconstructed aeolian dust accumulation during the Holocene from two radiocarbon-dated lake-sediment sequences from the Manga Grasslands in northeastern Nigeria in order to investigate long-term changes in the Harmattan dust system over West Africa and evaluate their possible causes. Flux values were low in the early Holocene, decreasing further to a minimum at around 6.2 kyr B.P. after which time they increased, steadily until around 2 kyr B.P. and then more sharply after this time. The long-term variations in dust flux agree broadly with changes in the exposed area of the Lake Chad Basin to the northeast of the study sites, which vary inversely with the volume of Paleolake Megachad. More proximal sources of dust, including the fine fraction of local dune sand and floodplains of nearby rivers, have also made a contribution to the total dust load during times of enhanced dune and fluvial activity. Sharp rises in dust flux over the past century may be related to human activity. Broad patterns of change in dust flux during the Holocene agree with other reconstructions over the same period. However, we see no evidence for a stepped rise during the middle Holocene, as seen at some sites from the northeastern tropical Atlantic, suggesting that controls on the Harmattan dust system have differed from those affecting dust deposition elsewhere across northern Africa.

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A three-year time series of mineral dust deposits on the West African margin: Sedimentological and geochemical signatures and implications for interpretation of marine paleo-dust records

Cited by 70 publications

References 57 publications

Seasonal provenance changes of present-day Saharan dust collected on- and offshore Mauritania

Seasonal provenance changes of present-day Saharan dust collected on- and offshore Mauritania

Composition and sources of sedimentary organic matter in the deep eastern Mediterranean Sea

Holocene dust records from the West African Sahel and their implications for changes in climate and land surface conditions

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