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Title:Variability in sediment particle size, mineralogy, and Fe mode of occurrence across dust-source inland drainage basins : the case of the lower Drâa Valley, Morocco
Authors:ID Gonzalez-Romero, Adolfo (Author)
ID González-Flórez, Cristina (Author)
ID Panta, Agnesh (Author)
ID Yus-Díez, Jesús (Author)
ID Reche, Cristina (Author)
ID Córdoba, Patricia (Author)
ID Moreno, Natalia (Author)
ID Alastuey, Andrés (Author)
ID Kandler, Konrad (Author)
ID Klose, Martina (Author)
Files:.pdf RAZ_Gonzalez-Romero_Adolfo_2023.pdf (7,63 MB)
MD5: 2BD06C6C6194C34243EB27736741022D
 
URL https://acp.copernicus.org/articles/23/15815/2023/acp-23-15815-2023.pdf
 
Language:English
Work type:Unknown
Typology:1.01 - Original Scientific Article
Organization:UNG - University of Nova Gorica
Abstract:The effects of desert dust upon climate and ecosystems depend strongly on its particle size and size-resolved mineralogical composition. However, there is very limited quantitative knowledge on the particle size and composition of the parent sediments along with their variability within dust-source regions, particularly in dust emission hotspots. The lower Drâa Valley, an inland drainage basin and dust hotspot region located in the Moroccan Sahara, was chosen for a comprehensive analysis of sediment particle size and mineralogy. Different sediment type samples (n= 42) were collected, including paleo-sediments, paved surfaces, crusts, and dunes, and analysed for particle-size distribution (minimally and fully dispersed samples) and mineralogy. Furthermore, Fe sequential wet extraction was carried out to characterise the modes of occurrence of Fe, including Fe in Fe (oxyhydr)oxides, mainly from goethite and hematite, which are key to dust radiative effects; the poorly crystalline pool of Fe (readily exchangeable ionic Fe and Fe in nano-Fe oxides), relevant to dust impacts upon ocean biogeochemistry; and structural Fe. Results yield a conceptual model where both particle size and mineralogy are segregated by transport and deposition of sediments during runoff of water across the basin and by the precipitation of salts, which causes a sedimentary fractionation. The proportion of coarser particles enriched in quartz is higher in the highlands, while that of finer particles rich in clay, carbonates, and Fe oxides is higher in the lowland dust emission hotspots. There, when water ponds and evaporates, secondary carbonates and salts precipitate, and the clays are enriched in readily exchangeable ionic Fe, due to sorption of dissolved Fe by illite. The results differ from currently available mineralogical atlases and highlight the need for observationally constrained global high-resolution mineralogical data for mineral-speciated dust modelling. The dataset obtained represents an important resource for future evaluation of surface mineralogy retrievals from spaceborne spectroscopy.
Keywords:mineral dust, aerosols, geology
Publication date:01.01.2023
Year of publishing:2023
Number of pages:str. 15815-15834
Numbering:Vol. 23, issue 24
PID:20.500.12556/RUNG-8752 New window
COBISS.SI-ID:180760579 New window
UDC:502.3/.7
ISSN on article:1680-7324
eISSN:1680-7324
DOI:10.5194/acp-23-15815-2023 New window
NUK URN:URN:SI:UNG:REP:AIFPZF9O
Publication date in RUNG:12.01.2024
Views:908
Downloads:3
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Record is a part of a journal

Title:Atmospheric chemistry and physics
Shortened title:Atmos. chem. phys.
Publisher:European Geophysical Society, Copernicus GmbH
ISSN:1680-7324
COBISS.SI-ID:1959012 New window

Licences

License:CC BY 4.0, Creative Commons Attribution 4.0 International
Link:http://creativecommons.org/licenses/by/4.0/
Description:This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.
Licensing start date:22.12.2023

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