TY - JOUR
T1 - Modern Sedimentation and Authigenic Mineral Formation in the Chew Bahir Basin, Southern Ethiopia
T2 - Implications for Interpretation of Late Quaternary Paleoclimate Records
AU - Gebregiorgis, Daniel
AU - Deocampo, Daniel M.
AU - Foerster, Verena
AU - Longstaffe, Fred J.
AU - Delaney, Jeremy S.
AU - Schaebitz, Frank
AU - Junginger, Annett
AU - Markowska, Monika
AU - Opitz, Stephan
AU - Trauth, Martin H.
AU - Lamb, Henry F.
AU - Asrat, Asfawossen
N1 - Funding Information:
Funding. This research was supported by NSF grant (NSF 1349651) to DD. The oxygen-isotope measurements were supported by a Natural Sciences and Engineering Research Council Discovery Grant of Canada and the Canada Research Chairs Program (FL). FS acknowledges further funding from the DFG through grants SCHA 472/13 and SCHA 472/18. MT acknowledges funding from the DFG through grants TR 419/8, TR 419/9, and TR 419/16. In addition, FS acknowledges funding from the CRC 806 Research Project “Our way to Europe” – Project Number 57444011. HL was funded by grant NE/K014560/1 from the UK Natural Environment Research Council. This was Western’s Laboratory for Stable Isotope Science Contribution #385.
Funding Information:
This research was supported by NSF grant (NSF 1349651) to DD. The oxygen-isotope measurements were supported by a Natural Sciences and Engineering Research Council Discovery Grant of Canada and the Canada Research Chairs Program (FL). FS acknowledges further funding from the DFG through grants SCHA 472/13 and SCHA 472/18. MT acknowledges funding from the DFG through grants TR 419/8, TR 419/9, and TR 419/16. In addition, FS acknowledges funding from the CRC 806 Research Project “Our way to
Publisher Copyright:
© Copyright © 2021 Gebregiorgis, Deocampo, Foerster, Longstaffe, Delaney, Schaebitz, Junginger, Markowska, Opitz, Trauth, Lamb and Asrat.
PY - 2021/4/30
Y1 - 2021/4/30
N2 - We present new mineralogical and geochemical data from modern sediments in the Chew Bahir basin and catchment, Ethiopia. Our goal is to better understand the role of modern sedimentary processes in chemical proxy formation in the Chew Bahir paleolake, a newly investigated paleoclimatic archive, to provide environmental context for human evolution and dispersal. Modern sediment outside the currently dry playa lake floor have higher SiO2 and Al2O3 (50–70 wt.%) content compared to mudflat samples. On average, mudflat sediment samples are enriched in elements such as Mg, Ca, Ce, Nd, and Na, indicating possible enrichment during chemical weathering (e.g., clay formation). Thermodynamic modeling of evaporating water in upstream Lake Chamo is shown to produce an authigenic mineral assemblage of calcite, analcime, and Mg-enriched authigenic illitic clay minerals, consistent with the prevalence of environments of enhanced evaporative concentration in the Chew Bahir basin. A comparison with samples from the sediment cores of Chew Bahir based on whole-rock MgO/Al2O3, Ba/Sr and authigenic clay mineral δ18O values shows the following: modern sediments deposited in the saline mudflats of the Chew Bahir dried out lake bed resemble paleosediments deposited during dry periods, such as during times of the Last Glacial Maximum and Younger Dryas stadial. Sediments from modern detrital upstream sources are more similar to sediments deposited during wetter periods, such as the early Holocene African Humid Period.
AB - We present new mineralogical and geochemical data from modern sediments in the Chew Bahir basin and catchment, Ethiopia. Our goal is to better understand the role of modern sedimentary processes in chemical proxy formation in the Chew Bahir paleolake, a newly investigated paleoclimatic archive, to provide environmental context for human evolution and dispersal. Modern sediment outside the currently dry playa lake floor have higher SiO2 and Al2O3 (50–70 wt.%) content compared to mudflat samples. On average, mudflat sediment samples are enriched in elements such as Mg, Ca, Ce, Nd, and Na, indicating possible enrichment during chemical weathering (e.g., clay formation). Thermodynamic modeling of evaporating water in upstream Lake Chamo is shown to produce an authigenic mineral assemblage of calcite, analcime, and Mg-enriched authigenic illitic clay minerals, consistent with the prevalence of environments of enhanced evaporative concentration in the Chew Bahir basin. A comparison with samples from the sediment cores of Chew Bahir based on whole-rock MgO/Al2O3, Ba/Sr and authigenic clay mineral δ18O values shows the following: modern sediments deposited in the saline mudflats of the Chew Bahir dried out lake bed resemble paleosediments deposited during dry periods, such as during times of the Last Glacial Maximum and Younger Dryas stadial. Sediments from modern detrital upstream sources are more similar to sediments deposited during wetter periods, such as the early Holocene African Humid Period.
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U2 - 10.3389/feart.2021.607695
DO - 10.3389/feart.2021.607695
M3 - Article
AN - SCOPUS:85105954498
SN - 2296-6463
VL - 9
JO - Frontiers in Earth Science
JF - Frontiers in Earth Science
M1 - 607695
ER -