Universität zu Köln

Gebregiorgis, Daniel, Deocampo, Daniel M., Foerster, Verena ORCID: 0000-0002-3480-5769, Longstaffe, Fred J., Delaney, Jeremy S., Schaebitz, Frank, Junginger, Annett ORCID: 0000-0003-3486-0888, Markowska, Monika, Opitz, Stephan, Trauth, Martin H., Lamb, Henry F. and Asrat, Asfawossen (2021). Modern Sedimentation and Authigenic Mineral Formation in the Chew Bahir Basin, Southern Ethiopia: Implications for Interpretation of Late Quaternary Paleoclimate Records. Front. Earth Sci., 9. LAUSANNE: FRONTIERS MEDIA SA. ISSN 2296-6463

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Abstract

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 delta O-18 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.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Gebregiorgis, Daniel UNSPECIFIED UNSPECIFIED UNSPECIFIED Deocampo, Daniel M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Foerster, Verena UNSPECIFIED orcid.org/0000-0002-3480-5769 UNSPECIFIED Longstaffe, Fred J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Delaney, Jeremy S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Schaebitz, Frank UNSPECIFIED UNSPECIFIED UNSPECIFIED Junginger, Annett UNSPECIFIED orcid.org/0000-0003-3486-0888 UNSPECIFIED Markowska, Monika UNSPECIFIED UNSPECIFIED UNSPECIFIED Opitz, Stephan UNSPECIFIED UNSPECIFIED UNSPECIFIED Trauth, Martin H. UNSPECIFIED UNSPECIFIED UNSPECIFIED Lamb, Henry F. UNSPECIFIED UNSPECIFIED UNSPECIFIED Asrat, Asfawossen UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-600699
DOI:	10.3389/feart.2021.607695
Journal or Publication Title:	Front. Earth Sci.
Volume:	9
Date:	2021
Publisher:	FRONTIERS MEDIA SA
Place of Publication:	LAUSANNE
ISSN:	2296-6463
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language EAST-AFRICAN CLIMATE; OLDUVAI GORGE; KENYA RIFT; HUMID PERIOD; LAKE; GEOCHEMISTRY; DIAGENESIS; ELEMENTS; TERMINATION; PROVENANCE Multiple languages Geosciences, Multidisciplinary Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/60069