Universität zu Köln

Foerster, Verena, Deocampo, Daniel M., Asrat, Asfawossen ORCID: 0000-0002-6312-8082, Guenter, Christina, Junginger, Annett ORCID: 0000-0003-3486-0888, Kraemer, Kai Hauke, Stroncik, Nicole A. and Trauth, Martin H. (2018). Towards an understanding of climate proxy formation in the Chew Bahir basin, southern Ethiopian Rift. Paleogeogr. Paleoclimatol. Paleoecol., 501. S. 111 - 124. AMSTERDAM: ELSEVIER SCIENCE BV. ISSN 1872-616X

Full text not available from this repository.

Abstract

Deciphering paleoclimate from lake sediments is a challenge due to the complex relationship between climate parameters and sediment composition. Here we show the links between potassium (K) concentrations in the sediments of the Chew Bahir basin in the Southern Ethiopian Rift and fluctuations in the catchment precipitation/evaporation balance. Our micro-X-ray fluorescence and X-ray diffraction results suggest that the most likely process linking climate with potassium concentrations is the authigenic illitization of smectites during episodes of higher alkalinity and salinity in the closed -basin lake, due to a drier climate. Whole-rock and clay size fraction analyses suggest that illitization of the Chew Bahir clay minerals with increasing evaporation is enhanced by octahedral Al-to-Mg substitution in the clay minerals, with the resulting layer charge increase facilitating potassium-fixation. Linking mineralogy with geochemistry shows the links between hydroclimatic control, process and formation of the Chew Bahir K patterns, in the context of well-known and widely documented eastern African climate fluctuations over the last 45,000 years. These results indicate characteristic mineral alteration patterns associated with orbitally controlled wet-dry cycles such as the African Humid Period (similar to 15-5 ka) or high-latitude controlled climate events such as the Younger Dryas (similar to 12.8-11.6 ka) chronozone. Determining the impact of authigenic mineral alteration on the Chew Bahir records enables the interpretation of the previously established pXRF-derived aridity proxy K and provides a better paleohydrological understanding of complex climate proxy formation.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Foerster, Verena UNSPECIFIED UNSPECIFIED UNSPECIFIED Deocampo, Daniel M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Asrat, Asfawossen UNSPECIFIED orcid.org/0000-0002-6312-8082 UNSPECIFIED Guenter, Christina UNSPECIFIED UNSPECIFIED UNSPECIFIED Junginger, Annett UNSPECIFIED orcid.org/0000-0003-3486-0888 UNSPECIFIED Kraemer, Kai Hauke UNSPECIFIED UNSPECIFIED UNSPECIFIED Stroncik, Nicole A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Trauth, Martin H. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-179728
DOI:	10.1016/j.palaeo.2018.04.009
Journal or Publication Title:	Paleogeogr. Paleoclimatol. Paleoecol.
Volume:	501
Page Range:	S. 111 - 124
Date:	2018
Publisher:	ELSEVIER SCIENCE BV
Place of Publication:	AMSTERDAM
ISSN:	1872-616X
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language AFRICAN HUMID PERIOD; OLDUVAI-GORGE; KENYA RIFT; ENVIRONMENTAL-CHANGE; NORTHERN TANZANIA; CLAY-MINERALS; LAKE; DIAGENESIS; SEDIMENTS; RECORDS Multiple languages Geography, Physical; Geosciences, Multidisciplinary; Paleontology Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/17972