Advanced Hyperspectral Analysis of Sediment Core Samples from the Chew Bahir Basin, Ethiopian Rift, in the Spectral Range from 0.25 to 17 µm: Support for Climate Proxy Interpretation

G.E. Arnold, V. Foerster, M.H. Trauth, H. Lamb, F. Schaebitz, A. Asrat, C. Szczech, C. Günter

Research output: Contribution to journalArticlepeer-review

Abstract

Establishing robust environmental proxies at newly investigated terrestrial sedimentary archives is a challenge, because straightforward climate reconstructions can be hampered by the complex relationship between climate parameters and sediment composition, proxy preservation or (in)sufficient sample material. We present a minimally invasive hyperspectral bidirectional reflectance analysis on discrete samples in the wavelength range from 0.25 to 17 µm on 35 lacustrine sediment core samples from the Chew Bahir Basin, southern Ethiopia for climate proxy studies. We identified and used absorption bands at 2.2 μm (Al–OH), at 2.3 μm (Mg–OH), at 1.16 μm (analcime), and at 3.98 μm (calcite) for quantitative spectral analysis. The band depth ratios at 2.3/2.2 μm in the spectra correlate with variations in the potassium content of the sediment samples, which also reflect periods of increased Al-to-Mg substitution in clay minerals during drier climatic episodes. During these episodes of drier conditions, absorption bands diagnostic of the presence of analcime and calcite support this interpretation, with analcime indicating the driest conditions. These results could be compared to qualitative analysis of other characteristic spectral properties in the spectral range between 0.25 and 17 µm. The results of the hyperspectral measurements complement previous sedimentological and geochemical analyses, allowing us in particular to resolve more finely the processes of weathering in the catchment and low-temperature authigenic processes in the sediment. This enables us to better understand environmental changes in the habitat of early humans. © Copyright © 2021 Arnold, Foerster, Trauth, Lamb, Schaebitz, Asrat, Szczech and Günter.
Original languageEnglish (US)
Article number606588
Number of pages16
JournalFrontiers in Earth Science
Volume9
DOIs
StatePublished - Jun 23 2021

Bibliographical note

Funding Information:
Support for HSPDP has been provided by the National Science Foundation (NSF) Grants and the International Continental Drilling Program (ICDP). Support for CBDP has been provided by Germany Research Foundation (DFG) through the Priority Program SPP 1006 ICDP (FS 472/13 and /18, MHT: TR 419/8, /10 and /16, FO 734/2) and the CRC 806 Research Project ?Our way to Europe? (Project Number 57444011). Support has also been received from the UK Natural Environment Research Council (NERC, NE/014K560/1, IP/1623/0516). We thank the Ethiopian authorities for permits for drilling in the Chew Bahir Basin, and the Hammar people for local assistance during drilling operations. Logistic support and supervision of drilling was provided by DOSECC Exploration, in co-operation with Ethio Der pvt. Ltd. Co. Initial core processing and sampling were conducted at the US National Lacustrine Core Facility (LacCore) at the University of Minnesota. The authors would like to thank DLR's Institute of Planetary Research, Berlin-Adlershof, for use of the laboratory and for their support in the spectral investigations. This is publication HSPDP#39 of the Hominin Sites and Paleolakes Drilling Project.

Funding Information:
Support for HSPDP has been provided by the National Science Foundation (NSF) Grants and the International Continental Drilling Program (ICDP). Support for CBDP has been provided by Germany Research Foundation (DFG) through the Priority Program SPP 1006 ICDP (FS 472/13 and /18, MHT: TR 419/8, /10 and /16, FO 734/2) and the CRC 806 Research Project “Our way to Europe” (Project Number 57444011). Support has also been received from the UK Natural Environment Research Council (NERC, NE/014K560/ 1, IP/1623/0516). We thank the Ethiopian authorities for permits for drilling in the Chew Bahir Basin, and the Hammar people for local assistance during drilling operations. Logistic support and supervision of drilling was provided by DOSECC Exploration, in co-operation with Ethio Der pvt. Ltd. Co. Initial core processing and sampling were conducted at the US National Lacustrine Core Facility (LacCore) at the University of Minnesota. The authors would like to thank DLR’s Institute of Planetary Research, Berlin-Adlershof, for use of the laboratory and for their support in the spectral investigations. This is publication HSPDP#39 of the Hominin Sites and Paleolakes Drilling Project.

Publisher Copyright:
© Copyright © 2021 Arnold, Foerster, Trauth, Lamb, Schaebitz, Asrat, Szczech and Günter.

Keywords

  • Chew Bahir Basin
  • Ethiopian Rift
  • paloclimate
  • sediment cores
  • VIS/IR spectroscopy

Continental Scientific Drilling Facility tags

  • HSPDP-CHB

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