Recurring types of variability and transitions in the ∼620 kyr record of climate change from the Chew Bahir basin, southern Ethiopia

M.H. Trauth, A. Asrat, A.S. Cohen, W. Duesing, V. Foerster, S. Kaboth-Bahr, K.H. Kraemer, H.F. Lamb, N. Marwan, M.A. Maslin, F. Schäbitz

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5 Scopus citations

Abstract

The Chew Bahir Drilling Project (CBDP) aims to test possible linkages between climate and hominin evolution in Africa through the analysis of sediment cores that have recorded environmental changes in the Chew Bahir basin (CHB). In this statistical project we used recurrence plots (RPs) together with a recurrence quantification analysis (RQA) to distinguish two types of variability and transitions in the Chew Bahir aridity record and compare them with the ODP Site 967 wetness index from the eastern Mediterranean. The first type of variability is one of slow variations with cycles of ∼20 kyr, reminiscent of the Earth's precession cycle, and subharmonics of this orbital cycle. In addition to these cyclical wet-dry fluctuations in the area, extreme events often occur, i.e. short wet or dry episodes, lasting for several centuries or even millennia, and rapid transitions between these wet and dry episodes. The second type of variability is characterized by relatively low variation on orbital time scales, but significant century-millennium-scale variations with progressively increasing frequencies. Within this type of variability there are extremely fast transitions between dry and wet within a few decades or years, in contrast to those within Type 1 with transitions over several hundreds of years. Type 1 variability probably reflects the influence of precessional forcing in the lower latitudes at times with maximum values of the long (400 kyr) eccentricity cycle of the Earth's orbit around the sun, with the tendency towards extreme events. Type 2 variability seems to be linked with minimum values of this cycle. There does not seem to be a systematic correlation between Type 1 or Type 2 variability with atmospheric CO2 concentration. The different types of variability and the transitions between those types had important effects on the availability of water, and could have transformed eastern Africa's environment considerably, which would have had important implications for the shaping of the habitat of H. sapiens and the direct ancestors of this species. © 2020 Elsevier Ltd
Original languageEnglish (US)
Article number106777
Number of pages12
JournalQuaternary Science Reviews
Volume266
DOIs
StatePublished - Aug 15 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 ( SCHA 472/13 and/ 18, TR 419/8,/10 and/16 ) 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/K014560/1 , IP/1623/0516 ). We also thank the Ethiopian permitting authorities to issue permits for drilling in the Chew Bahir basin. We also thank the Hammar people for the local assistance during drilling operations. We thank DOSECC Exploration Services for drilling supervision and Ethio Der pvt. Ltd. Co. For providing logistical support during drilling. Initial core processing and sampling were conducted at the US National Lacustrine Core Facility (LacCore) at the University of Minnesota. We thank Christopher Bronk Ramsey, Melissa Chapot, Alan Deino, Christine S. Lane, Helen M. Roberts and Céline Vidal for discussions on the geochronology and age modeling. S.K.B. has received further financial support from the University of Potsdam Open Topic Postdoc Program. This is publication 29 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 (SCHA 472/13 and/18, TR 419/8,/10 and/16) 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/K014560/1, IP/1623/0516). We also thank the Ethiopian permitting authorities to issue permits for drilling in the Chew Bahir basin. We also thank the Hammar people for the local assistance during drilling operations. We thank DOSECC Exploration Services for drilling supervision and Ethio Der pvt. Ltd. Co. For providing logistical support during drilling. Initial core processing and sampling were conducted at the US National Lacustrine Core Facility (LacCore) at the University of Minnesota. We thank Christopher Bronk Ramsey, Melissa Chapot, Alan Deino, Christine S. Lane, Helen M. Roberts and C?line Vidal for discussions on the geochronology and age modeling. S.K.B. has received further financial support from the University of Potsdam Open Topic Postdoc Program. This is publication 29 of the Hominin Sites and Paleolakes Drilling Project.

Publisher Copyright:
© 2020 Elsevier Ltd

Keywords

  • Eastern africa
  • Homo sapiens
  • Paleoclimate dynamics
  • Recurrence plots

Continental Scientific Drilling Facility tags

  • HSPDP-CHB

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