Stepwise Holocene aridification in NE Africa deduced from dust-borne radiogenic isotope records

S.J.A. Jung, G.R. Davies, G.M. Ganssen, D. Kroon

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

Transfer of tropical heat to higher latitudes is the major driving force of the Earth's climate. Consequently, sediments in regions to the north and south of the tropics potentially retain an archive of past major climate reconfigurations. The climate of one such region, around the Arabian Sea, sensitively depends on the coupled Asian and African monsoons that also control the dust transport. Here, we use the Sr-Nd isotope ratios of the dust fraction from Core 905 (Arabian Sea off Somalia), as a novel tool to deduce the Holocene weathering history of the Horn of Africa with emphasis on the climate transition that took place from a wet early to a dry late Holocene. The highly variable Sr isotope ratios are interpreted to reflect mainly changes in the evaporation/precipitation balance over NE Africa whilst the Nd isotope measurements record no significant variations and point to a prevailing NE African dust source. The Sr isotope record shows that the first aridification step occurred at 8.5 kyr BP followed by an unstable transitional period up to 6 kyr BP, characterized by decadal-scale high-amplitude variations in the evaporation/precipitation balance. A second aridification step began at 6 kyr BP and ceased at 3.8 kyr BP when modern-day dry climate was established. The combined Sr and Nd isotope records probably reflect north-south shifts of the Intertropical Convergence Zone controlling the evaporation/precipitation balance over NE Africa. © 2004 Elsevier B.V. All rights reserved.
Original languageEnglish
Pages (from-to)27-37
JournalEarth and Planetary Science Letters
Volume221
DOIs
Publication statusPublished - 2004

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aridification
Isotopes
climate
Dust
isotopes
dust
Holocene
isotope
Arabian Sea
Evaporation
evaporation
isotope ratios
Somalia
Tropics
monsoons
intertropical convergence zone
weathering
Weathering
tropical regions
polar regions

Cite this

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title = "Stepwise Holocene aridification in NE Africa deduced from dust-borne radiogenic isotope records",
abstract = "Transfer of tropical heat to higher latitudes is the major driving force of the Earth's climate. Consequently, sediments in regions to the north and south of the tropics potentially retain an archive of past major climate reconfigurations. The climate of one such region, around the Arabian Sea, sensitively depends on the coupled Asian and African monsoons that also control the dust transport. Here, we use the Sr-Nd isotope ratios of the dust fraction from Core 905 (Arabian Sea off Somalia), as a novel tool to deduce the Holocene weathering history of the Horn of Africa with emphasis on the climate transition that took place from a wet early to a dry late Holocene. The highly variable Sr isotope ratios are interpreted to reflect mainly changes in the evaporation/precipitation balance over NE Africa whilst the Nd isotope measurements record no significant variations and point to a prevailing NE African dust source. The Sr isotope record shows that the first aridification step occurred at 8.5 kyr BP followed by an unstable transitional period up to 6 kyr BP, characterized by decadal-scale high-amplitude variations in the evaporation/precipitation balance. A second aridification step began at 6 kyr BP and ceased at 3.8 kyr BP when modern-day dry climate was established. The combined Sr and Nd isotope records probably reflect north-south shifts of the Intertropical Convergence Zone controlling the evaporation/precipitation balance over NE Africa. {\circledC} 2004 Elsevier B.V. All rights reserved.",
author = "S.J.A. Jung and G.R. Davies and G.M. Ganssen and D. Kroon",
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Stepwise Holocene aridification in NE Africa deduced from dust-borne radiogenic isotope records. / Jung, S.J.A.; Davies, G.R.; Ganssen, G.M.; Kroon, D.

In: Earth and Planetary Science Letters, Vol. 221, 2004, p. 27-37.

Research output: Contribution to JournalArticleAcademicpeer-review

TY - JOUR

T1 - Stepwise Holocene aridification in NE Africa deduced from dust-borne radiogenic isotope records

AU - Jung, S.J.A.

AU - Davies, G.R.

AU - Ganssen, G.M.

AU - Kroon, D.

PY - 2004

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N2 - Transfer of tropical heat to higher latitudes is the major driving force of the Earth's climate. Consequently, sediments in regions to the north and south of the tropics potentially retain an archive of past major climate reconfigurations. The climate of one such region, around the Arabian Sea, sensitively depends on the coupled Asian and African monsoons that also control the dust transport. Here, we use the Sr-Nd isotope ratios of the dust fraction from Core 905 (Arabian Sea off Somalia), as a novel tool to deduce the Holocene weathering history of the Horn of Africa with emphasis on the climate transition that took place from a wet early to a dry late Holocene. The highly variable Sr isotope ratios are interpreted to reflect mainly changes in the evaporation/precipitation balance over NE Africa whilst the Nd isotope measurements record no significant variations and point to a prevailing NE African dust source. The Sr isotope record shows that the first aridification step occurred at 8.5 kyr BP followed by an unstable transitional period up to 6 kyr BP, characterized by decadal-scale high-amplitude variations in the evaporation/precipitation balance. A second aridification step began at 6 kyr BP and ceased at 3.8 kyr BP when modern-day dry climate was established. The combined Sr and Nd isotope records probably reflect north-south shifts of the Intertropical Convergence Zone controlling the evaporation/precipitation balance over NE Africa. © 2004 Elsevier B.V. All rights reserved.

AB - Transfer of tropical heat to higher latitudes is the major driving force of the Earth's climate. Consequently, sediments in regions to the north and south of the tropics potentially retain an archive of past major climate reconfigurations. The climate of one such region, around the Arabian Sea, sensitively depends on the coupled Asian and African monsoons that also control the dust transport. Here, we use the Sr-Nd isotope ratios of the dust fraction from Core 905 (Arabian Sea off Somalia), as a novel tool to deduce the Holocene weathering history of the Horn of Africa with emphasis on the climate transition that took place from a wet early to a dry late Holocene. The highly variable Sr isotope ratios are interpreted to reflect mainly changes in the evaporation/precipitation balance over NE Africa whilst the Nd isotope measurements record no significant variations and point to a prevailing NE African dust source. The Sr isotope record shows that the first aridification step occurred at 8.5 kyr BP followed by an unstable transitional period up to 6 kyr BP, characterized by decadal-scale high-amplitude variations in the evaporation/precipitation balance. A second aridification step began at 6 kyr BP and ceased at 3.8 kyr BP when modern-day dry climate was established. The combined Sr and Nd isotope records probably reflect north-south shifts of the Intertropical Convergence Zone controlling the evaporation/precipitation balance over NE Africa. © 2004 Elsevier B.V. All rights reserved.

U2 - 10.1016/S0012-821X(04)00095-0

DO - 10.1016/S0012-821X(04)00095-0

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