West African monsoon dynamics inferred from abrupt fluctuations of Lake Mega-Chad. / Armitage, Simon; Bristow, Charlie S.; Drake, Nick A.

In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 112, No. 28, 14.07.2015, p. 8543-8548.

Research output: Contribution to journalArticlepeer-review

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West African monsoon dynamics inferred from abrupt fluctuations of Lake Mega-Chad. / Armitage, Simon; Bristow, Charlie S.; Drake, Nick A.

In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 112, No. 28, 14.07.2015, p. 8543-8548.

Research output: Contribution to journalArticlepeer-review

Harvard

Armitage, S, Bristow, CS & Drake, NA 2015, 'West African monsoon dynamics inferred from abrupt fluctuations of Lake Mega-Chad', Proceedings of the National Academy of Sciences of the United States of America, vol. 112, no. 28, pp. 8543-8548. https://doi.org/10.1073/pnas.1417655112

APA

Armitage, S., Bristow, C. S., & Drake, N. A. (2015). West African monsoon dynamics inferred from abrupt fluctuations of Lake Mega-Chad. Proceedings of the National Academy of Sciences of the United States of America, 112(28), 8543-8548. https://doi.org/10.1073/pnas.1417655112

Vancouver

Armitage S, Bristow CS, Drake NA. West African monsoon dynamics inferred from abrupt fluctuations of Lake Mega-Chad. Proceedings of the National Academy of Sciences of the United States of America. 2015 Jul 14;112(28):8543-8548. https://doi.org/10.1073/pnas.1417655112

Author

Armitage, Simon ; Bristow, Charlie S. ; Drake, Nick A. / West African monsoon dynamics inferred from abrupt fluctuations of Lake Mega-Chad. In: Proceedings of the National Academy of Sciences of the United States of America. 2015 ; Vol. 112, No. 28. pp. 8543-8548.

BibTeX

@article{670fecd4924549c2a3665213854fbeed,
title = "West African monsoon dynamics inferred from abrupt fluctuations of Lake Mega-Chad",
abstract = "From the deglacial period to the mid-Holocene, North Africa was characterised by much wetter conditions than today. The broad timing of this period, termed the African Humid Period, is well known. However, the rapidity of the onset and termination of the African Humid Period are contested, with strong evidence for both abrupt and gradual change. We use optically stimulated luminescence dating of dunes, shorelines and fluvio-lacustrine deposits to reconstruct the fluctuations of Lake Mega-Chad, which was the largest pluvial lake in Africa. Humid conditions first occur at ~15 ka, and by 11.5 ka Lake Mega-Chad had reached a highstand, which persisted until 5.0 ka. Lake levels fell rapidly at ~5 ka, indicating abrupt aridification across the entire Lake Mega-Chad Basin. This record provides strong terrestrial evidence that the African Humid Period ended abruptly, supporting the hypothesis that the African monsoon responds to insolation forcing in a markedly non-linear manner. In addition, Lake Mega-Chad exerts strong control on global biogeochemical cycles since the northern (Bod{\'e}l{\'e}) basin is currently the World{\textquoteright}s greatest single dust source, and possibly an important source of limiting nutrients for both the Amazon basin and equatorial Atlantic. However, we demonstrate that the final desiccation of the Bod{\'e}l{\'e} Basin occurred around 1 ka. Consequently, the present-day mode and scale of dust production from the Bod{\'e}l{\'e} Basin cannot have occurred prior to 1 ka, suggesting that its role in fertilizing marine and terrestrial ecosystems is either overstated or geologically recent.",
keywords = "African monsoon, African Humid Period, Dust, Lake Chad",
author = "Simon Armitage and Bristow, {Charlie S.} and Drake, {Nick A.}",
year = "2015",
month = jul,
day = "14",
doi = "10.1073/pnas.1417655112",
language = "English",
volume = "112",
pages = "8543--8548",
journal = " Proceedings of the National Academy of Sciences of the United States of America",
issn = "0027-8424",
publisher = "National Academy of Sciences",
number = "28",

}

RIS

TY - JOUR

T1 - West African monsoon dynamics inferred from abrupt fluctuations of Lake Mega-Chad

AU - Armitage, Simon

AU - Bristow, Charlie S.

AU - Drake, Nick A.

PY - 2015/7/14

Y1 - 2015/7/14

N2 - From the deglacial period to the mid-Holocene, North Africa was characterised by much wetter conditions than today. The broad timing of this period, termed the African Humid Period, is well known. However, the rapidity of the onset and termination of the African Humid Period are contested, with strong evidence for both abrupt and gradual change. We use optically stimulated luminescence dating of dunes, shorelines and fluvio-lacustrine deposits to reconstruct the fluctuations of Lake Mega-Chad, which was the largest pluvial lake in Africa. Humid conditions first occur at ~15 ka, and by 11.5 ka Lake Mega-Chad had reached a highstand, which persisted until 5.0 ka. Lake levels fell rapidly at ~5 ka, indicating abrupt aridification across the entire Lake Mega-Chad Basin. This record provides strong terrestrial evidence that the African Humid Period ended abruptly, supporting the hypothesis that the African monsoon responds to insolation forcing in a markedly non-linear manner. In addition, Lake Mega-Chad exerts strong control on global biogeochemical cycles since the northern (Bodélé) basin is currently the World’s greatest single dust source, and possibly an important source of limiting nutrients for both the Amazon basin and equatorial Atlantic. However, we demonstrate that the final desiccation of the Bodélé Basin occurred around 1 ka. Consequently, the present-day mode and scale of dust production from the Bodélé Basin cannot have occurred prior to 1 ka, suggesting that its role in fertilizing marine and terrestrial ecosystems is either overstated or geologically recent.

AB - From the deglacial period to the mid-Holocene, North Africa was characterised by much wetter conditions than today. The broad timing of this period, termed the African Humid Period, is well known. However, the rapidity of the onset and termination of the African Humid Period are contested, with strong evidence for both abrupt and gradual change. We use optically stimulated luminescence dating of dunes, shorelines and fluvio-lacustrine deposits to reconstruct the fluctuations of Lake Mega-Chad, which was the largest pluvial lake in Africa. Humid conditions first occur at ~15 ka, and by 11.5 ka Lake Mega-Chad had reached a highstand, which persisted until 5.0 ka. Lake levels fell rapidly at ~5 ka, indicating abrupt aridification across the entire Lake Mega-Chad Basin. This record provides strong terrestrial evidence that the African Humid Period ended abruptly, supporting the hypothesis that the African monsoon responds to insolation forcing in a markedly non-linear manner. In addition, Lake Mega-Chad exerts strong control on global biogeochemical cycles since the northern (Bodélé) basin is currently the World’s greatest single dust source, and possibly an important source of limiting nutrients for both the Amazon basin and equatorial Atlantic. However, we demonstrate that the final desiccation of the Bodélé Basin occurred around 1 ka. Consequently, the present-day mode and scale of dust production from the Bodélé Basin cannot have occurred prior to 1 ka, suggesting that its role in fertilizing marine and terrestrial ecosystems is either overstated or geologically recent.

KW - African monsoon

KW - African Humid Period

KW - Dust

KW - Lake Chad

U2 - 10.1073/pnas.1417655112

DO - 10.1073/pnas.1417655112

M3 - Article

VL - 112

SP - 8543

EP - 8548

JO - Proceedings of the National Academy of Sciences of the United States of America

JF - Proceedings of the National Academy of Sciences of the United States of America

SN - 0027-8424

IS - 28

ER -