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Seasonality in equatorial climate over the past 25 k.y. revealed by oxygen isotope records from Mount Kilimanjaro

Philip A Barker, Elizabeth R Hurrell, Melanie J Leng, Christian Wolff, Christine Cocquyt UGent, Hilary J Sloane and Dirk Verschuren UGent (2011) GEOLOGY. 39(12). p.1111-1114
abstract
Multi-proxy analysis of a well-dated 25,000-year (25 ka) lake-sediment sequence from Lake Challa, on the eastern flank of Mt Kilimanjaro, reveal the climatic controls which govern both the lake’s palaeohydrology and the climate-proxy record contained in the mountain’s receding ice cap. The oxygen-isotope record extracted from diatom silica (d18Odiatom) in Lake Challa sediments captured dry conditions during the last glacial period and a wet late-glacial transition to the Holocene interrupted by Younger Dryas drought. Further, it faithfully traced gradual weakening of the southeastern monsoon during the Holocene. Overall, d18Odiatom matches the branched isoprenoid tetraether (BIT) index of rainfall-induced soil run-off, except during 25–22 ka BP and the last 5 ka when insolation forcing due to orbital precession enhanced the northeastern monsoon. This pattern arises because during these two periods, a weakened southeastern monsoon reduced the amount of rainfall during the long rain season and enhanced the opposing effect of evaporation intensity and/or length of the austral winter dry season. Importantly, our lake-based reconstruction of moisture-balance seasonality in equatorial East Africa also helps understand the oxygen-isotope record contained in Mt. Kilimanjaro ice. Negative correlation between ice-core d18O and Lake Challa d18Odiatom implies that temperature, not moisture balance, is the primary climate control on the long-term trend in ice-core d18O.
Please use this url to cite or link to this publication:
author
organization
year
type
journalArticle (original)
publication status
published
subject
keyword
ICE, LAKES, AFRICA, PRECIPITATION, FLUCTUATIONS, DROUGHT, GLACIER, MONSOON, HOLOCENE, DIATOM SILICA
journal title
GEOLOGY
Geology
volume
39
issue
12
pages
1111 - 1114
Web of Science type
Article
Web of Science id
000296793900006
JCR category
GEOLOGY
JCR impact factor
3.612 (2011)
JCR rank
1/46 (2011)
JCR quartile
1 (2011)
ISSN
0091-7613
DOI
10.1130/G32419.1
language
English
UGent publication?
yes
classification
A1
copyright statement
I have transferred the copyright for this publication to the publisher
id
4093136
handle
http://hdl.handle.net/1854/LU-4093136
date created
2013-07-01 18:38:59
date last changed
2016-12-19 15:43:10
@article{4093136,
  abstract     = {Multi-proxy analysis of a well-dated 25,000-year (25 ka) lake-sediment sequence from Lake Challa, on the eastern flank of Mt Kilimanjaro, reveal the climatic controls which govern both the lake{\textquoteright}s palaeohydrology and the climate-proxy record contained in the mountain{\textquoteright}s receding ice cap. The oxygen-isotope record extracted from diatom silica (d18Odiatom) in Lake Challa sediments captured dry conditions during the last glacial period and a wet late-glacial transition to the Holocene interrupted by Younger Dryas drought. Further, it faithfully traced gradual weakening of the southeastern monsoon during the Holocene. Overall, d18Odiatom matches the branched isoprenoid tetraether (BIT) index of rainfall-induced soil run-off, except during 25--22 ka BP and the last 5 ka when insolation forcing due to orbital precession enhanced the northeastern monsoon. This pattern arises because during these two periods, a weakened southeastern monsoon reduced the amount of rainfall during the long rain season and enhanced the opposing effect of evaporation intensity and/or length of the austral winter dry season. Importantly, our lake-based reconstruction of moisture-balance seasonality in equatorial East Africa also helps understand the oxygen-isotope record contained in Mt. Kilimanjaro ice. Negative correlation between ice-core d18O and Lake Challa d18Odiatom implies that temperature, not moisture balance, is the primary climate control on the long-term trend in ice-core d18O.},
  author       = {Barker, Philip A and Hurrell, Elizabeth R and Leng, Melanie J and Wolff, Christian and Cocquyt, Christine and Sloane, Hilary J and Verschuren, Dirk},
  issn         = {0091-7613},
  journal      = {GEOLOGY},
  keyword      = {ICE,LAKES,AFRICA,PRECIPITATION,FLUCTUATIONS,DROUGHT,GLACIER,MONSOON,HOLOCENE,DIATOM SILICA},
  language     = {eng},
  number       = {12},
  pages        = {1111--1114},
  title        = {Seasonality in equatorial climate over the past 25 k.y. revealed by oxygen isotope records from Mount Kilimanjaro},
  url          = {http://dx.doi.org/10.1130/G32419.1},
  volume       = {39},
  year         = {2011},
}

Chicago
Barker, Philip A, Elizabeth R Hurrell, Melanie J Leng, Christian Wolff, Christine Cocquyt, Hilary J Sloane, and Dirk Verschuren. 2011. “Seasonality in Equatorial Climate over the Past 25 K.y. Revealed by Oxygen Isotope Records from Mount Kilimanjaro.” Geology 39 (12): 1111–1114.
APA
Barker, P. A., Hurrell, E. R., Leng, M. J., Wolff, C., Cocquyt, C., Sloane, H. J., & Verschuren, D. (2011). Seasonality in equatorial climate over the past 25 k.y. revealed by oxygen isotope records from Mount Kilimanjaro. GEOLOGY, 39(12), 1111–1114.
Vancouver
1.
Barker PA, Hurrell ER, Leng MJ, Wolff C, Cocquyt C, Sloane HJ, et al. Seasonality in equatorial climate over the past 25 k.y. revealed by oxygen isotope records from Mount Kilimanjaro. GEOLOGY. 2011;39(12):1111–4.
MLA
Barker, Philip A, Elizabeth R Hurrell, Melanie J Leng, et al. “Seasonality in Equatorial Climate over the Past 25 K.y. Revealed by Oxygen Isotope Records from Mount Kilimanjaro.” GEOLOGY 39.12 (2011): 1111–1114. Print.