共 48 条
A progressively wetter climate in southern East Africa over the past 1.3 million years
被引:89
作者:
Johnson, T. C.
[1
,2
,3
]
Werne, J. P.
[4
]
Brown, E. T.
[1
,2
]
Abbott, A.
[5
]
Berke, M.
[6
]
Steinman, B. A.
[1
,2
]
Halbur, J.
[1
,2
]
Contreras, S.
[7
,8
]
Grosshuesch, S.
[1
,2
]
Deino, A.
[9
]
Lyons, R. P.
[10
,14
]
Scholz, C. A.
[10
]
Schouten, S.
[11
,12
,13
]
Damste, J. S. Sinninghe
[11
,12
,13
]
机构:
[1] Univ Minnesota, Large Lakes Observ, Duluth, MN 55812 USA
[2] Univ Minnesota, Dept Earth & Environm Sci, Duluth, MN 55812 USA
[3] Univ Massachusetts, Dept Geosci, Amherst, MA 01003 USA
[4] Univ Pittsburgh, Dept Geol & Planetary Sci, Pittsburgh, PA 15260 USA
[5] Macquarie Univ, Fac Sci & Engn, Dept Earth & Planetary Sci, Sydney, NSW 2109, Australia
[6] Univ Notre Dame, Dept Civil & Environm Engn & Earth Sci, 257 Fitzpatrick Hall, Notre Dame, IN 46556 USA
[7] Univ Catolica Santisima Concepcion, Dept Quim Ambiental, Casilla 297, Concepcion, Chile
[8] Univ Catolica Santisima Concepcion, CIBAS, Casilla 297, Concepcion, Chile
[9] Berkeley Geochronol Ctr, 2455 Ridge Rd, Berkeley, CA 94709 USA
[10] Syracuse Univ, Dept Earth Sci, Heroy Geol Lab 011a, Syracuse, NY 13244 USA
[11] NIOZ Netherlands Inst Sea Res, Dept Marine Microbiol & Biogeochem, POB 59, NL-1790 AB Den Burg, Netherlands
[12] Univ Utrecht, POB 59, NL-1790 AB Den Burg, Netherlands
[13] Univ Utrecht, Dept Earth Sci, Fac Geosci, POB 80-021, NL-3508 TA Utrecht, Netherlands
[14] Chevron Corp, 1400 Smith St, Houston, TX 77002 USA
来源:
基金:
美国国家科学基金会;
关键词:
SEA-SURFACE TEMPERATURES;
TETRAETHER LIPIDS;
TEX86;
PALEOTHERMOMETER;
LAKE;
RECORD;
VARIABILITY;
EQUATORIAL;
MEGADROUGHTS;
CALIBRATION;
EVOLUTION;
D O I:
10.1038/nature19065
中图分类号:
O [数理科学和化学];
P [天文学、地球科学];
Q [生物科学];
N [自然科学总论];
学科分类号:
07 ;
0710 ;
09 ;
摘要:
African climate is generally considered to have evolved towards progressively drier conditions over the past few million years, with increased variability as glacial-interglacial change intensified worldwide(1-3). Palaeoclimate records derived mainly from northern Africa exhibit a 100,000-year (eccentricity) cycle overprinted on a pronounced 20,000-year (precession) beat, driven by orbital forcing of summer insolation, global ice volume and long-lived atmospheric greenhouse gases(4). Here we present a 1.3-million-year-long climate history from the Lake Malawi basin (10 degrees-14 degrees S in eastern Africa), which displays strong 100,000-year (eccentricity) cycles of temperature and rainfall following the Mid-Pleistocene Transition around 900,000 years ago. Interglacial periods were relatively warm and moist, while ice ages were cool and dry. The Malawi record shows limited evidence for precessional variability, which we attribute to the opposing effects of austral summer insolation and the temporal/spatial pattern of sea surface temperature in the Indian Ocean. The temperature history of the Malawi basin, at least for the past 500,000 years, strongly resembles past changes in atmospheric carbon dioxide and terrigenous dust flux in the tropical Pacific Ocean, but not in global ice volume. Climate in this sector of eastern Africa (unlike northern Africa) evolved from a predominantly arid environment with high-frequency variability to generally wetter conditions with more prolonged wet and dry intervals.
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页码:220 / +
页数:16
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