Climatic conditions in Southern Africa since the last glacial maximum, inferred from pollen analysis

1989 ◽  
Vol 70 (4) ◽  
pp. 345-353 ◽  
Author(s):  
L. Scott
Keyword(s):  
Last Glacial Maximum ◽  
Pollen Analysis ◽  
Southern Africa ◽  
Climatic Conditions ◽  
Glacial Maximum ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial

The late Quaternary landscape at Sehonghong in the Lesotho highlands, southern Africa

Antiquity ◽  
1996 ◽  
Vol 70 (269) ◽  
pp. 623-638 ◽  
Author(s):  
Peter J. Mitchell
Keyword(s):  
Last Glacial Maximum ◽  
Southern Africa ◽  
Late Quaternary ◽  
Glacial Maximum ◽  
Stone Age ◽  
Later Stone Age ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial ◽  
Rock Shelters

In the rough and rugged country of the Lesotho highlands, rock-paintings and archaeological deposits in the rock-shelters record hunter-gatherer life-ways; at Sehonghong, a long sequence runs from recent times to and through the Last Glacial Maximum. Survey of the region's Middle and Later Stone Age sites shows a pattern of concentrations that likely applies to other parts of the Lesotho highlands.

Isotopic evidence for the past climates and vegetation of southern Africa

Bothalia ◽  
1983 ◽  
Vol 14 (3/4) ◽  
pp. 391-394 ◽  
Author(s):  
J. C. Vogel
Keyword(s):  
Last Glacial Maximum ◽  
Southern Africa ◽  
Glacial Maximum ◽  
Cape Coast ◽  
Marked Rise ◽  
Upper Pleistocene ◽  
Temperature Changes ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial

The stable isotopes of hydrogen, oxygen and carbon can potentially provide evidence of past climates. The most detailed information has been obtained from variations in the oxygen-18 content of foraminifera from ocean floor cores, the analysis of which has produced a record of ocean temperature changes through the Quaternary and beyond. The use of isotope analysis of continental materials to reveal climatic change is more limited, but some advances have been made in recent years. One approach has been to utilize the variations in the isotopic composition of precipitation as recorded in ancient groundwater. Thus groundwater samples from a confined aquifer on the southern Cape coast show a marked rise in temperature since the Last Glacial maximum. The temperature changes during the Upper Pleistocene and Holocene are also reflected in the oxygen-18 content of stalagmites from the Cango caves in the same region. The widespread occurrence of C4 grasses in the warmer summer rainfall areas of southern Africa provides a novel possibility of observing temporal shifts of climatic boundaries. The distinctly high carbon-13 content of C4 plants is clearly reflected in the skeletons of grazers so that faunal material from suitably situated archaeological sites can be used to observe changes in the composition of the local grass-cover. The evidence thus far accumulated suggests only minor changes since the Upper Pleistocene. The combined evidence to date indicates that temperatures and also precipitation in southern Africa have changed since the Last Glacial maximum, about 18 000 years ago, but that shifts in the boundaries of the various veld-types were probably not very extensive.

The Late Quaternary history of climate and vegetation in East and southern Africa

Bothalia ◽  
1983 ◽  
Vol 14 (3/4) ◽  
pp. 369-375 ◽  
Author(s):  
E. M. Van Zinderen Bakker Sr
Keyword(s):  
East Africa ◽  
Last Glacial Maximum ◽  
Southern Africa ◽  
Late Quaternary ◽  
Summer Precipitation ◽  
Vegetation Pattern ◽  
Glacial Maximum ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial

In the vast region of East and southern Africa the alternating glacial and interglacial periods of the Quaternarv were characterized by considerable changes in temperature and precipitation. During the last glacial maximum the influence of the ITCZ was limited, while the circulation systems were strengthened. The ocean surface waters were cooler and the Benguela Current was activated. In the montane areas of East Africa and also in southern Africa the temperature dropped by about 6°C. During this hypothermal period, rainfall on the east African plateau and mountains diminished. Summer precipitation could still penetrate the eastern half of southern Africa from the Indian Ocean, while the western half was arid to semi-arid. Cyclonic winter rain migrated further north beyond the latitude of the Orange River. The consequences of these climatic changes during the last glacial maximum were that the woodlands of East Africa opened up. On the plateau of South Africa austro-afroalpine vegetation dominated. The south coastal plain was very windy and cold to temperate, while the Namib and Kalahari were respectively hyper-arid and semi-humid. During hyperthermals the vegetation pattern resembled present-day conditions more closely.

Late Quaternary paleoenvironmental changes in East Africa: a review of multiproxy evidence from palynology, lake sediments, and associated records

2006 ◽  
Vol 30 (5) ◽  
pp. 633-658 ◽  
Author(s):  
Lawrence M. Kiage ◽  
Kam-biu Liu
Keyword(s):  
East Africa ◽  
Last Glacial Maximum ◽  
Late Quaternary ◽  
Climatic Conditions ◽  
Glacial Maximum ◽  
Ice Age ◽  
Last Glacial ◽  
Paleoenvironmental Changes ◽  
The Last Glacial Maximum ◽  
The Last Glacial

This paper presents an overview of paleoenvironmental changes in East Africa during the late Quaternary based on evidence from pollen, diatoms, microscopic charcoal, and lake level records and associated proxies. The paleoenvironmental records derived from different proxies complement each other to provide a more accurate and complete assessment of the paleoenvironmental changes in East Africa. The records show that the period prior to c. 42,000 14C yr BP was characterized by warm climatic conditions similar to the present. This was followed by a change to cold dry conditions from 42,000 to 30,000 14C yr BP, and cold and moist conditions from 30,000 to 21,000 14C yr BP. Temperatures during the latter period leading to the Last Glacial Maximum (LGM) were probably 2 to 4.1°C lower than the present. Between c. 21,000 and 12,500 14C yr BP East Africa's environment was generally cool, punctuated by two significant episodes of prolonged desiccation. Warm and moist conditions punctuated by rapid climatic changes prevailed in the region during the deglacial and middle Holocene period. Ice core records document two significant and abrupt drought events in the region, one at 8300 14C yr BP and the other at 5200 14C yr BP. The onset of a longer and more extensive desiccation period commencing 4000 14C yr BP was registered in nearly all sites. The climate of East Africa was generally drier than present during the Medieval Warm Period (MWP) while fairly wet conditions prevailed during the Little Ice Age (LIA) interrupted by three episodes of aridity, more severe than those of more recent times. Whereas this review advances our understanding of climate and vegetational changes in East Africa beyond the Last Glacial Maximum, it also highlights limitations of the paradigms that explain the forcing mechanisms behind the changes. However, unequivocal interpretation of the multiproxy data from East Africa with respect to paleoenvironmental changes becomes extremely complex and challenging especially when the anthropogenic input is considered.

scholarly journals Stable isotope and modelling evidence for CO<sub>2</sub> as a driver of glacial–interglacial vegetation shifts in southern Africa

2013 ◽  
Vol 10 (3) ◽  
pp. 2001-2010 ◽  
Author(s):  
F. J. Bragg ◽  
I. C. Prentice ◽  
S. P. Harrison ◽  
G. Eglinton ◽  
P. N. Foster ◽  
...  
Keyword(s):  
Last Glacial Maximum ◽  
Southern Africa ◽  
Co2 Concentration ◽  
Glacial Maximum ◽  
C3 Plants ◽  
Temperature Changes ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
Precipitation And Temperature ◽  
The Last Glacial

Abstract. Atmospheric CO2 concentration is hypothesized to influence vegetation distribution via tree–grass competition, with higher CO2 concentrations favouring trees. The stable carbon isotope (δ13C) signature of vegetation is influenced by the relative importance of C4 plants (including most tropical grasses) and C3 plants (including nearly all trees), and the degree of stomatal closure – a response to aridity – in C3 plants. Compound-specific δ13C analyses of leaf-wax biomarkers in sediment cores of an offshore South Atlantic transect are used here as a record of vegetation changes in subequatorial Africa. These data suggest a large increase in C3 relative to C4 plant dominance after the Last Glacial Maximum. Using a process-based biogeography model that explicitly simulates 13C discrimination, it is shown that precipitation and temperature changes cannot explain the observed shift in δ13C values. The physiological effect of increasing CO2 concentration is decisive, altering the C3/C4 balance and bringing the simulated and observed δ13C values into line. It is concluded that CO2 concentration itself was a key agent of vegetation change in tropical southern Africa during the last glacial–interglacial transition. Two additional inferences follow. First, long-term variations in terrestrial δ13Cvalues are not simply a proxy for regional rainfall, as has sometimes been assumed. Although precipitation and temperature changes have had major effects on vegetation in many regions of the world during the period between the Last Glacial Maximum and recent times, CO2 effects must also be taken into account, especially when reconstructing changes in climate between glacial and interglacial states. Second, rising CO2 concentration today is likely to be influencing tree–grass competition in a similar way, and thus contributing to the "woody thickening" observed in savannas worldwide. This second inference points to the importance of experiments to determine how vegetation composition in savannas is likely to be influenced by the continuing rise of CO2 concentration.

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