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.

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.

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 Exploring the phylogeography and population dynamics of the giant deer ( Megaloceros giganteus ) using Late Quaternary mitogenomes

2021 ◽  
Vol 288 (1950) ◽  
Author(s):  
Alba Rey-Iglesia ◽  
Adrian M. Lister ◽  
Paula F. Campos ◽  
Selina Brace ◽  
Valeria Mattiangeli ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Last Glacial Maximum ◽  
Late Pleistocene ◽  
Late Quaternary ◽  
Glacial Maximum ◽  
Climatic Fluctuations ◽  
The Holocene ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Late Quaternary climatic fluctuations in the Northern Hemisphere had drastic effects on large mammal species, leading to the extinction of a substantial number of them. The giant deer ( Megaloceros giganteus ) was one of the species that became extinct in the Holocene, around 7660 calendar years before present. In the Late Pleistocene, the species ranged from western Europe to central Asia. However, during the Holocene, its range contracted to eastern Europe and western Siberia, where the last populations of the species occurred. Here, we generated 35 Late Pleistocene and Holocene giant deer mitogenomes to explore the genetics of the demise of this iconic species. Bayesian phylogenetic analyses of the mitogenomes suggested five main clades for the species: three pre-Last Glacial Maximum clades that did not appear in the post-Last Glacial Maximum genetic pool, and two clades that showed continuity into the Holocene. Our study also identified a decrease in genetic diversity starting in Marine Isotope Stage 3 and accelerating during the Last Glacial Maximum. This reduction in genetic diversity during the Last Glacial Maximum, coupled with a major contraction of fossil occurrences, suggests that climate was a major driver in the dynamics of the giant deer.

THE LAST GLACIAL MAXIMUM IN TROPICAL EAST AFRICA

2016 ◽  
Author(s):  
Meredith A. Kelly ◽  
◽  
Margaret S. Jackson ◽  
James M. Russell ◽  
Jennifer A. Howley ◽  
...  
Keyword(s):  
East Africa ◽  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial

scholarly journals Late Quaternary fault movements in the Mt. Baldo-Lessini Mts sector of the Southalpine area (northern Italy)

2001 ◽  
Vol 80 (3-4) ◽  
pp. 187-208 ◽  
Author(s):  
Fabrizio Galadini ◽  
Paolo Galli ◽  
Augusto Cittadini ◽  
Biagio Giaccio
Keyword(s):  
Last Glacial Maximum ◽  
Late Quaternary ◽  
Historical Earthquakes ◽  
Lateral Spreading ◽  
Fault Scarp ◽  
Glacial Maximum ◽  
Last Glacial ◽  
Complex Structural ◽  
The Last Glacial Maximum ◽  
The Last Glacial

AbstractPaleoseismological investigations have been performed at Mt. Baldo and in the Lessini Mts. in order to collect quantitative data on the activity of minor faults showing geomorphic evidence of recent activation. The 4.5-km-long, NNE-SSW trending Naole fault was responsible for the formation of a narrow depression at the top of Mt. Baldo, bordered by a continuous bedrock (carbonate) fault scarp to the west. The extensional activity along this minor fault is probably due to gravitational deformations (lateral spreading) in response to the warping of the Mt. Baldo anticline. A 1.5-km-long graben is instead related to the 2.5-km-long, NNW-SSE trending Orsara fault (Lessini Mts.) which was responsible for the formation of bedrock (carbonate) fault scarps. This minor fault is part of a complex structural framework made of few-km-long faults which show evidence of Quaternary activity. Two trenches have been excavated across the Naole fault which showed the occurrence of displacement events subsequent to 17435-16385 BP (cal. age) and probably prior to 5455-5385/5330-5295 BP (cal. age). Two other trenches have been excavated across the Orsara fault whose analysis indicated that the most recent displacement event occurred between 20630-19795 BP and 765-675 BP (cal. age). The upper chronological limits of the displacements give some indications about the minimum elapsed time since the last fault activation (about 5,300 years for the Naole fault and 5-8 centuries for the Orsara fault). Both 1) the maximum expected magnitude of the earthquakes which may originate along the Mt. Baldo thrust and 2) the identification of a main fault responsible for the displacements along the complex net of minor faults affecting the Lessini Mts. are still open questions. As for point 1 although historical earthquakes with magnitude 4.5-5 may be associated with the Mt. Baldo thrust, the investigations carried out in this area did not clarify whether larger magnitude earthquakes may be expected. As for point 2, the cause of the displacements along the Orsara (Lessini Mts.) fault may be related to the activity of a major blind fault (which, however, has never been identified), responsible for the uplift of the Lessini Mts. More generally, the obtained results demonstrate the limits of traditional paleoseismological analyses in Alpine areas whose erosional/depositional activity has been strongly conditioned by the Late Pleistocene glacial history. The lack of units younger than loess and colluvial sediments related to the Last Glacial Maximum makes it impossible to define narrower chronological constraints for the displacements and to estimate the number and size of the displacement events. Moreover, the rebound following the retreat of the thick glacial cover affecting the Alpine area may have induced stresses responsible for higher deformation rates after the Last Glacial Maximum. Higher surficial deformation rates could imply shorter recurrence intervals for faulting episodes and/or larger magnitude earthquakes. Therefore, paleoseismologically inferred data in Alpine areas may not correctly define the fault behaviour related to the present tectonic regime.

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