Geography Department: Rhodes University
Third Year Course (GOG 302)
Module 3: The Quaternary in Africa
1. Introduction
The Quaternary Period is a subdivision of geological time that covers the last two
million years (or thereabouts) of Earth’s history. (Some scientists argue that the
Quaternary began 2.6 million years ago, others that it began 1.8 million years ago, while
others argue that there is no such thing as the Quaternary, it was just a continuation of the
Cenozoic Era). The Cenozoic Era comprises the Quaternary Period and the preceding
Tertiary Period. The Quaternary subdivides into two epochs: the Pleistocene (from some
two million years ago until about 11,000 years ago) and the Holocene (approximately the
last 11,000 years).
During the Quaternary there have been massive environmental changes, produced
essentially by climatic oscillations between very cold (glacial) and much warmer
(interglacial) conditions. These changing conditions have exerted a forcing effect on
plants and animals and it was during the Quaternary that much of hominid evolution took
place.
By the middle of the nineteenth century it was realized, in scientific circles, that
major changes had taken place in landscapes and environments during the Quaternary. In
Europe and North America evidence for the former existence of major ice sheets had
been discovered by that time. The Quaternary, consequently, became known as “The Ice
Age”. Subsequent research has shown that major ice masses also existed in the Southern
Hemisphere during the Quaternary, as in Antarctica, southern Argentina and Chile,
Tasmania, the uplands of eastern Australia and in the South Island of New Zealand.
During the 1990s it was shown that small glaciers even existed in the Drakensberg during
the Late Quaternary.
Evidence from cores recovered by drilling on the floors of the oceans has shown,
since about 1970, that some 25 million years ago the climate of the Earth began to cool
and the polar ice caps began to expand. The reasons for cooling are not fully known, but
are probably linked to changes in both atmospheric chemistry and in the circulation of the
atmosphere. These changes were caused by increased volcanic activity, which released
dust and gasses into the atmosphere, and by tectonic uplift, which caused the formation of
the high plateaux of Tibet and of Colorado. These plateaux, due to their altitude, became
very cold in winter and hence became associated with high pressure outblowing winds at
that season of the year. By contrast, in summer the plateaux were invaded by low
pressure cells and inblowing winds: essentially monsoonal conditions. The combination
of changes in atmospheric chemistry and uplift of great plateau areas brought Earth’s
climate close to a threshold of change, where variables that were previously of little
importance suddenly became very effective.
Global cooling, that had begun in the Tertiary, became accentuated during the
Quaternary and the climate began to oscillate between cold glacial conditions and much
warmer, interglacial, conditions. These major climatic oscillations owed their origins
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mainly to changes of the orbit of Earth relative to our Sun, in other words, to astronomic
variations.
The effect of these climatic oscillations is spatially variable so that, at the same
time, different regions of Earth experience different climatic conditions. In low latitudes,
for example, glacial stages may be associated with aridity rather than with excessive cold
and the development of ice sheets, while interglacials may be associated with moister
conditions. This is particularly well seen in southern Africa, where the Kalahari was more
extensive during the Last Glacial Stage than it is today, under interglacial conditions. The
margins of the Karoo have also waxed and waned as climates have altered.
The periodicity of glacial and interglacial stages has varied over time during the
Quaternary. During the last 750,000 years there have been ~100,000 year glacial stages
divided from each other by shorter (~15,000 years) warmer interglacial stages.
Temperatures during glacial stages are much lower than those of interglacials, as is
illustrated by comparing estimates of mean annual temperatures during the 20-13 ka
interval (the Last Glacial Maximum, LGM) in the midlands of Ireland with those of the
most recent thirty-year period in that area. Mean annual temperatures at present in the
Irish midlands are ~9 degrees C, whereas in the 20-13 ka interval they were of the order
of –8 degrees C, some 17 degrees C lower than at present.
Although little is known of Quaternary temperatures in southern Africa
investigations at the Cango Caves, allied with work on the Uitenhague aquifer, suggests
that during the LGM mean annual temperatures at low altitudes were at least 5 degrees C
below those of the present. Investigations at high altitudes in the East Cape Drakensberg
suggest that they may have been as much as 17 degrees C below those of the present,
partly because of the dryness of the atmosphere during glacial stages, resulting in
adiabatic cooling taking place as (Very) Dry Adiabatic Cooling (as in other Tropical/subTropical regions).
In addition to marked reductions of temperature during glacial stages, there were
also rapid temperature rises during the Quaternary, sometimes of over 10 degrees C in
less than a decade. Viewed in these terms, modern temperature changes and the present
global warming scare seem of limited significance!
Many Quaternary scientists believe that present trends in global warming, which
are thought to be human-induced, will probably be outweighed by natural trends within
the climatic feedback system. (There appears to have been an increase of ~0.6 degrees C
in mean annual temperatures over the last 100 years in many (but not all) parts of the
Earth. This increase is mainly due to increases in night temperatures rather than those of
daylight hours). A select committee of the House of Lords, in Britain, reported in July
2005 that some of the findings of the Intergovernmental Panel on Climate Change, ‘the
body on whose “research” Kyoto [Treaty] is built’, were ‘apparently influenced by
political considerations’, and that attempts to limit human-produced greenhouse gas
emissions [which is the basis of the Kyoto Treaty] “make[s] little difference to rates of
warming”, that “There are some positive aspects of global warming and these appear to
have been played down in the IPCC reports” and that, in effect, there is doubt on the
‘scientific consensus on climate change’ (Collins: The Daily Telegraph, 1.8.2005).
Many different landforms bear testimony to climatic conditions during the
Quaternary, such as those of glacial and of periglacial origin. Fluvial systems were also
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affected by climatic changes, as were local and global sea levels. Geomorphological
studies therefore help to elucidate Quaternary events.
There is also sedimentary evidence of former Quaternary conditions, both
organic and inorganic in nature. Unfortunately, however, the sedimentary record is
fragmentary and piecing it together is like completing a crossword puzzle in which some
of the pieces are missing. Scientists from many different disciplines therefore participate
in Quaternary science, such as palaeo-botanists/palynologists who study pollen profiles;
physicists who study isotopic evidence; archaeologists who study human artifacts,
skeletal remains and other cultural evidence; zoologists who examine faunal remains
(including the remains of hominids); and, of course, geologists and geographers.
Quaternary studies are exciting. Southern Africa, like most of the rest of the
continent, has not been studied in detail and there is much scope for research. During the
last decade it has been proven by geographers from Rhodes University that gelifluction is
active at high altitudes under present climatic conditions; that rock glaciers existed in the
Drakensberg during the Late Quaternary; that pro-glacial ramparts exist, also of Late
Glacial age; that small glaciers existed in the Drakensberg during the same time period.
An archaeologist from Fort Hare University has shown that human occupation of the East
Cape Drakensberg ceased some time between ~25,000 and ~24,000 BP (Before the
Present, the Present is 1950 AD) but that the uplands were reoccupied by ~12,000 BP.
The intervening years were those in which cold, glacial and periglacial, conditions
existed in those mountains. At lower altitudes, as geographers from Rhodes University
have shown, there were great fluctuations in runoff, as evidenced by deposits in
Howison’s Poort, near Grahamstown, with a major change in climatic and/or other
conditions soon after 4,000 BP. There were also mass movements (landslides) on valley
sides in and adjacent to Howison’s Poort, as elsewhere in Southern Africa, due to
adjustment of slope profiles to changing environmental conditions.
Scientists interested in human evolution have discovered that hominids developed
in Southern Africa (and elsewhere) during the Quaternary and that anatomically modern
humans existed in South Africa during the most recent glacial stage. Much research has
been undertaken into the interactions between these people and their environment and it
has been shown that the culture of Stone Age people adapted to environmental changes,
both natural and, possibly, human induced. Geographers are specialists in the study of the
interactions between people and their environments, so it is only natural that many
geographers are at the forefront of Quaternary Science.
The present course emphasizes Southern African Quaternary studies, but starts
with classic Quaternary studies, some of which established techniques that are still valid
and that have been used in Quaternary investigations in many parts of the world,
including Southern Africa.
Fieldwork is an integral party of the course and participants will be expected to
visit important Quaternary sites in the Eastern Cape. A weekend excursion to view
glacial, periglacial, cultural and fluvial sites in the East Cape Drakensberg is planned for
14-16 October, although participation in this event will be voluntary.
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2. Credit value
This module is worth 10 credits. Students should spend at least 20-25 hours per week
on the module. This time includes lectures, fieldwork, group and individual discussions
and individual reading.
3. Assumption of prior learning
Students are expected to have successfully completed First and Second Year
Geography.
4. Outcomes
a) Critical outcomes
On successful completion of this module students should be able to:
i)
identify and solve problems relating to the interactions between climates and
the environment
ii)
work in a team
iii)
collect, analyse and evaluate information
iv)
communicate effectively using visual, oral and written skills
v)
recognize problem solving contexts relating to climatic change
vi)
participate as responsible citizens in debates relating to climatic change
vii)
develop entreprenurial opportunities relating to sand and gravel exploitation,
tourism and scenery.
b) Specific outcomes
On completion of this module participants should be able to:
1. Appreciate that climates have changed throughout the Quaternary Period and have
a basic understanding of the reasons for those climatic changes.
2. Understand that climatic changes cause landscape changes.
3. Understand the basis of Quaternary stratigraphy.
4. Be able to identify and understand the origins of river terraces, lacustrine (and
especially pro-glacial lake) deposits and landforms, protalus ramparts, rock
glacier remains, glaciated valley landsystems, loess, cirque and valley moraines,
dune systems and other landforms associated with sea level change and wind
action.
5. Estimate Equilibrium Line Altitudes and apply the resultant information in order
to evaluate temperature changes in Tropical and sub Tropical areas during the
Late Quaternary.
6. Understand and apply the use of lithofacies codes and profile models.
7. Demonstrate the links between climatic change and human occupation of at least
one area in southern Africa.
8. Establish a research project to show the rate of regolith movement on a high
altitude slope and to demonstrate the linkages between climatic conditions and the
processes affecting regolith movement.
5. Teaching methods
These will include formal lectures, seminars, fieldwork and group discussion.
Details of lecture and other topics are given below.
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6. Module content and resources
The course may be adjusted to cater for students’ special interests, as long as they
are relevant to Quaternary science! Probable contents and readings will be:
1. Introduction.
Lewis, C. A. 2005 ‘Introduction’, in Lewis, C. A. and Richards, A. E. (editors) The
glaciations of Wales and adjacent areas, Logaston, Almeley, pp.1-16.
Davies, G. L. 1968 The Earth in decay, Macdonald, London, pp.263-316.
2. Alpine glaciations: the classic model.
Bowen, D. Q. 1978 Quaternary geology, Pergamon, Oxford, pp.10-20.
3. Constructing a glacial chronology: the work of Anthony Farrington.
Farrington, A. 1934 ‘The glaciations of the Wicklow Mountains’, Proceedings of the
Royal Irish Academy, 42B, 173-209.
Farrington, A. 1942 ‘The granite drift near Brittas on the border between County
Dublin and County Wicklow’, Proceedings of the Royal Irish Academy, 47B, 279291.
Farrington, A. 1944 ‘The glacial drifts of the district around Enniskerry, Co.
Wicklow’, Proceedings of the Royal Irish Academy, 50B, 133-157.
Farrington, A. 1949 ‘The glacial drifts of the Leinster Mountains’, Journal of
Glaciology, 1,220-225.
Farrington, A. 1957 ‘The Ice Age in the Dublin district’. Institute of Chemistry of
Ireland Journal, 5, 23-27.
4.Quaternary stratigraphy
Richards, A. E. ‘Stratigraphy’, in Lewis and Richards, op. cit., 17-23.
5. Global climatic variability during the Quaternary and the astronomic reasons
therefore.
Anderson, B. G. and Borns, H. W. 1994 The Ice Age World, Scandinavian University
Press, Oslo, 19-44.
6. River terraces, with special reference to the Eastern Cape.
Summerfield, M. A. 1991 Global geomorphology, Longman, Harlow, 224-228.
Hattingh, J. 1996 ‘Fluvial systems and landscape evolution’, in Lewis, C. A. (editor)
The geomorphology of the Eastern Cape, South Africa, Grocott and Sherry,
Grahamstown, 19-32 (and references in Hattingh’s chapter).
Lewis, C. A. and Illgner, P. M. 1998 ‘Fluvial conditions in the Holocene as evidenced
by alluvial sediments from above Howison’s Poort, near Grahamstown, South
Africa’, Transactions of the Royal Society of South Africa, 53, 53-67.
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7. Quaternary crustal deformation and the development of valleys: examples from
England.
Westaway, R. 2005 ‘Use of numerical modeling in investigations of Quaternary crustal
deformation in the UK’, Quaternary Newsletter, 105, 1-15.
Maddy, D. and Lewis, S. G. 2005 ‘The lower Severn valley’ in Lewis and Richards,
op. cit., 73-84.
Richards, A. E. 2005 ‘Herefordshire’, in Lewis and Richards, op. cit., 129-136.
8. Sundays River terraces.
Hattingh, J. 1994 ‘Depositionary environment of some gravel terraces in the Sundays
River Valley, Eastern Cape’, South African Journal of Geology, 97, 156-166.
9. Pro-glacial lake sediments, with reference to a lacustrine deposit in the Drakensberg.
Cohen, J. M. 1979 ‘Deltaic sedimentation in Glacial Lake Blessington, County
Wicklow, Ireland’, in Schlchter, Ch. Moraines and Varves, Balkema, Rotterdam,
357-368.
Farrington, A. 1957 ‘Glacial Lake Blessington’, Irish Geography, 3, 216-222.
Hanvey, P. M. and Lewis, C. A. 1990 ‘A preliminary report on the age and
significance of Quaternary lacustrine deposits at Birnam, north-east Cape Province,
South Africa’, South African Journal of Science, 86, 271-273.
10. Protalus ramparts, with special reference to the Drakensberg.
Shakesby, R. 2002 Classic landforms of the Brecon Beacons, Geographical
Association, Sheffield.
Lewis, C. A. 1994 ‘Protalus ramparts and the altitude of the local equilibrium line
during the Last Glacial Stage in Bokspruit, East Cape Drakensberg, South Africa’,
Geografiska Annaler, 76A, 37-48.
11. Rock glaciers and their origins, with special reference to the Drakensberg.
Shakesby, op. cit.
Lewis, C. A. and Hanvey, P. M., ‘The remains of rock glaciers in Bottelnek, East
Cape Drakensberg, South Africa’, Transactions of the Royal Society of South Africa,
48, 265-289.
12. The glaciated valley landsystem.
Selby,M. J. 1985 Earth’s changing surface, Clarendon press, Oxford, pp.417-467.
Bradshaw, M. J., Abbott, A. J. and Gelsthorpe, A. P. 1981 The earth’s changing
surface, Hodder and Stoughton, Sevenoaks, pp.185-214.
13. Quaternary glaciation in the Drakensberg.
Lewis, C. A. and Illgner, P. M. 2002 ‘Late Quaternary glaciation in southern Africa:
moraine ridges and glacial deposits at Mount Enterprise in the Drakensberg of the
Eastern Cape Province, South Africa’, Journal of Quaternary Science, 16, 365-374.
Mills, S. C. and Grab, S. W. 2005 ‘Debris ridges along the southern Drakensberg
escarpment as evidence for Quaternary glaciation in southern Africa’, Quaternary
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International, 129, 61-73.
14. Lithofacies codes and profile models, as used in the Drakensberg
Eyles, N., Eyles, C. H. and Miall, A D., 1993 ‘Lithofacies types and vertical profile
models’, Sedimentology, 30,
Miall, A. D. 1978 ‘Lithofacies types and vertical profile models in braided rivers: a
summary’, in Miall, A. D. (editor) Fluvial sedimentology, 5, 579-604.
Lewis, C. A. and Dardis, G. F. 1985 ‘Periglacial ice-wedge casts and head deposits at
Dynevor Park, Barkly Pass area, north-eastern Cape Province, South Africa’, South
African Journal of Science, 81, 673-677.
Hanvey, P. M. et al. 1986, ‘Periglacial slope deposits in Carlisle’s Hoek, near
Rhodes, Eastern Cape Province’, South African Geographical Journal, 68, 164-174.
14. Loess, with special reference to Namibia.
Pye, K. 1996 ‘The nature, origin and accumulation of loess’, Quaternary Science
Reviews, 14, 653-667.
Eitel, B., Blmel, W. D., Hser, K.and Mauz, B. 2001 ‘Dust and loessic alluvial
deposits in Northwestern Namibia (Damaraland, Kaokoveld): sedimentology and
palaeoclimatic evidence based on luminescence data’, Quaternary International,
76/7, 57-65.
15. Sea-level changes, especially along the southern African coast, but also in Southeast
Asia.
Rust, I. C., Stear, D. A., Illenberger, W. K., Smuts, W. J. and McMillan, I. K. 1990
‘The Alexandria coastal dunefield and its hinterland: a model for Pleistocene and
Neogene palaeogeography of Algoa Bay’, Palaeoecology of Africa, 21, 61-67.
Maud, R. R. 1990 ‘Sea-level movements as evidence of late Quaternary
environmental changes in southern Africa’, Palaeoecology of Africa, 21, 27-34.
Ramsay, P. J. and Cooper, J. A. G. 2002 ‘Late-Quaternary sea-level change in South
Africa’, Quaternary Reviews, 57, 82-90.
Compton, J. S. and Franceschini, G. 2005 ‘Holocene geoarchaeology of the Sixteen
Mile Beach barrier dunes in the Western Cape, South Africa’, Quaternary Research,
63, 99-107.
Voris, H. K. 2000 ‘Maps of Pleistocene sea levels in Southeast Asia: shorelines, river
systems and time durations’, Journal of Biogeography, 27, 1153-1167.
16. Estimation and reconstruction of Equilibrium Line Altitudes (ELA’s).
Osmaston, H. 2005 ‘Estimates of glacier equilibrium line altitudes by the Area x
Altitude, the Area x Altitude Balance Ratio and the Area x Altitude Balance Index
methods and their validation’, Quaternary International, 138-9, 22-31.
Benn, D. I., Owen, L. A., Osmaston, H. A., Seltzer, G. O., Porter, S. C. and Mark, B.
2005 ‘Reconstruction of equilibrium-line altitudes for tropical and sub-tropical
glaciers’, Quaternary International, 138-9, 8-21.
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17. Quaternary glaciation of Africa
Osmaston, H. A. and Harrison, S. P. 2005 ‘The Late Quaternary glaciation of Africa:
a regional synthesis’, Quaternary International, 138-9, 32-54.
18. Snowlines and climatic change over the last 21,000 years in the Tropics.
Mark, B. G., Harrison, S. P., Spessa, A., New, M., Evans, D. J. A. and Helmens, K. F.
‘Tropical snowline changes at the last glacial maximum: a global assessment’,
Quaternary International, 138-9, 168-201.
19. Late Glacial and Holocene palaeoenvironments in the uplands of the Eastern Cape.
Holmes, P. J., Boardman, J., Parsons, A. J. and Marker, M.E.2003‘Geomorphological
palaeoenvironments of the Sneeberg Range, Great Karoo, South Africa’, Journal of
Quaternary Science, 18, 801-813.
Lewis, C. A. 2005 ‘Late Glacial and Holocene palaeoclimatology of the Drakensberg
of the Eastern Cape, South Africa’, Quaternary International, 129, 33-48.
20. Establishing a research project to examine the interactions between modern climate
and regolith at high altitudes in the East Cape Drakensberg.
Kck, K. M. and Lewis, C. A. 2002 ‘terracettes and active gelifluction terraces in the
Drakensberg of the Province of the Eastern Cape, South Africa: a process study’,
South African Geographical Journal, 84, 214-225.
7. Assessment
Specific outcomes
Assessment critera
1. Appreciation of climate change Graded as in Z
2. Understanding that climate
change causes landscape change
ditto
3. Understanding the basis of
Quaternary stratigraphy
ditto
Assessment tasks
End of year exam
4. Ability to identify certain
landforms
Oral and written
description of field
evidence
5. E. L. A. estimation and use
Presentation of area x
altitude data
6. Use of lithofacies codes and
profile models
Evaluation of coding
and profile
8
ditto
ditto
Written description in
the field
ditto
Group work in field
Estimation of an E. L. A.
Logging of a field
section and end of
year exam
7. Demonstration of links between
climate change and human
occupation
Clarity and accuracy of
expression
Field description and
end of year exam
8. Knowledge of how to establish
Graded as in Z
End of year exam
a research programme
Z Grading criteria:
First: Analytical and clear conclusions/ descriptions, well grounded in theory and
showing mastery of the relevant literature, suitable maps and diagrams (if appropriate),
clear calculations (if appropriate), fluently written essay/report in clear and concise
English that synthesises the available material and shows evidence of original thought
and provides specific examples to substantiate statements/hypotheses.
Upper Second: Well written essay/report with suitable maps, diagrams and calculations
(if appropriate), competent (but not masterly) handling of the relevant literature
showing the beginnings of synthesis and with specific examples that substantiate
statements.
Lower Second: Limited conclusions/ descriptions and limited knowledge of the relevant
literature, limited maps, diagrams and calculations (where appropriate), writing lacking in
fluency, little or no evidence of synthesis, few or no specific examples to substantiate
statements.
Third: Basic knowledge of the topic and of the relevant literature, poorly expressed
essay/report, lacking in synthesis and, (where they are relevant to the essay/report) with
poor maps/diagrams/calculations and lacking specific examples to substantiate
statements.
Fail: exhibits little or no understanding of the question/task, writing lacks fluency, no or
very limited knowledge of the relevant literature, poor and/or misleading
maps/diagrams/calculations (where those are relevant to the answer/report/task).
8. Evaluation
The module will be evaluated using the standard questionnaire used by the Department of
Geography, by ongoing discussions between students and Professor Lewis and by the
class representative expressing student opinions on the module at meetings of the
staff/student committee.
Colin A. Lewis, August 2005.
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