To understand the rocks that
make up the cliffs and gorge walls of the Palmiet Nature Reserve it is
necessary to think in terms of a very different environment than exists
today. The Natal Group, to which these sandstones belong, was formed about
600 million years ago. Well known geographical features such as the Drakensberg
and Cape Mountains were still to be formed. KwaZulu-Natal lay near the
heart of the supercontinent Gondwanaland (the Indian and Atlantic Oceans
had not been formed).Animal life was only just beginning to evolve in
the warm seas and plants had yet to colonise the land.
The Palmiet area and most of KwaZulu-Natal, must have resembled a desert
similier toGobi Desert in China which is cold and arid. The total lack
of plants (other than algae) and animals made the region much harsher
than any modern equivalent and the climate one of even greater extremes.
There were no soils and vegetation to retain water, and even the atmosphere
was different, being richer in carbon dioxide and containing less oxygen.
So; envisage a long, flat-bottomed, sand-filled valley stretching from
a major lake or inland sea near Port Shepstone, north-eastwards to a mountainous
area in what is now southern Swaziland. Along the western edge of this
valley (by Pietermaritzburg) barren rolling hills rose and stretched away
to the far distance. On the eastern margin, which lay out past the present-day
coast, similar hills stretched several hundreds of kilometres to the area
that is now the Antarctic. A large river drained the highlands to the
north east and smaller tributaries flowed in from both margins. However,
as there was no soil or vegetation to form wetlands and retain water,
the flow rate and river level was highly variable. When rains fell in
the highland or hilly margins there was rapid runoff causing flash-floods
to sweep down the valley, scouring out new river channels during peak
discharge and depositing sheets of sandy alluvium after the flood. These
layers of sand, now converted to sandstone, preserve the ripple marks
and cross bedding caused by the flowing water during their deposition.
During major floods the mass of water also caused movement in the layers
of sand in the river bed, distorting the fine structures and sometimes
folding and deforming the bedding. The sequence of events during each
flood followed a very similar pattern. First the water would sweep down
the almost dry, or slowly flowing, river bed washing away obstacles and
often cutting new channels. As the power of the flood waters waned, first
the coarsest sediment (pebbles and coarse sand), then progressively finer
and finer material was deposited, so that in most sandstone beds the grain
size systematically decreases from bottom to top. Although most of the
material carried by the rivers was sand and gravel, after the floods some
pools of muddy water remained. The mud settled in these ponds to form
lens-shaped bodies of mudstone and siltstone while some ponds evaporated
completely producing mudflakes, just like those formed when modern puddles
dry out. In most cases the next flood eroded and destroyed the mud layers
before depositing another bed of sand, but occasionally a mudstone layer
was preserved, or the mudflakes survived long enough to be incorporated
into sandstone beds. Often river channels filled with sand during repeated
minor floods, so that during the stronger floods the river would overflow
and cut new channels through the layers of sand.
This environment existed for many millions of years, with movement along
fault lines at each side of the valley allowing the base of the valley
to sink so that the several hundreds of metres of sand and pebbles accumulated,
and were converted into rock by burial. However, during this time continental
drift was slowly moving the supercontintent Gondwanaland towards the South
Pole. The climatic change generated glaciers in the highlands, which steadily
grew until about 350 million years ago Arctic conditions prevailed. At
this stage the landscape must have appeared as a wasteland of snow and
ice, much like southern Greenland or Ellsworth Land (Antarctica), with
only the tops of a few rocky hills (nunataks) peeping through the ice.
During the cooling and initial glaciation much of the Natal Group was
eroded as the debris-rich ice sheets scoured the country side. This erosive
phase formed glacial pavements, such as the one in the University of Durban-Westville,
and the scratch marks made by boulders frozen in the base of the glacier
clearly indicate the direction of ice movement. Continental drift finally
carried the area past the pole and into slightly warmer climates where
the eroded debris could accumulate at the base of the glacier. In some
parts of KwaZulu-Natal there is evidence that this glacial debris, termed
the Dwyka Group, was reworked by flowing water, but in the Palmiet Nature
Reserve area the mass of blue-grey rock containing many exotic pebbles
and boulders is unsorted.
Although the deposition of the Dwyka Group marked the start of a major
geological episode called the Karoo Era, in which many hundreds of metres
of sediment accumulated, there is virtually no evidence of this phase
in the Palmiet area. Only when the Gondwanaland began to break up some
200 million years ago did geological events again impact on the nature
reserve. At this time the rocks that are now exposed on the land surface
were far underground, and magma from deep in the earth (about 20 km) was
able to escape upwards along the fractures in the splitting continent.
Much of the magma escaped onto the surface to form the basaltic lava's,
remnants of which are preserved in the Drakensberg and Lebombo region,
but some was trapped in the fractures where it solidified to form dolomite.
Occasionally fragments of sediments were caught up in the flow of magma
and these xenoliths (fragment of rock differing in origion composition
structure etc from the rock surrounding it}were altered to granite-like
lumps by the heat of the magma.
After the initial deep-seated fracturing that split Gondwana into the
African, Australian, Antarctic and Indian continents, there was a prolonged
period of seismic activity as thecontinents adjusted to the new configuration.
In the upper crust vertical and lateral movement occurred along fracture
planes known as faults to compensate for mass movement. The fractured
rock along the faults, called breccia, provided a pathway for the circulation
of ground water. This ground water carried dissolved minerals, most commonly
quartz, which were deposited in the breccia and associated fractures.
In many cases the breccia was cemented by the minerals deposit or the
fracture completely filled to form a vein, but in some cases the cavities
were not completely filled and crystals can be found.
The geological history of the Palmiet Nature Reserve during the last 10
million years is one of erosion and the development of the various African
Land Surfaces. However, in the most recent 50 000 years there have been
dramatic changes in sea level related to the Ice Age. The massive sea
level drop to about 120 m below the present level approximately 20 000
years ago caused the rivers meandering across the flat land surface to
cut down in to the plain. The sudden increase in gradient, due to the
change in sea level, combined with higher than present rainfall caused
the rivers to cut down into their existing channels creating a pattern
of incised meanders, and not the straighter lines associated with young
or high gradient drainage patterns.
Thus, the topographic features visible today, whereby a relatively small
river occupies a very deep and highly sinuous valley is a curious combination
of both the rocks formed many millions of years ago and the events of
relatively recent geological history.
Prof John Dunlevey
Palmiet Archaeological Sites
A COMMUNITY BASED EDUCATIONAL PROJECT -
EMPHASISING CULTURAL HERITAGE
- To provide an authentic archaeological
dig and interpretation thereof at the PNR for viewing by scholars, visitors
- To provide a mock dig at the Bergtheil
museum that echoes the archaeological finds at the PNR whereby hands-on
educational programs can take place regarding the prehistory of the
local area and how it fits into the greater puzzle of South African,
African and world prehistory.
- To create a visual recording of the process
of the archaeological dig for the historic record with a view to creating
a visual aid (video) for educational purposes.
- To provide employment opportunities for
the community through educational programs linked to the Palmiet archaeological
dig and the mock dig at the Bergtheil museum.
PALMIET NATURE RESERVE ARCHAEOLOGY
AND BERGTHEIL MUSEUM WESTVILLE
Artefacts found in the PNR
have been housed at the Bergtheil museum. These include Middle Stone Age
artefacts, bored stones that have been linked to Late Stone Age and grinding
stones and pottery shards that are associated with both Early and Late
Iron Ages. The artefacts have been used for educational programs run by
the museum and those initiated by a non-profit organisation, The Circle
Amafa, the heritage council
for Kwa-Zulu Natal was approached by Mary Lange, of The Circle Connection,
and Alvine Calboutin, curator of the Museum. Archaeologist, Annie van
de Venter of Amafa came to the PNR and confirmed that it would be suitable
as an educational archaeological site once a dig and interpretation had
Themba Zwane, an Amafa archaeologist,
after a preliminary test pit offered to continue with the project on a
voluntary basis. This he has done with the help of other volunteers.
The Palmiet prehistoric artefacts
have, with other archaeological finds in the Highway/Cato Manor area,
formed a collection of tangible prehistoric heritage important for educational
purposes for school learners and educators The PNR could serve as an ideal
location for outdoor learning and tourism. Not only could Learners and
visitors read and hear about the living areas of the Early Stone and Iron
Age inhabitants but would be able to experience early mans environment.
The Palmiet vegetation is also a unique visual aid to learners regarding
the geological history of the area and the greater Durban and Kwa-Zulu
There is in Westville the
opportunity to create a unique heritage project that will provide cultural
upliftment, empowerment, educational and tourism opportunities. This project
would be the result of a co-operative association of; Government heritage
agents such as Amafa KZN and the Bergtheil Museum, community cultural
and heritage organisations such as The PNR Management Committee, The Circle
Connection, the business sector, guides and educational assistants from
The project could facilitate
educational programs using local heritage to promote critical thinking.
September 2005 Update
We have cleared two squares up
to 15 cm below surface.Finds in the first ten centimetres below the
surface were the usual washdown
and picnicing visitors i.e. charcoal, glass etc.The first historical
cultural level has been reached in one of the squares which yielded old thick green tinted glass, a china sherd, some
interesting shells and charcoal. Investigations continue to determine if the shelter was used during the South African Ango
Boer War. This cultural level has been linked to the period due to
dating of the castle lager stopper plus a bullet
casing. Some coins have yet to be identified.
Steve Butler Palmiet Manager felt the site was unlikely to have been used in the winters as it
is very cold with frost and no sun. In Pre Settler times it would have been exposed with grass land compared to its present wooded state. Archaeologists Themba Zwane and Gavin Whitelaw
suspect that it was due to habitation during a time of conflict -we hope
further excavation especially of the 60 to 70 cm below surface cultural
level will add more evidence to this debate.
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