Buffelskloof Formation
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The Buffelskloof Formation is a
geological formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock expo ...
found in the
Western Cape The Western Cape ( ; , ) is a provinces of South Africa, province of South Africa, situated on the south-western coast of the country. It is the List of South African provinces by area, fourth largest of the nine provinces with an area of , an ...
province in
South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...
. It is the uppermost of the four formations found within the Uitenhage Group of the Algoa Basin. It is considered an informal formation by some of the literature as it is very thin and only outcrops as isolated horizons in the Oudshoorn-Gamtoos, Herbertsdale-Mossel Bay, and Heidelberg-Riversdale Basins. Along the Worcester-Pletmos Basin, it occurs in patches along the southern flanks of the
Langeberg The Langeberg Range is a mountain range in the Western Cape province of South Africa. Its highest peak is Keeromsberg at 2,072 m that lies 15 km northeast of the town of Worcester. Some of the highest peaks of the range are located just ...
mountain range - from
Worcester Worcester may refer to: Places United Kingdom * Worcester, England, a city and the county town of Worcestershire in England ** Worcester (UK Parliament constituency), an area represented by a Member of Parliament * Worcester Park, London, Engl ...
in the west and as far as
Mossel Bay Mossel Bay () is a harbour town of about 170,000 people on the Garden Route of South Africa. It is an important tourism and farming region of the Western Cape Province. Mossel Bay lies 400 kilometres east of the country's seat of parliament, Ca ...
in the east. From
Mossel Bay Mossel Bay () is a harbour town of about 170,000 people on the Garden Route of South Africa. It is an important tourism and farming region of the Western Cape Province. Mossel Bay lies 400 kilometres east of the country's seat of parliament, Ca ...
this formation is inter fingered by the informal Hartenbos Formation. The Buffelskloof and Hartenbos Formations only occur in the Oudshoorn-Gamtoos and Herbertsdale-Mossel Bay basins and seem to correlate to the Sundays River Formation in age.


Geology

The Buffelskloof Formation was formed along the southern section of South Africa during the break up of
Gondwana Gondwana ( ; ) was a large landmass, sometimes referred to as a supercontinent. The remnants of Gondwana make up around two-thirds of today's continental area, including South America, Africa, Antarctica, Australia (continent), Australia, Zea ...
when there was widespread
erosion Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust and then sediment transport, tran ...
of rocks comprising the
Cape Fold Belt The Cape Fold Belt (CFB) is a long fold-and-thrust mountain belt along the western and southern coastlines of Western Cape, South Africa. The Cape Fold Belt formed during the Permian period (300 to 250million years ago) in the late Paleozoic ...
. The Buffelskloof and Hartenbos Formations are tilted northwards, which is indicative of further crustal extension and faulting in the later phase of the break up of Gondwana. It is considered to be Early
Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...
in age although more thorough dating needs to be undertaken to confirm this. It provides important geological data on the change in landscape during the break-up of Gondwana in relation to the older
Kirkwood Formation The Kirkwood Formation is a geological formation found in the Eastern and Western Cape provinces in South Africa. It is one of the four formations found within the Uitenhage Group of the Algoa Basin – its type locality – and in the neighbour ...
which it overlies. The Buffelskloof and Hartenbos Formations are only found in the
Western Cape The Western Cape ( ; , ) is a provinces of South Africa, province of South Africa, situated on the south-western coast of the country. It is the List of South African provinces by area, fourth largest of the nine provinces with an area of , an ...
and do not overlie the Sundays River Formation, which may be indicative of an
unconformity An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval ...
. The relationship between the Buffelskloof and Hartenbos Formations, and the lower formations of the Uitenhage Group needs further study. The Buffelskloof Formation mainly comprises reddish conglomerates that are interbedded by
quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tet ...
-rich
sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...
lenses and angular
breccia Breccia ( , ; ) is a rock composed of large angular broken fragments of minerals or Rock (geology), rocks cementation (geology), cemented together by a fine-grained matrix (geology), matrix. The word has its origins in the Italian language ...
s. The conglomerates and
sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...
s were likely deposited in a high-energy
alluvial Alluvium (, ) is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Alluvium is also sometimes called alluvial deposit. Alluvium is ...
environment where
debris flow Debris flows are geological phenomena in which water-laden masses of soil and fragmented Rock (geology), rock flow down mountainsides, funnel into stream channels, entrain objects in their paths, and form thick, muddy deposits on valley floors. ...
s from flash floods were common during the rainy season, while the
breccia Breccia ( , ; ) is a rock composed of large angular broken fragments of minerals or Rock (geology), rocks cementation (geology), cemented together by a fine-grained matrix (geology), matrix. The word has its origins in the Italian language ...
s are the remains of
scree Scree is a collection of broken rock fragments at the base of a cliff or other steep rocky mass that has accumulated through periodic rockfall. Landforms associated with these materials are often called talus deposits. The term ''scree'' is ap ...
mountain-slope deposits. The
breccia Breccia ( , ; ) is a rock composed of large angular broken fragments of minerals or Rock (geology), rocks cementation (geology), cemented together by a fine-grained matrix (geology), matrix. The word has its origins in the Italian language ...
s were formed from renewed
erosion Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust and then sediment transport, tran ...
of the
Cape Fold Belt The Cape Fold Belt (CFB) is a long fold-and-thrust mountain belt along the western and southern coastlines of Western Cape, South Africa. The Cape Fold Belt formed during the Permian period (300 to 250million years ago) in the late Paleozoic ...
rocks due to the next phase of
tectonic Tectonics ( via Latin ) are the processes that result in the structure and properties of the Earth's crust and its evolution through time. The field of ''planetary tectonics'' extends the concept to other planets and moons. These processes ...
activity associated with the breakup of
Gondwana Gondwana ( ; ) was a large landmass, sometimes referred to as a supercontinent. The remnants of Gondwana make up around two-thirds of today's continental area, including South America, Africa, Antarctica, Australia (continent), Australia, Zea ...
. The reddish coloration of the rocks is due to
iron oxide An iron oxide is a chemical compound composed of iron and oxygen. Several iron oxides are recognized. Often they are non-stoichiometric. Ferric oxyhydroxides are a related class of compounds, perhaps the best known of which is rust. Iron ...
being supplied during deposition of the
sedimentary rock Sedimentary rocks are types of rock (geology), rock formed by the cementation (geology), cementation of sediments—i.e. particles made of minerals (geological detritus) or organic matter (biological detritus)—that have been accumulated or de ...
. The Hartenbos Formation predominantly comprises sandy
mudstone Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from ''shale'' by its lack of fissility.Blatt, H., and R.J. Tracy, 1996, ''Petrology.'' New York, New York, ...
and
claystone Mudrocks are a class of fine-grained siliciclastic sedimentary rocks. The varying types of mudrocks include siltstone, claystone, mudstone and shale. Most of the particles of which the stone is composed are less than and are too small to ...
which were likely deposited in
deltaic A river delta is a landform, archetypically triangular, created by the deposition of the sediments that are carried by the waters of a river, where the river merges with a body of slow-moving water or with a body of stagnant water. The creati ...
settings downstream and seaward from the Buffelskloof Formation deposits.


Paleontology

Only fragmented,
petrified In geology, petrifaction or petrification () is the process by which organic material becomes a fossil through the replacement of the original material and the filling of the original pore spaces with minerals. Petrified wood typifies this proce ...
and semi-petrified
fossil wood Fossil wood, also known as fossilized tree, is wood that is preserved in the fossil record. Over time the wood will usually be the part of a plant that is best preserved (and most easily found). Fossil wood may or may not be petrified, in ...
have been recovered from the Buffelskloof Formation. No fossil remains have been found in the Hartenbos Formation at this time. Poor
vertebrate Vertebrates () are animals with a vertebral column (backbone or spine), and a cranium, or skull. The vertebral column surrounds and protects the spinal cord, while the cranium protects the brain. The vertebrates make up the subphylum Vertebra ...
fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...
content is typical of high-energy environments that predominantly contain braided river systems. However, due to the similarities between the Buffelsdorp Formation and the older
Enon Formation The Enon Formation is a geological formation found in the Eastern and Western Cape provinces in South Africa. It is the lowermost of the four formations found within the Uitenhage Group of the Algoa Basin, its type locality, where it has been ...
, it is possible that
dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...
teeth and claws could be recovered from this formation in the future.


References

{{Geology of South Africa, formations Geologic formations of South Africa Cretaceous South Africa Upper Cretaceous Series of Africa Conglomerate formations of South Africa Sandstone formations Alluvial deposits