Border Cave

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View through the cave entrance over Swaziland

Border Cave ("Grenzhöhle") is an abri on the western slope of the Lebombo Mountains in the South African province of KwaZulu-Natal near the border between South Africa and Swaziland . In the course of dating using the electron spin resonance method in 2001, layers of ash were used to prove that the cave was already inhabited by anatomically modern humans ( Homo sapiens ) 200,000 years ago . As early as 1990 it was reported that fossils of anatomically modern humans discovered decades earlier were partly dated to the time 80,000 to 70,000 years ago and partly 60,000 to 50,000 years ago. This and other evidence suggests a remarkably continuous settlement of the cave.

In 2015, the government of South Africa proposed the cave for inclusion in UNESCO World Heritage , along with Blombos Caves , Pinnacle Point Caves , Klasies River Caves , Sibudu Cave and Diepkloof Rock Shelter .

geography

The cave, which opens to the west towards the Lowveld near Ingwavuma , is located about 100 m below the summit zone of the Lebombo Mountains and offers a wonderful view over the plain of Swaziland. The cave is a semicircular opening approx. 40 m in diameter and was formed in Jurassic lava as a result of differential weathering .

The cave is only 400 m from the Swaziland border, in the Kwazulu region . The Lebombo Mountains are an unusual mountain range, which is characterized by deep valleys and many eastern slopes. The underlying lowland planes at 170- 220  m above sea level. The Border Cave is approx. 600  m high, just below the edge of the mountainside.

The main watercourses in the region are Usuthu , Ngwavuma and Pongolo Rivers , all of which run from west to east. They all cut through the mountain bar and run as superimposed streams (superimposed river) above horizontal layers of rock faults. All flow into Delagoa Bay ( Mozambique ). The rivers accelerate the erosion of the underlying rock layers. The Lowveld therefore shows a younger layer of erosion and the rocks of the Karoo , especially the Storm Mountains - basalts and Ecca slates , show older surface layers. The geomorphological appearance is very diverse, as the lebombo rhyolites are only indistinctly stratified and only shows a slight banding with phenocrysts made of feldspar and partly quartz . The differences arose from the individual cooling processes, which means that the crystallization also took place differently. In the later Pleistocene the changes became weaker and seepage water in the walls was completely absent. It can therefore be assumed that the cave was formed in the Pleistocene.

At Ingwavuma (12 km away) there is annual rainfall of around 820 mm. The vegetation consists of a tree savannah, the composition of which changes depending on the depth of the soil. The climate in the region includes hot summers and moderately warm, dry winters ( Cwa after Koeppen), while a tropical savanna climate prevails in Mozambique and the coastal plains. In the Lebombo Mountains, scrubland, scrub forest and forest are combined at different altitudes within a few kilometers. Numerous documented plant species come from the genera Rauvolfia , Protorhus , Trichilia and Combretum and occur together with aloes , figs and milkweed plants . There are also acacias and marula trees in company with Digitaria and Themeda grasses.

Paleontological and archaeological finds

Excavation in 2018: The photo shows the stratigraphy in the northern area of ​​the cave

animals and plants

From the preserved fossils of animals in the cave, specific hunting patterns of their inhabitants during the Middle Stone Age and the Later Stone Age can be derived. The findings suggest that the inhabitants brought smaller animals into the cave as a whole, while they only brought parts of larger animals into the cave. Among the animal species that could be identified were a. an extinct springbok ( Antidorcas bondi ), whose habitat was savanna-like grassland, which is why these remains suggest that people used open grassland as a hunting ground at that time. The species died out around 9,000 years ago, and its occurrence in the cave has been proven around 38,000 years ago.

The remains from the cave also show that the early inhabitants may have a. fed on bush pigs , warthogs , zebras and cape buffalo .

Finds of small mammals suggest that the vegetation in the Upper Pleistocene from Miombo -Savannen Woodland or wet miombo woodland and Lowveld savannah, arid Lowveld vegetation, or Mopane -Vegetation existed. There were four major epochs. The humid miombo prevailed in the earliest period. Annual rainfall was about 25% higher than today, with 10% less rainfall in the winters. There were high and relatively high average annual temperatures, comparable to climates found further north today. In the Zululand Thornveld , on the other hand, winter precipitation seems to have increased by 20% to 30% compared to then. Frost also occurs sporadically in the Lowveld.

There were also characteristic changes in vegetation compositions between the Middle Stone Age and the Later Stone Age . The differences could be demonstrated using pollen in the relative proportions of grass pollen in relation to bush pollen. In the Middle Stone Age 1 and 2 and in the Early Late Stone Age, bush pollen was more present. This indicates that the climatic conditions have changed significantly.

There is a good soil map for Swaziland , but the soils in the KwaZulu region of the Lebombo Mountains have not yet been mapped. The predominant soil type is brown, clayey soil. In the basaltic areas of the Lowveld, the clays are more red to brown and clearly structured. In flat, low areas, the clays are black or even coal-like with coarse block structures.

Fossil traces of anatomically modern humans

Skull BC1 with lower jaw BC2 of an adult human from the Border Cave.

The first scientific inspection of the cave took place in July 1934 by members of Raymond Dart 's group. At the same time, a small test excavation was carried out on an area around ten meters long, one meter wide and 1.70 meters deep. Among the recent debris and surface disturbances from the use of the cave as a shelter for people living in the region, stone artefacts were recovered which, due to their nature , were ascribed to the Middle Stone Age . However, a new archaeological exploration of the cave was only carried out after a meter-thick layer of the cave floor was removed in 1940 in search of guano and fossil hominine bones were discovered, which were handed over to Raymond Dart in January 1941. An excavation team from the University of the Witwatersrand , led by geologist Basil Cook, carried out a more thorough investigation in July 1941 and July 1942. After that, more intensive excavations were only carried out again in the 1970s under the direction of the South African archaeologist Peter Beaumont (1935-2016); a total of more than 69,000 artifacts have been recovered so far.

The excavation area in the cave is 60 square meters. The sediment layers extend up to 4.50 meters in depth; they consist alternately of sand blown into it and layers of black and white colored ash, the ages of which range from the Middle Stone Age (MSA 1, MSA 2 = Howieson's Poort Industry , MSA 3a and 3b) through the early Later Stone Age to the Iron Age and which repeated one Evidence of the settlement of the cave for decades. In the area of ​​the oldest, 200,000 year old sediments, the remains of several layers of alternating charcoal and plant remains were discovered. The find was interpreted in 2020 as the probably oldest deposit covered by plant stalks ("straw deposit").

In the early 1940s, several fossils were recovered that are interpreted as the remains of anatomically modern humans. The following have been published so far:

  • an incomplete skull, reconstructed from several related fragments, of a man around 30 years old (the fossil BC 1) with a brain volume of approx. 1450 cm³, which is also common in people living today
  • a partially preserved lower jaw (BC 2)
  • the skeleton of a child (BC 3) who was buried together with the shell of a sea clam ( Conus bairstowi )
  • a skeleton from the Iron Age (BC 4) almost completely preserved except for the skull
  • an almost completely preserved lower jaw (BC 5)
  • Several individually recovered bones and bone fragments ( humerus , ulna , metatarsal bones ) that were discovered during the search for guano, but the exact location of which could no longer be reconstructed in the 1940s.

The fossils BC 1 and BC 2 are considered to be the oldest hominine finds from the cave, but their find layer was only inaccurately documented in the 1940s. The child fossil BC 3 was discovered in a deep layer, but it is probably much younger than this layer and probably got into the depths during the burial. In 1990 electron spin resonance (ESR) dating resulted in the following age information: for BC 1 and BC 2 an age of with great probability (“almost certainly”) less than 90,000 years and for BC 3 74,000 ± 4000 years. In 2003, ESR / ICP-MS dating was published for BC 5 , according to which the lower jaw is 74,000 ± 5000 years old.

The skull BC 1 has morphological features that differ from all human populations living today and most closely match features of the Khoisan living today . The children's skeleton BC 3 is considered to be the earliest evidence of a burial of anatomically modern humans in Africa and at the same time the earliest evidence of a piece of jewelry as a grave object .

In 2012, a specialist journal described the discovery of tools made of wood and bones, the oldest of which were dated to an age of around 40,000 years. These tools are similar to those still used by the San today. They are therefore the oldest evidence of the tool culture of the San, which, according to the researchers, has existed for at least 44,000 years.

Artifacts found in Border Cave include: a. a 39,000 year old ( cal BP ) wooden digging stick , 40,000 year old (cal BP) projectile points and ten centimeter long awls made of bone; several bone finds showed as a special feature workings in the form of adjacent notches. The projectile tips are similar to those still used by the San today. A small spiral was engraved into one of these projectile points and colored with red ocher: an ornament that the San use to mark their ownership of arrowheads even today. Another special find turned out to be a narrow wooden stick, broken into four parts, with numerous notches (24,000 years old, cal BP), on which remains of a heated poisonous substance could still be detected. This find was interpreted as a tool similar to that which the San still use to apply poison to their arrowheads. Ostrich egg shells around 42,000 years old (cal BP) have been interpreted as the remains of jewelry .

Also a special find is the 1970 salvaged fragment of a baboon - fibula , were engraved into the 29 scores and was named after the location of the cave in the Lebombo Mountains as Lebombo Bone ( "Lebombo bone"). The find, which is thought to be 37,000 years old, is similar to the calendar sticks used by the San in Namibia . It is therefore considered to be the oldest known artifact that was used as a counting measure.

literature

  • Paola Villa et al .: Border Cave and the beginning of the Later Stone Age in South Africa. In: PNAS . Volume 109, No. 33, 2012, pp. 13208-13213, doi: 10.1073 / pnas.1202629109 .

Web links

Commons : Border Cave  - collection of pictures, videos and audio files

Individual evidence

  1. ^ Rainer Grün and Peter Beaumont: Border Cave revisited: a revised ESR chronology. In: Journal of Human Evolution. Volume 40, No. 6, 2001, pp. 467-482, doi: 10.1006 / jhev.2001.0471 . pmid = 11371150.
  2. ^ A b Rainer Grün, Peter Beaumont and Chris Stringer : ESR dating evidence for early modern humans at Border Cave in South Africa. In: Nature . Volume 344, No. 6266, 1990, pp. 537-539. doi: 10.1038 / 344537a0 . pmid = 2157165.
  3. ^ The Emergence of Modern Humans: The Pleistocene occupation sites of South Africa . Retrieved August 16, 2020.
  4. ↑ Border Cave . Google Docs, (Retrieved January 14, 2010).
  5. ^ A b K. W. Butzer, PB Beaumont and JC Vogel: Lithostratigraphy of Border Cave KwaZulu, South Africa: a Middle Stone Age Sequence Beginning c. 195,000 BP In: Journal of Archaeological Science. Volume 5, No. 4, 1978, pp. 317-341. doi: 10.1016 / 0305-4403 (78) 90052-3
  6. ↑ a b c H. BS Cooke, BD Malan and LH Wells: Fossil Man in the Lebombo Mountains, South Africa: The 'Border Cave,' Ingwavuma District, Zululand. In: Man. Volume 45, 1945, pp. 6-13, doi: 10.2307 / 2793006 . jstor = 2793006. Full text (PDF)
  7. ↑ a b c d e f G. Rightmire: More on the Study of the Border Cave Remains. In: Current Anthropology. 1981, 22, 2: pp. 199-200. doi: 10.1086 / 202658 . JSTOR 2742725
  8. ^ A b c D. M. Avery: The environment of early modern humans at Border Cave, South Africa: Micromammalian evidence. In: Palaeogeography, Palaeoclimatology, Palaeoecology. Vol. 91, No. 1-2, 1992, pp. 71-87, doi: 10.1016 / 0031-0182 (92) 90033-2 .
  9. ^ A b c Richard G. Klein: The Mammalian Fauna from the Middle and Later Stone Age (Later Pleistocene) Levels of Border Cave, Natal Province, South Africa. In: The South African Archaeological Bulletin. Volume 32, No. 125, 1977, pp. 14-27. doi: 10.2307 / 3887843 . jstor = 3887843
  10. ↑ Michaela Ecker and Julia A. Lee-Thorp: The dietary ecology of the extinct springbok Antidorcas bondi. In: Quaternary International. Volume 495, 2018, pp. 136-143, doi: 10.1016 / j.quaint.2018.09.012 .
  11. ^ Border Cave opens for visitors . southafrica.info. January 15, 2004. Retrieved January 14, 2010.
  12. ↑ a b c d Keyword Border Cave in: Bernard Wood : Wiley-Blackwell Encyclopedia of Human Evolution . 2 volumes. Wiley-Blackwell, Chichester et al. 2011, ISBN 978-1-4051-5510-6 .
  13. ↑ Lucinda R. Backwell, Francesco d'Errico et al .: New Excavations at Border Cave, KwaZulu-Natal, South Africa. In: Journal of Field Archeology. Volume 43, No. 6, 2018, pp. 417-436, doi: 10.1080 / 00934690.2018.1504544 .
  14. ^ Lyn Wadley et al .: Fire and grass-bedding construction 200 thousand years ago at Border Cave, South Africa. In: Science . Volume 369, No. 6505, 2020, pp. 863-866, doi: 10.1126 / science.abc7239 .
  15. ^ World's oldest camp bedding found in South African cave. On: sciencemag.org from August 13, 2020.
  16. ^ Rainer Grün, Peter Beaumont, Phillip V. Tobias and Stephen Eggins: On the age of Border Cave 5 human mandible. In: Journal of Human Evolution. Volume 45, No. 2, 2003, pp. 155-167, doi: 0.1016 / S0047-2484 (03) 00102-7 .
  17. ^ G. Philip Rightmire: More on the Study of the Border Cave Remains. In: Current Anthropology. Volume 22, No. 2, 1981, pp. 199-200, doi: 10.1086 / 202658 .
  18. ↑ Robert S. Corruccini: Metrical reconsideration of the Skhul IV and IX and Border Cave 1 crania in the context of modern human origins. In: American Journal of Physical Anthropology. Volume 87, No. 4, 1992, pp. 433-445, doi: 10.1002 / ajpa.1330870405 .
  19. ↑ Francesco d'Errico and Lucinda Backwell: Earliest evidence of personal ornaments associated with burial: The Conus shells from Border Cave. In: Journal of Human Evolution. Volume 93, 2016, pp. 91-108, doi: 10.1016 / j.jhevol.2016.01.002 .
  20. ↑ a b c d Francesco d'Errico et al .: Early evidence of San material culture represented by organic artifacts from Border Cave, South Africa. In: PNAS . Volume 109, No. 33, 2012, pp. 13214-13219, doi: 10.1073 / pnas.1204213109 .
  21. ^ David J. Darling: The universal book of mathematics: from Abracadabra to Zeno's paradoxes . John Wiley and Sons, 2004, ISBN 978-0-471-27047-8 .

Coordinates: 27 ° 1 ′ 19 ″  S , 31 ° 59 ′ 24 ″  E