Rising Star Cave

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Rising Star Cave
Map showing the location of Rising Star Cave
Map showing the location of Rising Star Cave
Location in Gauteng
Location Near Krugersdorp in the Greater Johannesburg metropolitan area of Gauteng province, South Africa
Coordinates 25°55′S 27°47′E / 25.917°S 27.783°E / -25.917; 27.783Coordinates: 25°55′S 27°47′E / 25.917°S 27.783°E / -25.917; 27.783

The Rising Star cave system (also known as Westminster or Empire cave) is located in the Malmani dolomites, in Bloubank River valley about 800 meters (0.5 miles) southwest of Swartkrans, part of the Cradle of Humankind World Heritage Site.[1][2] Recreational caving occurred there in the 1960s.[2] Fossils found (starting in 2013) in the cave were in 2015 proposed to represent an extinct species of hominin, provisionally assigned to the genus Homo, named Homo naledi.[1]

Origins of names[edit]

In the 1980s, the names "Empire", "Westminster" and "Rising Star" were in parallel use.[3]

Dinaledi Chamber ("chamber of stars")[4] was so named by members of the Rising Star Expedition in 2013.

A portion of the cave is called Superman's Crawl because most people can fit through only by holding one arm tightly against the body and extending the other above the head, in the manner of Superman in flight.[2]

History[edit]

Geologists think the cave in which the fossils were discovered is no older than three million years.[5]

The cave was explored in the 1980s by the South African Speleological Association (SASA).[3]

Discovery of fossils in "Dinaledi Chamber"[edit]

Cross-section of a portion of the Rising Star cave system leading to the Dinaledi Chamber
Illustration of the Dinaledi Chamber, where H. naledi bones were excavated

On 13 September 2013 while exploring the Rising Star cave system, explorers Rick Hunter and Steven Tucker of the Speleological Exploration Club of South Africa found a narrow, vertically oriented "chimney" or "chute" measuring 12 m (39 ft) long with an average width of 20 cm (7.9 in).[2][6][7][8] Then Hunter discovered a room 30 m (98 ft) underground (Site U.W. 101, the Dinaledi Chamber), the surface of which was littered with fossil bones. On 1 October photos of the site were shown to Pedro Boshoff and then to Lee Berger.[7][9]

The arrangement of bones suggested "someone had already been there" as recently as a few decades earlier, and the appearance of limited fossilisation initially led the explorers to think the bones were from modern humans.[2]

Rising Star Expedition (2013 and 2014)[edit]

On 1 October 2013 paleoanthropologist Lee Berger was notified of the find and he headed an expedition to excavate the fossils, which started 7 November 2013.[9] The expedition was funded by the South African National Research Foundation and the National Geographic Society.[10][11]

The excavation team hired six female paleoanthropologists who could pass through an opening only 7 inches (18 cm) wide to the Dinaledi Chamber.[9][12][13]

The cave system was explored by paleontologists of the "Rising Star Expedition" of University of the Witwatersrand in 2013 and was assigned the designation UW-101. It came to public attention in October 2013 when the discovery of hominin fossils in a separate chamber, dubbed the Dinaledi chamber, or "chamber of stars", was announced.[4] More than 1,200 fossil elements were recovered and catalogued in November 2013,[14] representing at least a dozen individuals.[15] Only 20 out of 206 bones in the human body were not found in the cave as of summer, 2014.[16] By April 2014, between two localities, 1724 specimens were recovered.[17]

The layered distribution of the bones [in clay-rich sediments] suggests that they had been deposited over a long time, perhaps centuries.[2] Only one square meter of the cave chamber has been excavated; other remains might still be there.[10][18][19]

On 20 February 2014 a second site was found in the cave complex.[20] The site, designated UW-102 was found by cavers Rick Hunter and Steve Tucker on the last day of the first Rising Star Expedition and evaluated in February 2014 by Rick Hunter, Lee Berger, John Hawks, Alia Gurtov, and Pedro Boshoff.

As of September 2015, fossils of at least fifteen individuals, amounting to 1550 specimens, have been excavated from the cave.[2] About 300 bone fragments were collected from the surface of the Dinaledi Chamber, and about 1250 fossil specimens were recovered from the chamber's excavation pit.[6] The fossils include skulls, jaws, ribs, teeth, bones of an almost complete foot, of a hand, and of an inner ear. The bones of old, young and infants were found.[2]

The 15 partial skeletons found in a tiny underground chamber, invite speculation on the circumstances. No figures have been released on the dating of the fossil remains, as of 2015.[1][21] The team plans to date calcite deposits in the cave to establish the age of the remains.[22]

A collaborative workshop took place in May and June 2014 at Wits University,[2][22][22] On 10 September 2015 the fossils were publicly unveiled and given the name Homo naledi.[1][6]

Geology[edit]

The Rising Star cave system lies in the Bloubank River valley, 2.2 km west of Sterkfontein cave. It comprises an area of 250 × 150 m of mapped passageways situated in the core of a gently west dipping (17°) open fold, and is stratigraphically bound to a 15–20 m thick, stromatolitic dolomite horizon in the lower parts of the Monte Christo Formation. This dolomite horizon is largely chert-free, but contains five thin (<10 cm) chert marker horizons that have been used to evaluate the relative position of chambers within the system (Figure 2B). The upper contact is marked by a 1–1.3 m-thick, capping chert unit that forms the roof of several large cave chambers.[6] The altitude above sea level is 1450 m for the Dinaledi Chamber's floor.[23]

Description[edit]

The fossil-bearing chamber, named the Dinaledi Chamber, is ∼30 m below the surface and ∼80 m, in a straight line, away from the present, nearest entrance to the cave. [6] Access into the Dinaledi Chamber involves an exposed, ∼15 m climb from the bottom of a large ante-chamber (the Dragon's Back Chamber). From the top of the Dragon's Back, the Dinaledi Chamber is accessed via a narrow, northeast-oriented vertical fissure, and involves a ∼12 m vertical climb down ∼25–50 cm wide at its narrowest and ∼10 m long, and expands in width near the intersections with cross-cutting passages".[6]

The Dragon's Back Chamber can currently be accessed in two ways, both involving steep climbs along narrow fractures and tight passages: route 1, along an east-northeast trending passage that follows a fracture for a horizontal distance of ∼50 m past a narrow access point called the ‘postbox’; and route 2, along a more complicated set of broadly east-trending passages, via a network of southeast, east and north trending fractures for ∼120 m, and past a narrow access point called ‘superman crawl’. Route 1 is the most direct and contains abundant sediment accumulations once the deeper part of the cave is accessed (i.e., ∼20 m into the cave).[6]

See also[edit]

References[edit]

  1. ^ a b c d Berger, Lee R.; et al. (10 September 2015). "Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa". eLife 4. doi:10.7554/eLife.09560. Retrieved 10 September 2015. Lay summary. 
  2. ^ a b c d e f g h i Shreeve, Jamie (10 September 2015). "This Face Changes the Human Story. But How?". National Geographic News. Retrieved 10 September 2015. 
  3. ^ a b Paul Courbon (1989). Atlas of the Great Caves of the World. Cave Books. p. 38. ISBN 0939748215. Empire Cave [Western Transvaal]: 4010 m; Empire/Westminster/Rising Star Cave. Explored by SASA and Free Cavers 
  4. ^ a b Sesotho dinaledi is a class 10 plural noun built on the class 9 noun naledi "star" (Bukantswe v.3 dictionary).
  5. ^ Wilford, John Noble (10 September 2015). "New Species in Human Lineage Is Found in a South African Cave". New York Times. ISSN 0362-4331. Retrieved 10 September 2015. 
  6. ^ a b c d e f g Dirks, Paul H. G. M.; et al. (2015). "Geological and taphonomic context for the new hominin species Homo naledi from the Dinaledi Chamber, South Africa". eLife 4: e09561. doi:10.7554/eLife.09561. ISSN 2050-084X. PMC 4559842. Retrieved 12 September 2015. 
  7. ^ a b Tucker, Steven (13 November 2013). "Rising Star Expedition". Speleological Exploration Club. Retrieved 8 September 2015. 
  8. ^ André Doussy. "SEC-Caving: Rising Star Expedition Finds over 1,000 Hominid Fossils". sec-caving.co.za. 
  9. ^ a b c Yong, Ed (10 September 2015). "6 Tiny Cavers, 15 Odd Skeletons, and 1 Amazing New Species of Ancient Human". The Atlantic. Retrieved 13 September 2015. 
  10. ^ a b Greenfieldboyce, Nell (10 September 2015). "South African Cave Yields Strange Bones Of Early Human-Like Species". NPR. Retrieved 10 September 2015. 
  11. ^ "Rising Star Expedition - National Geographic (blogs)". nationalgeographic.com. 
  12. ^ Staff (6 November 2013). "Rising Star Expedition Launched". University of the Witwatersrand. Retrieved 8 September 2015. 
  13. ^ Brahic, Catherine (26 November 2014). "Bone Bonanza: Chamber of Secrets Yields Human Remains". New Scientist. Retrieved 8 September 2015. 
  14. ^ Andrew Howley. "Final Day of Excavations". nationalgeographic.com. 
  15. ^ "Anthropologist, ‘underground astronaut’ strike fossil gold in South Africa dig". 
  16. ^ "Anthropology Prof. John Hawks and UW-Madison students dig up crucial remnants of early hominids". 
  17. ^ Lee R. Berger. "Rising Star Empire Cave 2014 Annual Report". 
  18. ^ Alford, Justine (10 September 2015). "New Species Of Human Discovered In South Africa". 
  19. ^ Shreeve, Jamie (10 September 2015). "New Human Ancestor Elicits Awe—and Many Questions". National Geographic Society. Retrieved 17 September 2015. 
  20. ^ Hawks, John. "Scientists Return to Explore a Second Fossil Chamber". 
  21. ^ "New human-like species discovered in S Africa". BBC News. 
  22. ^ a b c "Crowdsourcing digs up an early human species". Nature News & Comment. 
  23. ^ "New species of extinct human found in cave may rewrite history". New Scientist. 

External links[edit]