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26-627: The Cango Caves are located in Precambrian limestones at the foothills of the Swartberg range near the town of Oudtshoorn , in the Western Cape Province of South Africa . The principal cave is one of the country's finest, best known, and most popular tourist caves and attracts many visitors from overseas. Although the extensive system of tunnels and chambers go on for over 4 km ( 2 + 1 ⁄ 2  mi), only about

52-708: A supereon , but this is also an informal term, not defined by the ICS in its chronostratigraphic guide. Eozoic (from eo- "earliest") was a synonym for pre-Cambrian , or more specifically Archean . A specific date for the origin of life has not been determined. Carbon found in 3.8 billion-year-old rocks (Archean Eon) from islands off western Greenland may be of organic origin. Well-preserved microscopic fossils of bacteria older than 3.46 billion years have been found in Western Australia . Probable fossils 100 million years older have been found in

78-650: A football field, and is named Van Zyl Hall in his honor. Further exploration was done and a second chamber discovered in 1792. The caves soon became a popular place to visit. In 1829 Dr Andrew Smith visited the Cango Caves, which contained much to tempt his scientific curiosity. A.J.H. Goodwin, an archaeologist at the University of Cape Town , carried out a test excavation in the Cango Caves in 1930 which found stone artefacts and other cultural material. The Cango Caves Ordinance of 1971 gave certain legal powers over

104-735: A possible 2450 Ma red alga from the Kola Peninsula , 1650 Ma carbonaceous biosignatures in north China, the 1600 Ma Rafatazmia , and a possible 1047 Ma Bangiomorpha red alga from the Canadian Arctic. The earliest fossils widely accepted as complex multicellular organisms date from the Ediacaran Period. A very diverse collection of soft-bodied forms is found in a variety of locations worldwide and date to between 635 and 542 Ma. These are referred to as Ediacaran or Vendian biota . Hard-shelled creatures appeared toward

130-475: A quarter of this is open to visitors, who may proceed into the cave only in groups supervised by a guide. Cave paintings and artifacts indicate that the caves were in use throughout prehistory over a long period during the Middle and Later Stone Ages . The caves were rediscovered in modern times in 1780 by a local farmer named Jacobus Van Zyl. The chamber he first was lowered down into was found to be as long as

156-664: Is known to occur during the RNA replication of extant coronaviruses . Evidence of the details of plate motions and other tectonic activity in the Precambrian is difficult to interpret. It is generally believed that small proto-continents existed before 4280 Ma, and that most of the Earth's landmasses collected into a single supercontinent around 1130 Ma. The supercontinent, known as Rodinia , broke up around 750 Ma. A number of glacial periods have been identified going as far back as

182-500: Is said to have calculated that he was 25 km ( 15 + 1 ⁄ 2  mi) from the entrance, and 275 m (902 ft) underground; his route apparently followed an underground river. So far, explorers are finding more and more caves to support this story. The first rough survey was done in 1897, mapping out the first 26 chambers. In 1956 the South African Spelaeological Association

208-521: Is thought that the Earth coalesced from material in orbit around the Sun at roughly 4,543 Ma, and may have been struck by another planet called Theia shortly after it formed, splitting off material that formed the Moon (see Giant-impact hypothesis ). A stable crust was apparently in place by 4,433 Ma, since zircon crystals from Western Australia have been dated at 4,404 ± 8 Ma. The term "Precambrian"

234-731: Is used by geologists and paleontologists for general discussions not requiring a more specific eon name. However, both the United States Geological Survey and the International Commission on Stratigraphy regard the term as informal. Because the span of time falling under the Precambrian consists of three eons (the Hadean , the Archean , and the Proterozoic ), it is sometimes described as

260-534: The Huronian epoch, roughly 2400–2100 Ma. One of the best studied is the Sturtian-Varangian glaciation, around 850–635 Ma, which may have brought glacial conditions all the way to the equator, resulting in a " Snowball Earth ". The atmosphere of the early Earth is not well understood. Most geologists believe it was composed primarily of nitrogen, carbon dioxide, and other relatively inert gases, and

286-522: The geologic time scale . It spans from the formation of Earth about 4.6 billion years ago ( Ga ) to the beginning of the Cambrian Period, about 538.8 million years ago ( Ma ), when hard-shelled creatures first appeared in abundance. Relatively little is known about the Precambrian, despite it making up roughly seven-eighths of the Earth's history , and what is known has largely been discovered from

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312-482: The oxygen catastrophe . At first, oxygen would have quickly combined with other elements in Earth's crust, primarily iron, removing it from the atmosphere. After the supply of oxidizable surfaces ran out, oxygen would have begun to accumulate in the atmosphere, and the modern high-oxygen atmosphere would have developed. Evidence for this lies in older rocks that contain massive banded iron formations that were laid down as iron oxides. A terminology has evolved covering

338-401: The 1960s onwards. The Precambrian fossil record is poorer than that of the succeeding Phanerozoic , and fossils from the Precambrian (e.g. stromatolites ) are of limited biostratigraphic use. This is because many Precambrian rocks have been heavily metamorphosed , obscuring their origins, while others have been destroyed by erosion, or remain deeply buried beneath Phanerozoic strata. It

364-563: The Adventure Tour. The smallest passage that tourists will have to pass through on the Adventure Tour is just under 15 cm to exit. Visiting the caves are considered to be part of exploring the scenic Route 62 . The Cinema Museum in London holds film of a visit to the caves in the 1930s. Precambrian The Precambrian is an informal unit of geologic time, subdivided into three eons ( Hadean , Archean , Proterozoic ) of

390-516: The caves to what was then the Administrator of the Cape; legally, these same powers now devolve to the local government members of the executive. However, day-to-day management of the caves is the responsibility of the municipality of Oudtshoorn . Mr. Johnny van Wassenaer, the cave’s first official guide is purported to have walked 29 hours to find the end of the caves in 1898. When there, he

416-507: The chamber of most of its water and crawled through what was previously an underwater passage. This led to the discovery of more caves, called Cango III. Altogether these caves are about 1,000 m (3,300 ft) long. The biggest of the chambers, stretches about 300 m (980 ft). Digby Ellis and Dave Land added 290 m (950 ft) to Cango III when they discovered a crawlway in December 1977. A further 90 m (300 ft)

442-401: The current scheme based upon numerical ages. Such a system could rely on events in the stratigraphic record and be demarcated by GSSPs . The Precambrian could be divided into five "natural" eons, characterized as follows: The movement of Earth's plates has caused the formation and break-up of continents over time, including occasional formation of a supercontinent containing most or all of

468-453: The early years of the Earth's existence, as radiometric dating has allowed absolute dates to be assigned to specific formations and features. The Precambrian is divided into three eons: the Hadean (4567.3–4031 Ma), Archean (4031-2500 Ma) and Proterozoic (2500-538.8 Ma). See Timetable of the Precambrian . It has been proposed that the Precambrian should be divided into eons and eras that reflect stages of planetary evolution, rather than

494-760: The end of that time span, marking the beginning of the Phanerozoic Eon. By the middle of the following Cambrian Period, a very diverse fauna is recorded in the Burgess Shale , including some which may represent stem groups of modern taxa. The increase in diversity of lifeforms during the early Cambrian is called the Cambrian explosion of life. While land seems to have been devoid of plants and animals, cyanobacteria and other microbes formed prokaryotic mats that covered terrestrial areas. Tracks from an animal with leg-like appendages have been found in what

520-631: The floor. In 1972 James Craig-Smith, Luther Terblanche and Dart Ruiters widened an obstructed passage to discover Cango II. It stretches 270 m (890 ft) beyond the end of the Devil’s Kitchen. At the end of Cango II there is a shaft that descends 20 m (66 ft) to a chamber filled with water. This water flowed in the direction of Cango I. In August 1975, during a symposium on cave biology, an exploration team led by Hans Oosthuizen, Luther Terblanche, Michale Schultz, Digby Ellis, Jean Paul Matisse, Bob Mann, Florus Koper and Peter Breedt drained

546-541: The landmass. The earliest known supercontinent was Vaalbara . It formed from proto-continents and was a supercontinent 3.636 billion years ago. Vaalbara broke up c. 2.845–2.803 Ga ago. The supercontinent Kenorland was formed c. 2.72 Ga ago and then broke sometime after 2.45–2.1 Ga into the proto-continent cratons called Laurentia , Baltica , Yilgarn craton and Kalahari . The supercontinent Columbia , or Nuna, formed 2.1–1.8 billion years ago and broke up about 1.3–1.2 billion years ago. The supercontinent Rodinia

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572-526: The same area. However, there is evidence that life could have evolved over 4.280 billion years ago. There is a fairly solid record of bacterial life throughout the remainder (Proterozoic Eon) of the Precambrian. Complex multicellular organisms may have appeared as early as 2100 Ma. However, the interpretation of ancient fossils is problematic, and "... some definitions of multicellularity encompass everything from simple bacterial colonies to badgers." Other possible early complex multicellular organisms include

598-622: Was added in June 1978. All these extensions were surveyed in August 1978 by Dave Land, Charles Maxwell, Brian Russell and Dave Crombie. Tours are conducted at regular intervals on most days—there is a "Standard Tour" which takes an hour and an "Adventure Tour" which takes an hour and a half. The "Adventure Tour" consists of crawling through narrow passages and climbing up steep rock formations guided by small lights. The caves contain halls and limestone formations (on both tours) as well as small passages on

624-482: Was lacking in free oxygen . There is, however, evidence that an oxygen-rich atmosphere existed since the early Archean. At present, it is still believed that molecular oxygen was not a significant fraction of Earth's atmosphere until after photosynthetic life forms evolved and began to produce it in large quantities as a byproduct of their metabolism . This radical shift from a chemically inert to an oxidizing atmosphere caused an ecological crisis , sometimes called

650-852: Was mud 551 million years ago. The RNA world hypothesis asserts that RNA evolved before coded proteins and DNA genomes. During the Hadean Eon (4,567–4,031 Ma) abundant geothermal microenvironments were present that may have had the potential to support the synthesis and replication of RNA and thus possibly the evolution of a primitive life form. It was shown that porous rock systems comprising heated air-water interfaces could allow ribozyme - catalyzed RNA replication of sense and antisense strands that could be followed by strand-dissociation, thus enabling combined synthesis, release and folding of active ribozymes. This primitive RNA replicative system also may have been able to undergo template strand switching during replication ( genetic recombination ) as

676-469: Was tasked to draw up an accurate mapping of the Cango Caves, and look for alternative entrances. Their results indicated that the caves were 775 m (2,543 ft) long in a single line, and that they never rise nor fell more than 16 m (52 ft). These were called Cango I. The nearest point to the surface in the caves is at the top of the shaft in the Devil's Kitchen, 52.6 m (173 ft) from

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