A rocky day at the ‘Cradle of Humankind’

Located in the Gauteng Province, about an hour’s drive, northwest of South Africa’s capital city, Johannesburg, the Cradle of Humankind Site is made up of dolomitic limestone caves which include the Sterkfontein Caves. They all contain fossils of ancient forms of animals, plants and most importantly, hominids which were half ape/half man and made the […]

Located in the Gauteng Province, about an hour’s drive, northwest of South Africa’s capital city, Johannesburg, the Cradle of Humankind Site is made up of dolomitic limestone caves which include the Sterkfontein Caves. They all contain fossils of ancient forms of animals, plants and most importantly, hominids which were half ape/half man and made the caves popular. The dolomite rocks, in which the caves formed, were initially coral reefs growing in a shallow sea about 2.3 billion years ago.

The sixty-metre trip underground below sea level via the one hundred and nineteen steps going down and one hundred and nine coming up, was entertaining, educative and very adventurous; but no  place for the asthmatic and claustrophobic.

Donated to the University of Witwatersrand by the Isaac Edwin Stegmann family on whose vast estate the caves exist, only a section of the caves is open to the public as excavation is still going on in other parts.

The first adult australopithecine was produced in the Sterkfontein caves in 1936. In 1947 the almost complete skull of an adult female Australopithecus africanus was found. It was initially named Plesianthropus transvaalensis (“near-man” of the Transvaal), which inspired the nickname ‘Mrs.Ples’.

“‘Mrs. Ples’ is estimated to be between 2.6 and 2.8 million years old and ranks high on the long list of australopithecine discoveries for which Sterkfontein is now famous. The world’s longest sustained excavation ever carried out at an ancient hominid site was started in 1966 and continues today. A further 500 hominid specimens have been recovered, making Sterkfontein the world’s richest hominid site. The site is also renowned for studies carried out on fossilised fauna, wood and stone tools which were made, used and discarded by hominids In the past.

Prof. Ron Clark, in 1997, found a complete skeleton of the remains of a hominid which he named ‘Little Foot’. He has been excavating from then on till date.

The elephant chamber so called because of its formation which looks like the face of an elephant but from another angle like the map of Africa, possesses white elements referred to as the floor stones. These were formed through the gradual flow of carbonated water inside the caves. Some parts of the rock have formed layers of crystals.

The tour guide informed that one of the tourists who visited a couple of years ago, got lost after he decided to go on a solo exploration of the cave beneath the forty kilometres already explored by his group. It took the rescue team six weeks to find his corpse.

Rocks formed from water and soilhave taken on unique and somewhat artistic forms that are pleasant to view. Engraved in one of such is a tiny fossil of the vertebra of what may have been an animal or humankind.

As a result of acidic mine drainage the water level rose and has forced authorities to close some of the routes in use in the cave. Due to the fact that the lake is stagnant, its original water is pushed higher up to fifty metres with draining activities.

With a centimeter of limestone taking a hundred years to form, some of the areas in the site have been shut off to preserve them.

The dolomite in which the caves are formed, started out as coral reefs growing in a worm shallow sea about 2.3 billion years ago.

The tour guide explained that as the reefs died off they were transformed into limestone which some time later was converted into dolomite. Years later after the sea had receded acidic groundwater began to dissolve out calcium carbonate from the dolomite to form underground caverns. As time went by and the water table dropped the underground caverns were exposed to the air.

“The percolation of acidic water through the dolomite also dissolved calcium carbonates out of the rock into the caverns, which formed stalactites, stalagmites and other crystalline structures. With erosion taking place on the earth’s surface and dissolution of the dolomite shafts or avens forming between the surface of the earth and the caverns below began to occur.

“Bones, stones and plants washed down these shafts into the caves; and animals and hominids fell into the caves, became trapped and died. The bone and plant remains became fossilised and along with various stones and pebbles became cemented in a hard mixture called breccia.”

Records have it that no fewer than seven of the twelve sites have yielded hominid remains. “In fact, together these cave sites have produced over 850 hominid fossil remains, so that to date they represent one of the world’s richest concentrations of fossil hominid bearing sites. The scientific value of this area lies in the fact that these sites provide us with a window into the past, to a time when our earliest ancestors were evolving and changing. Scientists have long accepted that all humans had their origins in Africa.”

Following excavations by Scottish Palaeontologist, Dr. Robert Broom, fossil remains are housed in the Transvaal Museum (Northern Flagship Institution), Pretoria, while the remains from 1966 onwards are housed at the University of Witwatersrand, Johannesburg.

According to records, “The Sterkfontein Caves lay claim to some of the most important discoveries about man’s evolution, including the famous discovery of the hominid fossils ‘Mrs Ples’ and ‘Little Foot’.”

Exhibited at the visitor centre of the caves are reconstructions of early men and their families, a mined cave as opposed to a pristine cave, early life forms, cave formations and geology, mammals and hominid fossils, as well as detailed description of the finding of ‘Mrs Ples’, the ‘Taung Child’ and ‘Little Foot’.