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Gcwihaba Caves

Date de soumission : 27/05/2010
Critères: (vii)(viii)
Catégorie : Naturel
Soumis par :
Department of National Museum and Monuments
Etat, province ou région :
Ngamiland
Coordonnées 20o 01.456’ S 021o 21.258’ E
Ref.: 5558
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Description

 In the northwest corner of Botswana several related groups of dolomite hills present a striking contrast to the surrounding sandveld. The Aha hills straddle the Botswana/Namibia border just north of the village Xai-Xai. Some 35km east of the village, Gcwihaba Valley with its fossil river features a cluster of 6 low-lying dolomite hills. Further 19km southwest of the Gcwihaba Caves lies Koanaka hills, with three hills. The Fascinating aspect is that all these hills have caves which are collectively referred to as the Gcwihaba Caves.

The Gcwihaba Caves have been part of the Kalahari landscape for at least the entire Pleistocene epoch, some 2 million years ago. The cave contains sediments useful for the regional paleoclimatic reconstruction. This was found out during the first scientific research undertaken by Cooke and Ballieul (1974).This cave system has two large (more than 5m wide) cavernous entrances, which have allowed access of a large number of bats and windblown sand deep into the cave. This has effectively buried much of the cave with sediment of up to at least 7m (Cooke, 1975).Adjacent to this cave is a recently discovered cave named !Wa Doum. This has only been researched on a few occasions. The cave's most important feature is the limited air exchange with surrounding atmosphere as it was more or less totally sealed off from the outside world until researchers entered it for the first time in October 1992. These caves have a very rich variety of secondary cave formations such as stalactites and stalagmites, but also many more unusual formations such as helictites, soda straws and cave pearls, totally untouched by man. The cave has been resealed after each visit by researchers to safeguard the interior air composition. The current exploration project has delineated a number of caves of which three have been confirmed. In addition, a lot of bones (both fossilized and modern) as well as archaeological finds have been unveiled through excavation programmes as part of the ongoing exploration work.

Due to the isolated nature of these dolomite hills with its caves, a special flora and fauna has developed. Some Aloe species and the Namaqua Fig, Ficus cordata, are only found in these hills. Of particular interest is the latter as it appears to be dependent on its roots access to the more humid cave space below. These roots create beautiful curtains inside the caves. This tree in its turn is the home of the Ruepels Parrot (Poicephalus ruepelli) which is also restricted to this area of Botswana. The area has quite a variety of bird species and also big mammals such as elephant, but perhaps scientifically more important biodiversity-wise is the invertebrate fauna surrounding as well as inside the caves.

Justification de la Valeur Universelle Exceptionelle

 Gcwihaba Caves have a diversity of cave formations found within the six cave systems which display a manifestation of exceptional natural beauty comprising massive stalactites, stalagmites, dripstones and columns/pillars as well as an array of spectacular micro-formations of helictites, straws, some of which seem to have defied the force of gravity which normally dictates the speleothems to be precipitated in a vertical position. The caves occurring in the three hills of Koanaka, the Bone Cave and the Blue Cave, contain a type of breccia which has very high densities of fossils. This is the richest cave fossil deposit in Botswana and possibly the richest in Southern Africa.  The Caves are unique in a sense that they occur in a desert environment and contain a detailed record of the evolution of the Kalahari Environment for the entire Plio-pleistocene epoch.

Criteria

The Gcwihaba Caves satisfy criteria vii and viii for natural properties

vii.          contain superlative natural phenomena or areas of exceptional natural beauty and aesthetic importance;

Although the formation of these caves are deciphered to have formed from the same physical and chemical interactions of climatic and hydrogeological activities, the  diversity of cave formations found within the six cave systems display a manifestation of exceptional natural beauty comprising massive stalactites, stalagmites, dripstones and columns/pillars as well as an array of spectacular micro-formations of helictites, straws, some of which seem to have defied the force of gravity which normally dictates the speleothems to be precipitated in a vertical position.

viii.         be outstanding examples representing major stages of earth's history, including the record of life, significant on-going geological processes in the development of landforms, or significant geomorphic or physiographic features;

 The episodic spatiotemporal distribution of wet and arid  conditions-formed cave deposits are a reflection of significant dynamic geological processes which have operated through out the Plio-pleistocene epochs leading to well preserved paleo-climatic record of the world renowned Kalahari Desert.  These caves contain a type of breccia which has very high densities of fossils. This is the richest cave fossil deposit in Botswana and possibly in Southern Africa. The presence of the Kalahari windblown sand in the caves is a direct indicator of clastic sediment provenance from the surrounding stabilized sand dunes whereas the adjacent massive pans are indicators of the periods of prolonged wetter conditions when cave mouths served as spring source points.

Déclarations d’authenticité et/ou d’intégrité

 Integrity

Gcwihaba and the surrounding caves occur in an area which can be described as one of the remotest and true wilderness locale of this country where nature dictates its terms without interference from man. The area where these caves occur and their surrounding plains is massive covering an area of about 2500 km2 which is only occupied by a small settlement with inhabitants who have harmoniously interacted with caves for a long time. The caves lie within a protected area with a community controlled natural resources utilization plan and is currently being converted from controlled hunting area to cultural and photographic tourism. All the caves have been listed as national monuments under the Monuments and Relics Act of 2001, which is administered by the National Museum and Monuments of the Republic of Botswana. The main Gcwihaba Cave has a management plan which is currently being revised to include all other caves and surrounding resources.

Comparaison avec d’autres biens similaires

 Gcwihaba Cave Systems compares well with the Australian Naracoorte Caves National Park. Naracoorte Caves National Park is part of the World Heritage site comprising two non-contiguous Australian fossil mammal sites. The 305-hectare Naracoorte site includes the caves and the series of stranded coastal dune ridges parallel to the present South Australian coastline. The Australian fossil mammal sites were inscribed on the World Heritage list in 1994 as outstanding examples representing major stages of the earth's evolutionary history, and as outstanding examples representing significant ongoing ecological and biological evolution. Some of the caves are set aside for scientific research or for protection of the cave and its contents just like is the case here in Botswana at Gcwihaba Caves.

The Sterkfontein Caves - about 50 km from Johannesburg - is the site of some of the most important discoveries concerning the evolution of man and have been declared a World Heritage Site. Although Gcwihaba Caves do not contain important hominid fossil remains, all deposits are still pristine with several interesting dripstone formations, while those of the Sterkfontein cave's spectacular stalactites and stalagmites were removed or damaged by early limestone-mining activities. In addition, Gcwihaba Caves are unique in a sense that they occur in a desert environment and contain a detailed record of the evolution of the Kalahari Environment in the Plio-pleistocene epoch.