Sima Aonda

Useful Information

Location:	Auyan Tepui, Canaima National Park, Bolívar state. (6.014336, -62.620804)
Open:	no restrictions. [2023]
Fee:	free. [2023]
Classification:	Tiankeng Quartzite Karst Caves
Light:	n/a
Dimension:	L=160 m, W=120 m, VR=383 m. Cave: L=2,128 m.
Guided tours:	self guided
Photography:	allowed
Accessibility:	no
Bibliography:	Marco Mecchia, Leonardo Piccini (1999): Hydrogeology and SiO2 geochemistry of the Aonda Cave System, Auyán-Tepui, Bolivar, Venezuela Bollettino Sociedad Venezolana Espeleologia, 33, 1-11. 1999. pdf
Address:	Sima Aonda.
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then. Please check rates and details directly with the companies in question if you need more recent info.

History

1993	speleological exploration by the Associazione Esplorazioni Geografiche "La Venta", supported by the Sociedad Venezolana de Espeleología and Societá Speleologica Italiana.
1996	second exploration by the Associazione Esplorazioni Geografiche "La Venta".

Description

We have classified Sima Aonda (Aonda Abyss) for the daylight shaft which is visible from a plane or on satellite images. Actually, it is so huge, it is not just a tiankeng, it is also the biggest tiankeng in quartzite in the world. But there is also a cave behind the shaft, which is probably the best known cave complex developed in siliceous rock in the world. It drains a part of the Auyán-tepui with a discharge between 200 l/s to a maximum of 2500 l/s. During the rainy season short time peaks exceeding 10-15 m³/s are possible. The mean discharge is between 0.5 and 1 m³/s. The underground river is called Río Superior and reappears on the surface in the Resurgencia Aonda.

The Auyán Tepui belongs to the Roraima-Canaima Province, named after the outcrops of Roraima Group rocks. The silico-clastic rocks (quartzites) have an age of about 1.8 Ga, and they lie on top of a granitic basement which is 2.3-1.8 Ga old. The rocks are crossed by basaltic dikes and sills which are between 1.4-1.8 Ga old.