| Sima Humboldt | |
|---|---|
Sima Humboldt is seen in middle part of picture, in the far background - Sima Martel |
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| Location | Venezuela, Bolívar (state), Sarisariñama |
| Depth | 314 m (1,030 ft) |
| Discovery | 1961 |
| Geology | Quartzite |
| Access | By special researcher permit only |
Sima Humboldt (Sima Major) is an enormous sinkhole located on the summit of the plateau of Sarisariñama tepui in Bolívar State, Venezuela. It is unusual for several reasons, including its enormous size and depth, its location on the top of the only forested tepui, having a patch of forest on its base and also due to the rare quartzite weathering process that formed this sinkhole. The feature is named after scientist and explorer Alexander von Humboldt.
Together with the neighbouring Sima Martel it was first spotted in 1961 by pilot Harry Gibson.[1]
The sinkhole was descended for the first time in 1974 and more thoroughly explored in 1976. Its volume is 18,000,000 cubic metres (640,000,000 cu ft) whilst the maximum width at its upper rim is 352 metres (1,155 ft) and 502 metres (1,647 ft) below.[2]
Only 700 metres from the rim of Sima Humboldt there is another enormous sinkhole - Sima Martel. In total there are four quartzite caves on Sarisariñama.