A dissolution sinkhole a hole formed in soluble rock by the action of water, serving to conduct surface water to an underground passage. They can sometimes become ponds if the depression gets lined with debris, trapping water inside. Dissolution sinkholes happen slowly and are generally not dangerous, but ones that become a pond can drain suddenly if water makes it through the protective bottom layer.
This is a cenote. Cenotes and dissolution sinkholes are very similar. The only difference between the two is that a cenote is a deep natural well formed by the collapse of surface usually limestone that exposes ground water underneath.
Meanwhile, a dissolution sinkhole is a hole formed in soluble rock by the action of water, serving to conduct surface water to an underground passage. If dissolution sinkholes get clogged by debris they can hold water like cenotes though. Cenotes are very common on the Yucatan Peninsula of Mexico. There are more than 2,000 cenotes on the Yucatan, and they are a main source of fresh water for people there. Ancient Mayans believed cenotes were passageways to the underworld.
Cover - Subsidence Sinkhole
The second type of sinkhole is a cover-subsidence sinkhole. These sinkholes happen in areas where sand covers the bedrock. The sand filters down into openings in the rock, gradually causing the land surface to sink. Continued erosion increases the size of the depression. Like dissolution sinkholes, cover-subsidence sinkholes happen slowly.
Cover-subsidence sinkholes tend to develop gradually where the covering sediments are permeable and contain sand. In areas where cover material is thicker or sediments contain more clay, cover-subsidence sinkholes are relatively uncommon, are smaller, and may go undetected for long periods.
Cover - Collapse Sinkhole
The most dangerous type of sinkhole is a cover-collapse sinkhole. Cover-collapse sinkholes may develop abruptly and cause catastrophic damages. In these cases, the bedrock is covered by a layer of clay. Beneath this ground cover, however, water dissolves an underground cavern.
Cover collapse sinkholes form when the bedrock roof of a cave becomes too thin to support the weight of the bedrock and the soil material above it. The cave roof then collapses, forming a bedrock-collapse sinkhole. Bedrock collapse is rare and the least likely way a sinkhole can form, although it is commonly incorrectly assumed to be the way all sinkholes form. Gradually, ground sediments begin to erode into the cavern from the bottom. The ground continues to crumble from beneath until only a thin layer remains between the surface and the underground opening. When that layer collapses, like when someone walks on it, the sinkhole opens up suddenly, swallowing any structures on top.
Where Have Recent Devastating Sinkholes Occurred?
A very devastating sinkhole that happened not to long ago was the 2010 Guatemala City Sinkhole. After being hit by Hurricane Agatha and being hit by a ton of rain, the rain eroded the ancient volcanic ash Guatemala City is built on. This caused the huge 20 metre in diameter and 90 metre in depth sinkhole. It was caused by a corroded sewage pie deep underground. This sinkhole swallowed a whole factory.
Other very devastating sinkholes are located in the Sarisarinama field in Venezuela. There are four sinkholes here but the largest is the Sima Humboldt which is 352 metres wide and 314 metres deep. That means it's as deep as the New York Chrysler Building is tall.