Introduction to Sanmen Sea Scenic Area

Sanmenhai Scenic Area is the only water-touring tiankeng scenic area in the world.

Sanmenhai Ecological Tourism Zone is located in Poxin Village, Sanmenhai Town, Fengshan County, Guangxi. It is the core area of ??the world's typical karst landforms. Sanmenhai is the outlet section of the Poxin Underground River, the source of the longevity zone in the Bama Panyang River Basin, the hometown of longevity. There are seven karst sinkholes developed here, and they are connected by open lakes and dark lakes covering an area of ??several square kilometers formed by the exit cave section of the Poxin underground river. Currently, there are three skylights that can be entered by boat through natural channels, giving people a sense of being in the mountains. There is a mysterious feeling of a sea and a door on the sea, hence the name Sanmenhai.

Fengshan Sanmenhai Tourist Scenic Spot is currently recognized by the World Cave Association as the only water tour tiankeng scenic spot in the world. It is a tourist attraction in our region that integrates natural landscape, longevity culture and revolutionary historical relics. A tourist attraction with international quality.

The causes of tiankeng are listed as follows:

1. Collapse tiankeng

Collapse tiankeng is caused by the strong dissolution and erosion of underground rivers, which causes the continuous erosion of rock layers. Collapse and reach the surface. The formation of a collapse-type tiankeng should meet the following necessary conditions: there are continuous deposition, huge thickness of carbonate rock layers, and a wide range of continuous exposure and distribution; the rock formations are horizontal to gentle in appearance, especially wide and flat anticlines. The axis is the most favorable; the relatively low drainage base level and the vadose zone of the aquifer are thicker than 50 to 200m; the tropical to subtropical climate conditions are warm, humid and rainy, etc.

2. Erosion-type tiankeng

Erosion-type tiankeng is a sinkhole-type or blind valley-type tiankeng formed under special geological, geomorphological and hydrological conditions. . Only two cases have been discovered so far.

Reference for the above content: Baidu Encyclopedia-Tiankeng