Caving - Thailand
Mae Lana Cave (Mae Hong Son Province)Caving: Austria, France, Germany, Laos, Thailand, Vietnam
Caves in Thailand: Bor Krai Cave, Chiang Dao Cave, Lot Cave, Mae Lana Cave, Muang On Cave
Speleothems in Mae Lana Cave.
The Mae Lana cave is one of the finest caves in Thailand and of international importance for conservation. When it was discovered by an Australian team in 1986, Mae Lana cave was the longest recorded cave in mainland SE-Asia. Since then, several longer caves have been discovered in Laos and Vietnam, as well as Phra Wa Daeng cave in Phitsanolok which is 13 km long. However, with a total length of 12.6 km Mae Lana cave is still the longest through cave in Thailand. The cave system is situated within Permian limestone and has several levels, with the Mae Lana stream at its base.
The Mae Lana stream sinks in an impenetrable hole 500 m south of Mae Lana village, re-emerging in an enclosed depression 2 km to the south which also contains a number of caves (at higher levels). The stream flows on the surface for 300 m before plunging into the upstream entrance of Mae Lana cave, in approximately 3 km walking distance to the villages Bor Krai and Mae Lana.
The main river passage has a length of 7.2 km. Most of the first half of the cave is very spacious with passages up to 40 m high, extensive rock breakdown and many rapids.
Two substantial tributary streams join the main river about 2 km and 3km from the entrance, the first of which can be followed for over 2 km. This tributary stream cave might originate in the vicinity of Bor Krai village, and is probably related to a line of sinkholes along a north-south trending fault. Its stream has at least two different species of blind and white fish. The subterraneous outlet of this first tributary stream cave is approximately 5 m above the main stream, forming waterfall over a cascading flowstone. 3.8 km from the inflow entrance, the main river enters a large sump, re-emerging again after 100. This level can be bypassed at higher flood level passages more than 10 m above the main stream. This flood level passages are active during rainy season (May until October), when the water level rise within certain sections to more than 10m. One of these flood level passages led to a volcanic intrusion in the central part of the cave. This intrusion can be classified as latite and is associated with veins of iron ore within the limestone. Both latite and iron ore occur also at the surface. There, iron ore occurrences are often associated with Ferralsols. The lower half of the river passage below the sump consists mainly of narrow canyons with many rapids.
Extend and variety of speleothems in Mae Lana cave is quite exceptional, including good examples of almost all cave formations known from Northern Thailand. The main river passage has some massive decorations including 20 m high columns, but the majority of the unusual speloethems are in the side passages and upper level where air movement is more restricted. The collection of cave pearls (oolites) is particularly outstanding, with several thousand in one chamber alone. Other unusual features include calcite spar crystals, anthodoites, pendulites, mud stalagmites, birdbath conulites and cave shields.
At the downstream exit of Mae Lana cave, the stream bed is blocked with huge limestone boulders of a rockfall.
Speleothems in Mae Lana Cave.
Sidisunthorn, P., Gardner, S., Smart, D., 2006. Caves of Northern Thailand. Sirivatana Interprint Public Co., Ltd., Thailand.
Schuler, U., 2008. Towards regionalisation of soils in Northern Thailand and consequences for mapping approaches and upscaling procedures. Hohenheimer Bodenkundliche Hefte 89: 1-308.
Schuler 2008 -