Language: English with trilingual abstract in English, German, and French
Before the publication of Dreybrodt & Laumanns (2005), which summarises the exploration done between 2000 and 2005, northern Laos was virtually unknown to speleology. Only a few reconnaissance projects were conducted prior to 2000 in the province of Luang Phrabang. The afore-mentioned publication provided information on 24,3 km of cave passages from 68 caves.
In the framework of the “Northern Lao–European Cave Project” (www.laoscaveproject.de) the investigations were continued in 2006 (Louang Nam Tha province, Vieng Phouka), 2007 and 2008 (mainly Houaphan province, Vieng Xai). In the Houaphan province (Vieng Xai) the communist Pathet Lao had its headquarters for 9 years during the Vietnam War. Extensive military and logistical use of caves was made in this heavily bombed region, including underground cave bunkers for the communist party leaders and subterranean hospitals. These historical cave sites are maintained as national monuments and symbolize the birthplace and rise of the communist party of Laos.
The caves attract a growing number of foreign visitors. Underground river courses with huge and beautifully decorated cave passages are abundant and many of them are through caves including the 4,5 km long Tham Nam Long as well as the 3 km long Tham Nam. Nine other caves were explored in 2007 yielding a total of well over 10 km of mapped passages. During the 2008 speleological project 6,7 km of passage from 22 caves were added in the same area, including Tham Ma Liong at 1565 m of length. The 2008 project was subject of a professional film documentary by ARTE TV channel.
Another caving area north of Vieng Thong was briefly visited in the Houaphan province. This region belongs to the Nam Et Phou Louey National Park from where several caves were described by environmental projects with emphasis on eco-tourism. Three days yielded over 2 km of passage from three caves, including the unfinished Tham Thia Thong where about 200 m of passage needs to be added to the already surveyed 1,2 km. Many more caves await exploration. The remaining three of the 15 cave kilometres mapped during the 2007 project came from other regions, mainly from the Phou Khoun area (Luang Phrabang/Vientiane province) where the 2 km long Tham Deu–Tham Dout system consists of two unconnected river caves.
Overall, 51,3 km of cave passage from 136 caves has been surveyed to date in northern Laos. This publication reports on the findings of the years 2006– 2008.
1. Acknowledgements/Team Meübers 7
2. Introduction 12
2.1 History of speleological exploration in Laos 12
2.2 General remarks 14
3. Cave descriptions 17
3.1 New caves of the Luang Phrabang province 17
3.1.1 Geological overview 17
3.1.2 Area A: Nong Khiaw / Muang Ngoy 18
3.1.3 Area I: Phou Khoun 20
3.2 New caves of the Luang Nam Tha province 22
3.2.1 Geological overview 22
3.2.2 Area J: Vieng Phouka 22
3.3 The caves of the Houaphan province 39
3.3.1 Geological overview 39
3.3.2 Area K: Vieng Xai memorial caves (by Liz Price) 39
3.3.3 Area K: Other caves of the Vieng Xai and Xam Neua region 56
3.3.4 Area L: Caves of the Vieng Thong region 73
3.4 Area M: The caves of the Xieng Khouang province 78
3.5 Area N: The caves of the Vientiane province 85
4. Physiochemical data (by François Brouquisse) 89
5. Biospeleological observations (by Helmut Steiner) 95
6. Conclusions 104
7. References 104
Caves explored during the 2006, 2007 and 2008 speleological projects 111
Photo tables 114
Atlas sheets cave survey Tham Pasat (Nam Mai) 120
Atlas sheets cave survey Tham Nam Long 126
Atlas sheets cave survey Tham Chaloun 136
Atlas sheets cave survey Tham Thia Thong 139
Survey of Kout Nam Rou 143