Northern Lao - European
The 2012 expedition consists of two independent expedition teams focusing on two areas. One team explores the Luang Nam Tha province and Luang Prabang province in the north while the other team visits Houaphan province in the east. A reece to Myanmar is done after Laos in order to extend the activities of the project into a bordering country.
Two areas have been visited that are familar from the first expeditions of the project in 2002 and 2005. Since then the infrastructure has improved and new areas are accessible. The first week of the expedition was spent in Vieng Phouka district. The area north of the town was checked during a two day jungle trek and several river and fossil caves found. Furthermore areas close to Bang Eng and Ban Mai were revisited. New river caves of 200-300 m length were surveyed. The villages along the new road heading north to Muang Long were checked for caves. Though the hills look very interesting with bare limestone cliffs, caves similar to the several km long Tham Nam Eng are not found. We heard of more caves to the east near Ban Nam Fa which might be worth to visit when passing by.
The base camp for the second week was in Nong Khiaw district. The tourism office remembered the Dutch expedition from 2000 and supported us with permission and guide. The first day a cave known since only few years was shown to us up river from Muang Ngoy. It has a beautiful upper fossil passage and an active river which is reached after a descent of 20 m. The cave called Doun Mai was visited for three days to survey while one day was spent to check for caves down river on the Nam Ou. The village of Ban Houaykhou is surrounded by step cliffs. Surprisingly only short fossil caves were found.
The Myanmar reece proofed successful. We were allowed to visit an area that is closed for foreigners since more than 10 years The Pinlaung district hosts in one ridge several large chambers of about 80 m length, 60 m width and 35m height which have a depth potential below -100 m. The Mai Lone Kho is now the deepest cave in Myanmar with -160m vertical extension.
This team targeted Houaphan province, which was visited before by the Project in 2007, 2008, and 2010. The purpose of the investigations was to check out the cave potential in the karst mountains along the main road from Vieng Xai towards Na Meo (Viengxai district) as well as in the surroundings of the district capitol of Xamtai. The first goal was achieved by surveying 40 new caves.Generally, the karst between Nam Seua and Na Meo is located in a narrow synclinal structure approximately 3-5 km wide with the limestone hills increasing in size from west to east. The surrounding mountains are higher and mainly consist of schist. Cave development was phreatic in the beginning. Especially the canyon-like passages in the caves around Ban Siang Luang, Ban Nam On and Ban Khang Muang that often have anastomotic tubes in the roof. In a later phase these tubes incised and keyhole-like cross-sections were formed. This most likely coincides with a general tectonic uplift of the area. In Tham Han cracks in columns and stalagmites show these tectonic movements. Longer river caves only exist up to the road pass east of Ban Khang Muang - further east only smaller fossil caves were found. Unfortunately, it became apparent that the karst in Xamtai district is quite difficult to reach. The district government cannot provide clean water and electricity to the villages further northwest of Xamtai city and has started a program to resettle the villagers to other places. Consequently, the karst, supposed to be about 25-30 km northwest of Xamtai city, is depleted of settlements where assistance for a surveying team can be provided. As these logistics were impossible during the 2012 trip a closer investigation of the karst area northeast of Xamtai was waived.
A positive surprise on the very last day of the 2012 expedition was a brief look into an area about 25 km north of Sam Neua in Sam Neua district. Here, near the villages of Ban Nam Koup and Ban Na Seng, a couple of supposed sinkholes and resurgences were located by Helmut Steiner on topographical maps. This assumption proved to be correct and the villagers, who belong to the Thai Deng minority, confirmed a through cave (Tham Nam Oogh) stretching for about 2-3 km between the sinkhole close to Ban Na Seng and the large resurgence cave, which can be reached by a 2 km walk through a scenic tower karst landscape from the village. The resurgence cave was investigated for about 200 m. The stream passage is about 15 m wide and 20 m high and has rich calcite decoration. The cave also has an extensive fossil level. Consequently, a cave system possibly 4-5 km in length is suggested near Ban Na Seng. The villagers also indicated the existence of 2-3 other caves in the surroundings, including Tham Loum (Wind Cave). The neighbouring village (Ban Nam Koup) has a large through cave just across the paddy fields, which is about 100 m long. An underground river flows through the cave. Along the way back to Sam Neua a couple of other karst outcrops were spotted and inquiries in the (Hmong) villages confirmed 3 small caves in Ban Long Oued and three stream caves along the same river in Ban Pa Char. The latter caves were not entered by the locals who reported one of these caves to be long. Consequently, exploration of these karst areas can be best made by day-trips from Sam Neua. If a permit for cave exploration in this area can be obtained from the provincial authorities, a future expedition is highly recommended.
We acknowledge the support of the FSE and NSS.