Tham Seua / Tham Nam Lot

DREYBRODT JOERG informations

Frédéric Urien - 23/06/2024

History:-- This big room, located about 100 m from the cave entrance, has banana leafs spread on the floor as well as remains of candy wrappers and beer bottles. Generally, all the easier accessible cave passages are well known to the locals and litter is abundant. Exclusively the lower levels with the stream passages are untouched [5158] Explo history: -- 01.-04.02.2005 explored and surveyed to 2.650 m by Northern Lao European Cave Project 2005 [5158], [8525] Cave description: Citation: Analysis: [5158]: The Tham Seua – Nam Lot system was originally known as two separate caves which were successfully linked during the survey to one system. Tham Nam Lot: A small river flows over some cascades into the beautiful 15 m wide and 3 m high entrance of Tham Nam Lot. After 20 m another stream enters the cave from a small 2m wide and 2 m high passage. This is the connection to Tham Seua (Tiger Cave). The main passage goes straight into the mountain for 120 m until some boulders block the way. The ceiling has a stunning height of 20 m. To the left is a climb that connects via a nasty traverse to an upper gallery and a higher entrance. The main passage continues with sand and gravel on the floor and a twisting river bed. After 70 m the stream vanishes to the left and the passage makes a turn to the right until it connects after 30 m again to the river. The passage changes its character and the walls show the bedding of the limestone layers. A 15 m wide and 25 m long chamber with a flat mud floor is reached. The river disappears again and a 5 m higher fossil passage opens up to the right. The cave passage changes slowly in direction from north-south to west-east. After 100 m the fossil passage descends to the reappearing river. Shortly prior to this an unclimbed lead with blowing air branches off. About 500 m from the entrance the ceiling suddenly lowers from 3-5 m to less than one meter. A muddy wet passage continues into the mountain with flowstone formations on the walls. The end was not explored due to lack of time, but it is obvious that the river reaches the surface as a spring after few hundred meters. The spring required another day to intensely investigate, and was found to be completely blocked with boulders. The guide claimed that several years ago it was possible to exit the cave this way. The upper three entrances to Tham Nam Lot are reached by a half hour climb straight up the mountain. The cave is best entered by the 4m wide and 4 m high middle entrance. An easy 10 m climb leads down to a first chamber with nice flowstone columns. To the left a passage continues with strong air flow towards the cave. A series of bigger, nicely decorated chambers with short underlying passages follow until after 150m another entrance with a tree in its centre is reached. Phou Khoun is clearly visible from here on the other side of the valley. Below in the valley are paddy rice fields that receive water from the stream that re-enters the surface from the lower river passage. To the right of the first chamber the biggest hall of the cave is entered after 50 m. An impressive room opens up with 70 m in length, 25 m in width with more than 30 m in height difference. Daylight from the upper eastern entrance shines on two big flowstone columns. A drop at the lower end of the chamber leads further down to the gallery of the active stream passage. It is not easy to find the way down to the river. A dangerous traverse below a big boulder has to be negotiated before the river bed is reached. The 30 m high ceiling can be climbed by two upwards leading side passages with large dripstone columns. Tham Seua: The secondary entrance to Tham Seua is an inconspicuously small cave hole (1 by 2 m) that leads to a spacious chamber of 6 x 4 x 15 m. A passage continues to the left at the very end of this room. Rimstone formations at the right hand side leads to a vertical edge from where a lower passage can be seen. Following the main continuation, with some flat mushroom shaped formations on the floor, a 2 m deep climb is reached that leads to a junction. To the right one reaches the series of passages that was previously seen from above. A rather large room follows that have big boulders on the floor. This room ends with a big pit (see below). To the left a series of up-and-down climbs lead to another junction. The passage to the right ends on top of a several meters deep climb. After the drop a passage with a sandy floor leads to the right but soon ends in small anastomotic tubes. To the left from the drop one gets to the top level of a bolder choke. This is the bottom of the above-mentioned pit. It is possible to climb down this pit through the boulder but this is dangerous and thus not recommended. The way on continues at the beginning of the boulder choke where a small man-sized hole in the wall gives way to a gentle slide down into a succession of rooms from where a stream passage can be reached. The stream passage to the right is a low and wet belly crawl that was not pushed during the survey. To the left a meander continues for quite some distance. Occasionally, the meander is blocked by boulder which requires climbing. The meander ends in a non-climbable blockage but it is supposed to continue for unknown distance behind the obstacle. A crack to the right starting after the second boulder choke in the meander leads to another lower dry continuous stream passage. This stream passage connects to the other sections of the cave system. Earlier after the second boulder choke the most obvious continuation leads to the left. Large passage can be followed until they get smaller and ascend. Here a tight and steep crack leads down to bigger rooms. The floor slopes down and the passage are rather flat, with nice calcite formations. The gallery gets smaller to the left but there is a continuation going up to the right. After some meters a narrow and steep climb descends to the right. Staying at the same level one will reach the end of this cave section soon. The steep narrow climb leads to another big room that re-connects to known passage. This big room, located about 100 m from the cave entrance, has banana leafs spread on the floor as well as remains of candy wrappers and beer bottles. Generally, all the easier accessible cave passages are well known to the locals and litter is abundant. Exclusively the lower levels with the stream passages are untouched >> survey >> shown in map [6415]: only mentioned in a historical overview & shown in map [8525]: A joint Dutch-German expedition to northern Laos was conducted in February 2005, bringing together members of both teams. The first part of the project was focussed on caves in the Phou Khoun area (close to the Kasi Hills further south). During the expedition several known caves were linked to a 2.6 km long underground system (Tham Seua-Nam Lot). [9273]: Localities: [...] Luang Prabang Province. L82: Muang Phou Khoun, Tham Seua, N 19°26' 35,80'', E 102° 26' 19,10'', 1240m altitude, in cave, vegetation along trail, on ground vegetation layer, bushes bamboo, trees, by hand, day and night, P. Jäger & S. Bayer leg. 13.XI.2009 [9410]: only mentioned in a history of cave research in Laos [9628]: fauna record, from outside! the cave [9813]: Psechrus ancoralis Bayer & Jäger, 2010 [...] additional material examined: LAOS: [...] Luang Prabang Province: Phou Khoun, Tham Seua, N 19°26'55.7'', E 102°26'09.4'', in cave; H. Steiner leg. 04.II.2005; |119/05|, 1 ♀ (SB 75), 1 juv. (SB 89), SMF. Phou Khoun, way to Tham Seua, N 19°26'35.8'', E 102°26'19.1'', 1226 m, slopes at wayside (with escarpments); P. Jäger and S. Bayer leg. by night 13.XI.2009; 3 ♂♂ (SB 320–322), 6 ♀♀ (SB 324–326, 383–385), 2 s.a. ♀♀ (SB 386–387), SMF, 1 ♂ (SB 323), 1 ♀ (SB 327), DUY. [9845]: Argiope pulchella Thorell 1881 (Figs 115–118) Material examined [...] 1 female [2 emboli] (SMF 60414), Muang Phou Khoun, Tham Seua, L82, N 19°26’35.80”, E 102°26’19.10”, 1240 m altitude, in cave, vegetation along trail, on ground, ground vegetation layer, bushes, bamboo, trees, by hand, day and night, P. Jäger & S. Bayer leg. 13.XI.2009. [10090]: fauna records Equipment: Remarks:N 19o26’48,7’’ – E 102o26’17,1’’, alt. 1,191 m (Tham Seua), N 19o27’00,8’’ – E 102o26’02,6’’, alt. 1,134 m (Tham Seua resurgence), N 19o26’55,7’’ – E 102o26’09,4’’, alt. 1,237 m (1st upper entrance), N 19o26’59,3’’ – E 102o26’05,5’’, alt. 1,207 m (2nd upper entrance), N 19o26’50,4’’ – E 102o26’14,9’’, alt. 1,155 m (Tham Nam Lot) References: [5158]: Dreybrodt, J. & Laumanns, M. (eds.) 2005: The unknown North of Laos (Karst and Caves of the Provinces Luang Phrabang and Luang Nam Tha). Berliner Höhlenkundliche Berichte 16. 105 pp & Annex. [5494]: Zillig, W. 2005: Laos 2005. URL: www.student.kuleuven.ac.be/~s0167070/expeditions/l… [5495]: Dreybrodt, J. & Laumanns, M. 2004: Laos. Gli ultimi cinque anni di esplorazioni europee nel generoso mondo ipogeo laotioano. Speleologia 25 (51): 76. [6097]: Jäger, P. 2007: Spiders of Laos with descriptions of new species (Arachnida: Araneae). - Acta Arachnologica 56 (1): 29-58. [6415]: Dreybrodt, J. & Laumanns, M. (eds.) 2008: The Unknown North of Laos. Part 2 - 2006-2008: Karst and Caves of the Provinces Luang Phrabang, Luang Nam Tha, Xieng Khouang, Houaphan and Vientiane. - Berliner Höhlenkundliche Berichte 32. 143 pp. [7987]: Bayer, S. & Jäger, P. 2010: Expected species richness in the genus Psechrus in Laos (Araneae: Psechridae). - Revue Suisse de Zoologie 117 (1): 57-75. [8525]: Dreybrodt, J. & Laumanns, M. (eds.) 2010: The Unknown North of Laos (Part 3 - 2009-2010: Karst and Caves of the Provinces Houaphan and Oudomxay). - Berliner Höhlenkundliche Berichte 38. 94 pp + Annex. [9273]: Jäger, P. & Praxaysombath, B. 2011: Spiders from Laos with forty-two new records and first results from the provinces Bolikhamsay and Champasak (Arachnida: Araneae). - Acta Arachnologica 60 (1): 9-31. [9410]: Dreybrodt, J. & Laumanns, M. (eds.) 2011: The unknown North of Laos (Part 4 - 2011: Karst and caves of the Provinces Oudomxay and Sayabouli). - Berliner Höhlenkundliche Berichte 44. 50 pp + Appendix. [9628]: Jäger, P. 2012: New species of the spider genus Olios Walckenaer, 1837 (Araneae: Sparassidae: Sparassinae) from Laos. - Zootaxa 3228: 61-68. [9813]: Bayer, S. 2012: The lace-sheet-weavers - a long story (Araneae: Psechridae: Psechrus). - Zootaxa 3379: 1-170. [9845]: Jäger, P. 2012: A review on the spider genus Argiope Audouin 1826 with special emphasis on broken emboli in female epigynes (Araneae: Araneidae: Argiopinae). - Beitr. Araneol. 7: 272-331. [10090]: Steiner, H. 2013: Biospeleological Research in the Lao P.D.R: - Pp. 413-419 in: Filippi M., Bosák P. (Eds), 2013. Proceedings of the 16th International Congress of Speleology, July 21- 28, Brno. Volume 1, p. 453. Czech Speleological Society. Praha.