The karst of Sagada Mountain Province,Luzon, Philippines

Speleological investigations during a three month period in late 1982 and early 1983 in the karst of Sagada, Mountain Province, Luzon, Philippines further clarified the initial 1980 study by Deharveng and Orousset. Over 13 km of cave passages were mapped and two main watersheds, Ambasing Spring and Balangagan Spring, were recognized.

The karst of Sagada lies between 1100 and 1600 m elevation in the Oligocene limestones of the Tineg formation. The karst is well developed, both on the surface and in the subsurface. The caves fall into five main types:

1. Potholes (Kitungan Kampus Pit, entrance to Tataya En).

2. Fossil Caves (Lomyang Cave, upper part of many caves).

3. Swallets (Latang Cave, many small swallets, especially during the wet season).

4. Underground rivers (Agoyo-Ige System. Lomyang-Latipan System, Agew Na Nayawakan System, Tataya En System, part of Balangagan Cave).

5. Springs (Ambasing and Balangagan Springs).

The caves are characterized by very wide passages, massive secondary calcite deposits, voluminous collapses, abundant volcanic debris and floods up to 600 times the low flow discharge. Study is not complete, and much work needs to be done, especially to differentiate completely the watersheds of the two main springs.