ABSTRACT
This chapter interprets the origin and development of the extensive fossil and active cave systems found in the limestone hills of the Gunung Mulu National Park, Sarawak, and to relate their sedimentary sequences, with the terraces of the Melinau valley. The region can be divided into two topographical zones, an eastern upland area rising to 2400 m on the summit of Gunung Mulu and a western lowland, generally below 200 m. The autogenic drainage of the limestone uplands is also underground, and combines with runoff from the adjacent lowlands to resurge at major risings, such as that of the Clearwater Cave complex, which drains a major part of G. Api. A regional drainage pattern to the north-west developed in response to the tilting of the accreted sedimentary prism towards the subduction zone north-west of the present Borneo coast. However, this pattern was modified by active uplift along a plunging north-east/south-west axis passing through G. Mulu, and forming an elongate dome.
