Maliau Basin Scientific Expedition

Located in the centre of the southern part of the Malaysian state of Sabah in Borneo (Fig. 1), Maliau Basin is approximately the shape of a saucer, perched on highlands. The rim of the elevated basin ranges from 1500 m above sea level to 1900 m, the peak of Gunung Lutong, the highest mountain in the area (Fig. 2). The almost circular Basin is delimited by cliffs on almost all sides. This peculiar shape had been moulded by faults and earth movements resulting in the Tanjung Formation during the early to middle Miocene age (Tjia & Komoo 1988). The Tanjung Formation consists of rocks which are mudstones intercalated with thin and thicker layers of siltstone to medium grained sandstones. A set of the Sungai Maliau tributaries fans out into the area. Sungai Maliau itself gorged out of the south-eastern corner of the basin into Sungai Kuamut which in turn feeds the longest and largest river in Sabah, Sungai Kinabatangan. The first scientific expedition of 1988 documented a variety of scientific findings. The duration then was three weeks (April-May 1988) and 43 people participated. The final report compiled by the late Dr Clive Marsh (1989) reported on the geology, soil, hydrology, geomorphology, climate, plant studies, animal studies and human impacts. The report also suggested future management considerations.