Tebat Rasau is a fascinating geosite in Belitong that combines geology, biodiversity, and cultural stories in one unique landscape. The area is part of the Kelapa Kampit Formation, composed mainly of weathered metasedimentary rocks that also contain rare earth elements (REE).
The highlight of Tebat Rasau is the Lenggang River, which represents a mature river ecosystem. Along its calm waters, visitors can witness a rich variety of freshwater fish species, many of which are rare or even endemic to Belitong. Among the most remarkable discoveries here are the silver arowana (Osteoglossum bicirrhosum) and the Ampong fish (Channa marulius). These species are not found in western Belitong, making Tebat Rasau an important site for biogeography and evolutionary studies.
Scientists believe that these unique fish populations may provide clues about the island’s ancient history. During the Sundaland era in the Ice Age, when Belitong was still connected by land to Sumatra, Kalimantan, and Java, rivers in the northeast flowed northward and eventually joined river systems emptying into the Natuna Sea. In contrast, rivers in the southwest drained southward toward the Lombok Strait. This ancient connection may explain why Tebat Rasau hosts species that are otherwise absent in other parts of the island.
Beyond its scientific significance, Tebat Rasau has become a natural tourism destination. Visitors can enjoy river trips, explore the lush riverbanks, and observe wildlife in its natural habitat. The calm environment makes it an excellent spot for eco-tourism, nature photography, and environmental education.
By protecting the river and its biodiversity, Tebat Rasau showcases how geology, ecology, and culture intertwine to create a place of beauty, science, and sustainable tourism.