Geological Heritage – Labuan Geopark

GEOLOGICAL HERITAGE OF LABUAN

The geological history of Labuan began with the deposition of more than 12 kilometers of deep marine sediments in the northwestern Sabah Basin during the Oligocene period (approximately 30 million years ago) until the Middle Miocene (around 20 million years ago).

Stories Written in Stone

An exploration of Labuan’s unique geological formations, where every rock and landscape reveals the timeless story of Earth’s history, evolution, and heritage.

The geology of Labuan Island is a continuation of formations found in the western part of Sabah, Brunei Darussalam, and northern region of Sarawak (Liechti et al., 1960). The island is underlain by three main geological units, entirely composed of sedimentary rocks and alluvium. From oldest to youngest, these units are the Temburong Formation, Western Crocker Formation, and Belait Formation. These rock units are folded into a large, asymmetrical anticline plunging towards the northeast.

The geological history of Labuan began with the deposition of more than 12 kilometers of deep marine sediments in the northwestern Sabah Basin during the Oligocene period (approximately 30 million years ago) until the Middle Miocene (around 20 million years ago). These sedimentary sequences formed what are now known as the Western Crocker Formation and the Temburong Formation.

During the Middle Miocene, tectonic uplift occurred as a result of the subduction of the ancient South China Sea crust beneath the northwestern margin of Borneo (Mazlan, 1994).

This process caused the deep marina environment to gradually become shallower, eventually creating coastal environments along the northwestern coasts of Sabah, Brunei, and Labuan. This transition led to the formation of extensive shorelines, deltas, and a range of intermediate environments such as mangrove swamps, estuaries, delta plains, floodplains, and river channels, each accumulating different types of sediments.

Some of these environments accumulated abundant plant debris, which over time transformed into coal deposits, while other areas became sites of gravelly and sandy sediment deposition, eventually forming hydrocarbon reservoir rocks. Collectively, these shallow marine to coastal deposits make up the Belait Formation. During the Late Miocene to Pliocene, the final stages of subduction folded the entire sequence of rock formations, creating a large anticline structure. Periodic folding and uplift of these rock layers occurred in tandem with delta advancement and the development of gravity faults (Morley et al., 2002).

Location Information

Location details for Labuan’s geological heritage, including map references, approaches, and visitor wayfinding

G1 – 15 MILLION YEARS

BELAIT SANDSTONE TANJUNG KUBONG

River channel deposits from approximately 15 million years ago, part of the lower Belait Formation. Fresh outcrops exhibit near-horizontal thick sandstone layers. A scenic and diverse coastal landscape with alternating sandy and rocky shorelines, featuring sea caves and arches in several locations.

G2 – 15 MILLION YEARS

BELAIT SANDSTONE TANJUNG BATU

Thickly bedded sandstone layers representing ancient tidal-influenced river channels. Abundant shallow marine trace fossils such as Ophiomorpha isp., Teichichnus isp. are visible. Exceptionally well-developed tafoni (honeycomb weathering structures) formed by salt spray from the sea, creating intricate voids on coastal rock surfaces.

G3 – 15 MILLION YEARS

CROSS-BEDDED SANDSTONE TANJUNG LAYANG-LAYANGAN

Fresh rock surfaces reveal large-scale cross-bedding with embedded charcoal fragments, a unique feature not recorded elsewhere in Malaysia. The site features a broad tidal flat with current and wave ripple structures visible during low tide, and Belait Formation strata extending offshore toward Pulau Ular, with a sea arch sculpted by marine erosion.

G4 – 35 MILLION YEARS

TEMBURONG SEDIMENTARY ROCKS BEBULOH DARAT

Deep marine sedimentary deposits exceeding 2,000m depth, comprising dark grey to reddish mudstone with interbedded siltstone and medium-grained sandstone. Rich in deep-sea trace fossils, indicating a highly valuable scientific geosite.

G5 – 15 MILLION YEARS

OIL RESERVOIR ROCKS GANGGARAK

Exposed ancient hydrocarbon reservoir rocks still showing signs of seepage and oil odour — the only known locality where such reservoir rocks can be observed at surface level in Labuan.

G6 – 35 MILLION YEARS

SAND SPIT PULAU KURAMAN

A sand spit formed by longshore drift depositing sediment at the island’s tip, shaped by wind and wave action into a curved coastal feature.

G7 – 15 MILLION YEARS

PULAU RUSUKAN BESAR

A marine abrasion platform displaying distinctive box-jointing and fault structures within the rock, evidence of past tectonic activity in western Borneo.

G8 – 15 MILLION YEARS

LUBOK TEMIANG COAL MINING RELIC

Site of one of Southeast Asia’s earliest coal mining operations (19th century). Remains of tunnels, shafts, and adits are still visible in the island’s northern sector.

G9 – 12–35 MILLION YEARS

JURASSIC RIDGE LABUAN

Tectonic uplift and folding from around 12 to 3 million years ago raised Labuan from the seafloor, folding its sedimentary layers into hills and ridges.

G10 – 15 MILLION YEARS

SIMPANG SWEETMAN COASTAL DEPOSITS

Coastal deposits featuring sedimentary sequences from terrestrial environments with trace fossils (Ophiomorpha isp.) and charcoal fragments within sandstone layers.

G11 – 15 MILLION YEARS

DEEP-SEA TRACE FOSSILS TANJUNG PUNEI

Rich in trace fossils such as Paleodictyon isp., associated with ancient deep-sea farming behavior (Agrichnia). The site also features well-preserved erosion platforms along the beach.

Discover Labuan National Geopark, where ancient rock formations, fossil-rich cliffs, and submerged volcanoes reveal a story written over millions of years. From towering chimneys to coral-fringed islands, every layer tells a tale—waiting for you to explore.