Structural geology of the Neogene Maliau Basin, Sabah

Abstract

The Maliau Basin (Maliau outlier) is made up of about 7,500 metres thick sandstone and mudstone layers deposited in a deltaic-coastal environment, assigned the Kapilit Formation. The layers at the base of the basin consist mainly of mudstones reaching up to 2,000 metres thick. Near the rim of the basin, thick sandstone layers and coal seams occur. Towards the centre of the basin a series of sandstone-dominated and mudstone-dominated sequences of various thicknesses occur. The deposition took slight unconformity place during the Middle Miocene (10-15 million years ago). The basin sits with slight unconformity on older sedimentary rocks (Tanjong Formation), also comprising of thick layers of sandstone and mudstone. The orientation of bedding generally follows the semi-circular shape of the basin. The dip of bedding varies from 5-10 degrees at the centre to 45-50 degrees at the rim. Subvertical to vertical fractures shows four main fracture orientations, NW-SE, NE-SW, NNW-SSE and WNW-ESE. Faulting is quite rare inside the basin. However, outside the basin, minor normal faults occur trending E-W and NE-SW. A sheared zone occurs at the southeastern part of the basin, possibly due to a major fault, the Lonod Fault. Based on regional and local structures the Maliau Basin is interpreted to have. developed initially in an extensional regime, whereby an enormous amount of sediments were deposited in a subsiding basin and later subjected to compression (inversion).

Neogene rock uplift and erosion in northern Borneo: evidence from the Kinabalu granite, Mount Kinabalu

“…These episodes of extension could account for emergence and growth of a landmass in Sabah during the Middle and Late Miocene (e.g. Hall 2002Hall , 2013Balaguru et al 2003;Tongkul & Chang 2003;Morley & Back 2008), creating a topographic feature (Fig. 8) into which the Kinabalu granite was intruded.…”

“…Shelf edges offshore of northern Sabah moved progressively outwards from the Middle Miocene onwards (e.g. Hazebroek & Tan 1993;Sandal 1996), and the region became emergent once more in the Late Miocene or Early Pliocene (Hall 2002;Balaguru et al 2003;Tongkul & Chang 2003;Morley & Back 2008). The Pleistocene glacial tills of the Pinosuk Gravels (Collenette 1958) are the youngest sedimentary rocks known from the Kinabalu area.…”

Nature and demise of the Proto-South China Sea

“…The Crocker Formation in western Sabah is unconformably overlain by the Lower Miocene shallow marine Meligan Formation (Wilson & Wong, 1964) and Kudat Formation. To the east of the Crocker Mountains during the Middle and Late Miocene there was subsidence and deposition of a thick succession of fluvio-marine deposits (Noad, 1998;Balaguru et al, 2003;Balaguru & Nichols, 2004) in the Central Sabah Basin (Hutchison, 1992) whose remnants are now found in the circular basins of eastern Sabah (Tongkul, 1993;Clennell, 1996;Balaguru et al, 2003;Tongkul & Chang, 2003).…”

Mesozoic and Cenozoic accretionary orogenic processes in Borneo and their mechanisms

“…The NNE-trending transform faults rotated into NNW-striking. Meanwhile the subduction zone mainly extended from NE to SW, but it is curved to near-E-Wtrending in North Sabah (Tongkul and Chang, 2003). Corresponding to the subduction, the thrusting generated the S 2 foliation, which was NE-trending in most of Sabah but WNW-trending in North Sabah (Fig.…”