“Where, when and why” for the arc-trench gap from Mesozoic Paleo-Pacific subduction zone: Sabah Triassic-Cretaceous igneous records in East Borneo

Causes of Late Cretaceous subduction termination below South China and Borneo: Was the Proto-South China Sea underlain by an oceanic plateau?

“…The declination data of the different sections suggest that they all underwent a similar rotation, of about 40° clockwise for a normal, southern hemisphere magnetization, or 140° counterclockwise for a reverse, northern hemisphere magnetization. The pillow basalts of a thrust slice below section 5 formed during the Early Cretaceous (c. 135 Ma; Wang et al, 2023), around which time the magnetic field underwent multiple polarity reversals, which means that the polarity of the magnetic field during magnetization is unknown. In addition, the Baliojong River section is a largely deformed accretionary prism, where large-scale rotations cannot be excluded.…”

“…9). Thus, the Baliojong turbidites were likely deposited around the Turonian-Coniacian, which is reasonably younger than the underlying Albian-Cenomanian cherts and Early Cretaceous basalts (Jasin and Tongkul, 2013;Wang et al, 2023).…”

“…Similar mélange complexes are also present in northern Sabah, where they comprise gabbro, plagiogranite, pillow basalt, Cretaceous radiolarian chert, and trench-fill clastics (Jasin, 2000(Jasin, , 2018. Zircon U-Pb dating of gabbro samples from these North Borneo accretionary complexes, of which the (tectono-)stratigraphic context is not well known, yielded mean ages between 112±2 and 123±1 Ma and basalt samples yielded 40 Ar/ 39 Ar plateau ages of ~134.5±2.8 and 135.9±2.2 Ma (Wang et al, 2023). Trench-fill sandstones yielded maximum depositional ages of ~114 Ma, based on detrital zircon geochronology (Wang et al, 2023).…”

“…Zircon U-Pb dating of gabbro samples from these North Borneo accretionary complexes, of which the (tectono-)stratigraphic context is not well known, yielded mean ages between 112±2 and 123±1 Ma and basalt samples yielded 40 Ar/ 39 Ar plateau ages of ~134.5±2.8 and 135.9±2.2 Ma (Wang et al, 2023). Trench-fill sandstones yielded maximum depositional ages of ~114 Ma, based on detrital zircon geochronology (Wang et al, 2023). The OPS mélanges in North Borneo are unconformably overlain by middle Eocene sandstones (Hutchison, 1996;Hutchison et al, 2000;Jasin and Tongkul, 2013;Van Hattum et al, 2013;Rahim et al, 2017) that farther to the north were incorporated into a north-vergent fold-thrust belt known as the Rajang-Crocker accretionary prism that formed during southward subduction below north Borneo along-strike of Palawan (Van Hattum et al, 2006.…”

Evolution of Arc‐Continent Collision in the Southeastern Margin of the South China Sea: Insight From the Isugod Basin in Central‐Southern Palawan

“…In contrast, a large accretionary wedge primarily composed of the Late Eocene–Oligocene Crocker Formation (i.e., the Crocker accretionary wedge) was well developed around northern Borneo, owing to sufficient sediment supply from the upper plate (van Hattum et al., 2013). Ophiolites are widespread in Sabah, and a recent study suggested that most of the ophiolites are of Triassic to Cretaceous age (185–85 Ma) and were generated in a forearc setting related to the Mesozoic Paleo‐Pacific subduction (Wang et al., 2023). However, there are also ophiolite of Eocene age (47–42.5 Ma) that might be correlated to the Central Palawan Ophiolite (Chien et al., 2019) and ophiolite of Late Miocene age (10.5–9.2 Ma) that might be related to the opening of the SE Sulu Sea (Tsikouras et al., 2021).…”