Assessing controls on isolated carbonate platform development in Central Luconia, NW Borneo, from a regional 3D seismic facies and geomorphology investigation

Abstract

The Central Luconia province in the South China Sea, offshore Sarawak, features extensive development of Middle to Late Miocene isolated carbonate platforms. This study presents a regional seismic architecture - seismic facies review of platform flank geometries and off-platform depositional styles, with the goals of understanding their patterns and exploring the controlling processes. The information on flank steepness and predominant shedding direction is contextualized with respect to extrinsic and intrinsic factors of carbonate platform growth, including tectonics, eustatic sea level fluctuations, hydrodynamics and regional paleogeography. Results reveal that flank geometries are consistent throughout the Middle to Late Miocene. In the north of the province eastern flanks are dominantly aggradational, steep, and sediment-starved escarpments, whereas western flanks show more progradation and are accretionary in nature. Discrepancies from this pattern are observed among closely spaced platforms. The eastern aggrading flanks are interpreted to have been highly influenced by monsoonal wind driven currents. Further south in the province tidal currents, antecedent topography and syn-depositional tectonics were more important controls on platform architectural development. This study of regional processes and geomorphic products provides a basis for enhanced conceptual facies models and reservoir quality predictions.

Carbonate contourite drifts in the southwest South China Sea: Sedimentary, paleoceanographic and economic implications

“…The W-E and NNE-SSW orientated moats in UIII in the study area indicate possible directions of wind-driven currents (Figure 10), which are comparable with the observation on the proto-Sunda Shelf (Ting et al, 2021). The reconstructed Middle Miocene winddriven currents, resembled the modern pattern (Mathew et al, 2020;Ting et al, 2021), was namely flowed towards the northnortheast and the east during summer and winter monsoon in the study area (Figure 9A). Thus, wind-driven currents were responsible for the formation of the Middle Miocene contourite depositional system in UIII.…”

“…Siliciclastic materials were transported to the ocean, forming carbonate reefs and contourite drifts e.g., in the Maldives and on the proto-Sunda Shelf (Lüdmann et al, 2013;Betzler et al, 2016;Betzler et al, 2018). The W-E and NNE-SSW orientated moats in UIII in the study area indicate possible directions of wind-driven currents (Figure 10), which are comparable with the observation on the proto-Sunda Shelf (Ting et al, 2021). The reconstructed Middle Miocene winddriven currents, resembled the modern pattern (Mathew et al, 2020;Ting et al, 2021), was namely flowed towards the northnortheast and the east during summer and winter monsoon in the study area (Figure 9A).…”

“…The Middle Miocene was also a significant period for the onset of the modern-like East Asian monsoon system (Betzler et al, 2016). The intensification of the East Asian monsoon at ~15-10 Ma greatly enhanced the seasonal wind-driven currents Holbourn et al, 2021;Ting et al, 2021). Siliciclastic materials were transported to the ocean, forming carbonate reefs and contourite drifts e.g., in the Maldives and on the proto-Sunda Shelf (Lüdmann et al, 2013;Betzler et al, 2016;Betzler et al, 2018).…”

“…The present-day continental slope of the southwest South China Sea consequently transferred from shallow-marine to bathyal environments (Ding et al, 2013;Yan et al, 2020) (Figure 9B). Terrigenous clastic input greatly increased and most of the previously constructed carbonates reefs were drowned (Wu et al, 2016;Makhankova et al, 2021;Ting et al, 2021).…”

“…The middle Miocene South China Sea was widely influenced by the monsoonal wind-driven currents (Figure 9A). The enhanced East Asian monsoon promoted surface currents (Farnsworth et al, 2019;Holbourn et al, 2021;Ting et al, 2021), which strongly shaped the morphology of the proto-continental shelves in the northern (Tian et al, 2015), the northwest (Zhuo (Tian et al, 2015), the Zhongjian basin (Yang et al, 2021) and the study area (Figure 11). The development of these contourite features terminated at 10.5 Ma.…”