Geomorphology and Karstification of the Southern Field High Carbonates in Central Luconia Province

Abstract

The development of the Central Luconia carbonates in offshore Sarawak has been governed by the orientation of the Luconia Platform, syn-depositional features generated by the rifting and oceanographic parameters, such as sea level fluctuations, hydrodynamic, climate changes, salinity, and oxygen levels. The studied carbonate platform is developed over a southern field high of Central Luconia Province. The prevalent high frequency sea level fluctuations during the Miocene (Burdigalian to Serravallian stages) developed an extensive array of karst by rapid sub-aerial exposure and re-submergence of the carbonate platforms. Multi-attribute was applied to the 3D seismic volume of one of the selected carbonate platforms in Central Luconia Province to recognise karstic feature developed within the platforms. Though it is explicit that karstification occurred mainly along fractures and faults, the karst distribution in the Central Luconia carbonates remains to be an enigma due to their heterogeneous nature, which in turn provides a challenge in drilling and exploration. The studied platform exhibits patchy growth distribution during the Burdigalian stage. This growth is deemed as the initial stage of carbonate growth followed by a combination of build-out and backstepping for the second growth stage. A major karstification stage is highlighted on the second stage build-up, which correlates with a major sea level drop and the distinctive collapsed-paleocave topography. Drowning is evident on the final stage of the platform that can be correlated to the final surge of sea level rise in the Serravallian.

Seismic stratigraphy and sedimentology of a Miocene carbonate platform in Luconia, South China Sea

“…Located in the South China Sea, covering an area of ~45,000 km 2 along the northern shore of Borneo, Central Luconia encloses >200 carbonate buildups (Figure 1), of which, less than 100 have been explored and proved to be of economic significance (Koša, 2015). In the past, mostly regional investigations focused on the sedimentation history (Ali & Abolins, 1999; Epting, 1980), controls of sea‐level fluctuations (Bracco‐Gartner, Schlager, & Adams, 2004; Epting, 1980; Vahrenkamp, 1996, 1998) and tectonics of the Luconia Province (Menier, Pierson, Chalabi, Ting, & Pubellier, 2014; Ting, Chung, & Al Jaaidi, 2010; Ting, Pierson, Al‐Jaaidi, & Hague, 2012; Wei Kiat, Menier, Jamaludin, & Ghosh, 2016; Zampetti, Schlager, van Konijnenburg, & Everts, 2004) with the exception of a few studies focusing on isolated buildups (Janjuhah, Salim, & Ghosh, 2017; Kosters, Hague, Hofmann, & Hughes, 2008; Saw et al, 2019;Warrlich et al, 2010). To date, the studied platforms that belong to the same geological period have been associated with diverse palaeogeographic and structural settings (Ali & Abolins, 1999; Doust, 1981; Ho, 1978; Zampetti et al, 2010), thus emphasizing the necessity for a comprehensive understanding of the evolution of individual platforms.…”