Numerous isolated carbonate platforms developed in the Central Luconia
Province of offshore Sarawak (during Middle to Late Miocene time). Fault-bounded
highs produced largely by extensional deformation and later overprinted by strike-slip
deformation provided substrates for the platforms and affected their growth histories.
Flooding of these structural highs at ~16.5 Ma initiated carbonate sedimentation nearly
simultaneously across the area. Later, third-order sea-level fluctuations and extrinsic
factors such as differential subsidence, paleowind patterns and siliciclastic influx then
controlled the internal architecture of the platforms. 2-D regional seismic lines, publicdomain
data and published literature were used to analyze growth patterns and demise of
carbonate platforms across the study area.
Five Growth Stages were recognized in the carbonate platforms based on seismic
facies analysis and stratigraphic relationships between reflectors. Platforms from the
southeastern part of Central Luconia are thicker and larger than platforms located toward
the central and northwestern areas, which reflect greater long-term tectonic subsidence
to the southeast. Additionally, northwestward prograding siliciclastic sediments from mainland Borneo caused additional flexural subsidence in the eastern part of the area and
environmental deterioration for platforms located beyond the range of active siliciclastic
sedimentation. Both of these factors reduced the growth potential of platforms and thus
subdued carbonate development.
Platform termination was regionally diachronous and was produced in two steps.
The first platforms drowned (~12.5-9.7 Ma) were in the eastern parts of the study area
which were affected by incoming siliciclastic sediments and high local subsidence.
Platforms drowned later (~6.3-5.5 Ma) were caused by a rapid sea-level rise combined
with an intense local subsidence. Carbonate accumulation rates were measured between
intraplatform markers, resulting in a trend that indicates a decrease in sedimentation rate
with the square root of time.
Comparisons between Central Luconia carbonates and age-equivalent carbonate
platforms elsewhere in East Natuna Basin showed that Central Luconia carbonate
platforms were drowned earlier (latest late Miocene time) than East Natuna carbonate
platforms (Early Pliocene time).
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-1795 |
| Date | 02 June 2009 |
| Creators | Olave Hoces, Sergio |
| Contributors | Dorobek, Steven L. |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | electronic, application/pdf, born digital |
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