--> ABSTRACT: Sequence Stratigraphy of the Upper Cycle V (Late Miocene) succession of the Baram field, Baram Delta, East Malaysia, by A. R. Hadi Abdul; #91021 (2010)

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Sequence Stratigraphy of the Upper Cycle V (Late Miocene) succession of the Baram field, Baram Delta, East Malaysia

ABDUL HADI, A. R.

The Baram Delta is a Tertiary basin located in the northeastern part of Sarawak. The Neogene section comprises a thick succession of coastal to shallow-marine sands and shales, deposited in a wave influenced deltaic environment. A sequence stratigraphic study of the Late Miocene Upper Cycle V succession of the Baram field (a small oilfield in the north-eastern flank of the delta) allows the delineation of several hierarchies of depositional cycles related to sea level fluctuations.

The cored intervals display successions dominated by thick swaley cross-stratified sandstones and other storm-dominated facies interbedded with shelfal mudstones. The vertical facies organization suggests deposition during shoreface progradation related to a relative sea level fall. Parasequence stacking patterns indicate that deposition was controlled by superposed short-, medium- and long-term sea level changes. Well-log analyses reveal three scales of depositional cyclicity; parasequences (~10 to ~30 m thick), parasequence sets (~45 to ~130 m thick) and major cycles (~600 to ~800 m thick). Dip-oriented seismic sections reveal a ramp-type basin floor which lacked a distinct shelf-slope margin.

It is interpreted that the parasequences and parasequence sets represent the ~20K precessionary and ~100K eccentricity Milankovitch cycles respectively. This interpretation places the lower boundary of the Upper Major Cycle (Upper Cycle V) to ~6.3 Ma, which correlates well with a major global eustatic sea level fall. 

AAPG Search and Discovery Article #91021©1997 AAPG Annual Convention, Dallas, Texas.