Philip Bassant¹, Anthony J. Lomando²

(1) now at Chevron Bahrain Ltd, Manama, Bahrain
(2) Chevron Overseas Petroleum Co, San Ramon, CA

ABSTRACT: A Comparison of Two Lower Miocene Carbonate Margins: The Zhujiang Carbonate Platform (Subsurface, South China Sea) and The Pirinç Platform (Outcrop, Southern Turkey)

Miocene carbonate platform complexes have been the subject of extensive exploration efforts in the Far-East (for example, the Gunung Putih carbonate complex - East Java Sea; the Zhujiang and Liuhua Platforms - Pearl River Mouth Basin). However, few outcrop equivalents of these Miocene platforms have been published to-date: this study presents such an outcrop.

The Pirinç outcrop is a carbonate platform-to-basin transition exposed on the northern flank of the Mut Basin (Southern Turkey). The platform was deposited against a relict palaeotopography during a time of relative tectonic quiescence. The Burdigalian interval described here has been interpreted to contain three large relative sea-level cycles with a 100-150m amplitude. These generate a steep-edged platform with prograding slope geometries during highstands, while during lowstands thin carbonate platforms develop in onlap against slump-deposits. Stratigraphic relationships indicate collapse of the platform margin occurs during late highstand to early lowstand, and is coincident with sea-level fall. During transgression an isolated platform complex develops. Production on these platforms shuts-down before the maximum flooding because of limited production potential.

The subsurface Zhujiang Platform (Pearl River Mouth Basin, China) is a Lower Miocene Platform, showing a gradual to steeply sloping prograding margin with major zones of slumping along strike. The resemblance of seismically imaged slumping in PRMB with the Pirinç platform outcrops is striking. Information gained from the outcrop study serves to constrain the stratigraphic processes active in the sub-surface example and hence to better understand the spatial distribution of rock fabrics when evaluating the formation's prospectivity.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado