Philip Bassant1, Frans Van Buchem2, André Strasser3
(1) now at Chevron Bahrain Ltd, Manama, Bahrain
(2) IFP, Paris, France
(3) Institut de Géologie, Université de Fribourg, CH-1700 Fribourg, Switzerland
ABSTRACT: Impact Of Basin Topography On Depositional Systems During A Time Of High-amplitude Relative Sea-level Fluctuations: The Early Miocene (Burdigalian) Of the Mut Basin (Southern Turkey)
Antecedent basin topography is a key controlling factor of stratal architecture and the evolution of depositional systems in the shallow marine environment. This study uses the Lower Miocene (Burdigalian) mixed carbonate-siliciclastic shallow-marine systems of the Mut Basin (Southern Turkey) as an example to illustrate the relationship between basin topography and the geometries of sedimentary bodies.
During the Lower Miocene a rapid marine transgression floods large areas of Southern Turkey. Marine waters invade a relict horst-and-graben topography in the Mut Basin, and a number of different depositional systems develop across the basin largely as a result of the structural configuration. Three Burdigalian large-scale sequences have been identified across the basin, and these have been interpreted as resulting from relative sea-level cycles with amplitudes of 100-150m and mean cycle periods of less than 570ka. Medium and small-scale sequences have also been observed, defining a sequence hierarchy.
In the south-east corner (Silifke) of the basin a graben structure forms a marine strait linking the Mut Basin to the Tethys. During sea-level lowstands strong tidal currents develop in this passage, and a thick body (80m) of cross-bedded bioclastic grain-rudstones is deposited. During sea-level transgressions and highstands fringing carbonate platforms develop against the graben walls in areas where the slope is sufficiently shallow. In the north-east corner of the basin (Mut) an isolated platform complex develops across a 15km-wide shelf during sea-level lowstand and early transgression. During late transgressive and highstand times a fringing carbonate platform with a steep prograding slope is established.
AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado