The drilling strategy outlined for Leg 194 utilizes the stratigraphic relationship between a lower to middle Miocene second-order highstand carbonate platform complex and an upper Miocene second order lowstand platform complex to establish the magnitude of the middle Miocene N12-N14 sea level fall. An important characteristic of this platform relationship is that the proposed sites are essentially located along a single strike line without intervening structural elements. Thus, subsidence of the platform will have affected all sites equally, enabling determination of the true amplitude of the sea-level fall that caused a shift in the locus of carbonate platform deposition.
The carbonate platforms and adjacent slopes of the Marion Plateau also preserve a superb record of
third-order sea-level variations within a mixed carbonate-siliciclastic depositional environment.
High-resolution seismic data collected for the Leg 194 site surveys provide quasi-three-dimensional
images of Oligocene-Pliocene depositional geometries. The correlation of these seismic images with
drill core and logging data will provide a synoptic view of depositional processes in a mixed
carbonate-siliciclastic carbonate platform setting.
Introduction | Table of Contents