Messinian Paleomorphological and Sedimentological Characteristics from a 3-D Survey in Tarraco Concession Area (Spanish Mediterranean Sea)

Gerard M. Stampfli, Christian F. W. Hocker

Characteristics of the Messinian unconformity have been extracted with great detail from a 3-D seismic survey shot in the Tarraco concession area, offshore the Ebro delta. Paleomorphological features in combination with well data confirm that, during the Messinian, sea level dropped rapidly and substantially the magnitude of which is estimated as being at least 2,000 m. The sea level drop resulted in a marked relief cut into the sub-Messinian shelf-and-slope sequence under subaerial conditions. In thalweg positions of paleovalleys, a residual deposit of cemented conglomerates has been observed. Outstanding high reflection amplitudes are associated with these sediments. The distribution pattern of the amplitude anomaly clearly shows fluvial patterns. The final return to no mal global sea level, as well as sea level fluctuations during the Messinian, must have been very rapid, as indicated by the apparent lack of intermediate sedimentation between Messinian deposits and overlying deep marine strata.

AAPG Search and Discovery Article #91032©1988 Mediterranean Basins Conference and Exhibition, Nice, France, 25-28 September 1988.