Detailed Kinematics of the Mediterranean: 1--Framework for Exploration Strategy

Marc L. Helman, J. F. Dewey

The motion of Africa relative to Europe is most commonly presented as a series of time-lapse frames at 10-15 m.y. intervals. The finite-difference rotations between relative continental positions in such reconstructions describe, to a first approximation, the path of relative motion for the interval in question. While such models are useful in providing a broad background, they fall short of providing the detailed tectonic and kinematic setting needed for high-resolution stratigraphic and structural basin analysis. The data now exist to make reconstructions that are resolvable at 2 to 3 m.y. intervals, the average length of a chron in the Tertiary.

The motion of Africa relative to Europe is the finite difference between the independent separations of Africa and Europe from North America, as deduced from the pattern of magnetic anomalies and fracture zones in the Atlantic. To make our reconstructions we have remapped all Late Cretaceous and Tertiary magnetic anomalies in the North and Central Atlantic. Using this data we have remodeled both the opening history of the Atlantic, using fracture zone trends as a major constraint, and the pattern of Africa's motion for this interval. The intimate relationship of this motion to changes in the sea-floor-spreading pattern in the Atlantic is evident.

The pattern of Africa's motion is simpler and smoother than previously thought. Previous models were characterized by sudden changes in direction. These are a consequence of a lack of, or misinterpretation of, data and the errors produced in computing the Atlantic motion(s). As a result there has been a great deal of uncertainty concerning the Africa/Europe motion path. The uncertainty is the product of combining errors from the Atlantic motions and takes the form of unusual and unexplained direction changes.

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