Neogene Crustal Extension in Aegean, Revisited

S. C. Stiros

The Neogene evolution of the Aegean and adjacent areas has been described as the result of homogeneous, subduction-associated lithosphere stretching by a factor near two, interrupted or not by short regional compressional intervals. However, reconsideration of some of the existing data (structural, volcanological, heat flow) and new or unpublished information from Greece, southern Bulgaria, and Yugoslavia concerning different scales, structural (tectonics of lignite and other basins), morphotectonic (describing bulges, differential coastal movements, rotations of blocks around vertical axes, etc), some seismic lines offshore, and aeromagnetic data suggest the following. (1) The patterns of Neogene volcanism, heat flow, and vertical motions are inconsistent with the idea o homogeneous stretching. (2) There is no evidence of features that should have accommodated the postulated level of regional extension. (3) The evolution of most Neogene basins, compressional features, and bulges in normal faulting environments most likely does not reflect cycles of regional extension-compression but of transtension-transpression associated with Mesozoic and still active shear zones and deeper processes. These data suggest that for the Aegean the uniform extension model is unsatisfactory in both large and local scale; small amounts of probably secondary extension are likely; and processes other than subduction must be anticipated.

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