D. Avigad et al., Ductile and brittle shortening, extension-parallel folds and maintenance of crustal thickness in the central Aegean (Cyclades, Greece), TECTONICS, 20(2), 2001, pp. 277-287
In contrast to previous studies that concentrated on the two-dimensional cr
ustal strain in the central Aegean region brittle stretching and low-angle
detachments was accompanied and/or alternated with horizontal shortening pe
rpendicular to the stretching direction since at least the early Miocene. R
oughly EW directed ductile shortening produced large-scale overturned and u
pright folds having axes parallel or slightly oblique to the stretching lin
eation. Upright folding and arching of low-angle normal faults occurred abo
ve the brittle-ductile transition and brittle E-W compression culminated wi
th vertical axis block rotations, strike-slip faults and minor thrusts. Sin
ce at least the early Miocene, the structure of the Cycladic massif evolved
through alternating and/or coeval increments of horizontal shortening and
vertical thinning associated with an approximately constant NNE-SSW stretch
ing. Exact magnitudes of the vertical and horizontal deformational componen
ts are difficult to assess. Nevertheless, we note that extensional tectonic
s that affected the Cyclades during the last 15-20 m.y. have produced no ne
t crustal thinning. We suggest that crustal thickness was maintained by ext
ension-parallel folds, which represent true contractional structures, and t
hat crust was fed into the extended region from its margins.