JOURNAL OF GEOLOGY, vol.101, no.1, pp.51-84, 1993 (SCI-Expanded)
Five maps showing spatio-temporal evolution of magmatism along the Tethysides for the following time intervals: Late Carboniferous and Permian (320-248 Ma), Triassic and Early Jurassic (247-188 Ma), Middle Jurassic-Early Late Cretaceous (187-98 Ma), early Late Cretaceous-early Cainozoic (97-25 Ma), and late Cainozoic (24-0 Ma) reveal that convergent plate margin (subduction and collision) magmatism is a reliable guide for mapping suture zones. Where large (approximately 1000 km), temporally persistent (>50 Ma) gaps exist in convergent margin magmatism, they indicate either the absence of a suture or later disruption, mainly by strike-slip faulting. At times of dominant subduction (late Paleozoic and Late Cretaceous-early Cainozoic), convergent magmatism was generally confined to continuous but narrow (approximately 200 km) strips that did not cross sutures, whereas at times of dominant collision and intra-continental convergence (middle Jurassic-Early Cretaceous, late Cainozoic), its distribution was patchy, occurring in wide lumps that crossed sutures. Convergent plate margin magmatism increased in volume from west to east along the Tethysides at all five time intervals. From the late Paleozoic to the present it also migrated southward in discrete episodes and in a leap-frog fashion, following the accretion of new Tethyside blocks to Eurasia. Even the smallest of these blocks have fossil magmatic arcs all around them. Magmatism associated with rifting was much less common along the Tethysides, similar to that along the presently active rift belts and along the margins of the Atlantic ocean. Most of this sporadic distribution is probably an original feature. Ophiolites are more common along the strike of sutures. Magmatic rocks along the Tethysides record a continuous tectonic evolution and provide critical guides to the study of the evolution of the Tethyside orogenic collage, including the detection of large, approximately orogen-parallel, strike-slip fault-systems.