No abstract

The Neogene-Quaternary Central Anatolian Volcanic Province (CAVP) is elongated in a north-east-south-west direction within pre-Oligocene basement in central Turkey. This study investigates the field evidence relating to the development of the CAVP.Two dominant fault systems are recognized in the area. The first consists of the major conjugate faults in the region, namely, the right-lateral Tuzgolu and left-lateral EcemiS fault zones, and other faults parallel to these zones. The faults in this system are mostly active and cut the CAVP almost at right angles. The second fault system trends in a N60°-700E direction, parallel to the volcanic axis and to the alignment of the major eruption centres. These faults, which are of the normal type, are mostly buried beneath the products of recent volcanic eruptions.The behaviour of the first system is explained with reference to the present north-south convergence that occurs in the eastern Mediterranean region. These faults, which might be reactivated palaeotectonic structures, are a response to a present day compressive stress direction of about NIOOW. The second fault system, in contrast, is the product of a short-term tensional period that occurred during the Mid-Late Miocene to Pliocene. This extension is almost at right angles to the convergence. As a result, the pre-Oligocene basement in the area was fractured in a N60°-700E direction and these fractures served as pathways for the extrusive rocks that formed the CAVP. The major eruption centres of the CAVP (i.e. the Hasandag, KeGiboyduran and Melendiz stratovolcanoes) are located at the intersection of the major faults of these two fault systems.

No abstract

No abstract

The Galatean volcanic province (GVP), located in northwestern Anatolia, is an ENE-WSW-oriented belt. The province as a whole corresponds to a depression filled with volcanic and sedimentary rocks. The northern margin of the GVP is truncated by the North Anatolian fault, whereas it is surrounded by a continental sedimentary pile interfingering with volcanics on the south. Field and aerial photographic studies reveal that the GVP consists of several volcanic complexes scattered throughout the province. Nine of these complexes are recognized, each covering an area of hundreds of km 2 of circular or ellipsoidal form, with moderately to wellpreserved morphology. They include calderas, stratovolcanoes characterized by central vent(s), and radial flows of both lava and volcaniclastics. Several continental basins are disposed between the major volcanic complexes. These basins are isolated from one another or are partly connected and may differ in age and lithology. Available radiometric and paleontologic age determinations suggest that almost all volcanic complexes as well as the sedimentary basins started to develop during early to middle Miocene and continued to late Miocene time. The faults detected in the southern part of the province are Pliocene and older, and reflect normal faulting.