Figure 1. Simplified regional geology of NW Turkey and location map of the Korudag Anticlinorium, oil and gas fields, dry wells and seismic lines. Legend: 1) Istranca Massive, 2) Istanbul Paleozoic sediments, 3) Paleotethys remnants, 4) Upper Cretaceous arc volcanics, 5) Neotethys subduction-accretionary complex, 6) Thrace Basin sediments.