IMPLICATIONS OF JURASSIC CHERT IDENTIFIED IN THE TOKAT COMPLEX, NORTHERN TURKEY

The Tokat Complex is a strongly deformed tectono-sedimentary mixture o f low-grade metamorphic rocks with abundant recrystallized limestone a nd relatively rare serpentinite and radiolarian chert in blocks of var iable size. Samples from the radiolarian chert blocks, found in highly crushed zones, each of which corresponds to a thrust sheet within an imbricate thrust zone, have yielded a Tithonian fossil assemblage. The y are interpreted as tectonic inclusions emplaced within the Tokat Com plex after its main post-early Permian-pre-Liassic metamorphism, and w ere derived from the rifting and opening of a Neotethyan ocean. The pr esence of Tithonian blocks within low-grade metamorphic rocks of the T okat Complex shows that Tethys ocean was in existence in this region b y latest Jurassic time. We also suggest that the presence of ophioliti c slices imbricated with the Pontide basement, Tokat Complex, explains the swarm of North Anatolian Fault Zone (NAFZ) splays in this region where the NAFZ likely followed a major pre-existing crustal weakness.