The Tokat Complex is a strongly deformed tectono-sedimentary
mixture of low-grade metamorphic rocks with abundant recrystallized
limestone and relatively rare serpentinite and radiolarian chert in
blocks of variable 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. They are interpreted as tectonic inclusions
emplaced within the Tokat Complex after its main post-early
Permian–pre-Liassic metamorphism, and were derived from the
rifting and opening of a Neotethyan ocean. The presence of Tithonian
blocks within low-grade metamorphic rocks of the Tokat Complex shows
that Tethys ocean was in existence in this region by latest Jurassic
time. We also suggest that the presence of ophiolitic 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.