Abstract: Chlorite minerals are commonly found in the units of Karakaya Complex that reflect different tectonicsettings and evolution. In this study, the availability of chlorites has been investigated as a parameteron the interpretation of the diagenetic-metamorphic evolution and revealing the geological history fromthe different units of the complex. Primary and secondary chlorite minerals in the low-very low-grademetamorphic rocks have interference colors of blue and brown and an optical isotropic appearance withvery low birefringence. Chlorites are seen in the matrix, pores and/or pods of rocks as platy/flaky andpartly radial forms. According to X-ray diffraction (XRD) data; Mg-Fe chlorites with entirely IIb polytype(trioctahedral) exhibit various compositions such as brunsvigite-diabantite-chamosite. Furthermore,chlorite minerals correspond to felsic and metabasic origins in terms of the rocks from which they derived.Similarly, geochemical data such as the major element contents and structural formulas of chlorites alsosuggest a different composition and origin. Trace and especially rare earth element (REE) concentrationsof chlorite minerals increase from schist towards slate depending on their degree of metamorphism andnature of the host rocks. This relationship can be significantly noticed in the chondrite-normalized REEand trace element patterns. These changes show that are they are related to the structures, formationmechanisms and tectonic environments of the chlorite minerals. In other words, they suggest that chloritesmay play a key role in distinguishing of units with different geological history.