Abstract: The aim ofthisstudy is to examine the mineralogical and chemical changes, caused by epithermalsolutionswhich were mineralizingfluids ofTertiary mercury deposit, in trachyandesite wall-rocks. The oldest unit in thestudy area is marble of the Silurian - Lower Carboniferus Bozdağ formation. The Carboniferous - PermianBağrıkurtformation lies comformablyon the Bozdağformation and consists ofgenerallyphyllite, metasandstone,metachert, quartzite, calcschist with limestone lens. The Triassic aged metatrachyandesite cut across these unitsand cover them. In the metatrachyandesite common alteration products such as uralitation, chlorization,sericitation, silicification, saossuritization are observed. The metatrachyandesite shows thatstandart deviationsofAu, Ba, Cu, Hg, Pb, and Sb values are high, and refects that epithermal stage metals enrichment related to  typical primary alteration. The amounts of REEs, especially LREEs of metatrachyandesite are cpiite high.Chondrite- andMORB-nortnalizedpatterns ofREEsshowgradual and regular decreasesfrom LREEs to HREEs.The results ofclusterandfactoranalysesofthe data indicate a hydrothermal alteration tracer.