In this study, we present new field and chronological data from 2 antique quarries of marmor troadense (Kestanbol quartz-monzonite) in northwestern Turkey. Marmor troadense has been mined and the building stones have been exported all over the Mediterranean region since approximately 2500 years ago. Analysis of 11 samples from the quarried bedrock for cosmogenic Be-10 showed that the landscape is so old that the inheritance obscured the absolute dating of the operation periods. Nonetheless, C-14 analysis of 4 charcoal samples from the sediments covering the ruins of Alexandria Troas indicated that these quarries stopped operating no later than 395 AD. These lines of evidence are in accordance with the results of field mapping. First, we mapped Kestanbol quartz-monzonite in detail and prepared a detailed geoarchaeological map of the quarrying activity in this area. We estimated the excavated amount of rock in 2 quarries to be >750 m(3) and identified 60 columns of granite and other building stones. Our findings suggest a gross budget of approximately 150 million euros for the quarry operations in this region based on present costs. Various operation periods of this large economy, if present, still remain to be uncovered.