Quarry landscape of the month

February 2007: Marmor Troadense in the province of Ezine, Western Turkey.

This month we continue our presentation of ancient granite quarries in Western Turkey.

Known to the Roman as Marmor Troadense , this granitoid rock is found in the Troas on the slopes of Mount Çigri, province of Ezine. It was already in use as a building material during the Archaic-Hellenistic period in the city of Neandria, situated on that mountain, and its use continued into the Hellenistic-Roman Age, in nearby Alexandria Troas (now Dalyan). From there, Marmor Troadense spread all over the Mediterranean, with particularly broad expansion from the second century A.D. on. In fact, columns made of this rock were exported throughout the ancient world. They have been found at Palmyra and at Baalbeck in the east, at Arles and Tarragona in the west, and very large sections were used in Asia Minor, for instance in agoras of Smyrna and Ephesus, and in Italy, in Rome, Ravenna and Aquileia. During the Middle Ages and Renaissance, columns of Marmor Troadense were frequently reused in mosques, churches, and palaces. Some instances of this adaptation to italian monuments are the churches of Bari, Troia, Trani, and Canosa in Apulia, the Broletto in Brescia, Saint Mark's Basilica in Venice, the churches of S.Vitale and S.Prassede in Rome, etc. Today however, in many buildings the columns made of this stone show such great deterioration that their support function is seriously hindered.

According to Cook and Ponti, the quarries of Marmor Troadense, in recent times also called Granito Violetto, were probably imperial property. Some of the ancient quarries are located on the northwest side of Mount Çigri. In one of them, in a place called Yedi Ta s lar (= Seven Stones), near the modern village of Kocali, it is still possible to see seven large, unfinished columns, which may have been abandoned in the late imperial period. The columns were made from huge single blocks detached from the mount with the use of wedges and then cut with an axe and chisel. They average 11-11,5 meters in length, 1,50-1,70 meters in diameter at their top. Some of the bases were recently broken in an attempt to turn them into grinding stones for a mill. Two more columns lie not far away, as well as some square-cut blocks. Beyond the quarries, which are undoubtedly Roman, owing to the characteristic axe-carving marks, a few traces of modern extraction can be seen. In fact, small blocks of Granito Violetto are presently used for paving the streets in the nearby towns of Ezine and Ayvacik, as they were used in the past in Istanbul. The region of Çigri Dagi is very difficult to travel through because of the lack of roads. Preliminary examination of geological maps of the Troas was not very helpful in locating the limits of the granite formation, nor did it offer any indication of the age of the rock. North of the granite mass, however, there are phyllites and micaschists, while to the south the mass is in contact with lava consisting of trachyte and trachytic andesite.

The lithotype that best represents the quarry of Yedi Taslar is a rock of grey-violet colour and an medium grain size. The structural characteristic most evident to the naked eye is the presence of feldspar of a violet hue and of considerable dimension – up to 3 cm in length – which gives the stone the appearance of having “eyes”. A textural peculiarity results from the not uncommon black “Schlieren” distributed in random throughout the rock. Less frequent are yellowish aplitic veins. The modal analysis clearly indicated that this is a rock type which fits into the quartz-monzonite group. Its structure is granular porphyritic. Feldspar and Plagioclase are the most plentiful minerals accounting in equal amounts (33%). Quatz (8-10%) fills the interstices. Of the coloured components, green hornblende slightly prevails over biotite (20% in total). Common accessory minerals are iron oxides and sulphides, titanite, apatite and rare epidote.

Text and photos by Lorenzo Lazzarini.

Further reading

Birkle P., Satir M., 1995, Geological aspects of the use of Kestanbol quartz-monzonite intrusion

(Troas/Turkey) as constructing material in archaeological sites around the Mediterranean sea.

Studia Troica , IV, 143-155.

Lazzarini L., 1987, I graniti dei monumenti italiani e i loro problemi di deterioramento. Bollettino

d'Arte, Supplemento al n.41, vol.II, 157-172.

Ponti G., Marmor Troadense - granite quarries in the troad. A preliminary survey, 1995. STUDIA

TROICA, 5, 291-320.

Location of one of the quarries of Marmor Troadense, the Yedi Taslar or "Seven Stones" quarry. Click here for bigger picture from Google Earth, or click here to travel the Google Earth way. If you are not familiar with Google Earth, please visit http://earth.google.com to get the necessary information.

The Yedi Taslar or "Seven Stones" quarry, in which large, unfinished columns are located.

Macroscopic aspect of Marmor Troadense.

Microscopic fabric of Marmor Troadense, showing twinned crystals of plagioclase (right), Kfeldspar (upper left), horneblend and quartz (center).

Map of distribution of Marmor Troadense artifacts, each number corresponds to an ancient locality (for ref. see the relevant paper by L. LAZZARINI in forthcoming ASMOSIA VII proceedings)