Site Conservation 2015

As in 2013 and 2014, the primary focus of our architectural conservation activities this year was the Early Phrygian Gate, which is the best-preserved citadel gate in Iron Age Asia Minor (figs. 1-3). A significant bulge developed in the masonry following a major earthquake in 1999, and we formulated a five-year strategic plan for conserving the stones and stabilizing the building. With generous support provided by the J. M. Kaplan Fund, the Selz Foundation, and the Merops Foundation, we had the resources to acquire and erect a new scaffolding system for the gate, supplied by Tamer Kalıp ve İskele Sistemleri in Ankara. Above it we placed an aluminium gantry crane capable of lifting 1500 kilos, designed by our engineer David Biggs, of Biggs Consulting Engineering PLLC, and produced by the German firm of Schilling Gerätebau (figs. 1, 2). This gave us the capability of removing the damaged or displaced stones from the Gate and moving them to the scaffolding where they were conserved (fig. 3).

All of the masonry surrounding the damaged area was first consolidated by inserting chinking stones in the open joints and filling voids with lime mortar and grout. Fractured blocks at the northeast corner of the Gate were then consolidated in place with micro-injections and the insertion of stainless-steel bars.

In order to remove the damaged stones, we first had to lift the concrete cap that had been set in place above the Gate’s South Court in 1988. Such caps were common in architectural conservation several decades ago, but they routinely crack in the course of each winter and summer, so that moisture enters the masonry and weakens its stability. Once the cap had been lifted, we used the gantry crane to remove the facing stones in the area of the bulge. Sixteen such blocks were lifted, all of which have been documented and conserved with epoxy and the insertion of stainless-steel bars. The extent of the earthquake damage was immediately apparent once we began to remove the stones, which highlighted the urgency of our project.

The conservation of the Early Phrygian Terrace Building, an eight room industrial complex with a length of over 100 m, has continued since 2009, with our primary attention devoted to the masonry foundations that were badly damaged in a major conflagration of ca. 800 B.C. Our focus in 2015 was the conservation of the wall dividing the fifth and sixth rooms of the complex (figs. 4, 5), which included epoxy repair of fractured blocks, rebuilding the walls with the newly conserved blocks, and the insertion of stainless-steel bars to reinforce the conserved stones. Very little new stone replacement was needed for the reconstruction, and we inserted chinking stones into the open joints of the reconstructed masonry portion, thereby following Early Phrygian building practice.

The strategies used for all architectural conservation at Gordion were first developed by Frank Matero of Penn’s Historic Preservation program. Elisa del Bono and Angelo Lanza served as field directors, and were assisted by Giuseppe Bomba and Renzo Durante, while the engineering components of the project were overseen by David Biggs and Semih Gönen. A critically important role was played by archaeobotanist Naomi Miller, who helped develop the “soft capping” technique of using shallow-rooted plants as the cover of conserved walls.

Pebble Mosaic

One of the treasures of the Gordion Museum is the multi-colored pebble mosaic from one of the elite Early Phrygian buildings, Megaron 2 (figs. 6-8). Dating to the second half of the ninth century B.C., it ranks as the oldest colored stone mosaic ever discovered, which is why we have devoted several seasons to its conservation. One of the panels will be traveling to the Penn Museum for the Gordion exhibit that opens in February, and that received the majority of our conservators’ attention this summer. The work was directed by Cricket Harbeck and Jessica Johnson, and assisted by William Shelley, Eda Kaygusuz, and Pshtiwan Ahmed Ibrahim, our conservation Intern from the Iraqi Institute for the Conservation of Antiquities and Heritage in Erbil, Iraq.

In 2013 and 2014 the panel had been safely removed from the exhibit at the Gordion Museum, flipped upside down, and the heavy concrete on the reverse (applied in the 1960s) was trimmed down. When the original concrete was set in place, some of it had spread onto the surface, thereby obscuring the original design. At the beginning of the 2015 season the panel was flipped back and the concrete overgrout was removed from the surface of the original pebbles while ensuring that they were carefully anchored in place.

New pebbles of white, red, and black were collected in the Porsuk valley from the same sources that had supplied the original pebbles, which are located only a few kilometers from Gordion.  These were used to fill in the missing sections of the mosaic and render the design more intelligible to viewers, and you can see the successful results of this treatment in fig. 7.  The replacement stones were painted with shellac which will glow orange in ultraviolet light, thereby allowing restored areas to be easily distinguished from the original. A packing support structure was constructed by Richard Liebhart to ensure that the heavy mosaic panel can be properly protected and supported during crating and shipping to the Penn Museum.