Petra lies in southern Jordan near the eastern rim of the Jordan Valley rift. Near the edge of the rift, the Upper Cretaceous limestone of the high plateau of the Sharah mountains gives way to silvers of Paleozoic fluvial sandstones dated to the Cambrian and Ordovician periods. The hard nature of the sandstone led to the formation of a rugged terrain in which steep slopes and narrow valleys could form, providing a perfect setting for a city such as Petra. Despite the general image of Petra being carved into stone facades, a considerable portion of the ancient Nabatean city was actually built with locally derived sandstone. While rock-cut tombs are today the dominant features of Petra, freestanding colonnades would have stood out in this vast landscape 2,000 years ago.
The upper Honeycomb sandstone consists of white and mauve-red, coarse to medium grained, hard, massive sandstone. Old quarries are present in this part, which was used by Nabateans and Romans as a building stone. The high, steep, natural slopes and very steep man made cut faces indicate that the "honeycomb sandstone" posesses a considerable strength component beyond that of normal dense homogenous sandstone. Over 12 quarry sites have been identified in the Petra area. The most notable sites are at Um Saihoun to the northwest of the city and at Wadi Sayagh to the west in the valley draining the basin in which Petra is located. These sites contain steeply cut faces, tool marks and climbing niches or steps from which the ancient masons hung as they cut the stones. These sites appear to have been chosen based on the quality of the stone as well as being distant enough from the city so as to save cliff faces for monumental endeavours, and yet close enough to be practical for transportation.
The quarries were first prepared by cutting the edges of the wall to have a relatively vertical, dressed surface. Step ladders were then carved into the rock all the way upwards and along the corner edges, with two hollowed out holes at the top horizontal plane of the mountain, these were probably climbed. Channels were cut into the platform from the top of the creating slabs or blocks still attached to the bedrock. In order to detach the slabs from the rock, the Rockwell method was implemented whereby wooden wedges would have been hammered into the holes worked out at the base of a block, and upon wetting, the wood would have swollen, thus splitting the stone slab. As an alternative, metallic wedges could have been used and metallic strips would have been placed between the stone and the single wedges, which were then hammered out. Usually several wedges were used in a series of the holes carved along a line, marking the edge of the block to be quarried. Moreover, in order to simplify the cutting process, the Nabateans used a natural joint that existing in the natural rock and hence made it to be the edge of quarried stones.
The intimate relationship between the nature of the city and stone used and the quarries from which it was extracted makes these quarries an integral part of the story of Petra. Until now, this story is poorly presented and the importance of the quarries has been marginalized. While the quarries are protected by default because they are located in the Petra national reserve, it is important to tell this story to reveal another interesting aspect of the history of this magnificent city.
Text: Nizar Abu-Jaber, Ziad Al Saad, Abeer al Zoubi (all at Yarmouk University)
The image of Petra – the façade of a rock-cut tomb carved into the sandstone.
Sandstone quarries are an integral part of the landscape surrounding the city.
Steep and tall quarry faces – typical of the Petra quarries.
Carving marks on the quarry face.
The landscape of Petra.
December 2009 New book: a special volume with papers from the QuarryScapes project soon printed.
November 2008 Final workshop: the third QuarryScapes workshop was held in Aswan 12. - 15. October