September 2006: The Gabal Balaq limestone quarries near Marib, Yemen
One of the greatest of the ancient South Arabian kingdoms was Saba (Biblical ‘Sheba'), which dominated the southern Red Sea region during much of its existence from 1000 BC to 200 AD. The Sabaean capital was at modern-day Marib in northeastern Yemen. Here there are the impressive remains of a large walled city, many temples and an especially famous flood-control dam, which supplied the irrigation water necessary to sustain agriculture in the desert around Marib. All of these structures are built largely with limestone ashlars from the Gabal Balaq mountain range several kilometers to the west. ‘Balaq' is an ancient Sabaean word that is still used in Yemen and translates as “hard limestone”. Scattered across the east flank of Gabal Balaq are hundreds of excavations along the exposed edges of the inclined limestone layers, and these are connected by a dense network of quarry roads. Although the existence of these quarries has long been known, they have not been previously studied and until now the Sabaean method of quarrying was a mystery. The limestone was extracted as roughly rectangular blocks, and some of these would have weighed many tons. Broad, shallow straight trenches, marking the back and two sides of a block, were first chiseled along the top of a limestone layer to remove the weathered exterior. The open face of the outcrop edge formed the front of the block and its bottom was delimited by the underlying bedding plane. Next, a narrow groove was cut down the center of each shallow trench, and then a pointed chisel was hammered at closely spaced intervals down the length of the groove, leaving a line of small pits, until the limestone broke along it. This is the well-known pointillé technique, which is thought to have originated in the Aegean region in the early 6 th century BC, and is still in use today. The tools employed were probably made from iron, but bronze is also possible, especially during the early Sabaean period. And finally, once the back and sides were separated from the bedrock along the lines of pointillé pits, levers would have been used to separate the block from the underlying bedding plane and ease it away from the limestone outcrop. The blocks were then presumably taken off the mountain on sledges dragged along the quarry roads.