Science Story

02 December 2008 22:45 BST

Secrets of an obelisk quarry

Archaeologists claim to have found a canal that was used to transport stone monuments from quarries to their permanent locations in Egypt.

An international team found the canal at the Aswan obelisk quarry and say it could once have connected to the river Nile.

"Transporting huge granite monoliths by boat to the Nile during the annual flood would appear to be easier than having to transport these blocks overland from the quarry to the Nile," said Dr Richard Parizek, professor of geology and geo-environmental engineering at Penn state university.

The 8ft-deep canal was first uncovered in 2002 when excavations were made to the quarry, located on the east bank of the Nile in the centre of Aswan City, to prepare it for tourists.

Since then researchers have used a number of methods to track the route of the canal to see if it connected with the Nile.

Excavation of the supposed route was not possible as a cemetery and the recently-completed tourist amenities lie in the way.

Instead the archaeologists used both soil temperature readings and shallow seismic reflection to outline the canal.

Temperature was measured by drilling holes into the ground; how hot the soil is could indicate the canal route as sediment-filled areas would respond to groundwater circulation and show temperature differences.

"The temperature readings, taken in spring and winter, did establish that the canal continued another 495ft past the aborted excavations," said Dr Parizek. "We did not go any further because we were at the boundary of the antiquities site and would have entered the cemetery."

Seismic reflection and refraction surveys confirm that the canal continued and suggest that it deepened as it reached the Nile.

The results were presented at the second international conference on geology of the Tethyr at Cairo University.