Analysing
gypsum mortar connecting that slab to the bedrock allowed them to determine its age, dating it to 335-345 AD.
"The Use of
Gypsum Mortar in Historic Buildings," Structural Repair and Maintenance of Historic Buildings, II, ed C.A.
The ancient Egyptian workers had sealed off the chamber with a gypsum mortar that protected the wood from water, oxygen and bacteria--the principal elements of decay.
The gypsum mortar used by the ancient Egyptians to seal both chambers is a crack-filling agent that expands when wet, says Rogers.
Evidence of monumental ashlar walls has also been revealed in a series of
gypsum mortar setting beds for large stone blocks.
Extensive evidence for monumental ashlar walls was revealed in a series of
gypsum mortar setting beds for large stone blocks, most likely robbed out during the Early Byzantine period (6th-7th century AD) for construction of the Christian basilicas across the way at Agios Georgios, the Antiquities Department said.