After further study and identification of this area as a quarry, it appears that this is one of a series of cuts into the bedrock associated with quarry machinery. This one, specifically, may have accommodated one of the posts to which cranes’ tie-rods were tied

Possible garbage pit because of the amount of material within the layer (SU132). If this is not a garbage pit, it may be some form of receptacle for a vessel for either mortuary or domestic purposes.