Age of the Sphinx
The profile of the Sphinx with similar light
on the cheek: the fundamental
resemblance to Khafres statue is clear.
Heavy and frequent rain he judged not to have fallen well before Egypt's dynastic history began in about 3100 BC. Dr. Schoch pointed to certain mud-brick tombs at Saqqara of the Archaic Period (Dyns I and II) that show no signs of erosion by exposure to rains to point up his conclusion that his rain-weathered Sphinx must be older than the beginnings of Egyptian
Dr Schoch noted that there is some evidence for a period of heavier (if sporadic) rains between about 4000 BC and 3000 BC and that, as we have seen, even in Old Kingdom times until about 2300 BC, conditions were less arid in Egypt than they have been since; but he did not want to assign the better part of his rainwater weathering of the Sphinx to these periods since he judged the degree of erosion to demand a long period of heavy and regular rainfall since the carving of the monument. In a note at the end of his KMT article, he acknowledged the observation that burial in wet sand might have contributed to the erosion if it could be shown to have occurred, but again he clearly thought this mechanism inadequate to explain the very great erosion of the body.
In wishing to push back the date of the carving (and the commencement of erosion) into the wetter period before 5000 BC, Dr Schoch was fortified by the findings of the seismic research conducted at the Sphinx at the same time as his own work. Data collected by detecting the reflected and refracted effects of sledge-hammering a steel plate on the floor of the Sphinx enclosure suggested to him and his seismographer colleagues that there is deep subsurface dissolution of the limestone bedrock beneath the floor of the enclosure, indicative again of long exposure at some time in the past (since cutting) to heavy rainfall.
Son et lumiere at Giza, with laser projection of sphinxes
that once stood in these positions in front of Khafres
valley temple beside the temple of the Great Sphinx.
Dr Schoch further noted that the limestone core blocks of the Sphinx temple and of the valley temple of Khafre were cut from rock removed from the Sphinx enclosure, and that they show a similar pattern of erosion to the body of the Sphinx and the Sphinx enclosure walls. He went so far as to think that the granite casing applied to these core blocks was cut to fit their highly eroded surfaces. In this way, he arrived at a two-stage theory of construction history for these temples: in his view they were originally made, like the Sphinx, thousands of years before Khafre came on site to find them badly eroded and ready for restoration with new granite facings. (Dr Schoch acknowledged that the head of the Sphinx is certainly an Old Kingdom carving, if not of Khafre himself, but he thought Khafre or another Dyn. IV king might have ordered an original lion's head to be recarved in his own image.)
Egyptologists were bound to be tickled at the thought that the ancient Egyptians might have gone to the trouble of laboriously carving hard granite to fit the randomly eroded surfaces of much softer limestone blocks that could easily have been dressed to take the granite facings, even assuming for the sake of argument that they had found the temples already old and in need of repair. As with the temples, so with the Sphinx. Dr Schoch suggested that Khafre or some other Old Kingdom ruler had found a monument badly in need of restoration and proceeded to clad much of it in repair blocks as long ago as 2500 BC. But in fact, the Egyptologists had concluded that parts at least of the Sphinx, for instance its right hind paw and maybe the slope of its back behind the head- dress, were from the start built on to the core of living rock. Dr Zahi Hawass has been prepared to think that the original construction work went further than that, but Dr Lehner has concluded that most of the add-on work at the Sphinx belongs to New Kingdom and later times.
The seismic work around the Sphinx gave Dr Schoch an additional line of reasoning in discussion of a possible date for the original carving of the monument. Seismography suggested that subsurface erosion goes less deep behind the rump of the Sphinx to the west than it does on the northern, southern and eastern sides. This in turn suggested either that the rump of the Sphinx was not carved as early as the rest or that it was originally only just freed from the rock without a floor surface behind it, which was subsequently cut out by Khafre or another in Old Kingdom times.
As with the pyramids, it might give a slightly too early date for the work, since mortar may contain organic material (wood, in fact) that was already a century or two old when it was used to make the mortar. But in any case, such a dating would only apply to the fitting (or refitting) of the repair blocks. Much of that work almost certainly occurred in New Kingdom and later times; and, if some of it was done in Dyn. IV, its dating would still not establish the date of
the original carving of the monument.