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In the present issue of KMT, [Professor] James A. Harrell takes "another look at the geological evidence" bearing on the age of the Sphinx. Specifically, Harrell takes issue with my conclusion that the geological evidence can be interpreted to mean that the structure we now know as the Great Sphinx was built in stages (originally it may not have been a sphinx) and that the initial carving of the core body of the Sphinx (that is, the present Sphinx, exclusive of the current face and headdress, paws, and rump) may have taken place during the period of approximately 7000 to 5000 B.C.
Harrell argues that the data I have interpreted as evidence for an older Sphinx (that is, older than the traditional attribution of ca. 2500 B.C.) can be re-interpreted to fit the Great Sphinx into a time period that is "more consistent with the archaeological orthodoxy." After reading Harrell's paper, I remain convinced that the simplest explanation for the data at hand is that the Great Sphinx has its origins earlier than previously suspected. In this note I briefly outline the main reasons for maintaining my hypothesis of an older Sphinx.
The crux of Dr. Harrell's argument is that the weathering features on the body of the Sphinx and in the Sphinx enclosure, which I have interpreted to be the result of precipitation-induced weathering (rainfall and surface runoff), can alternatively be interpreted as the result of the Sphinx enclosure being filled with wet sand. I find the "wet-sand theory" inadequate to explain the data at hand. Indeed, I regard it as an ad hoc hypothesis that is being promulgated simply as a last-ditch effort to save the traditional dating of the Great Sphinx.
My primary reasons for rejecting the wet-sand theory are as follows:
(1) I am not convinced that the Sphinx enclosure was ever actually filled with wet sand. The idea of wet sand filling the Sphinx enclosure appears to have originated from the observation of Gauri et al. that, when they removed recent sand that had piled up in the Sphinx enclosure, it was "completely soaked with water a few inches below the surface." Gauri et al. hypothesized that the source of the water was the atmosphere, but they never definitively demonstrated this to be the case. Indeed, they never conclusively demonstrated that, just because they found some wet sand in the Sphinx enclosure in modem times, the enclosure would have been filled with wet sand in ancient times from ca. 2500 B.C. to 1400 B.C., when the earliest repairs to the Sphinx (covering and repairing of the erosional features in question) were made.
(2) If the Sphinx enclosure had been filled with wet sand, then Old Kingdom rock-cut tombs and other rock-cut structures south of the Sphinx, cut from the same strata and located at approximately the same elevation as the Sphinx, should also have become filled with wet sand. Furthermore, the wet sand filling these tombs should have weathered the rock surfaces in the same manner as in the Sphinx enclosure. Unfortunately for Harrell's argument, this is not the case. Comparable Old Kingdom tombs at comparable elevations on the eastern edge of the Giza Plateau do not show the same weathering features seen in the Sphinx enclosure, thus discrediting Dr. Harrell's wet-sand theory.
(3) For the sake of argument, let us assume for a moment that the Sphinx enclosure was filled with wet sand during some period in its history. Would wet sand give the weathering profile and erosional features observed in the enclosure and on the body of the Sphinx under the ancient repairs?
My answer is no. As Harrell points out, "...the lower few meters of the Sphinx enclosure and the lower several meters of the temples would have suffered the most from a wet sand-cover" and the less durable layers of limestone (the "marly limestones") would be especially prone to accelerated weathering.
Harrell's wet-sand theory is falsified by the actual data from the Sphinx enclosure. In the enclosure the least durable layers of the middle member of limestone (from which the core body of the Sphinx is carved) generally lie at the bottom of the stratigraphic section, yet they are generally better preserved (and jut out further) than the higher and more durable layers. The wet-sand theory predicts that the lower and less durable layers should be heavily eroded and significantly undercut the more durable and higher layers above, yet they do not. The exact opposite of the weathering profile predicted by the wet-sand theory is actually found in the Sphinx enclosure.
The profile found in the enclosure is, however, compatible with precipitation-induced weathering. Rainfall and surface runoff coming from above and running down the rocks of the enclosure would preferentially weather the upper-most layers, even though they are characterized by higher durabilities, and would cause the upper layers to recede at a faster rate than the lower layers. Such precipitation and runoff would also open up the major vertical crevasses, fissures and cracks seen in the walls of the Sphinx enclosure, whereas the wet-sand theory cannot adequately account for these features. Harrell himself admits that "...abundant rainfall and runoff probably can produce the kind of weathering profiles seen in the area of the Sphinx." His wet-sand theory, however, cannot produce these kinds of weathering profiles.
(4) Dr. Harrell points out that in recent times (over the last two centuries) there have been numerous reports of Nile flood-waters reaching the base of the Sphinx. If such flooding were responsible for the erosional features seen in the Sphinx enclosure, it would cause undercutting of the lowermost strata - which is not the case, as already described above. Furthermore, Harrell correctly notes that flood levels have progressively risen over time and, whereas the Sphinx and its associated temples "...are now within the upper limits of the modern flood range, they were not during the Old Kingdom."
In his critique of my work, Dr. Harrell briefly attacked some of the other points that I have suggested in support of an older Sphinx. Here I briefly counter his arguments:
Mastabas at Sakkara: I stand by my observation that the First and Second Dynasty mastabas on the Sakkara Plateau do not show the classic precipitation-induced weathering features that would be expected if, in fact, they pre-dated the features in the Sphinx enclosure that show precipitation-induced weathering. Yes, the mastabas at Sakkara are poorly preserved in some cases, but this is not the point. The point is the nature of the weathering features seen on what is preserved. The Sakkara mastaba weathering features indicated that these structures were not subject to the same degree of rainfall as was the Sphinx.
Granite Facing on the Sphinx and Valley Temples: In an ad hoc manner, Harrell suggest that the softer limestone [of the core blocks] was carved to fit irregularly finished granite facing blocks. Based on my observations, I simply do not agree with his hypothesis. I remain convinced that the backs of the Old Kingdom granite facing stones were carved to match or complement the earlier weathering features (not just irregular carving) seen on the surfaces of the core limestone blocks of the temples.
Limestone Durability: Dr. Harrell and I apparently agree that durability trends and paleokarst features seen in the limes tones of the Sphinx enclosure are the result of pre-5000 B.C. precipitation-induced weathering. Harrell, however, does not believe that these features bear on the age of the Sphinx, whereas I believe they do. Specifically, the rolling, undulating weathering profile developed on the walls of the Sphinx enclosure and on the core body of the Sphinx dates to the initial carving of these surfaces to at least ca. 5000 B.C., when there was a wetter climactic regime in the Giza area.
Limestone Stratigraphy: Harrell questions my stratigraphic correlations and analysis, suggesting that maybe I am comparing more resistant limestone layers to less resistant ones. 1 reject this argument and stand by my correlations and comparisons.
Seismic Profiles: Dr. Harrell likewise questions the seismic work that Thomas Dobecki and I carried out on the Giza Plateau. Basically, he attempts to discredit this work by suggesting that we did not know what we were looking at and that our interpretations are in error. After reading Harrell's comments, I stand by our original interpretations. Based on the analysis of numerous seismic lines taken on the Giza Plateau, we have good reason to believe that the low-velocity layer is the result of weathering - it is not "merely an assumption" on my part, as Harrell states. I do not believe that this low-velocity layers vs. the high-velocity layer is "...a reflection of the original depositional character of the limestone," as he posits. In particular, the interface between our low and high velocity layers does not follow the dip of the strata, as would be expected if we were simply mapping the boundary between a shoal-reef facies and a nummulite-bank facies. Early in my studies, I considered such an interpretation and found it lacking.
Also, the somewhat-lower velocities for both weathered and sound limestone at the back of the Sphinx do not necessarily lead to a contradiction. As Dobecki and I have already pointed out: "The slower velocities recorded on line S3 (behind the back of the Sphinx) may be due to the more limited range of offset on this shorter line; or, quite simply, the natural bedrock in this area may be less hard (that is, less hard or durable originally - not more greatly weathered, as Harrell suggests) than along the other three sides of the Sphinx." I reject the suggestion made by Harrell that errors were made in preparing line S3. It seems that such an accusation is simply a convenient way for him to dismiss the data.
I should perhaps note that, even without the seismic data, there is still abundant evidence that the Great Sphinx of Giza predates its traditional attribution of ca. 2500 B.C.
In conclusion, I do not find Dr. Harrell's arguments - particularly his wet-sand theory - convincing as a way to explain the erosional features seen in the area of the Sphinx enclosure. The traditional dating of the Great Sphinx to 2500 B.C. is contradicted by the geological evidence. James Harrell's mistake is to give too little weight to the geological evidence supporting a pre-Old Kingdom origin for the core body of the Sphinx. Instead, he accepts a priori the standard Egyptological dating of the Sphinx to 2500 B.C., and then tries his best to either explain away or simply dismiss data so as to preserve the orthodox view. Harrell and others like him who promote poorly supported yet-orthodox views sometimes need to be challenged.
I greatly appreciate the fact that Dr. Harrell encouraged me to respond to his comments, and that KMT has provided a form for the airing of this debate. I believe that such dialogue is healthy and all parties benefit from such open and unfettered discussions.
Dr. Robert M. Schoch