THE SPHINX

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 Of the four modes of weathering listed above, some rocks may show one mode overlain by another-thus, in particular cases, the various modes of weathering may be somewhat difficult to sort out. On the whole, however, they are clear and distinct from one another at the Giza site.

What is interpreted as precipitation-induced weathering is the oldest predominant weathering mode identified on the Plateau. It is found to any significant degree on only the oldest structures there, such as on the Sphinx body and the walls of the Sphinx enclosure. Of course, it still rains at Giza on occasion, and thus precipitation-induced weathering can be said to exist on all structures on the Plateau to some small degree; here we are talking in generalities and attempting to look at the broad picture. In many places this precipitation-induced weathering mode has superimposed upon it wind-induced weathering. Presumably the major portion of this precipitation-induced weathering occurred prior to the onset of the current and regime exhibited at Giza (i.e., prior to the modern climatic regime of the Sahara Desert).

 

          On the Sakkara Plateau, some ten miles (sixteen kilometers) to the south of Giza, there are fragile mud-brick structures, mastabas, that are indisputably dated to the First and Second dynasties-presumably several hundred years earlier than the standard dating of the Sphinx-that exhibit no evidence of the precipitation-weathering features seen in the Sphinx enclosure. As noted above, well-documented Old Kingdom tombs at Giza, cut from the identical sequence of limestones as the body of the Sphinx, exhibit well-developed wind-weathering features, but lack significant weathering which is precipitation-induced. For these reasons it can be concluded that the well-developed precipitation-weathering features seen on the Great Sphinx and its associated structures predate Old Kingdom times and, in fact, may well predate dynastic times altogether.

         

        The other two modes of weathering noted above appear to be, on the whole, very recent phenomena that have been most active since ancient times. Other researchers have focused attention on such weatherings relative to the Sphinx, particularly the damage currently being done by mobilized salts.[8] These studies are of extreme importance in the attempt to halt the current destruction of the monument; but it must be remembered that such studies of weathering agents currently damaging the Sphinx may not be of relevance in any attempt at determining the genesis of ancient weathering and erosional features which are observable on it, as well.[9]

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If the Great Sphinx of Giza was weathered heavily, and at an early period in its existence, by precipitation, this suggests that it initially may have been carved prior to the last great period of major precipitation in this part of the Nile Valley. Egypt was subjected to erratic floods and what is sometimes referred to as the "Nabtian Pluvial" (a period of relatively heavy rainfall) from 12,000 or 10,000 to about 5,000 years ago; and it has been suggested that there were sporadic but relatively heavy rains during the Fourth Millennium (4000 to 3000 B.C.), and a less and climate along the Nile as late as 2350 B.C. (with relatively wetter conditions and unusually high Nile inundations recorded sporadically during historical times).[10]

 

        Thus, on the basis of the climatic history outlined above, one might tentatively suggest that the Great Sphinx was sculpted in very early dynastic times, or in the Predynastic Period (late-Fourth Millennium or earliest-Third Millennium B.C.). However, one must account for the considerable weathering that appears on the walls of the Sphinx hollow, on the body of the sculpture itself, and on the walls of its associated temples-weathering that was possibly covered up or repaired during the Old Kingdom (ca. 2600-2400 B.C.). One must also take seismic data into account (see below)-in particular, the fact that it indicates the subsurface dissolution of the limestone beneath the floor of the Sphinx enclosure is very deep and non-uniform. These latter considerations suggest the possibility that the initial carving of the Great Sphinx may have taken place several millennia earlier than its standard attribution.

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                           Two-Stage Construction of the Sphinx and Valley Temples

 



          As far as can be determined, the core of the Sphinx Temple (and possibly the core of the Valley Temple) is constructed out of titanic limestone blocks taken directly from the ditch around the Sphinx.[11]Therefore, the limestone core of the Sphinx Temple (and also possibly the Valley Temple) must be as old as the great sculpture itself.

 

          The ancient Egyptians later faced the limestone cores of these temples with ashiars made of Aswan granite. Based on my field observations of the granite ashiars and the underlying limestone core blocks, I believe that the core blocks in both temples were exposed to the elements and underwent considerable weathering and erosion before the granite facings were installed. In places the backs of the granite blocks were cut in irregular, undulating patterns so that they complemented or matched the irregular weathering patterns on the limestone blocks which they were used to refurbish. In observing the Valley Temple in particular, one also notes that the limestone walls, where stripped of their granite facings, are not cut smoothly. Rather, they have a higgledy-piggledy surface pattern, where apparently the ancient Egyptians, before applying the Aswan-granite facings, slightly cut back and smoothed out the weathered surface of the walls, they did not, however, take off enough of this weathered surface to make the walls perfectly smooth.

 

          The general Egyptological community is in agreement that the granite facings on the Sphinx and Valley temples are attributable to King Khafre.[12] On site I found an inscription carved into the granite of the Valley Temple which appears,[13] on stylistic grounds, to be of Old Kingdom date. It seems a good assumption that the limestone core blocks would have been freshly cut-that is, unweathered-when initially used in construction of the Sphinx-associated temples. Therefore, it the granite facings cover deeply weathered limestone, the original limestone structures must predate by a considerable degree their granite facings. Obviously, if the limestone cores (originating from the Sphinx ditch) predate the granite ashlars (facings), and the latter are attributable to Khafre of the Fourth Dynasty, then the Great Sphinx was carved prior to the reign of that king.

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                          Ancient Repair Campaigns to the Body of the Great Sphinx

 



          The body of the Sphinx has been subjected to various repair campaigns, beginning with the ancient Egyptians themselves and continuing up to the present day. The earliest of these repairs to sculpted surfaces of the monument were carried out using what appear to be Old Kingdom-style masonry techniques.[14] If the oldest repairs to the eroded body of the sculpture do date to Old Kingdom times, this is another strong argument in favor of a much earlier date for its carving.


          American Egyptologist Mark Lehner has analyzed the repairs to the Sphinx [15] and concluded that, despite his own evidence to the contrary, "To seek agreement with known historical facts [e.g., his contention, among other things, that the Sphinx was carved in ca. 2500 B.C. by order of Khafre], we should probably expect the earliest restoration to have been done in the New Kingdom [ca. 1500-1000 B.C.].[16]

In summary, in order to save the attribution of the Sphinx to King Khafre and ca. 2500 B.C., Lehner suggests that the earliest level of "large-block" (Old Kingdom-style?) masonry was added to the monument during the New Kingdom, over 1,000 years later. Furthermore, he points out that this still leaves only on the order of 500 years for the majority of the weathering and erosion experienced by the Sphinx to have occurred. Taking not only Lehner's work into account, but also the evidence for a two-stage construction of the Sphinx-associated temples (discussed above), the research that has been carried out concerning different modes of weathering on the Giza Plateau (discussed above), and the seismic surveys in the area of the Sphinx complex which give data on the subsurface depth and distribution of weathering around the monument (discussed below), and considering the fact that attribution of the carving of the Sphinx to Khafre is based on circumstantial evidence to begin with, I find one conclusion is inescapable: The initial carving of the core body of the colossal sculpture predated the time of Khafre. Lehner's own work is more easily reconciled with the hypothesis that the Fourth Dynasty Egyptians merely restored, refurbished and added on to the Sphinx and its neighboring structures, rather than being the original creators of this Giza Plateau complex.

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                                          Seismic Surveys of the Sphinx Area

 




          Seismic geophysical surveys indicate that the subsurface weathering of the Sphinx enclosure is not uniform. This strongly suggests that the entire Sphinx ditch was not excavated at one time. Furthermore, by estimating when the less-weathered portion of this area was excavated-and thus first exposed subaerially-one can tentatively estimate when initial excavation of the Sphinx enclosure may have begun. Dr. Thomas L. Dobecki, a seismologist with McBride-Ratcliff and Associates of Houston, Texas, assisted in carrying out some low-level seismic work in the vicinity of the Great Sphinx; this was done with the permission of the Egyptian Antiquities Organization.[17] We were able to gather a quantity of seismic data, and with this we have been able to establish subsurface geometries of the bedrock and have located several previously unknown sub-surface features. Seismic lines taken in front of and along the body of the sculpture on either side-east (seismic line S4), north (seismic line S1) and south (seismic line S2) of the monument-indicate that below the surface the limestone is weathered up to a depth of six to eight feet (1.8 to 2.5 meters). However, along the back-west side (seismic line S3) -of the Sphinx the identical limestone has been weathered only to a depth of approximately four feet (1.2 meters). These results were completely unexpected. The same limestone surrounds the great sculpture (the floor of the Sphinx enclosure where our seismic lines were taken consists of Gauri's [18] Rosetau Member, or Member 1), and if the entire body of the Sphinx was carved out of living rock at one time, it would be expected that the surrounding limestone would show the same depth of subsurface weathering.

 

          One possible interpretation of this seismic data is that, initially, only the sides and front (eastern portion) of the Sphinx body were carved free of the surrounding rock, so that the Sculpture projected as an outcropping, with what would later become the figure's rump or rear (western portion) still merged with the natural rock. To be more precise, the leonine rump was probably initially carved down only to the level of the upper terrace, which to this day remains immediately west of the sculpture within the general Sphinx enclosure; below the level of the terrace, the backside of the figure merged with the bedrock. Egyptian Egyptologist Selim Hassan [19] suggested that the Sphinx was originally meant to be viewed only from the front (rather than from the sides or rear), so that, with the Sphinx Temple in front of it, it seemed to sit upon a pedestal.Alternately, the rump or western end of the sculpture may have been freed from the bedrock originally, but only by a very narrow passage not sampled by our April 1991 seismic line.

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In order to determine accurately when the western end of the Great Sphinx was freed from the bedrock, and to establish a chronology of the possible widening of the passage between the rear portion of the sculpture and the west wall of the surrounding enclosure, more detailed work (including the collection of several more seismic profiles parallel to seismic line S3) will be necessary. However, it is already clear that the limestone floor behind the rump of the figure-which we sampled seismically in April 1991-was exposed later (i.e., possibly in Khafre's time) than the east, north and south limestone floors of the enclosure. Once the sides of the body and eastern end of the Sphinx were carved, the limestone floors surrounding these three sides of the sculpture began to weather; but what was to become the limestone floor behind the figure was still protected by a thick layer of solid rock.

 

          A reasonable hypothesis is that when Khafre repaired and refurbished the Great Sphinx and its associated temples in ca. 2500 B.C., he had the back (western end) of the colossal sculpture carved out and freed from the cliff (or enclosure wall). It is difficult to argue that the rump of the figure was carved any later than Khafre's time; the base of the rump has, like the rest of the core body of the Sphinx, been weathered and repaired with limestone blocks. Furthermore, one must account for the non-trivial four feet (1.2 meters) of subsurface weathering detected in the area behind the carved figure, between the rump and the enclosure wall. If, for instance, one hypothesized that the rump of the Sphinx had been freed during New Kingdom restoration efforts to the sculpture, how could we account for this deep subsurface weathering, given the prevailing and conditions on the Giza Plateau from New Kingdom times to the present and the historical fact that the Sphinx enclosure has been filled with desert sands for much of the period since the New Kingdom?

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As an alternative to the scenario that Khafre had the back of the Sphinx carved free from the bedrock, one could suggest that if the rear portion of the figure already had been freed completely from the adjoining limestone prior to the Old Kingdom, but was separated from the resultant cliff by a very narrow passage, Khafre may have had this passage widened and therefore uncovered the limestone floor that we sampled seismically. (Our seismic line was positioned very close to the western wall of the Sphinx ditch.) Thus, at this time (ca. 2500 B.C.), the limestone floor on the western end of the sculpture began to weather.

 

          Based on either this chain of reasoning, or the scenario suggested immediately above-and given that the weathering of the limestone floor of the Sphinx enclosure is fifty to 100 percent deeper on the front and sides of the figure than at its rear-we can estimate that the initial carving of the Great Sphinx (i.e., the carving of the main portion of the body and the front end) may have been carried out ca. 7000 to 5000 B.C. (in other words, that the carving of the core body of the figure is approximately fifty to 100 percent older than ca. 2500 B.C.). This tentative estimate is probably a minimum date; given that weathering rates may proceed non-linearly (the deeper the weathering is, the slower it may progress due to the fact that it is "protected' by the overlying material), the possibility remains open that the initial carving of the Great Sphinx may be even earlier than 9,000 years ago.

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                               In Search of a Context for the Great Sphinx

 



          As a geologist, the current evidence taken as a whole suggests to me that the Great Sphinx of Giza is considerably older than its traditional attribution of ca. 2,500 Indeed, I am currently estimating-based on evidence at hand-that the origin of the colossal sculpture can be traced to at least 7000 to 5000 B.C., and perhaps even earlier. Of course, the Sphinx may not have looked like it does today some 8,000 years ago. The original surface details of the body have weathered away in the distant past, and the current head of the figure-which everyone agrees is almost surely the result ot recarving.


          Certainly, the Great Sphinx has suffered much work, repairs, refurbishing and abuse from prehistoric times onward to the present. Special attention seems to have been paid to it periodically, for instance during the Old Kingdom (ca. 2500 B.C.), in New Kingdom times (ca. 1400 B.C.), in the Twenty-sixth Dynasty (or Late Period, ca. 650-400 B.C.) and during the Graeco-Roman era (ca. 300 B.C.-400 A.D.). During these periods of repair or refurbishing activity, the contemporary ruler often had the Great Sphinx excavated from the sands that quickly (in just a matter of decades) fill its hollow enclosure if left unattended and, after each re-excavation of the figure, repair whites were often mortared to the weathered body in an attempt to restore the sculpture to its original outlines.[20]

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As a general academic scholar, I have to ask myself whether the evident extreme age for the Great Sphinx that I am suggesting makes sense archaeologically and culturally. Dating this unique sculpture to the Seventh or Sixth Millennium B.C. (or perhaps even earlier)-is this compatible with the broad context of known archaeological remains? In other words, is there any context or precedent for a 7,000-or 9,000-year-old (or even older) colossal man-made monument? What were other Mediterranean peoples and cultures like at this time? What types of structures were they creating? In taking a quick look at the relevant archaeological literature, I found that in Egypt for the period from about 10 000 to 5000 B.C. there is little known today that would suggest there were peoples capable either technologically or organizationally-of carving the Great Sphinx or building its associated temples.[21] However, the relatively simple Neolithic sites known in Egypt dating to this period may, in fact, be 'backwater' peripheral or marginal settlements that were, and are, non-representative of the highest level of Egyptian cultural and technological attainment at this time. Quite possibly other cultural remains are, for the most part, buried deep under the Nile alluvium. In addition, rises in sea level since ca. 10,000 or 15,000 years ago may have submerged vast expanses along the Mediterranean coast inhabited by early cultures.[22]

 

          If we move beyond Egypt, however, we find that by the Eighth Millennium B.C. there were already major city-sites around the eastern end of the Mediterranean Sea. Two particularly well-attested examples are ancient Jericho in Palestine and Catal Hüyük in Turkey.

Catal Hüyük, a city built of mud bricks and timber, dates back to at least the late-Seventh Millennium B.C.. This was no primitive settlement, however; rather, the known remains demonstrate a sophistication and opulence previously unimagined by archaeologists for such a remote period in time. The inhabitants built elaborate houses and shrines, covered walls with paintings and reliefs, and apparently had a rich and complex symbolic and religious tradition.[23]

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Jericho dates back to the Ninth Millennium B.C. and the city-site included a massive stone wall and tower, and a ditch cut in the bedrock-all dating from ca. 8000 B.C. The remains of the stone wall are at least six and one-half feet (two meters) thick and still stand in places twenty feet (six meters) high (nobody knows how high it was originally). Outside of this protecting wall, a ditch was excavated into the solid bedrock to a depth of nine feet (2.7 meters) and a width of twenty-seven feet (8.2 meters). Inside the wall are the remains of a stone tower thirty feet (9.1 meters) in diameter, the ruins of this structure still standing thirty feet (9.1 meters) high. In the center of the Jericho tower is a flight of steps built from huge stone slabs. This construction has been compared favorably to the towers seen on the great medieval castles of Europe.[24]

 

          The evidence of Jericho, in particular, suggests that the Sphinx complex-the sculpture and its associated stone temples-would not have been a totally isolated phenomenon in the Neolithic world: Other massive stone structures were being built around the Mediterranean as early as 10, 000 years ago.


http://www.robertschoch.net/Redating%20the%20Great%20Sphinx%20of%20Giza.htm

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http://www.robertschoch.net/Redating%20the%20Great%20Sphinx%20of%20Giza.htm







                                          Where Do We Go from Here?

 



          This is a project that is continuing to develop and unfold. More research is needed. An immediate task to be undertaken, in my opinion, is additional seismic studies within the Sphinx enclosure specifically, and on the Giza Plateau generally. I would also like to eventually acquire permission to sample the limestones of the Plateau. With such samples, I could perhaps determine more accurately the exact nature and mode of weathering observable on the Sphinx and other structures of the Plateau; and there is even the possibility of attempting to date the exposure age of the surface of the rock (which, in turn, could date the initial carving of the Sphinx) by measuring the concentration of isotopes produced in situ on the surface of the rock by the bombardment of cosmic rays.[25] Likewise, it would be extremely useful to be allowed to take some cores of the limestone, especially on the Plateau immediately adjacent to the Sphinx ditch, in order to look at the various weathering products and mineralogical changes produced at depth. I am also interested in trying to obtain some isotopic dates on the earliest mortar used in conjunction with the first repair campaigns to the Sphinx.

 

          In presenting the hypothesis that initial carving of the Great Sphinx of Giza may predate its traditional attribution, it appears that I have stirred up much controversy within the Egyptological/archaeological community.[26] I have no desire to be the proponent of a controversial hypothesis; I am simply advocating a tentative assumption that, in my opinion, best fits the evidence. My purpose is not to be dogmatic-I do not claim to have the 'truth"-but simply to present a testable hypothesis relative to the age of the Sphinx. I am willing to see my explanation proven wrong on the basis of evidence outweighing the evidence which corroborates it. However, such empirical evidence as would falsity my hypothesis has, in my opinion, not yet been presented. I remain convinced, thus far, that the standard story told by Egyptologists as to when the Great Sphinx was created-namely, by Old Kingdom Egyptians during the reign of King Khafre-does not hold up under close examination.[27]

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                                                   REFERENCES

 



[1] Recent work on the stratigraphy, sedimentology and general geology of the Giza Plateau is summarized in: T. Aigner, 'Event-stratification in nummulits accumulations and in shell beds from the Eoceine of Egypt,' in G. Einsele and A. Seilacher, eds., Cyclic and Event Stratification (Berlin, 1982), 248-262; T. Aigner, 'A Pliocene cliff-line around the Giza Pyramids Plateau, Egypt,' Palaeogeogr., Palaeoclimatol., Palaeoecol. 42 (1983a), 313-322; T. Aigner, 'ZurGeologie und Geoarchaeologie des Pyramidenplateaus van Giza, Aegypten,' Natur und Museum 112 (1983b), 377-388; T. Aigner, 'Facies and origin of nummulitic buildups: an example from the Giza Pyramids Plateau (Middle Eocene, Egypt),' N. Jb. Geol. Palaont. Abh. 166 (1983c), 347-368; K. O. Emery, 'Weathering of the Great Pyramid,' J. Sediment Petrol. 30 (1960), 140-143; K. L. Gauri, 'Geologic study of the Sphinx,' Newsletter of the American Research Center in Egypt 127(1984), 24-43; K. L. Gauri, 'How Old is the Sphinx?' Abstracts for the redating_the_sphinx Annual Meeting of the American Association for the Advancement of Science (Chicago, redating_the_sphinx), 202; K. L. Gauri and G. C. Holdren, 'Deterioration of the stone of the Great Sphinx,' NARCE 114 (1981), 35-47; Geological Survey of Egypt, Cairo, Geological Map of Greater Cairo Area (I 983), Scale 1:100,000; M. Lehner, 'The Development of the Giza Necropolis: The Khufu Project,' Mitt. des Deutschen Archaologischen lnst., Cairo, Abt. 41 (1985), 109-143; R. Said, The Geology of Egypt (Amsterdam, 1962); P. Said, The Geological Evolution of the River Nits (New York, 1981); R. Said, 'The geological evolution of the River Nile in Egypt,' Z. Geomorphol., N.F. 26 (1982), 305-314; R. Said, ed., The Geology of Egypt (Rotterdam, 1990); R. Said and L. Martin, 'Cairo Area geological excursion notes,' in F.A. Reilly, ed., Guidebook to the Geology and Archaeology of Egypt (Petroleum Exploration Society of Libya, Sixth Annual Field Conference, 1964), 107-121; R. M. Schoch, 'How Old is the Sphinx?,' Abstracts for the redating the sphinx Annual Meeting of the American Association for the Advancement of Science (Chicago, redating the sphinx), 202; R. M. Schoch and J. A. West, 'Redating the Great Sphinx of Giza, Egypt,' Geological Society of America, abstracts with programs 25:5 (1991), A253; M. Sears, "Nummulites: Time capsules of the desert sands," Rotunda, The Magazine of the Royal Ontario Museum 13:1 (Fall, 1990), 12-19.

[2] For instance, J. Baines and J. Malek, Atlas of Ancient Egypt (Oxford, 1980), 36, state that Khafre (= Chephren, = Khephren) ruled Egypt from 2520 to 2494 B.C.

[3] "As to the exact age of the Sphinx, and to whom we should attribute its ****, no definite facts are known, and we have not one single contemporary inscription to enlighten us upon this point": from S. Hassan, The Sphinx: Its History in the Light of Recent Excavations (Cairo, 1949), 75. The current standard attribution of the Great Sphinx and its associated temples to Khafre seems to be based on four major pieces of evidence: 1) a statue of Khafre recovered during the Nineteenth Century from the Valley Temple; 2) an ambiguous (and now effaced) inscription on a New Kingdom stela of ca. 1400 B.C.; 3) an alleged similarity between the face of the Great Sphinx and that of Khafre; and 4) the physical proximity of the Great Sphinx to Khafre's pyramid. As Hassan and J. A. West (Serpent in the Sky: The High Wisdom of Ancient Egypt [New York, 1979], 215-220) and others have noted, all of this evidence is circumstantial and none of it proves that the Sphinx was carved by order of Khafre.

At present the consensus among Egyptologists seems to be that the face of the Great Sphinx resembles the face of its reputed builder, Khafre. This is a relatively recent notion, and far from certain. The face of the sphinx is severely damaged, but what remains of it does not indisputably appear to resemble the face seen on known statues of Khafre. American Egyptologist Mark Lehner ('Computer rebuilds the Ancient Sphinx," National Geographic [April 1991], 32-39) has done work on restoring the battered face of the Great Sphinx, but his effort has not necessarily shed any light on what the face of the Sphinx originally looked like. Instead of attempting to reconstruct the face of the sculpture based on actual physical evidence, Lehner dogmatically insists that the monument was carved by Khafre's order and, therefore, the face must resemble that king; accordingly, he used a computer to reconstruct the face so that it looked like known portraits of the Fourth Dynasty ruler, remarking (National Geographic, 33) that "with the face of Khafre, the Sphinx came alive." Here Lehner clearly seems to imply that his reconstruction of the face of the Sphinx helps to confirm that the sculpture was created under Khafre; if so, this is simply a case of circular reasoning.

 

          Recently New York City Police forensic officer Detective Frank Domingo made a detailed analysis of the face of the Sphinx, as compared to the known face of Khafre (see article by R. Grossman, Chicago Tribune, Section 5, 24 February Redating the Sphinx, 1,5). In October of 1991, Domingo traveled to Egypt with the express purpose of measuring and examining the surviving facial features of the Sphinx and the statues known to portray Khafre. After thoroughly studying the problem, Domingo concluded definitely that the face of the great Sphinx is not the same face seen on statues of the builder of the second great pyramid. My hypothesis-that the initial carving of the Sphinx of Giza was undertaken prior to the reign of Khafre-is actually neither corroborated nor refuted on the basis of whether or not the face of the sculpture represents the likeness of Khafre. Even if the face of the Sphinx is a portrait of the Fourth Dynasty ruler, this does not falsify my hypothesis, as I believe that Khafre did, indeed, work on restoring and refurbishing the monument. He may have even ordered the recarving of the face of the Sphinx in his own image.

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[4] Lehner has suggested (1985, 116) that along the eastern edge of the Giza Plateau (the area where the Sphinx is located) all land higher than an elevation of 60.7 feet (18.5 meters) above sea level remained above the annual inundations of the Nile during the Fourth Dynasty. In fact, Lehner (1985) found some suggestions of an Old Kingdom surface that is only 57.4 feet (17.5 meters) above sea level. As Lehner (1985, citing the work of K. Butzer) notes, the flood plains of the middle-Third Millennium B.C. (Old Kingdom times) have persisted in essentially the same form until the present day; there has not been a rise in the alluvial plain since the Old Kingdom period, as was once assumed.
Hassan (1949).stated that in the Old Kingdom, during the annual inundation of the Nile, barges could be floated right up to the edge of the Giza Plateau. Even in this century, unusually high Nile waters have flooded around the base of the Great Sphinx (Ali Hassan, personal conversation, June 1991).


          In April of 1991, using seismic techniques, we located the water table at an elevation of about forty-six to forty-nine feet (fourteen to fifteen meters) above sea level in the sand-filled courtyard area approximately 328 feet (100 meters) east of the Sphinx Temple, between the modern restaurant and the Sphinx and Valley temples. In this courtyard area, the bedrock surface is buried under approximately forty-nine to fifty-nine feet (fifteen to eighteen meters) of sand; that is, the surface of the bedrock in this local area is at an elevation of about 6.6 to 16.4 feet (two to five meters) above sea level. The pyramids of the Giza Plateau sit at a higher elevation than does the Sphinx; thus, the base of Khafre's pyramid is situated at an elevation of approximately 230 feet (seventy meters) above sea level.

[5] See reference and discussion in R.M. Schoch, Stratigraphy: Principles and Methods (New York, 1989), 261. [ back]

[6] See M. M. El Aref and E. Refai, "Paleokarst processes in the Eocene limestones of the Pyramids Plateau, Giza, Egypt," J. Afr. Earth Sci. 6 (1987), 367-377, who thoroughly describe these features.

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[7] It has been suggested that subsurface moisture migrating up into the Sphinx and the surrounding rocks of the Sphinx enclosure may account for much of this activity (see Gauri and Holdren, 1981). Alternatively, or complementarily to the migration of subsurface ground water, similar weathering is actively taking place during the present day, due to the condensation of atmospheric moisture on the rock. As described by K. L. Gauri, A. N. Chowdhury, N. Fl. Kulshreshtha and A. R. Punuru ('Geologic features and durability of limestones at the Sphinx,' in P. G. Marinos and G. C. Koukis, eds., Engineering Geology of Ancient Works, Monuments and Historical Sites (Rotterdam, 1988), 723-729 [725-726]), 'the moisture is able to condense as droplets of water in the cool of the night. This moisture forms concentrated salt solution, a process augmented by the hygroscopicity of the existing halite. The salt solution enters the pores under the influence of capillary force. At sunrise, as the water begins to evaporate, crystals of salt grow producing crystallization pressure. Often one can hear in the morning the sound of popping stone resulting from pressures produced under the surface layers."


          K. L. Gauri, G. C. Holdren and W. C. Vaughan ('Cleaning Efflorescences from Masonry,' in J. R. Clifton, ed., Cleaning Stone and masonry, (Philadelphia 1986], 3-13) have suggested that much of the deterioration of the Sphinx is due to the migration of salts under the influence of water originating from the atmosphere. These authors (Gauri, et.al., 4-5) state: "Burial of the Sphinx for centuries under the desert sand has, it appears, resulted in the migration of salts from the depth of the bedrock toward the surface. The authors deduced this phenomenon from observations made in the process of mapping the Sphinx geologically [Gauri, 1984], when sand was removed that had piled up in recent times against the rock surfaces bounding the ditch around the Sphinx. Even though the sand appeared dry at the surface, it was completely soaked with water a few inches below the surface. Also, the bedrock in contact with the sand was soaked with water. The source of this water is the atmosphere, and not the subsurface, because the water table lies many meters below the surfaces under consideration. Therefore, during the long burial of the Sphinx, the rock must have become wet to a considerable depth, and as it dried when exposed to the sun, salts must have become concentrated in the surface layers."


          As noted by Lehner (The ARCE Sphinx Project: A preliminary report,' NARCE 1 1 2 [I 980], 3-33), the vast majority of the weathering and erosion occurred to the Sphinx prior to ca. 1400 B.C. In places the walls of the Sphinx enclosure exhibit over a meter (3.3 feet) of erosion, and in places perhaps over two meters (6.5 feet) of erosion (see, for instance, the profile in Gauri, 1984, 32). It is hard to imagine that the mechanism of migrating salts, described in the quotation above, could be solely responsible for producing these deep-weathering features in the time span from 2500 B.C. (when Khafre allegedly had the Sphinx carved) to 1400 B.C. It is particularly difficult to reconcile Gauri et. al.'s proposed weathering mechanism with the observed surficial morphology of the rocks in consideration of the following points: 1) the Sphinx enclosure was probably buried in sand for at least half of the period between 2500 and 1400 B.C. (see Lehner, 1980); 2) the weathering patterns seen on the body of the Sphinx and walls of the Sphinx enclosure clearly exhibit features associated with precipitation-induced weathering (cf. El Aref and Retai, 1987); and 3) Old Kingdom tombs and other structures on the Giza Plateau that were carved from the same member of the Mokattam Formation do not exhibit the same weathering features to the degree seen on the Sphinx body and surrounding enclosure walls. If Gauri et al.'s mechanism of migrating salts since 2500 B.C. was the primary agent responsible for the weathering and erosional features seen on the body of the Sphinx, and on the walls of the Sphinx enclosure, then one should expect to observe such features of a similar nature and degree on the Old Kingdom tombs and other structures that are carved out of the same sequence of limestones as the body of the Sphinx, and that have been subjected to identical climatic and weathering conditions since they were constructed.

[Bianca]

[8] See, for instance, the work by Gauri and his colleagues cited above, as well as the following: A. N. Chowdhury, A. R. Punuru and K. L. Gauri, 'Weathering of limestone beds at the Great Sphinx," Environ. Geol. Water Sci. 15 (1990), 217-223; K. L. Gauri and A. R. Punuru, 'Characterization and durability of limestones determined through mercury intrusion porosimetry,' in F. Zerra, ed., The Conservation of Monuments in the Mediterranean Basin (Proc. First Intern. Syrnpos. Bari, 1989), 255- 258; A. R. Punuru, A. N. Chowdhury, N. J. Kulshreshtha and K. L. Gauri, 'Control of porosity on durability of limestone at the Great Sphinx, Egypt,' Environ. Geol. Water Sci. 15 (1990), 225-232. See also, C. Hedges, 'Sphinx poses riddle about its fate: Experts ponder ways to save monument from man and time,' New York Times (10 March Redating the Sphinx), C4.

[9] In their work on the weathering of the Sphinx, Gauri and his colleagues (see references cited above) have suggested that, in general, the upper beds of the middle member (Member II or Setepet Member) of the core body or thoracic region of the Sphinx are more durable than the lower beds. These authors have calculated durability factors for different beds of this member; such factors range from about 100 (high durability) for the uppermost bed, just below the neck of the Sphinx, to about 11 for the lowermost bed of the member. There is a general trend of increasing durability factors, as calculated by these authors, going up section. Thus, their bed 4i (located approximately halfway up the body of the Sphinx) has a calculated durability factor of 75 (see summary of this work in Gauri et al., 1988).


          The primary factor that determines the durability of the various beds, according to Gauri and colleagues, is the relative pore-size distributions in the various beds (they calculated their durability factors on the basis of the relative volume of the pores in various beds). In summary, stone with a greater volume of large pores will tend to be more durable. The reason for this is explained succinctly by Gauri et al. (1988, 727-728): "The influence upon durability of the interconnected small and large pores may also be visualized qualitatively in terms of transport of water through stone. Large pores become easily filled due to the mass movement of water into the pores. But when pores communicate with the exterior of the stone through narrow throats, the throats influence the filling of the large pores. Small (narrow) capillaries have large suction. An abundance of these capillaries will fill the small and large pores completely. But if many large pores are present and the small capillaries are somewhat larger, some empty space may then continue to exist in the stone. When crystals begin to grow in a solution, the resultant pressure will be experienced on the walls of the completely filled pores, but such pressure will be 'released' in the empty space of the partially filled pores. Consequently, stone with a large volume of large pores and a small volume of narrow capillaries will be more durable."