THE SPHINX

[Bianca]

What determines the microporosity of a particular stone? It is a function of the original constitution of the rock as formed during deposition, diagenetic changes that modify primary textures and, finally, leaching of the rock matrix. The limestones composing the core body of the Sphinx are not uniform, as Gauri and colleagues have pointed out. These authors classify the lower half of Member II (their beds I through 3) as a sparse biomicrite and the upper half of Member II (their beds 4 through 7) as a packed biomicrite. In general, packed biomicrites might be expected to have a larger volume of large-pore space and, therefore, be characterized by higher durability factors than sparse biomicrite. Even taking this into account, Gauri et al's data show a consistent trend of increasing durability factors toward the top of the section within the packed biomicrites (beds 4-7).


          How might we account for the trend noted for the packed biomicrites? I would suggest that this trend is compatible with the hypothesis that the stone was subjected to leaching of the matrix-which opened the pores and increased durability-due to precipitation. As rain fell on the back of the Sphinx (or, at least. on the stone that was to become the Sphinx), and on the Giza Plateau in general, it would soak into and leach the rock from the top down giving rise to the pore-volume distribution seen in these rocks today.


          It is interesting to note that on the wall of the Sphinx ditch the beds for which Gauri and colleagues calculated the highest durability f actors are not consistently the least weathered and receded in profile (assuming that the wall of the Sphinx ditch was originally cut vertically or nearly vertically). For instance, utilizing Gauri's own data (Gaud, 1984, 32, fig. 3C), in an east-west profile of the rear of the Sphinx and the wall of the Sphinx ditch one sees that beds 1i and 2i-which both have low durability factors of 11-are greatly receded and undercut the overlying units of higher durability (beds 1ii and 2ii). However, in the same section, bed 2ii (with a durability factor of 76) is receded further back than is bed 1 ii (durability factor of 56). Likewise, bed 3ii (durability factor of 76) is receded back further than bed 3i (durability factor of 42), and beds 4i and 4ii (durability factors of 75 and 86 respectively) are receded further back than bed 3ii. In general, the amount that a bed has receded is not so much a function of its present-day durability factor, but primarily a function of its geometric position on the exposure. It would be logical that precipitation failing down from above would preferentially weather the uppermost beds and cause them to recede back at a faster rate than the lower beds. Again, this train of thought suggests that the Sphinx and walls of the Sphinx enclosure (or ditch) were subjected to precipitation-induced weathering.

[Bianca]

There have been a few other previous studies of note concerning weathering and erosion on the Giza Plateau. Emery (1960), and Said and Martin (1964) discussed briefly the weathering to the pyramids, but their work is not directly applicable to the present discussion. More pertinent to the topic at hand, El Aref and Refai (1 987) made a comprehensive macroscopic study of paleokarst processes and features on the Plateau, concentrating in particular on the area of the Sphinx enclosure. These authors pointed out many paleokarst features that are attributable to periods of seasonal rainfall. They illustrate and discuss solution holes, solution depressions, solution joints, symmetrical concentric cross-cutting diffusion fronts, and other dissolution features found on the body of the Sphinx and walls of the surrounding ditch. El Aref and Refai (1987, 376) note that "The karstic rocks are mantled by soil material and/or surficial calcareous duricrust. The solution features are partially or completely filled with clay precipitates together with concretions of iron and manganese oxides and collapse breccia fragments." (As a side note, these iron and manganese oxides often take on a red or ocher color. Lehner [ 1 991, 36] noted that "if you probe any seam in the masonry covering the lower part of the body [of the Sphinx], a red powder appears." This may simply be red earthy/clay material, typical karst sediments that one would expect in such a limestone terrane that has been subjected to weathering via precipitation. Lehner [1991] and Hassan [1949] have both suggested that the Sphinx and its surroundings were traditionally painted red. This putative red paint, however, may actually consist, in part, of natural weathering products of the rock, although the Sphinx may have been artificially painted red, as well). El Aref and Refai conclude (1987, 376) that "The development of these karst features and the associated sediments indicate that the study area was subjected to intensive seasonal rainfall and evaporation of temperate (Mediterranean) climatic conditions."


          Professor Farouk El-Baz has also noticed the anomalous and very ancient weathering seen an the core body of the Sphinx. However, in order to save the attribution of the sculpture to Khafre's reign, El-Baz has long promulgated his notion that the Great Sphinx of Giza is nothing more than a yardang (an aerodynamically stable natural erosional landform-essentially a wind-shaped hill) that was merely "dressed up" by the Old Kingdom Egyptians to look like a sphinx (F. El-Baz, "Desert builders knew a good thing when they saw it," Smithsonian [April 1981],116-121; F. El-Baz, "Egypt's desert of promise," National Geographic [February 1982], 190-221). Thus, El-Baz believes that the Old Kingdom architects and sculptors incorporated very ancient (pre-Old Kingdom) erosional features found on a natural hill into their sculpting of the Sphinx.

Relative to the Great Sphinx of Giza, El-Baz's yardang hypothesis is untenable. The body of the Sphinx was not carved from a natural hill or yardang. In order to carve the figure's body, the ancient Egyptians had to excavate a ditch or moat around it, so that the full sculpture now sits in a hollow or depression below the general surface of the Giza Plateau. This ditch or hollow is clearly an artificial, man-made excavation, and it is well-established that the blocks removed from it were used to build the two structures today called the Sphinx and Valley temples. Certainly, the core body of the Sphinx was not a natural hill that was heavily eroded prior to being sculpted into the human-headed leonine figure. The head may have originally been a yardang, but it has been too heavily modified by carving and recarving to tell for sure at this point.

[Bianca]

10] For a recent summary of the evidence bearing on the Holocene climatic history of northern Egypt, see Said (1990).


        W.C. Hayes summarized (in his Most Ancient Egypt [Chicago, 1965, K.C. Seele, ed.], 23) much of the classical work carried out on reconstructing the climate of this period in Egypt's history when he wrote: 'Toward the end of the sixth millennium B.C. Egypt and neighboring lands appear to have enjoyed another slight, but effective increase in temperature and precipitation and to have entered upon a prolonged sub-pluvial or relatively moist phase, extending from early Neolithic times until late in the Old Kingdom (ca. 5000-2350 B.C.) .... Since the end of the third millennium B.C. the climate of Egypt has been generally similar to that of the present day. Between 2350 B.C. and A.D. 700 the average temperature seems to have been, if anything, a trifle above and the average rainfall a little below the modern levels, but with at least two 'quite moist' spells, one in late-Ramesside times [ca. 1200-1100 B.C.) and one about 850 B.C."


          K.W. Butzer summarized his well-known work an the same topic (Environment and Archaeology: An Ecological Approach to Prehistory [Chicago, 1971], 584):The Nile Valley provides further details and confirmation of several moist intervals... A period of accelerated wadi activity that began 9200 B.C. terrninated by 6000 B.C. Shell proliferations suggest rather more vegetation in the wadis. A little later, ca. 5000 B.C., a red paleosol suggests a mat of vegetation and more frequent gentle rains. Finally, after a second dry interlude, accelerated wadi activity and extensive sheet washing-in the wake of sporadic but heavy and protracted rains-are indicated ca. 4000- 3000 B.C. Historical and archaeological documents suggest that the desert wadi vegetation of northern and eastern Egypt was more abundant as late as 2350 B.C., when the prevailing aridity was established.'

[11] See the work of Aigner (1983b) and Lehner (1980).

[12] See, for instance, Z. A. Hawass, The Pyramids of Ancient Egypt (Pittsburgh, 1990).

[13] See also I. E. S. Edwards, The Pyramids of Egypt (New York, 1985); L. Grinsell, Egyptian Pyramids (Gloucester, 1947); and Hawass (1990).

[14] Gauri and his colleagues (see, for instance, Punuru et al, 1990, 230) consistently refer to these in such terms as "Pharaonic veneer stones" that have experienced "5,000 years of exposure to local conditions," that is, they were applied during Old Kingdom times. Recently Egyptian Egyptologist Zahi Hawass (Abstracts for The First International Symposium on the Great Sphinx-Towards Global Treatment of the Sphinx, Cairo 29 February-3 March Redating the Sphinx [Egyptian Antiquities Organization, Cairo, Redating the Sphinx], 14) stated: "It seems that the Sphinx underwent restoration during the Old Kingdom because the analysis of samples found on the right rear leg proved to be of Old Kingdom date." [back]

[Bianca]

[15] See Lehner (1980) and D. J. Hamblin ("A unique approach to unraveling the secrets of the Great Pyramids" [article about the work of M. Lehner], Smithsonian [April 1966), 78-93).

[16] Lehner (1980), 18.

[17] Nineteen refraction profiles, two reflection profiles and a refraction tomography data-set were collected on the Giza Plateau during April 1991. The seismic work performed around the base of the Sphinx consisted of hitting a sledgehammer on a steel plate, thus generating energy waves that entered the rock, traveled into the subsurface, and reflected and refracted off of subsurface features. In the Sphinx enclosure, refraction profiles gave us information on the subsurface weathering of the rock. In addition, we located various voids, cavities and other subsurface features (the subject of a paper currently being prepared by Dobecki and me). For instance, the apparent thinner weathering around stations 150 to 160 feet (forty-five to forty-nine meters) on seismic line S2, taken along the south flank of the Sphinx, may not be real; it is probably due to induced resonance caused by a subsurface void. For a summary, in abstract form, of the April 1991 seismic survey of the Giza Plateau, see T. Dobecki, "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.

[18] Gauri (1984).

[19] Hassan (1949).

[20] For popular discussions of the history of the Great Sphinx since Khafre's time, see Baines and Malek, 1980; E. A. Wallis Budge, A Guide to the Egyptian Collections of the British Museum (London, 1909); Edwards, 1985; H. Goedicke, "Sphinx" in Encyclopedia Americana, International Edition 25 (1965), 403-404; Grinsell, 1947; Hassan, 1949; Hawass, 1990: Lehner, 199 1; J. Malek, In the Shadow of the Pyramids: Egypt during the Old Kingdom (Norman, 1986); W. M. Flinders Petrie, The Pyramids and Temples of Gizeb (with an 'Update" to the original 1883 edition by Z. Hawass, London, 1990); J. Putnam, Egyptology., An Introduction to the History, Culture and Art of Ancient Egypt (New York, 1990); and references cited in these works.

[21] See M. A. Hoffman, Egypt Before the Pharaohs (New York, 1979), for a review of Predynastic Egypt.

[22] M. Ters ("Variations in Holocene Sea Level on the French Atlantic Coast and Their Climatic Significance," in M. R. Rampine, J. E. Sanders, W. S. Newman and L. K. Konigsson, eds., Climate: History, Periodicity, and Predictability [NewYork, 1987], 204-237) notes that "in general, the mean level of the oceans has risen 60 m [200 feet) during the past 10,000 yr" [i.e., since 8000 B.C.]).

[23] See D. J. Hamblin, The First Cities (New York, 1973), for a popular discussion of Catal Hüyük.

[Bianca]

[24] See Hamblin (1973) for a popular discussion of Jericho. Concerning Jericho and its potential relationship to Egypt, Hayes (1965, 92) had this to say: "Jericho lies a scant two hundred miles [320 km] to the east of the Nile Delta, and it would seem inevitable that a Neolithic, food-producing, village culture of the type attested there before 7000 B.C. should have reached northern Egypt from this immediately adjacent southwest Asian area in the course of the seventh or, at the latest, the sixth millennium B.C." Hayes (111) also points out that pendants found at the Sixth-to-Fifth Millennium site of Merimda (Merimde beni-Salame; see Hoffman, 1979, 168-169), on the western edge of the Nile Delta about thirty-seven miles (sixty kilometers) northwest of Cairo, are very similar to pendants found in the early-Neolithic levels of Jericho. Baines and Malek (1980, 20) state that "contacts between Egypt and the Near East are attested already in the Predynastic Period, and the name of Narmer, the latest Predynastic [Egyptian] king, has been found at Tel Gat and Tel Arad in Palestine." Baines and Malek (31) illustrate a "probable route" for trade between Egypt and Palestine, and even suggest that there may have been an early (latest Predynastic? or the beginning of the Dynastic Period?) Egyptian settlement in southern Palestine.

[25] See P. Bierman and A. Gillespie, "Range fires: A significant factor in exposure-age de- termination and geomorphic surface evolution," Geology 19 (1991), 641-644; T. Graf, C.P. Kohl, K. Marti and K. Nishiizumi, "Cosmic-ray produced neon in Antartic rocks," Geophysical Research Letters 18 (1991), 203. 206; and M.D. Kurz, "In situ production of terrestial cosmogenic helirn and some applications to geochronology," Geochemica et Cosmochemica Acta 50 (1986), 2855-2862; and references cited therein.

[26] For comments made to the popular press by various archaeologists and Egyptologists, as well as general news coverage of the "Sphinx-age story," see, for example, articles printed in The New York Times, 24 October 1991 and 9 February redating the sphinx; The Washington Post, 11 November 1991 and 17 February redating the sphinx: Newsday (New York), 25 October 1991; The Independent (London), 14 October 1991; USA Today, 10 October 1991; The Boston Globe, 23 October 1991; The San Diego Union, 23 October 1991; Los Angeles Times, 23 October 1991; The Chronicle of Higher Education, 13 November 1991, 11 December 1991 and 15 January redating the sphinx; The Egyptian Gazette, 28 October 1991; Vancouver Sun, 28 October 1991; International Herald Tribune, 12 November 1991; The San Francisco Chronicle, 8 February Redating the Sphinx; The Daily Telegraph (London), 10 February Redating the Sphinx; and The Houston Chronicle, 23 October 1991 and 12 February 1999.

[27] My research concerning the age of the Great Sphinx would not have been possible without the help and cooperation of many individuals and organizations. In particular, I thank Drs. Mohamed I. Bakr, Ali Hassan and Zahi Hawass (all of the Egyptian Antiquities Organization) for permission to pursue geological and geophysical studies on the Giza Plateau. I thank Drs. Gabor Barakat, L. Abdel-Khalek, M. M. El Aref and Egial Refai (all of the Faculty of Science, Cairo University) for their interest, advice and help. Dr. Thomas Dobecki (McBride-Ratcliff and Associates, Houston) has provided valuable assistance with the geophysical studies on the Giza Plateau. Dr. Robert Eddy (College of Basic Studies, Boston University) first introduced me to John Anthony West, and it was as a result of discussions with West that I became interested in the problem of the age of the Sphinx. Thus, West is responsible for initiating this research and he, along with Boris Said, deserve credit for their hard work relative to the logistics of the Sphinx Project. Of course, all matters of fact and interpretation expressed in this paper are solely my responsibility.

 

Many thanks to Dr. Colette M. Dowell for piecing my article together from segments of unfinished papers and files.
 

Dr. Robert M. Schoch  ©  1992


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


http://www.robertschoch.homestead.com/main.html

[Bianca]

                                   







                                             Remnants of a Lost Civilization?





 Writer John Anthony West and Boston University geologist Robert Schoch contend that weathering of the Member II  layers indicates that the Sphinx was built between 5000 and 7000 BC. If  Egyptologists tend to ignore West and Schoch it is because the two mostly ignore the evidence of the Old Kingdom Egyptian society that surrounds the Sphinx, concluding that the monument must be the remnant of a much older civilization, otherwise unknown to archaeology. They do not explain how their lost civilization disappeared from the archaeological record, nor how the Old Kingdom society of Khufu, Khafre, and their cohorts are so abundantly represented in that record. Nor do they explain what happened to this lost civilization during the thousands of years between their mysterious Sphinx builders and the Old Kingdom (2575-2134 BC). Apart from these problems, the West-Schoch case is flawed in the specifics they cite about erosion on the Sphinx. 

During the American Research Center in Egypt Sphinx project, we identified Member II layers in our drawings by giving each one a number (and a Roman numeral for subdivisions); for example, li denotes the soft bottom, lii the hard top of the first Member II layer above Member I. Geologists Thomas Aigner and Lal Gauri have studied these layers. Gauri has analyzed samples from their surfaces at the Stone Conservation Laboratory at the University of Louisville to understand the mechanics of how the layers eroded, a process that has left a profile of rounded protrusions at the top and deep recesses at the bottom of each layer.

The bases of the lowest layers (li, 2i, and 3i), which are the most recessed, are so soft that in places (such as the inner side of the left forepaw) you can crumble the stone with your fingertips. The surface of the harder, protruding  layers is constantly flaking in large patches, like giant potato chips. A gust of strong wind sends these flakes rattling across the stone surface of the Sphinx, after which more flakes appear on the surface.

In 1978 when we carried out the first thorough cleaning around the base of the Sphinx since the late 1920s  and 30s, Sphinx "dust" from these disintegrated chips had accumulated around the base of the chest and the rock walls of the ditch. In places along the upper edge of the Sphinx's back, where the 1926 restorers poured gray cement into cracks and fissures, the surrounding stone has flaked away, leaving the cement protruding.

[Bianca]

While geologists and conservators may not agree on why the surface of Member II is constantly shedding, or what to do about it, anyone can see that this erosion does progress daily. Schoch is aware that if the same rapid deterioration occurred in antiquity, we would not need to push back the origin of the Sphinx 5,000 years. The 1,100 years between Khafre and first major restoration in the 18th Dynasty. or even half this time, would have been more than enough to erode the Member II into the deep recesses behind Phase I I restoration masonry. In the unabridged version of The Mystery of the Sphinx, a video production about the West-Schoch hypothesis, narrated by Charlton Heston, Schoch dodges this issue: "But the weathering I'm looking at," he says, "is ancient weathering...that we see under ancient repairs, and that's a whole different ball game, a whole different set of evidence than modern weathering." Schoch cites pollution and "acid rain" as possible causes for faster weathering but offers no data to back this claim. Given that we are dealing with the weathering processes (wind or water erosion) on the same limestone layers with the same intrinsic qualities. ancient and modern weathering on the Sphinx are, for the most part, the same ball game.

The Member I and II rock is also transected by many fractures or joints, eroded by subsurface water to form fissures. These run through the rock for many yards. When joints intersect near the surface of the Sphinx they isolate boulder-size pieces that will eventually fall off the body if not supported. This is precisely why a three ton chunk fell from south shoulder in 1988. Such fractures occur throughout the Giza Plateau and were probably created in post-Eocine geological times when regional tectonic forces lifted the formation at Giza. Underground water dissolved the limestone along the joints to create subsurface channels and cavities. When the Egyptians quarried the Sphinx ditch they had to cope with these fissures and cavities. the largest and most problematic of which passes through the waist and is more than three feet across at the top of the back. It extends vertically through the entire 40 feet of the lion body and deep into the floor of Member I. The Major Fissure, as we call it, is formed from a series of  of smaller joints that traverse this part of the geological formation and run together at the Sphinx. It can be easily traced on both sides of the Sphinx, and through the wall of the ditch to the south.

[Bianca]

In some of the West-Schoch photographs we see West standing inside the opening of one of the larger fissures in the walls of the Sphinx ditch. He would have us believe that it is a major piece of evidence for rainwater erosion that occurred after the sphinx was created. We are apparently supposed to believe that the other joints are also surface features created by torrents of rainwater running over the sides of the Sphinx and into its ditch. In Mystery there is a graphic of the Sphinx layers entirely unblemished by any vertical fissures. Rainwater then pours over the edge of the rock wall and gouges out vertical gullies suggesting how the fissures were created. In fact the joints existed in the rock long before the ancient quarrymen ever fashioned the Sphinx and its ditch. That the television scenario may look convincing testifies more to the power of animated video graphics than to bedrock reality. Schoch is aware of the technical studies that discuss how these fissures were formed--he cites them in his articles. But in the unabridged Mystery, he points to a fissure on the south wall of the Sphinx ditch, "clearly formed by water running down the wall, pecking out weak spots."

Next Schoch and West point to the façade of the tomb of Debehen, who lived during the 4th Dynasty. They claim it was carved, as Heston reads from his teleprompter, from "the exact same layers as the Sphinx," and that the facade is weathered by wind.

The evidence, apparently, is the sharp angle between the harder protruding layers and the softer recessed ones. Schoch and West find it chronologically significant that the tomb was eroded by wind, evidenced by an angular profile, while the Sphinx (they claim) was eroded by rain, evidenced by the rounded profile.

[Bianca]

Thus their case for the lost civilization rests, ultimately, on angularity. Schoch, however, never shows any other examples of wind or rain weathering so that we can judge the Giza profiles by comparison. If he did, we would then be interested in how he establishes rates of erosion to demonstrate that the Sphinx was built between 5000 and 7000 B.C. Even if the Sphinx were eroded by rain, Schoch never demonstrates why the rainfall over the last 4,500 years would not be sufficient to round off the corners. We have been caught in many downpours during our work at Giza over the last 20 years. Schoch must present more evidence than a few photographs and some video animation to make the case that these different erosional patterns are chronologically significant. To point simply to the "morphology of the rock"--that is, "the way it looks" --is not enough to convince us of the enormous ramifications that West and Schoch attach to this distinction.

Another problem with Schoch's comparison between the Sphinx and "the exact same layers" in the Old Kingdom tomb concerns the location of the two. The Sphinx sits at the lowest part of the plateau, around 63 feet above sea level, and close to the damp Nile floodplain that today is about 55 to 59 feet above sea level.

Schoch does not tell the audience that those Debehen tomb layers are much higher and drier, 458 yards (more than four football fields) out in the desert west-southwest of the Sphinx, at an elevation between 154 and 206 feet above sea level. Between the Sphinx and the tomb of Debehen there are numerous rock-cut tombs and, most significant, a yawning open-air quarry 250 yards wide, from which Khufu probably took much of the stone for his pyramid. Correlating stratigraphic layers from the Sphinx to the tomb of Debehen is not as easy as Schoch, or Heston's script, would have us believe.

[Bianca]

The layers in the tomb of Debehen are not, in Fact, the same as those in the Sphinx. Certainly all the layers at Giza are part of the Mokattam Formation, but from the bottom to the top of the sequence they vary considerably in quality. Starting at the edge of the Khafre causeway, which is the south side of the Sphinx ditch, one can trace the Sphinx layers southwest. The top of the causeway is formed by layers 4 and 5 as we numbered them in the Sphinx profile. South of the Sphinx ditch and causeway, the surface slopes radically to the south. It is possible to follow the Sphinx layers down this slope, then, proceeding through the cemetery of rock-cut tombs to the west, toward Debehen, you can trace layer 5 and then layer 6 (with some gaps between quarry blocks and tombs). Proceeding west through this quarry, which was later converted to a cemetery of rock-cut tombs, it becomes apparent that as the ground surface rises, layers equivalent to the neck and head of the Sphinx and, farther west, layers that are higher (i.e., younger) in the Mokattam sequence than the Sphinx's head are exposed. Farther west and higher in elevation, the layers of the Debehen tomb are younger, closer to the top frosting in the "layer cake" of limestone, than the Member II layers of the Sphinx, which are at the very bottom.

Schoch also fails to mention in his public presentations the simple fact that different limestone layers, like those in the Debehen tomb and the Sphinx, weather in different ways. Angularity and roundness of weathered rock profiles are due as much to the rate at which one layer grades into another as to different weathering agents. In fact, between Debehen and the Sphinx there are Old Kingdom rock surfaces with both rounded angular profiles. For Schoch to present a creditable argument about erosion patterns and the date of the Sphinx relative to Old Kingdom tombs, he must offer more evidence than a single photograph of one tomb facade. His argument should at least begin with a detailed Stratigraphic correlation that demonstrates he is not comparing apples and oranges. So many factors can affect the erosion of a stone surface that surface erosion is simply not a good basis for dating stone monuments or for postulating the existence of a civilization lost somewhere in Epipalaeolithic or Neolithic times.

[Bianca]

West and Schoch's treatment of the evidence tying the Sphinx to Khafre's pyramid complex is incorrect. They point to the two-stage construction of the Khafre temples, but never cite the detailed architectural studies of this kind of construction at Giza. There is no doubt that the large limestone blocks of the core mid the granite blocks of the casing of the temple walls were built at the same time. In both the Sphinx Temple and Mortuary Temple of Menkaure's Pyramid there are frozen moments where the builders left the work incomplete. Even today you can see where one team was trimming back the rough limestone core walls while another, working several yards behind, was fitting the granite casing. The limestone blocks are not weathered under the intact granite casing on the Khafre Valley Temple. Where the granite casing remains in situ, the original face of the limestone core block behind it is preserved.

Vest and Schoch perceive that the south and west walls of the Sphinx ditch are eroded more at the top than at the bottom--the effect, they say, of rain water beating back a rock face that was originally vertical.

But looking.at the eastern end of the south wall, where much of the original face is still preserved, it is clear that the ancient quarrymen cut the face at this slope in the first place. Regarding the west wall, West and Schoch seem to get tangled in their own argument. Selim Hassan, who excavated at the Sphinx in 1936, pointed out that the drainage channel along the north side of the Khafre causeway opens into the southwestern corner at the back of the Sphinx ditch. This suggests that the ancient quarrymen formed the Sphinx ditch after the Khafre causeway. Schoch, however, believes that Hassan's point is "negated" because "the back of the Sphinx enclosure" was excavated by Khafre five millennia after the time of the mysterious Sphinx builders. Accordingly, the back wall should not show rain weathering because in West-Schoch logic that would date it thousands of years before Khafre. Why, then, do we see Schoch in the Mystery video patting that same back wall of the Sphinx ditch and calling it a "classic textbook example of what happens to a limestone wall when you have rain beating down on it for thousands of years"?

[Bianca]

Geologist Robert Schoch claims that the angularity between recessed and protruding layers on the facade of the

Tomb of Debehen indicates that it was eroded by wind. The rounded profile of the Sphinx, he contends, resulted

from water erosion and proves that the sculpture is much older. Archaeologists believe both tomb and Sphinx were

carved during the 4th Dynasty (2575-2134 B.c.). The tomb facade--originally the western side of the Khufu quarry,

459 yards west of the Sphinx and 75 to 141 feet higher--is carved in bedrock higher in the geological sequence of

layers than those of the Sphinx. The different weathering profiles reflect differences ill the physical properties of the

rocks, not the age of the monuments. Schoch and West cite the roundness of the protrusions and recesses in the

south wall of the Sphinx ditch as evidence of rain erosion, and believe that fissures in the rock were caused by

rainwater after the Sphinx was carved. Most scholars believe the fractures were caused by tectonic forces and

eroded by groundwater long before the monument was carved.



--ZAHI HAWASS AND MARK LEHNER


http://guardians.net/hawass/remnants.htm

[Bianca]

                                 









                      Response in 'Archaeology Magazine' to Zahi Hawass and Mark Lehner



 

by Robert M. Schoch

            In their critique of my research on the age of the Great Sphinx (ARCHAEOLOGY, September/October 1994); Zahi Hawass and Mark Lehner direct their attack primarily toward a popular television show, The Mystery of the Sphinx, which was never intended to take the place of the serious articles I have published on the subject.

            I do not know who was responsible for carving out the core body of the Sphinx. However, carving the core need not have been beyond the capabilities of the Neolithic peoples who inhabited the area. I am familiar with the works by Thomas Aigner and K. Lal Gauri on the stratigraphy of the Sphinx enclosure. These contributions, however, do not fully explain the weathering profiles seen on these rocks. The work of geologists M.M. El Aref and E. Refai, and my own work, supplements Aigner and Gauri's studies and demonstrates that various types of weathering and erosion can be observed on the Giza Plateau, each type being dominated to varying degrees by different weathering/erosional agents: rainfall or wind. El Aref and Refai have independently confirmed water weathering in the Sphinx enclosure. These features can only be the result of the significantly wetter climatic regime that occurred in the region during predynastic times. The seismic studies that Thomas Dobecki and I pursued in the Sphinx enclosure support these conclusions and allow one to confidently propose a minimum age for the oldest portion of the core body of the Sphinx.

            Much of the Hawass-Lehner argument for a younger Sphinx hinges on the assertion that its present style and rate of weathering and erosion are representative of its past weathering. They state "ancient and modern weathering on the Sphinx are, for the most part, the same ball game." They discuss how soft the limestone is in some places and the flaking of the stone to produce "giant potato chips" without realizing that these superficial weathering features are due to modern-day pollution, acid deposition, salt deposited by rising water tables from the adjacent village, the damming of the Nile, and so forth. Arguably the Sphinx has suffered more during the past century than it did during the previous 5,000+ years.

[Bianca]

  The limestones of the Giza Plateau are criss crossed with fractures or joints, and these joints date back millions of years. However, the joints are not opened up as fissures everywhere on the Giza Plateau. Fissures such as those on the Sphinx enclosure wall can only be produced by water, primarily precipitation, and do bear on the age of the Sphinx. This is dramatically illustrated on the eastern portion of the southern wall of the enclosure where the fissures are much less extreme; here the wall has not taken the brunt of the runoff. Hawass and Lehner do not distinguish between naturally occurring joints and fissures developed only through weathering processes.

            I have used the 4th Dynasty tomb of Debehen as a convenient illustration of classic wind weathering/erosion (which has occurred since Old Kingdom times) versus the precipitation-induced weathering/erosion (predating Old Kingdom times) observed in the Sphinx enclosure. The hypothesis of an older Sphinx does not solely rely on comparing this tomb to weathering profiles in the Sphinx enclosure. Rather, the wind weathering seen at Debehen is typical of the weathering that predominates on much of the Giza Plateau as compared to that seen in the Sphinx enclosure. Of course I am aware that it still rains on the Giza Plateau (about an inch a year), and slight amounts of rain weathering are found elsewhere on the plateau, but not to the degree and extent seen in the Sphinx enclosure.  Hawass and Lehner try, unconvincingly, to dismiss my data as a function of differences in the "rate at which one layer grades into another" at the Sphinx enclosure and the tomb of Debehen, thus producing "angularity" versus "roundness of weathered rock profiles." Yet they fail to demonstrate that the layers grade into one another differently in these different areas or how such differences, if they existed, could account for the major discrepancies seen in the weathering profiles of the different areas under consideration.

[Bianca]

Despite the objections of Hawass and Lehner, I stand by my correlation that the tomb of Debehen is carved from the Secepet Member (Member II) of the Mokattam Formation, as is the majority of the core body of the Sphinx. Lithologically the rocks are comparable. Furthermore, although they are virtually flat lying in a few isolated areas, overall the rocks of the Giza Plateau dip about 5-10 degrees to the southeast and strike NE-SW; the rocks of Debehen to the west-southwest of the Sphinx should be about 100 feet higher in elevation than the same member in the Sphinx enclosure. Given that the tomb and the Sphinx are less than 500 yards from each other, it is valid to compare the weathering and erosional features of the two areas. The fact that the tomb of Debehen is today "higher and drier" can be taken into account when comparing weathering profiles, and has little bearing on the ancient weathering agents that have been a focus of my research.

            Hawass and Lehner disagree with my analysis of the two-stage construction of the Sphinx and Valley Temples, asserting that the limestone and granite were emplaced at the same time. Yet, they do not offer any evidence for their assertion other than an analogy between the construction of Menkaure's Pyramid (which has granite facing limestone) and the Sphinx Temple. I have studied both Menkaure's Pyramid and the Sphinx Temple on site and I do not believe that construction details are comparable.

            I never meant to imply that the walls of the Sphinx enclosure were originally absolutely vertical. In a published illustration I show them at an approximately 80 degree angle before being weathered. However, the fact remains that even taking such a small slope into account the harder layers at the top of the section have been in general eroded back further than softer layers lower in the section, thus corroborating the hypothesis of an older Sphinx.