Pyramid Quest (12 page)

Further evidence that this could be the case comes from the Valley and Sphinx temples, which are situated in front of the Sphinx. It is absolutely certain that the limestone blocks used to build the Sphinx Temple were quarried from the enclosure when the body of the Sphinx was first carved, and highly probable that the limestone blocks of the Valley Temple were as well. The temple limestone blocks were subsequently faced over with an outer layer of granite ashlars marked with Old Kingdom inscriptions dated to the approximate time of Khafre’s reign. Interestingly, the ashlars are weathered very differently from the underlying limestone blocks. The granite shows only minimal wind weathering, yet the limestone beneath reveals the uneven surface to be expected from long-term exposure to rainfall. Egyptian stonemasons actually fitted some of the ashlars to the wavy surface of the limestone to make a smooth and esthetically pleasing outer layer. Clearly, the limestone had been subject to rainfall weathering much like the Sphinx, and then was repaired with the granite outer layer at a later date—possibly during the reign of Khafre.

The words
Egypt
and
rain
do not usually appear in the same sentence, yet Egypt has not always been the desert it is today. When the most recent Ice Age ended, circa 13,000 B.C., heavy rain typified the climate of the Mediterranean, until 9500 B.C. What is now desert in Egypt was then green, well-watered grassland dotted with clumps of trees. A drier period followed, between 9500 and 7000 B.C., as the temperate zone’s rain belt moved north. Then came another rainy period, from 7000 B.C. until between 3000 and 2350 B.C., when arid conditions more or less the same as the current climate set in, and water weathering yielded to wind.

This climatological history, combined with the weathering and erosional features seen on the stone, indicates that both the Great Sphinx and the Sphinx and Valley temples were originally built at a time when Egypt was wet and rainy. And they must have been built far enough back in that rainy period to allow the obvious, substantial water weathering to develop.

Data indicating just how far back came from seismological testing conducted in the Sphinx enclosure by seismology expert Thomas Dobecki in 1991. The data gave Dobecki and me a look at a cross-section of the structures under the Sphinx, and revealed an interesting pattern of uneven weathering. The Sphinx itself faces east. The northern, southern, and eastern floors of the Sphinx enclosure are weathered to a depth that varies between 6 and 8 feet below the surface. The western floor, however, is weathered less deeply, to a maximum of just 4 feet. The difference isn’t due to variations in the rock; the exposed floor of the enclosure on all sides belongs to the same stratum of limestone. Rather, the western floor has been weathering for a shorter period of time. Obviously, it must have been excavated at a considerably later date.

The western end of the Sphinx enclosure shows further evidence of two-stage construction. There are two excavation walls at this end of the enclosure. The higher wall, which lies farther west, is deeply coved and fissured by rain and runoff. It must have been dug out when Egypt’s climate was wet and rainy, well before the Old Kingdom. The second, lower wall, which is closer to the Sphinx’s rump, shows much less precipitation weathering. It was along the base of this lower wall that the western seismic line, showing a depth of only 4 feet of weathering, was taken. The lower wall may have been excavated later than the higher wall—and certainly the western floor of the enclosure, where we took our seismic readings, was excavated later than the remainder of the enclosure—at a time when Egypt had already turned dry, perhaps during the Old Kingdom.

The evident two-stage construction of the Sphinx enclosure and the Valley and Sphinx temples gives rise to a likely scenario. All three structures were built well before the reign of Khafre—and Khufu, for that matter—when heavy rain regularly washed across Egypt. Then Khafre claimed this corner of Giza for himself by refurbishing the temples and altering the Sphinx. Originally, I suspect, the sculpture’s body emerged from the bedrock as if it were an integral part of the plateau. By carving the rump and digging out the western enclosure to a second, lower level, Khafre divided the monument from the rock and gave it its own separate esthetic existence.

The two-stage construction hypothesis also helps explain another anomaly of the Sphinx: the curious size of its head. When the sculpture is viewed from the side, the head appears disproportionately small. This is by no means a convention of Egyptian art; all the monuments I know of have a correct body-head balance except, notably, the Great Sphinx. When I inspected the head up close, I saw relatively recent (Old Kingdom versus earlier) chisel and tool marks. This evidence, along with the appearance of the stone itself, have led me to believe that the current head, complete with the dynastic headdress of a dynastic pharaoh, was recarved from an earlier, larger head—perhaps, given the leonine form of the rest of the sculpture, that of a lion. This recarving possibly took place at the same time as the excavation of the rump, or it may have happened during earlier dynastic times.

The Sphinx and the temples had to have been built long enough before Khafre that the rains could weather them sufficiently to require repair in c. 2500 B.C. Just how long would that take? In other words, how old is the Sphinx?

The seismology data provide a scale. It has taken 4,500 years for the subsurface weathering at the younger, western floor of the Sphinx enclosure to reach a depth of 4 feet (comparable to the weathering depth found around Old Kingdom structures of c. 2500 B.C.). Since the weathering on the other three sides is between 50 and 100 percent deeper, it is reasonable to assume that this excavation is 50 to 100 percent—or approximately 2,200 to 4,500 years—older than the western end. If we accept Khafre’s reign as the date for the western enclosure, then this calculation pushes the date for the Great Sphinx’s original construction back to the 4700 to 7000 B.C. range, or 6,700 to 9,000 years ago.

A number of scholars have argued that my research is wrong. According to them, I have misinterpreted the evidence.

One of those scholars is Mark Lehner, who is director of the Giza Plateau Mapping Project, is affiliated with the University of Chicago, is a research associate at the Harvard Semitic Museum, and is sometimes cited as the world’s most prominent authority on the Egyptian pyramids. Lehner has said that present climatic conditions in Egypt account for the weathering of the Sphinx. The country has been industrializing rapidly, and Cairo is growing by leaps and bounds because of a high birthrate and steady immigration from rural areas. Extreme air pollution makes the small amount of rain that falls during the Egyptian winter very acidic. As we know from pollution studies in other areas, limestone holds up poorly against acid rain. Thus, Lehner argues, I am mistaking the destructive weathering of the present for past damage, and confusing the new with the old.

Two fundamental problems plague Lehner’s argument. For one, acid rain wouldn’t produce the runoff patterns obvious on the walls of the Sphinx enclosure. For another, how is it that the acid rain has done so much damage to the Sphinx alone, when indisputably Old Kingdom structures constructed from the same limestones are holding up much better under the same chemical assault?

K. Lal Gauri, a University of Louisville geologist, maintains that the weathering of the Great Sphinx came not from rainfall but from the various effects of chemical weathering, particularly something known as “exfoliation,” or the flaking away of the limestone surface. According to Gauri, dew forming at night on the rock dissolves soluble salts on its surface, making a liquid solution drawn into tiny pores in the stone by capillary action. During the heat of the day, the solution evaporates, and salt crystals precipitate in the pores. The forming crystals exert pressure that causes the surface of the limestone to flake away.

This process is, in fact, an important current weathering factor on the Giza Plateau. However, it alone cannot account for all of the weathering features seen in the Sphinx enclosure or, more important, for the specific weathering features in the Sphinx enclosure, such as the more intense weathering, erosion, and degradation in the western end of the Sphinx enclosure. In addition, the weathering processes Gauri proposes have their maximum effect under extremely arid conditions when the Sphinx is exposed to the elements. If the Sphinx and Sphinx enclosure are buried under a layer of sand—as they have been for much of their existence—they are largely protected from these effects. Interestingly, the exfoliation Gauri proposes should be operating on all the limestone of the Giza Plateau, yet somehow no other surface shows the same type of weathering and erosional profile as the Sphinx enclosure. While salt crystal growth is indeed damaging the Sphinx and other structures at present, this mechanism does not explain the ancient degradation patterns seen on the Sphinx’s body and in the Sphinx enclosure.

James Harrell, a geologist at the University of Toledo, gives a different spin to the same line of logic as Gauri’s argument. According to Harrell, the culprit is sand piled for centuries against the Sphinx and wetted by rainfall, Nile floods, and capillary action. Flooding, though, would have undercut the base of the Sphinx and the enclosure, yet there are no such features. Nor does wet sand around the base of the Sphinx explain the obvious and pronounced weathering on the upper portions of the enclosure walls and the body of the monument. Indeed, there is no documented mechanism known by which wet sand piled against a limestone surface will produce the weathering and erosional profile seen on the body of the Sphinx and on the walls of the enclosure. Sand, even wet sand, may actually have done more to preserve the Sphinx. Capillary action, far from being a mechanism capable of keeping numerous feet of piled sand wet over many centuries, is negligible in loose sands in arid areas. Furthermore, according to Harrell’s theory, the Twenty-sixth Dynasty (c. 600 B.C.) tombs cut into the back wall of the Sphinx enclosure should show a similar weathering profile to that seen on the Sphinx and Sphinx enclosure walls. They do not, however. Harrell’s wet-sand theory is all wet.

There is another major problem with the work of Harrell and, for that matter, Gauri. Neither exfoliation nor wet sand can make the coved rock and vertical fissures, or runnels, that are wider at the top than at the bottom and are a prominent feature of the western end of the Sphinx enclosure. Runnels come only from water that is running.

Farouk El-Baz, a geologist who directs Boston University’s Center for Remote Sensing, argues that the Sphinx was carved from already-weathered rock. The Great Sphinx is, he maintains, what we geologists call a yardang, a hill of stone harder than the surrounding rock and carved out by weathering over the eons, like the mesas of the American Southwest. This idea, though, flies in the face of the obvious fact that all but the head of the Great Sphinx lies below the level of the Giza plateau and had to be excavated from the limestone bedrock. The head, it is true, may have been a yardang carved in place by ancient Egyptian stonemasons. The rest of the sculpture had to be excavated first, then carved.

Finally, there is the counterargument of Zahi Hawass, the Egyptian archaeologist who is the director of the Giza Plateau. Hawass claims that the Sphinx was built from limestone of such poor quality that it needed repair almost immediately. The Sphinx has indeed been repaired repeatedly. The question concerns when those repairs occurred, and what they signify. According to Hawass, the poor quality of limestone explains the apparent erosion, but not everyone agrees.

The earliest repairs to the Great Sphinx utilized limestone blocks that conform to the style followed by Old Kingdom masons. Hawass maintains that the repairs were done during the Old Kingdom, most likely soon after Khafre had the Sphinx carved from the limestone bedrock. Lehner disagrees. He holds that New Kingdom masons scavenged Old Kingdom blocks from other Giza sites and used them for the repairs.

Lehner’s hypothesis raises logical problems, however. Since each repair block had to be shaped to fit, using existing material would have saved no labor over new. This makes it reasonable to assume that Hawass is right, and that the first repairs to the Sphinx were made during the Old Kingdom.

This solution, however, presents Hawass with a new and serious problem. How could the Sphinx have weathered so fast that it needed repair almost immediately after construction? The Sphinx is carved from what geologists call a competent limestone, one that stands up well enough to weathering to perform effectively as a building material. In addition, tombs adjacent to the Sphinx and cut from the same limestone during the Old Kingdom did not require the same kind of immediate repair the Sphinx did. How can it be that the same material weathered so differently at the same site?

The limestone is not the issue. Rather, the Sphinx had already been in place for so long that it was severely weathered by the time of the Old Kingdom and needed refurbishing. When Khafre set to work, the Sphinx was already old.

As John Anthony West has pointed out, another problem plagues the counterarguments: they are inconsistent with one another. The Sphinx cannot have been weathered because of capillary action, modern acid rain, wet sand, ancient yardang processes,
and
particularly poor-quality limestone. Each of the arguments, weak on its own merits, contradicts some of the others. They are all attempts to salvage the circumstantial case that Khafre built the Sphinx. To allow that the Sphinx is older than Khafre is to admit the inadmissible: something big was happening in Egypt well before Egyptologists think it was.

Two more recent geological studies of Giza add to the evidence for a Great Sphinx much older than Khafre. Writing in 1998 in the journal
InScription ,
geologist David Coxill confirms my observations of the weathering patterns at Giza and supports my hypothesis that the Sphinx must date to a time of heavy rainfall well before the Old Kingdom. Coxill hesitates to push that date back to the 5000-7000 B.C. range on the basis of seismological data, but he agrees that the Sphinx “is clearly older than the traditional date.”
⁵
How much older he does not say.