<HTML>I have been reading Ishmael's links.
He posted a link to Coxhill's analysis, that can be found at
<a href="[
www.sufog.org.uk] view on the Sphinx</a>
Coxhill disputes the arguments of Gauri and Harrell:
<i>Other theories have been put forward to try to counter this claim. Lal Gauri et. al. ('1995) considers that being porous., Member 2 limestone, will suffer from morning dew condensation that dissolves salts within the Iimestone. When the heat of the day j ~ evaporates the water, the salts crystallise out and progressively exert minute pressure " I 11j weakening the rock and opening up fissures already present. Both they, Hawss, and Lehner (1994), suggest that sub-surface water movements, during Eocene times., caused ~ the fissures to open as the water table dropped. This is intriguing, but unlikely to be the case. Firstly, condensation affects all monuments in the Giza complex, but very rarely do they show the same type of w weathering features of the Sphinx, surrounding pit and cut stone blocks of the Valley Temple.
Secondly, these weathering features require intense weathering to form their present profile, and, condensation/evaporation is a relatively mild and insignificant form of mechanical weathering, in this arid climate. Thirdly, fluctuations in the waer table, do not lead to fissures being produced wider at the top. Lal Gauri (1995) also suggests that the roundness of the laminars is due to gradational differences in the hardness of the strata. This does not account for variations in the weathering profile, within Member2 beds, as previously discussed on the Sphinx's body or the presence of open fissures.
Harrell (1994) suggests that wet sands from Nile floodwaters, and occasional rainfall, would have produced wet sands, leading to these weathering features. That is not acceptable, since floodwaters would have produced a wave cut bench and notch, which would certainly be seen today in the surrounding excavation pit. This is not the case, and again this theory does not satisfactorily explain the presence of erosion features higher up the Sphinx' body and pit face. In Karst topography, cavities and natural fissures open up, not by surface run off, but by percolating ground waters. This would not explain the smoothness of the rolling laminars at the top of the Sphinx' body and the surrounding excavated pit.
Therefore, by a process of elimination, it appears that floodwaters and fluctuating ground water' levels cannot explain these weathering features, but rainfall does. Chemical rain weathering, involving dissolved carbon dioxide, have leached the limestone along the lines of least resistance, in the softer Member 2 beds that have been most exposed. Chemically this can be expressed as:
CaCo3 (Limestone} + H20 (Water) + C02 (Carbon Dioxide) = Ca (HC03)2 (Calcium Bicarbonate, soluble</i>
Does anyone know if Gauri and / or Harrell have replied to these comments?
Thanks
Claire</HTML>
