Re: you bickerers about pyramids, your Bible theories disgusts God
August Matthusen (matthuse@ix.netcom.com)
Thu, 09 Jan 1997 17:56:50 -0800
Michiel Tiller wrote:
>
> The last major flooding of the earth dates back to 10500 B.C., at the
> end of the last ice age. Recent discoveries has led some scientists to
> believe that the pyramids of Giza and the nearby sphinx were built
> around that time.
Who are these scientists and in which peer-reviewed journals
did they publish?
> The sphinx shows signs of extreme erosion, which even an amateur
> geologist would recognize as being caused by very heavy rainfall. The
> last time rain of this extremity has occurred in Egypt would be after
> the melting of the ice caps of the last ice age.
[snip]
*Extreme* erosion is not the focal point of the argument upon
which the suppososed old age is based. The supposed old age is
based on an interpretation of the conditions supposedly required
for the generation of the weathering morphology (i.e., a "rounded"
vs. a "straight" morphology.
I'm not exactly sure what you mean by "very heavy rainfall".
Bull (1991; _Geomorphic Responses to Climatic Change_) has a
figure (fig. 3.3, p. 127) which shows the climate change for
the northern Africa area. Northern Sudan, Central Sahara,
and Egypt all became more arid c. 5000 years ago after experiencing
wetter conditions from c. 12000 years to 5000 years ago.
These "wetter" conditions ranged up to semi-arid (average approx 10 to
20 inches/year; Bull states: "In northern Africa, areas that now are
extremely arid were wet enough in the early to mid-Holocene for
sustenance of semiarid land snails, plants, ostriches, and hydrolytic
pedogenesis." [note: Bull's citations and references not listed]); the
current arid conditions equate to less than 10 inches/year average.
Unless you consider 10 to 20 inches per year "very heavy rainfall"
then the area in question has not had "very heavy rainfall" for a
*much* longer time than since the melting of the ice caps.
To go into the Sphinx weathering argument in more detail:
The argument really hinges on weathering of the in situ rock. Erosion
is the process which removes material; weathering is the process which
degrades the rock in place. Schoch (see biblio below for citations)
has indicated that the rounded profile of some of the Sphinx was due to
"precipitation-induced weathering" rather than "wind-induced
weathering" which supposedly produced a straight profile on other
weathered rock structures. Supposedly there was only sufficient water
to produce this "precipitation-induced weathering" during a wet period
some 7000 years ago. Thus, Schoch makes his argument for increased
antiquity of the Sphinx (i.e, it had to exist more than 7000 years ago
rather than the approx 4500 years ago that it is normally dated to).
West has pushed this age back further and has tried to relate it to
Atlanteans with out any apparent scientific basis.
The Sphinx comprises several different strata of limestone. The
different strata have different lithologic properties, among which are
different styles of weathering.
Schoch (and West) want to claim that "precipitation-induced weathering"
differs from "wind-induced weathering." However, they have not
demonstrated that this is true and indeed they have not even tested
this hypothesis, merely averred that it is true. In reality, most
weathering morphologies are due to lithologic differences among various
strata. Additionally, Schoch (and West) want to exclude other
weathering processes and lump things into the poorly defined categories
of "precipitation-induced weathering" and "wind-induced weathering"
without explaining what is meant by these terms, without fully defining
the processes involved, and without explaining how or why these
categories result in the respective morphologies. If the
"precipitation-induced weathering" occurred 7000 years ago and the
"wind-induced weathering" occurred on structures 4500 years old, why
didn't the "wind-induced weathering" obliterate the older
"precipitation-induced weathering"? Gauri et al. (1995) have been
working on the Sphinx for years studying its rapid weathering and have
found that the rapid weathering (which predates high atmospheric acid
content) is due to formation of salt crystals in the rock pores which
causes exfoliation due to hydrostatic pressure.
Salt crystal exfoliation occurs when the sphinx is in the open air
(sub-aerial weathering). After sunset the atmospheric moisture
(humidity) condenses on the sphinx, the salts are hydroscopic and help
draw the water into pores and the capillarity of the pores also helps
draw the water in; this dissolves the salts. The next morning after
sunrise, the heat and aridity causes the water with dissolved salts to
evaporate and the crystals to precipitate as the solution evaporates.
The crystals expand and push against the remaining solution to provide
a hydrostatic pressure against the pore walls. Over time this helps to
physically break down the rock and cause exfoliation.
This exfoliation results in a rounded profile similar to that which
Schoch indicates could only be due to "precipitation-induced
weathering."
Schochs dating is based on the premise that the weathering was an
"either-or" situation. Either "precipitation-induced weathering" or
"wind-induced weathering". That is, if it wasn't "wind-induced
weathering" then it was "precipitation-induced weathering" which could
have only occurred during the pluvials.
Things are not this straight forward, as other weathering mechanisms
are also capable of producing this "rolling profile". For example
salt crystal exfoliation or sub-soil weathering by dissolution or
hydrolysis can also produce rounded profiles.
There are also concerns on the entire idea of "wind-induced weathering"
producing a "straight morphology". This is a rather dated idea which
has been outmoded by the consideration of how much altitude a sand
grain can achieve while being wind blown.
To quote from the _Encyclopedia of Geomorphology_ (1968) regarding wind
erosion: "As recently as 1920 many geologists attributed much of the
broad-scale modeling of desert landscapes to wind erosion. We now know
that this view to be seriously in error. Many features thought clearly
to indicate the abrasive actions of wind blown particles are becoming
increasingly suspect. Bagnold's [1941; _The Physics of Blown Sand and
Desert Dunes_] studies indicating that the relative density of sand
flow falls off sharply above a few centimeters over a sand surface, and
less than 10 cm over a pebble strewn surface, has eliminated many
pedestal rocks with notches from 30-150 cm above the ground as possible
wind blown erosion features. The coincidence of notching with
lithology and, in selected areas, the discovery of clear crystalline
selenite (a variety of gypsum, a mineral easily frosted by wind blast)
as a surface litter near pedastel rocks and the preservation of
Paleolithic rock pictures above the abrasion zone are further evidence
of restricted wind cutting even in desert areas."
Gauri et al also include a figure which shows both the "rolling
profile" and the "straight profile" in the same structure in the
pharonic necropolis; something which should not be possible if Schochs
either-or premise was correct.
All in all, Schoch seems to have focused on one explanation and ignored
several other working hypotheses which explain the phenomenon much more
concisely than having to resort to the Sphinx being carved 2500 years
before there is a well recognized civilization in Egypt (not to mention
the Atlanteans). And while this idea has been spread far and wide,
Schochs hypothesis has not been tested, it has just been maintained
that it is true.
I'd suggest reviewing the Gauri et al. (1995) paper for a more detailed
explanation of the controversy and the evidence.
WEST, John Anthony. "Serpent in the Sky: The High Wisdom of Ancient
Egypt." NY: Harper and Row, 1979
MAGAZINE ARTICLES on or by SCHOCH, Robert M.
ARCHAEOLOGY, Sep-Oct, 1994 [Article critical of Schoch's theory on age
of Sphinx]
ARCHAEOLOGY, Jan-Feb, 1995 [Schoch's reply to previous article]
FORTEAN TIMES, Feb-Mar, 1995 [latest update]
GEOARCHAEOLOGY, Vol 7, No 6 (December, 1992). [Dobecki did the sound
wave tests]
KMT, Summer, 1992; Summer-Fall, 1994
OMNI, August, 1992; April, 1993
Chowdhury, A.N., A.R. Punuru, and K.L. Gauri, 1990. Weathering of
Limestone Beds at the Great Sphinx; _Environmental Geology and
Water Science_, Vol. 15, No. 3, pp. 217-225.
Gauri, K.L., A.N. Chowdhury, N.P. Kulshreshtha, and A. R. Punuru,
1990.Geologic Features and Durability of Limestones at the Sphinx;
_Environmental Geology and Water Science_, Vol. 16, No. 1, pp.
57-62.
Gauri, K. L., J.J. Sinai, and J.K. Bandyopadhyay, 1995. Geologic
Weathering and its Implications on the Age of the Sphinx;
_Geoarchaeology_, Vol 10, No. 2, pp. 119-133.
Harrell, J. A., 1994. The Sphinx Controversy: Another Look at the
Geologic Evidence; _KMT_, vol 5., pp. 70-74.
Punuru, A.R., A.N. Chowdhury, N.P. Kulshreshtha, and K.L. Gauri, 1990.
Control of Porosity on Durability of Limestones at the Great
Sphinx,Egypt; _Environmental Geology and Water Science_, Vol. 15,
No. 3, pp. 225-232.
Schoch, R. M. and J. A. West, 1991. Redating the Great Sphinx of Giza,
Egypt [abs.]; Geological Society of America Annual Meeting
Abstracts with Programs, San Diego, Cal.
Regards,
August Matthusen
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