"Albrecht" > wrote in message
ups.com...
On Apr 3, 8:50?am, "Wayne Lundberg" >
wrote:

> It's been said by some
> anthropologists that Tehotihuacan (The sun and moon pyramid complex north
of
> Mexico City) culture came to a sudden demise because of over use of the
> trees to cook the caliche used to make plaster to smooth over the pyramids
> so they could be painted.

Hmmm. That's a different use of the term "caliche" from what I
understood, but I learn new and interesting facts every day. And I can
use those facts to astonish other people with the breadth of my
knowledge. ;-)

As you drive south from Phoenix towards Tucson, you'll encounter the
ruins of Casa Grande, a Native America structure which the National
Park Service sign says is made of "caliche", not adobe as most would
assume.There's a roof over the ruins, to keep them from melting in the
rainy seasons.

"Caliche", in my former understanding, was a coarse dried mud,
composed of sand and tiny pebbles and some soil. There was no straw
used in caliche, unlike adobe. Caliche is tan colored, and adobe is
dark brown, at least when it's made of river bottom mud.

Perhaps the NPS' mistaken definition of "caliche" came from a
misunderstanding of what Spaniards meant, when they talked to
Americans entering the Southwest?

Webster's says that "caliche" comes from the Spanish "cal", which in
turn comes from the Latin "calx".

"Caliche" is impure sodium nitrate, NaNO3, found in Chile and Peru.
It is also a crusted calcium carbonate formed on certain soils in dry
regions by evaporation of rising solutions.

Interesting. I thought caliche is plaster, made from superheated calcium or
gypsum. Now you've motivated me to get into Google for som serious research!
Bottom line is the pyramids were wildly decordated by painting over
plastered walls and fronts. Some can still be seen and enjoyed.

And surely the lime (lye?) used to make nixtamal is made from wood ash left
from the cooking sites, potash (potassium carbonate) and lime (calcium
oxide)?

Wayne