caliche - tan hardpan caliche from the Mojave Desert - hand/display specimen

Description

If making multiple purchases, please follow the instructions after the
red
text below.
Tan hardpan caliche from the Mojave desert - hand/display specimen
Caliche underlies desert soils in a large part of the Western U.S. and in other arid areas. It is composed of calcium carbonate and can be tens of feet thick. An ideal caliche profile would have a
hardpan
at the surface progressing downward into a
platy
or
laminar layer
which overlies a
nodular zone
,
and then intercepts the bedrock. Since a caliche takes tens to hundreds of thousands of years to form, changes in climate disrupt this sequence and an ideal profile is seldom seen.
The term
caliche
is Spanish from the Latin
calx
for lime. It forms when calcium carbonate is leached from the overlying soil and accumulates some distance below the surface.
In the Mojave desert, a major period of calcium carbonate deposition appears to have occurred 20,000 years ago, forming a horizon below a depth of 100 cm during a period of greater rainfall than at present. As the climate dried, CaCO
3
precipitated to form caliche.
The mill for the Copper World Mine was at Valley Wells. The caliche there served as the roof of the mill workers' dugout cabins during the first 20 years of the 1900s, where, comfortable underground, they simply excavated under the caliche from the side of a ravine. In other parts of the Southwest, caliche posed a challenge for pioneers when they attempted to dig wells.
An example of this culturally interesting rock.
The field photo shows one of the mill workers' dugout cabins with a caliche roof.
Select a specimen:
When more than one specimen is shown, you can select a particular specimen by telling us what is in the photo with it - a black mechanical pencil, a silver and black pen, a silver and blue pen, or one of those plus some number of coins, or you can let us make the selection.
Making multiple purchases?
Just add items to your cart. When finished shopping, click on
“request total”
at upper right in the Shopping Cart window.
Do not proceed to checkout.
We will send an eBay invoice with the correct combined shipping.
The combined shipping will often be less than eBay shows. Please wait for that invoice before paying.
There is no obligation to purchase. You can decide after seeing what shipping will cost.
Shipping:
Priority Mail, which varies by weight and zip code. We can ship for less than eBay will charge, and will refund the overpayment as soon as the box is packed.
.
International customers:
We sell and ship internationally. If eBay’s page does not let you enter your country name to determine the shipping cost for something you are interested in, please contact us.  We can tell you what the shipping would cost and how to make the purchase. You can then decide if you wish to complete the transaction. Use the
Contact Seller
link in the Seller Information box on the right side of this page.
Pay securely with your debit or credit card through PayPal! You do not need a Pay Pal account to do this. Yes, we do combine shipping!