Hi Batavus,
As a resident of Central Texas, I can tell you that this stuff is
absolutely ubiquitous here in the Lone Star State, covering as it does
numerous surfaces from country roads to driveways, to playgrounds,
fields, and backyards everywhere. But I, probably like most Texans,
never gave much thought as to its origins or distribution patterns.
It’s just there – everywhere! So I found your question most
intriguing.
To begin, the most commonly used spelling of the word is “caliche”
rather than “koliche, ” which may be helpful for you to know as you
hunt down further information. What I’ve discovered is that there are
a great many definitions of caliche, and some scholarly disagreement
as to which might serve as the “official” one. In fact, there seems
to be quite a variety of caliche. I had no idea there were so many
kinds, or that the stuff was so difficult to classify. The common
thread of agreement seems to be that the word itself stems from the
Latin “cal,” which means lime, and might thus be presumed to refer to
a type of limestone or lime deposit.
However, caliche is rather usually defined as a type of calcium
carbonate deposit. This latter definition is found in a number of
places, such as this Texas A&M University discussion group mailing
list: http://twri.tamu.edu/septictalk/archive/2000-Sep/Sep-12.3.html
or this rather lighthearted page from Southwestern Archaeology’s
newsletter: http://www.swanet.org/news.html Here’s yet another
definition: “n 1: crust or layer of hard subsoil encrusted
with calcium-carbonate occurring in arid or semiarid regions
[syn: {hardpan}]” from Word Net at this site:
http://www.beetfoundation.com/words/c/caliche.html . And
HyperDictionary agrees with that, as you can see from their definition
here: http://www.hyperdictionary.com/dictionary/caliche . The rocks
you describe are likely what is known as “caliche nodes,” as opposed
to caliche clay or layers, though they are all related. In fact, in
speaking of caliche nodes, one place says that their “presence is
highly indicative of a caliche layer at some depth.” (
http://www.tec.army.mil/research/products/desert_guide/lsmsheet/lscal.htm
)
Since you indicate your interest runs a little deeper than the merely
superficial, you might be interested in a report prepared by the
Texas Natural Resource Conservation Commission (TNRCC) on wastewater
and caliche soils, which contains a very comprehensive, in-depth
description of exactly what caliche is, both scientifically in
geological terms, as well as a working definition for their particular
purposes: http://twri.tamu.edu/reports/2002/2002-003/2002-003.pdf See
pages 10-11.
This same report also details the regional distribution of caliche
soils in general, and in specific regions of Texas, including mention
of areas where such soils are not usually expected to be found in
general, but contain, nevertheless, local deposits of caliche. This
discussion begins on page 12, and includes references to several maps
and figures that illustrate the locations referred to. It is very
clear that caliche is found throughout the state and not just in the
north central area between Dallas and Waco.
As to its formation, caliche is generally regarded as the result of a
chemical process whereby certain minerals are leached out of the
surface soils and redeposited below the surface. For example, in this
discussion of the Ogalalla Aquifer, ( http://www.npwd.org/Ogallala.htm
)which extends into northwestern Texas, it is stated that caliche “is
formed by the leaching of carbonate and silica from surface soils and
the re-deposition of the dissolved mineral layers below the surface,”
an explanation of its origins further supported by other experts.
Another site links caliche formation to climate, as it says, “Caliche
forms due to the rise and fall of mineral-rich groundwater during wet
and dry seasons. When the water rises it deposits calcium carbonate
into the soil which accretes into caliche nodules ...” (Horner, John.
1988. Digging Dinosaurs. New York: Workman Publishing.) (
http://www.dinosauria.com/dml/diction.htm )
Formation on sea bottoms, as you described, would be more typical of
actual limestone which is composed of the decomposed skeletons of
organic specimens. There is an excellent discussion of limestone
formation at this site: http://www.geobop.com/Symbols/Geo/1/Limestone/
From reading the foregoing descriptions of caliche vs. limestone
formation, it might almost seem as if water were leaching the calcium
carbonate from limestone formations, and redepositing this to form the
caliche deposits. But this site says that caliche is actually a type
of pre-limestone formation:
http://www.cmpbs.org/publications/AD3.4-Sust_Building.pdf See 3.2
paragraph 2. Here is another site with an interesting discussion on
the origin of caliche, and some further good descriptions of its
various forms: http://www.tec.army.mil/research/products/desert_guide/lsmsheet/lscal.htm
And here are some more links on caliche for you to pursue:
See AGL 3 on the nature of caliche development:
http://www.agl.uh.edu/mbdthesislist.htm
“Definition and Delineation of Cemented Deposits:”
http://www.ce.unlv.edu/egl/projects/current/def_del_cem_dep/def_del_cem_dep.html
Ground Water Atlas of the US (USGS):
http://sr6capp.er.usgs.gov/gwa/ch_e/E-text.html
UT Walter Geology Library – Virtual and Online Geologic Field Trip
Guides:
http://www.lib.utexas.edu/geo/onlineguides.html
Caliche deformation in Kerr County, Texas:
http://www.lgsweb.org/field03z.html
Article by Dr. J.R. Feucht, Colorado State University on gypsum and
caliche in soils:
http://www.wtamu.edu/~crobinson/DrDirt/gypsum.html
I hope this information meets or exceeds your expectations, but please
do request clarification if you don’t understand something. I
appreciate this opportunity to be of assistance to you, while at the
same time learning more about the area in which I live. Thank you.
Best wishes,
--Byrd
Search terms used:
texas caliche
caliche formation OR origin
central texas caliche
north central texas caliche geology
caliche definition OR distribution OR formation
limestone formation OR origin
“what is caliche” texas |
