Soil Survey of Jackson County, Texas Page: 91
vii, 147, [2] p., 50 folded p. of plates : ill., maps (some col.) ; 28 cm.View a full description of this book.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
Jackson County, Texas
clay that has montmorillonite as the dominant clay
mineral. These soils shrink and develop wide, deep
cracks when dry and swell and become very plastic and
cohesive when wet. Because of overburden pressure,
soil movement, and stress caused by wetting and
drying, a platy and wedge-like structure can form in the
Bss horizon. Individual structural aggregates have
distinct cleavage planes and polished faces known as
slickensides. When the soil is dry, soil material from the
surface often falls into the wide, deep cracks or is
washed into the cracks by rain. When the soil is wet,
lateral pressure caused by the swelling can result in
surface heaving, which eventually leads to the formation
of gilgai microrelief that consists of microknolls and
microdepressions. This gilgai microrelief is locally
referred to as "hogwallow land." Laewest and Francitas
soils have Bss horizons that have slickensides. They
have gilgai microrelief.
The C horizon is relatively unchanged by soil-forming
processes, although in some places it is modified by
weathering. It is generally below the B horizon, such as
in Laewest and Morales soils. In some alluvial
sediments near streams, rivers, and bays, the C horizon
is directly below the A horizon. Placedo, Swan, and
Zalco soils have C horizons directly below A horizons.
A horizon that is gray and shows evidence of
reduction and segregation of iron compounds is
designated by the addition of the symbol "g." Relatively
long periods of wetness in poorly aerated horizons can
reduce the amount of these iron compounds. In the
more soluble, reduced form, appreciable amounts of
iron can be translocated by water from one position to
another within the soil. The presence of brown, yellow,
or red mottles in predominantly gray horizons indicates
segregation and local concentration of oxidized iron
compounds as a result of oxidizing and reducing
(wetting and drying) conditions in the soil. Aransas,
Cieno, Placedo, and Swan soils are examples of soils
that have mottles in these colors.
Another important process in soil formation is the
loss of components from the soil. Water can leach
many soluble components, such as calcium carbonate,
to the lower horizons in the profile. A horizon that has a
significant accumulation of calcium carbonate is
designated by the addition of the symbol "k." Other
accumulations of soluble components, such as
exchangeable sodium, is designated by the addition of
the symbol "n". Ganado, Inez, Marcado, Palacios, and
Texana soils are examples of soils that have
accumulations of calcium carbonate in the lower
horizons. Livco and Palacios soils are examples of soils
that have accumulations of other soluble components,
such as exchangeable sodium.Surface Geology
Prepared by Saul Aronow, Department of Geology, Lamar
University, Beaumont, Texas.
Jackson County lies in the West Gulf Coastal Plain
geomorphic unit (14). The formations in the unit dip
toward the gulf at an angle less than 3 degrees. They
crop out in bands that parallel the gulf coast and are
broken by normal faults that dip toward the gulf (23).
The central part of the county is drained by the
Lavaca and Navidad Rivers, the southwestern part is
drained by Garcitas and Arenosa Creeks, and the
southeastern part is drained by Carancahua Creek. All
of these rivers and creeks flow into subbays of the
Matagorda Bay complex. The streams belong to the
intrabasinal group of smaller Gulf Coast streams that
have drainage basins that are essentially confined to
the coastal plain (10). They have incised channels and
are depositing small bayhead deltas into drowned lower
channel portions. The major streams of the Texas Gulf
Coast, however, are extrabasinal streams, such as the
Rio Grande and Colorado Rivers, and have drainage
basins that extend well beyond the coastal plain or are
basin-fringe streams, such as the Guadalupe River, and
have drainage basins that include areas peripheral to
the coastal plain. The basin-fringe rivers are building
deltas into drowned valleys. The larger, extrabasinal
streams fill the drowned lower valleys and flow directly
into the gulf.
The surface geology of Jackson County is shown on
several regional maps (1, 16, 17, 30, 31). The surface
geologic units in the county are all Pleistocene or
younger in age, less than 2.5 million years old. The
oldest unit is the Lissie Formation, which crops out in
the northwestern part of the county. The next youngest
unit is the Beaumont Formation in the southeastern part
of the county. The Lissie and Beaumont Formations are
both Pleistocene in age and contemporaneous with
several global advances and retreats of continental ice
and the associated fall and rise in sea level.
The youngest units in the county are Holocene in
age, about 10,000 years old. They include the flood
plain deposits along the major and minor streams, the
deltas being built in Lavaca and Carancuhua Bays, and
the shoreline features around the edges of the bays.
The terraces that flank the Lavaca River are possibly
late Pleistocene in age.
Lissie and Beaumont Formations
The Lissie Formation is probably mid Pleistocene in
age. It crops out in the northwestern part of the county
in areas of the Morales-Cieno, Nada-Cieno, and the
northern part of the Inez-Milby general soil map units. It
consists of sediments of fluvial and deltaic origin that
are the parent materials of the soils in these units. The91
Upcoming Pages
Here’s what’s next.
Search Inside
This book can be searched. Note: Results may vary based on the legibility of text within the document.
Related Items
Other items on this site that are directly related to the current book.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Book.
Miller, Wesley L. Soil Survey of Jackson County, Texas, book, May 1997; Washington D.C.. (https://texashistory.unt.edu/ark:/67531/metapth224539/m1/101/: accessed April 28, 2024), University of North Texas Libraries, The Portal to Texas History, https://texashistory.unt.edu; crediting UNT Libraries Government Documents Department.