Age-dating implications from the morphologic, petrologic, and isotopic investigations of a calcic soil, Terrell County, Texas /

"marginal" conditions for calcic soil development.

Bibliographic Details
Main Author: Jolley, Darren Manning, 1965-
Format: Thesis eBook
Language:English
Published: [Place of publication not identified] : [publisher not identified] ; 1994.
Subjects:
Online Access:Link to OAKTrust copy
Description
Summary:"marginal" conditions for calcic soil development.
]) indicate the Km and K horizon carbonates are the result of
180 ︢20 Kyr.
A fine grained calcic soil has developed upon Pliocene-
accumulation will allow the use of a calcic soil
an area classified by the Soil Conservation Service as having
analyses on portions of the Km horizon show that CACO, is the
area. The soil has a 109 cm thick Stage IV K horizon at
as reflecting carbonate precipitation in a C4 vegetative
composition, the 8"C results (-3.4 to 1.4%o) are interpreted
Cretaceous (Segovia) limestone. 8"O differences between the K
depths of 68-80 cm. In gravelly areas of the soil a 15-20 cm
developmental index to obtain age-dates in this "marginal"
distinct isotopic signature and correlate with depth. Bulk
dominant material present and displaced the clays forming
dominated by CaCO3 (98% by weight) with minor amounts of
environment. This C4 environment remained dominant
Establishing pedogenesis as the mechanism of carbonate
horizon were analyzed, The comparison of individual laminae
horizons (-3.0 to -1.7%o) and local limestone (-6.1 to -4.9[
in the soil resulting in an average soil development age of
inheritance from limestone as factors influencing isotopic
interface. After ruling out atmospheric mixing and isotopic
isotopic analyses were run on the K horizon and local
Km horizon show a 8"O shift of 2-49voo across the soil-rock
laminar and pisolith features. The carbonate chemistry is
MgCO3 (0.7% by weight). Two stable C and 0 isotope transacts
Miocene alluvial gravels derived from Cretaceous limestone of
novaculite from the Marathon uplift. This soil is located in
pedogenesis is responsible for the carbonate in the soil.
sampled at I and 2.5 mm intervals across the laminated Km
soil processes. Transects across limestone clasts within the
the Stockton Plateau and Paleozoic limestone, chert, and
thick laminar Km horizon caps the K horizon. Microprobe
throughout Km horizon deposition. These results imply
Thus, a calcic soil development index can be response applied
to obtain an age-date. The index analysis of the K horizon
within two transacts shows that individual laminae have a
yields an average amount of secondary carbonate of 92 g/CM2
Item Description:"Major subject: Geology".
Vita.
Physical Description:xiii, 85 leaves : illustrations, maps ; 28 cm.
Also available online.
Bibliography:Includes bibliographical references.