Use of carbonate morphology and clay content to determine paleosol genesis in the Plio-Pleistocene St. David Formation, southeastern Arizona

Conference · Wed Jan 01 04:00:00 EST 1992 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5807844

Slate, J L; Smith, G A ^[1]

---

1. Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Earth and Planetary Science

Paleosols in the Plio-Pleistocene St. David Formation, southeastern Arizona, were studied to determine the origin of carbonate layers and relation of clay translocation to paleoenvironment. Paleosols that formed above the influence of the ground water table (vadose) have carbonate and clay accumulations similar to those found in nongravelly Quaternary surface soils. Carbonate-enriched zones are beneath clay-rich, carbonate-depleted zones. Carbonate is disseminated in the matrix and is segregated into small ([le]1 cm) nodules, filaments, and seams. Layers of increased clay accumulation have a higher ratio of fine to coarse (or total) clay than overlying or underlying layers indicating that clay in these layers was probably translocated. Paleosols that formed within the influence of the ground water table (hydromorphic) have carbonate and clay accumulations unlike those found in modern, well-drained surface soils. Carbonate is segregated into large (2--10 cm) concretions in a noncalcareous or weakly calcareous matrix. Layers of increased clay accumulation seldom have a genetic relation to zones of increased carbonate. These layers lie above or below or correspond to the zones of carbonate concretions. Thus, carbonate morphology and clay content, in addition to spatial relationships of carbonate- and clay-enriched zones, may be used to infer paleo-ground water table.

• OSTI ID: 5807844
• Report Number(s): CONF-921058--
• Conference Information: Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 24:7
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
ARIZONA
CARBONATE ROCKS
CLAYS
DEVELOPED COUNTRIES
GEOLOGIC FORMATIONS
GEOLOGIC HISTORY
GEOLOGY
GEOMORPHOLOGY
GROUND WATER
HYDROGEN COMPOUNDS
MINERALOGY
NORTH AMERICA
ORIGIN
OXYGEN COMPOUNDS
PALEOCLIMATOLOGY
PALEONTOLOGY
ROCKS
SEDIMENTARY ROCKS
SOILS
USA
WATER
WATER TABLES