Paleosol sequences within Lower Permian cyclothems of Kansas: Evidence of climatic cyclicity

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

OSTI ID:5806596

Miller, K B; McCahon, T J ^[1]

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1. Kansas State Univ., Manhattan, KS (United States). Dept. of Geology

The Lower Permian (Wolfcampian) cycles of Kansas are broadly similar to the better known Upper Pennsylvanian (Missourian) cyclothems of the midcontinent. The morphological features of paleosols within five successive variegated mudstone units of the Council Grove and Chase Groups have been described in detail. A consistent pattern has emerged with aridic paleosols near the bases of the mudstones intervals and vertic paleosols toward the tops. The lower paleosol profiles are typically calcareous with well-developed carbonate accumulation (Bk) horizons. These may contain carbonate nodules, rhizocretions, or less commonly calcretes (K-horizons). Drab haloed root races are a common feature of these grayish reddish brown B horizons. The reddish color records oxidation under fairly well drained conditions, the underlying greenish gray horizons probably indicating the average position of the water table. Thin greenish gray to gray elluvial (E) horizons are preserved at the tops of many profiles. The upper paleosols within each variegated interval are characterized by well-developed vertic structures. Pedogenic slickensides, pseudoanticlines, and occasional gilgai result from the expansion and contraction of the soil such as occurs in a seasonal wet/dry environment. These paleosols are greenish gray to olive gray and often have abundant concertina root traces. The absence of a red oxidized horizon suggests more poorly drained conditions. The upward trend from drier, better drained soils to vertic, poorly drained soils could have been generated by short-term climate change toward increasing, though still seasonal, precipitation. If so, this observation suggests that cyclic climatic change may have been an important factor in generating Lower Permian cyclothems. Such a conclusion is consistent with other evidence that the limestone and shale facies of these cyclothems were deposited in consistently shallow depositional environments.

• OSTI ID: 5806596
• 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
ATMOSPHERIC PRECIPITATIONS
CLIMATIC CHANGE
DEVELOPED COUNTRIES
GEOLOGIC AGES
GEOLOGIC STRUCTURES
GEOLOGY
GEOMORPHOLOGY
KANSAS
NORTH AMERICA
PALEOCLIMATOLOGY
PALEONTOLOGY
PALEOZOIC ERA
PERMIAN PERIOD
SEASONAL VARIATIONS
SEDIMENTARY BASINS
SOILS
STRATIGRAPHY
USA
VARIATIONS