Glacial-eustatic/climatic model for Upper Pennsylvanian marine and nonmarine cyclothems in the Appalachian basin
- Univ. of Iowa, Iowa City, IA (United States). Dept. of Geology
Only glacial-eustatic sea-level fluctuations can account for all the characteristics of Upper Pennsylvanian marine cyclothems in the Midcontinent. Because this control is global, it must have affected deposition during this time everywhere. In the Appalachian basin widespread well developed paleosols represent long-term sea-level lowstand. During Conemaugh marine incursions, rising sea level ponded fresh-water influx to form peat swamps that migrated landward ahead of transgression and produced early transgressive coals. Marine highstand deposits commonly are conodont-rich limestones, typically skeletal packstone with glaucony and phosphorite. Regression resulted in progradation of detrital shorelines with local delta cycles, followed eventually by more paleosol formation and local erosional incision that removed older sediments including the marine units in places. Fluvial sands filled many of these channels. During Monongahela deposition when marine incursions no longer entered the Appalachian basin, the climatic fluctuations recognized by Cecil can reasonably be related to sea-level fluctuations nearby, but with shifts in climatic significance of gross lithotopes. Coal swamps would more likely have formed at maximum marine highstand when the nearby sea would have provided both high base level and an abundant source of rainfall. Nonmarine limestones would more likely have formed at maximum lowstand when the sea was most distant and the climate driest. The intervening detrital deposits between the coals and limestones formed under intermediate seasonal rainfall regimes during both marine transgression and regression farther west in the Midcontinent. Conemaugh and Allegheny coals without overlying marine units probably also represent mainly marine highstand elsewhere, and nonmarine limestones of these ages typically are associated with lowstand paleosols.
- OSTI ID:
- 6135746
- Report Number(s):
- CONF-921058--
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Journal Name: Geological Society of America, Abstracts with Programs; (United States) Vol. 24:7; ISSN GAAPBC; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
Similar Records
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Lowstand versus highstand eustatic models for peat preservation: The coal-bearing rocks of the Breathitt Group, Eastern Kentucky
Related Subjects
011000 -- Coal
Lignite
& Peat-- Reserves
Geology
& Exploration
58 GEOSCIENCES
580000* -- Geosciences
APPALACHIAN BASIN
CARBONATE ROCKS
CARBONIFEROUS PERIOD
CLIMATIC CHANGE
COAL DEPOSITS
DEPOSITION
ENERGY SOURCES
FLUCTUATIONS
FOSSIL FUELS
FUELS
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC STRUCTURES
LEVELS
LIMESTONE
MATTER
MINERAL RESOURCES
ORGANIC MATTER
PALEOCLIMATOLOGY
PALEONTOLOGY
PALEOZOIC ERA
PEAT
RESOURCES
ROCKS
SEA LEVEL
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
VARIATIONS