Allocyclic constraints on coal formation in late Carboniferous basins of maritime Canada

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

OSTI ID:6106377

Calder, J H; Naylor, R D ^[1]; Gibling, M R ^[2]

---

1. Nova Scotia Dept. of Natural Resources, Halifax, NS (Canada)
2. Dalhousie Univ., Halifax, NS (Canada). Dept. of Earth Sciences

Continental sedimentation predominated after the Visean, with restricted estuarine deposits in the east late in the Westphalian. Peat formation was constrained to the less arid climate of the Westphalian A-early Stephanian. The intermontane, equatorial setting generated a strongly seasonal paleoclimate locally, requiring the peats be in part groundwater-fed. During the Westphalian A-B, peat accumulated in rapidly subsiding intermontane basins that formed along major strike-slip faults, a tectonic setting partly analogous to the Basin and Range. Peat formation was constrained in each depocenter to a coal window that reflects basin hydrology, a function of local subsidence history, orographic climate and sediment supply. As a result, peat formation was highly diachronous regionally. In the Cumberland Basin, mires sustained in drier periods by alluvial fan discharge formed elongate coals 4.3m thick, of variable ash and sulfur. Elsewhere coals are thinner and of high sulfur. Individual mires had to keep pace with extreme basin subsidence; sediment supply and orbitally forced climate change may have determined whether or not peat accumulation was in equilibrium. In the Westphalian C to early Stephanian, broad basinal areas of moderate, thermal subsidence and the establishment of a Maritime climate permitted areally extensive peat accumulation. Eustatic effects attributed to Gondwanan glaciations become apparent, with mire formation at times of stillstand/highstand and paleovalley incision during lowstands. These cyclothems offer potential for regional Euramerican event correlation. Coals are up to 4.3m thick and high in sulfur. At the same time in the rapidly subsiding lacustrine Stellarton pull-apart basin, basin subsidence, hydrology and sediment supply remained influential. Here, low sulfur, high ash coals reach 13.4m thick.

• OSTI ID: 6106377
• 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

01 COAL, LIGNITE, AND PEAT
011000* -- Coal
Lignite
& Peat-- Reserves
Geology
& Exploration
CANADA
CARBONIFEROUS PERIOD
COAL DEPOSITS
COAL SEAMS
DEVELOPED COUNTRIES
DIMENSIONS
ENERGY SOURCES
FOSSIL FUELS
FUELS
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC HISTORY
GEOLOGIC STRUCTURES
GEOLOGY
HYDROLOGY
MATTER
MINERAL RESOURCES
NORTH AMERICA
ORGANIC MATTER
PALEOCLIMATOLOGY
PALEONTOLOGY
PALEOZOIC ERA
PEAT
RESOURCES
SEDIMENTARY BASINS
STRATIGRAPHY
SULFUR CONTENT
THICKNESS