Origin of the Cambrian-Ordovician sedimentary cycles of Wisconsin using tectonic subsidence analysis

Journal Article · Sun Oct 01 04:00:00 EDT 1989 · Geology; (USA)

DOI:https://doi.org/10.1130/0091-7613(1989)017<0879:OOTCOS>2.3.CO;2· OSTI ID:6966997

Watso, D C; deV Klein, G ^[1]

---

1. Univ. of Illinois, Urbana-Champaign (USA)

Cambrian-Ordovician stratigraphy of the Wisconsin dome is organized into five cycles consisting of basal quartzose sandstone, overlain by glauconitic sandstone and capped by limestone or dolostone. Unconformities at the base of each cycle are found to be coeval with known times of rapid tectonic subsidence in the Illinois basin at approximately 512, 502, 495, and 461 Ma. These times of rapid basin subsidence in the Illinois basin are interpreted to represent resurgent faulting events concurrent with thermal subsidence. Such regional extensional faulting would cause concomitant minor uplift of the Wisconsin dome, developing erosional unconformities observed at the base of each Cambrian-Ordovician stratigraphic cycle. Because sea level was rising at a constant global rate during deposition of the Cambrian-Ordovician cycles, stabilization of minor uplift permitted local transgression and deposition of a successive cycle. Repeated faulting during thermal subsidence in the Illinois basin caused repeated minor uplift on the Wisconsin dome, each time initiating a new stratigraphic cycle. Exceptions to this model include initial Late Cambrian transgression onto the midcontinent and a global drop in sea level at 485 Ma. The findings suggest that geodynamic models proposing a two-stage process from mechanical fault-controlled subsidence to thermal subsidence during evolution of extensional basins may need to be modified to include the occurrence of coeval extensional faulting and thermal subsidence during initial stages of basin thermal subsidence.

• OSTI ID: 6966997
• Journal Information: Geology; (USA), Journal Name: Geology; (USA) Vol. 17:10; ISSN GLGYB; ISSN 0091-7613
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
CAMBRIAN PERIOD
CARBONATE ROCKS
CHALCOGENIDES
DEPOSITION
FEDERAL REGION V
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC HISTORY
GEOLOGIC MODELS
GEOLOGIC STRUCTURES
GEOLOGY
GROUND SUBSIDENCE
ILLINOIS BASIN
LEVELS
LIMESTONE
MINERALS
NORTH AMERICA
ORDOVICIAN PERIOD
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PALEOZOIC ERA
QUARTZ
ROCKS
SANDSTONES
SEA LEVEL
SEDIMENTARY ROCKS
SHALES
SILICON COMPOUNDS
SILICON OXIDES
STRATIGRAPHY
TECTONICS
USA
WISCONSIN