Transcript ESCI 536 - Rocky Mountains Structural Evolution and Styles

ESCI 536 - Rocky Mountains FT
Precambrian-Cambrian
Stratigraphy & Paleogeography:
North American Cordillera
February 3, 2010
J. Morgan
Precambrian
Crystalline
Basement &
Belt Supergroup
1500-900 m.y.
2400-1500 m.y.
(Stewart & Suczec, 1977)
Diamictite &
Volcanic
Sequences
900-800 m.y.
(Stewart & Suczec, 1977)
540-500
m.y.
650-540
m.y.
900-800
m.y.
1500-900
m.y.
Shallow water carbonates
Shallow water terrigenous sediments
Local diamictite, volcanics & more
Belt supergroup (correlative)
Proterozoic basement
2400-1500 m.y.
(Stewart & Suczec, 1977)
Stratigraphy
Belt Supergroup
• PC: Crystalline rocks
• UPC: Discontinuous, locally up (N Cordielleran)
to 3000 m of diamictite,
mudstone, sandstone, cgl, &
mafic volcanics
• UPC-LC: Westward thickening
wedge, locally > 6000 m, of
terrigenous detrital rocks
• MC-UC: Predominantly shallow
water carbonates, up to 2000 m
thick
Precambrian & Cambrian Stratigraphy
(Stewart & Suczec, 1977)
Late Precambrian
rifting (850 m.a.)
Late Precambrian-Cambrian
Evolution, Western NA
(Stewart & Suczec, 1977)
Stratigraphy
• PC: Crystalline rocks
• UPC: Discontinuous, locally up
to 3000 m of diamictite,
mudstone, sandstone, cgl, &
mafic volcanics
• UPC-LC: Westward thickening
wedge, locally > 6000 m, of
terrigenous detrital rocks
• MC-UC: Predominantly shallow
water carbonates, up to 2000 m
thick
• Craton
• Deposition in
local rift valleys
• Rapid erosion
of uplifted rift
margins
• Accumulation
on subsided
shallow-water
shelf
Lower
Paleozoic
Rifted
Margin
Laramide Reactivation
of Basement Structures
Inherited Structural Trends
Cottonwood
Canyon