Stratigraphy and depositional setting of the Proterozoic Snowy Pass Supergroup, southeastern Wyoming: Record of an early Proterozoic Atlantic-type cratonic margin

Karlstrom, Karl E.; Flurkey, A.J.; Houston, Robert S.

doi:10.1130/0016-7606(1983)94<1257:sadsot>2.0.co;2

Cited by 84 publications

(31 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2; Houston et al, 1992). A transition from rift to open marine conditions occurred at the level of the Vagner Formation before the end of the glacial epoch (Karlstrom et al, 1983). The youngest glacial horizon is overlain by thick, mature, Alrich and hematite-bearing quartzites (Medicine Peak Quartzite).…”

Section: Regional Geology and Stratigraphymentioning

confidence: 99%

“…Detrital zircon age is after Premo and Van Schmus (1989). were dated in the Sierra Madre and Laramie Mountains at 2.09 Á/2.01 Ga (U Á/Pb zircon and baddeleyite; Premo and Van Schmus, 1989;Snyder et al, 1995;Cox et al, 2000). Evolution in dike and sill composition to calc-alkaline magmatism was related to a progressive change in the tectonic environment from rift to passive margin and to foredeep (Karlstrom et al, 1983). Pegmatitic metagabbro intruding the Cascade Quartzite of the Snowy Pass Group in the Sierra Madre was dated at 20929/9 Ma (UÁ/Pb zircon; Premo and Van Schmus, 1989).…”

Section: Regional Geology and Stratigraphymentioning

confidence: 99%

“…The Deep Lake Group and the lower Libby Creek Group record rift and passive margin settings, whereas the upper Libby Creek Group reflects either a transition from a passive margin to a foredeep (Karlstrom et al, 1983), or a reactiva- tion of the mature passive margin (Bekker and Eriksson, in press). Mafic sills and dikes that range in composition from tholeiitic to calc-alkaline intrude the whole succession.…”

Section: Regional Geology and Stratigraphymentioning

confidence: 99%

“…Atmospheric p O 2 may have changed episodically during the glacial epoch in response to fluctuations in the exogenic carbon cycle (Bekker et al, 2001a). Worldwide, the end of the Paleoproterozoic glacial epoch was followed by deposition of mature, Al-rich quartzites suggesting a climate change to greenhouse conditions favoring chemical weathering (Young, 1973;Karlstrom et al, 1983;Marmo, 1992;Schreiber and Eriksson, 1992;Gutzmer and Beukes, 1996;Ojakangas, 1997). The ca.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Chemostratigraphy of Paleoproterozoic carbonate successions of the Wyoming Craton: tectonic forcing of biogeochemical change?

Bekker

2003

Precambrian Research

144

View full text Add to dashboard Cite

Section: Regional Geology and Stratigraphymentioning

confidence: 99%

Section: Regional Geology and Stratigraphymentioning

confidence: 99%

Section: Regional Geology and Stratigraphymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Chemostratigraphy of Paleoproterozoic carbonate successions of the Wyoming Craton: tectonic forcing of biogeochemical change?

Bekker

2003

Precambrian Research

144

View full text Add to dashboard Cite

“…Prior to that time (circa 2.1-1.8 Ga), the southern margin of the Wyoming province was characterized by rifting and development of a passive margin [Karlstrom et al, 1983;Karlstrom and Houston, 1984;Chamberlain, 1998]. The Cheyenne Belt, a series of east to northeast trending, south dipping shear zones that are exposed in southern Wyoming, marks the current northern boundary of the Colorado province [Hills and Houston, 1979;Karlstrom and Houston, 1984;Duebendorfer and Houston, 1987;Houston et al, 1989;Chamberlain, 1998].…”

Section: Overviewmentioning

confidence: 99%

Early Proterozoic oceanic crust in the northern Colorado Front Range: Implications for crustal growth and initiation of basement faults

Cavosie¹,

Selverstone

2003

Tectonics

View full text Add to dashboard Cite

Early Proterozoic oceanic crust exposed in a shear zone in the northern Colorado Front Range provides insight into the tectonic evolution of the Colorado province. Tectonically intermingled mylonitic amphibolite (locally pillowed), metagabbro, clinopyroxenite, metachert, and mélange are preserved within the Buckhorn Creek shear zone west of Fort Collins. Whole rock geochemical data support formation of the igneous protoliths in an oceanic environment. Major and trace element data overlap samples from modern oceanic ridges, and are distinct from modern arc trends. Metagabbros and clinopyroxenites preserve a subhorizontal lineation defined by igneous pyroxenes; core and mantle microstructures indicate initial deformation at temperatures >900°C. Secondary amphiboles define both subhorizontal and subvertical lineations. Kinematic analysis indicates that the rocks experienced E‐W strike‐slip deformation prior to and during amphibolite‐facies metamorphism, followed by N‐S shortening. 40Ar/39Ar data from secondary hornblende yield age steps as old as 1.9 Ga. Based on the chemical data and kinematic evidence for strike‐slip deformation, we propose that the Buckhorn Creek rocks originated at an oceanic ridge‐transform intersection. The high‐T pyroxene fabrics formed during ocean floor deformation prior to 1.7 Ga regional deformation of the Colorado province. The Buckhorn Creek fragment likely represents original oceanic basement for 1.8–1.7 Ga arc magmatism and sedimentation that ultimately formed the Colorado province continental crust. Reactivation of original oceanic fracture zones may be responsible for the network of regularly spaced northeast trending shear zones in Colorado. Once formed, subvertical transform faults are likely to survive the transition from oceanic to continental crust and persist as long‐lived crustal discontinuities.

show abstract

Tectonic evolution of a Laramide transverse structural zone: Sweetwater Arch, south central Wyoming

2016

View full text Add to dashboard Cite

Structural, anisotropy of magnetic susceptibility (AMS), and paleomagnetic data record patterns of layer‐parallel shortening (LPS), vertical‐axis rotation, and regional fault‐fold evolution across the Sweetwater Arch, a major west to WNW trending, basement‐cored Laramide uplift in Wyoming. The southern arch flank is bounded by a WNW striking reverse fault zone that imbricated basement and cover rocks, the northern flank is bounded by a west striking fault zone with a component of strike‐slip and NW trending en echelon folds, and the eastern plunge transitions into an area of multiple‐trending faults and folds. Synorogenic strata record major arch uplift from Maastrichtian to Early Eocene time, followed by arch collapse. LPS, with development of systematic minor fault sets and AMS lineations, preceded large‐scale folding. LPS directions, estimated from both minor fault and AMS data, were oriented WSW along the northern flank, subparallel to Laramide regional shortening, but were refracted to the SSW along the southern flank, and to the west along the eastern arch plunge. Additional minor faults developed along steep fold limbs during continued shortening, with directions remaining SSW along the southern flank but becoming more variable along the eastern plunge where an increasingly heterogeneous stress field developed as additional faults were activated along basement heterogeneities. Vertical‐axis rotation was limited along the arch flanks, whereas the eastern plunge underwent counterclockwise rotation. Deflections in shortening directions were partly related to basement heterogeneities, including weak supracrustal belts on the arch flanks, a strong granitic core, and local reactivation of Precambrian shear zones.

show abstract

Stratigraphy and depositional setting of the Proterozoic Snowy Pass Supergroup, southeastern Wyoming: Record of an early Proterozoic Atlantic-type cratonic margin

Cited by 84 publications

References 0 publications

Chemostratigraphy of Paleoproterozoic carbonate successions of the Wyoming Craton: tectonic forcing of biogeochemical change?

Chemostratigraphy of Paleoproterozoic carbonate successions of the Wyoming Craton: tectonic forcing of biogeochemical change?

Early Proterozoic oceanic crust in the northern Colorado Front Range: Implications for crustal growth and initiation of basement faults

Tectonic evolution of a Laramide transverse structural zone: Sweetwater Arch, south central Wyoming

Contact Info

Product

Resources

About