Plate-tectonic mechanism of Laramide deformation.

W. Hamilton

Home/Archive/USGS

USGS · 70011903

Plate-tectonic mechanism of Laramide deformation.

W. Hamilton

View original source ↗Export metadata ↓

Abstract

The Laramide compressive deformation of the craton was caused by a clockwise rotation of about 2-4o of the Colorado Plateau region relative to the continental interior, during late Late Cretaceous and early Tertiary time. Late Paleozoic and Neogene deformation of the craton also were produced by motion of a southwestern subplate relative to the continental interior. -from Author

Explore related subjects

Contributions to Geology - University of Wyoming, Laramie Article

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

W. Hamilton. 1981. Plate-tectonic mechanism of Laramide deformation.. https://pubs.usgs.gov/publication/70011903

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS1988

Geologic history and palynologic dating of Paleocene deposits, western Rock Springs uplift, Sweetwater County, Wyoming

During the latest Cretaceous or earliest Paleocene, a northwest-southeast trending anticline developed in the area of the present Rock springs uplift in southwestern Wyoming. This ancestral structure was eroded to a surface of fairly low relief on which a paleosol developed. The surface was formed on the Upper Cretaceous Almond Formation throughout the study area. In the early middle Paleocene (P3 palynomorph zone), topographic lows on the erosion surface were infilled by alluvial deposits that accumulated in channel, floodplain, and backswamp environments. An organic-rich facies contains numerous coal beds and is middle to late Paleocene in age (P3 to P5 zones). The assemblage of pollen that defines the late middle Paleocene (P4 zone) is absent from the area suggesting a hiatus, although no lithologic break was observed at this boundary. The younger organic-poor facies begins in the late Paleocene (P5 zone) and continues to the top of the studied sequence. This change in facies has been used to map the contact between the Fort Union Formation of Paleocene age in this area, and the Wasatch Formation which was though to be of Eocene age. This study demonstrates that, as currently mapped, the lower part of the Wasatch Formation is Paleocene in age. Stratigraphically higher parts of the Wasatch, which presumably contain rocks of latest Paleocene (P6 zone) and earliest Eocene age, were not studied. -Authors

Contributions to Geology - University of Wyoming, ↗

USGS1986

Paleontology and deposition of the Phosphoria Formation.

The Phosphoria Formation and related rocks were deposited in an interior sag basin developed in the Cordilleran miogeocline of western North America. Deposition can be characterized as a fringing bank complex on a carbonate ramp. Conodont-brachiopod biostratigraphy provides a sufficient relative time framework for correlation of the many units. These age correlations and the distribution of fossils, plus the biofacies of conodonts and brachiopods in particular, indicate that phosphate deposition was a cool-water, deeper ramp facies that transgressed over the carbonate bank twice, representing the Meade Peak and Retort Phosphatic Shale Members of the Phosphoria Formation. Conodont data that substantiate the above are presented, and a new genus and species, Sweetina triticum, is described. -Authors

Contributions to Geology - University of Wyoming, ↗

USGS1986

The South Fork detachment fault, Park County, Wyoming: discussion and reply ( USA).

Blackstone (1985) published an interpretation of South form detachment fault and related features. His interpretation of the area between Castle and Hardpan transverse faults is identical to mine of 1941. Subsequent detailed mapping has shown that the structure between the transverse faults is more complicated than originally envisioned and resurrected by Blackstone. The present paper describes and discusses geologic features that are the basis for my interpretations; also discussed are differences between my interpretations and those of Blackstone. Most data are shown on the geologic map of the Wapiti Quadrangle (Pierce and Nelson, 1969). Blackstone's 'allochthonous' masses are part of the South Form fault. Occurrences of Sundance Formation, which he interpreted as the upper plate of his 'North Fork fault', are related to Heart Mountain fault. Volcaniclastic rocks south of Jim Mountain mapped as Aycross Formation by Torres and Gingerich may be Cathedral Cliffs Formation, emplaced by movement of the Heart Mountain fault. - Author

Contributions to Geology - University of Wyoming, ↗