Wyoming Craton

Trans-Hudson orogen (blue) surrounded by the Wyoming Hearne–Rae and Superior cratons (fuchsia) that constitute the central core of the North American Craton (Laurentia).
The North American Craton, also called Laurentia

The Wyoming Craton is a craton in the west-central United States and western Canada – more specifically, in Montana, Wyoming, southern Alberta, southern Saskatchewan, and parts of northern Utah. Also called the Wyoming Province, it is the initial core of the continental crust of North America.

The Wyoming Craton was sutured together with the Superior and Hearne-Rae cratons in the mountain-building episode that created the Trans-Hudson Suture Zone to form the core of North America (Laurentia). It was incorporated into southwest Laurentia approximately 1.86 billion years ago.[1]

Local preservation of 3.6–3.0 Ga gneisses and widespread isotopic evidence for crust of this age incorporated into younger plutons indicates that the Wyoming Craton originated as a 100,000 km2 middle Archean craton that was modified by late Archean volcanic magmatism and plate movements and Proterozoic extension and rifting.[2]

The Wyoming, Superior and Hearne-Ray cratons were once sections of separate continents, but today they are all welded together. The collisions of these cratons began before ca. 1.77 Ga, with post-tectonic magmatism at ca. 1.715 Ga (the Harney Peak granite). This tectonic-magmatic interval is 50–60 million years younger than that reported for the Hearne-Superior collision of the Trans-Hudson orogeny in Canada.

Younger metamorphic dates (1.81–1.71 Ga) also typify the eastern and northern Wyoming province peripheries in the western Dakotas and southeastern Montana. The final assembly of the eastern Wyoming Craton as part of the continent Laurentia began during the ca. 1.78–1.74 Ga interval of island-arc accretion along the southern margin of the growing craton.[3]

  1. ^ Foster, David A., Paul A. Mueller, David W. Mogk, Joseph L. Wooden and James J. Vogi (2006). "Proterozoic Evolution of the Western Margin of the Wyoming Craton: Implications for the Tectonic and Magmatic Evolution of the Northern Rocky Mountains". Can. J. Earth Sci. 43 (10): 1601–1619. Bibcode:2006CaJES..43.1601F. doi:10.1139/E06-052.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  2. ^ Chamberlain, Kevin R., Carol D. Frost, and B. Ronald Frost (2003). "Early Archean to Mesoproterozoic evolution of the Wyoming Province: Archean origins to modern lithospheric architecture". Canadian Journal of Earth Sciences. 40 (10): 1357–1374. Bibcode:2003CaJES..40.1357C. doi:10.1139/e03-054.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  3. ^ Dahl, Peter S., Daniel K. Holm, Edward T. Gardner, Fritz A. Hubacher, and Kenneth A. Foland (1999). "New constraints on the timing of Early Proterozoic tectonism in the Black Hills (South Dakota), with implications for docking of the Wyoming province with Laurentia". Geological Society of America Bulletin. 111 (9): 1335–1349. Bibcode:1999GSAB..111.1335D. doi:10.1130/0016-7606(1999)111<1335:NCOTTO>2.3.CO;2.{{cite journal}}: CS1 maint: multiple names: authors list (link)