Permian Paleogeography, Southwestern US

Permian Paleogeography, Southwestern US (280-270 Ma). Parts of the Ancestral Rockies remain high and shed sediments into adjacent basins. The Havallah back arc basin expands over the site of the previous Antler Mountains

View to west of above. The Stikine fragment has moved NW to a position west of the Quesnell fragment. In other words, the McCloud arc is a double arc; the western portion was transported along a transform fault

Latest Permian Paleogeography, Southwestern US (250 Ma). The Western Interior, like most continental regions around the Earth, was well above sea level at this time

View to west of above. The Stikine arc collapses against the Quesnell arc. The Havallah basin is thrust eastward over the continental shelf and the Sonoman orogeny occurs. Oceanic plateaus, derived from the Tethyian Ocean half-way around the globe, are caught against and between the various subduction zones. This is how this interpretation resolves "exotic elements" within arcs not exotic to North America

Permian Paleogeography, exotic interpretation, SW US.

These maps present a contrasting hypothesis to the one shown above

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