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2.67 Ga H-P granulite metamorphism in the Tetons The earliest Himalayan-type orogeny in North America. B. Ronald Frost, Carol D. Frost, Patrick Hughes, and Kevin R. Chamberlain Dept. Of Geology and Geophysics University of Wyoming. Structural provinces of the Wyoming province.
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2.67 Ga H-P granulite metamorphism in the Tetons The earliest Himalayan-type orogeny in North America B. Ronald Frost, Carol D. Frost, Patrick Hughes, and Kevin R. Chamberlain Dept. Of Geology and Geophysics University of Wyoming
Structural provinces of the Wyoming province 2.55 Ga. deformation no deformation since 2.83 Ga. 2.67 Ga. orogenic belt 2.66 - 2.63 Ga. accretion Proterozoic accretion
High-pressure granulites (Moose Basin gneiss) are preserved as a enclave in the northernmost Teton Range.
Structural Relations in the Moose Basin gneiss Metapelitic schist Q-Plag-Bio-Ky-Gar f2 f2 f1 foliated garnet amphibolite Mafic garnet granulite Isotropic amphibolite
Garnet-bearing leucosome in partially melted mafic granulite
Ky Cord Sil St Decompression textures in pelitic schist
Sketch showing the Structural Relations between the Moose basin and Webb Canyon gneisses
Structural provinces of the Wyoming province 2.55 Ga. deformation no deformation since 2.83 Ga. 2.67 Ga. orogenic belt 2.66 - 2.63 Ga. accretion Proterozoic accretion
Schematic cross section across the western Wyoming province at 2.67 -2.68 Ga
Age and pressure of some Precambrian HP granulite terranes Typical P for Archean metamorphism
Conclusions • Continental collisions clearly were occurring by 2.67 Ga. • Continental collisions may have been operating before 2.67 Ga, but either have not been recognized or completely recrystallized to lower pressure conditions