Contrasting structural histories of the Salmon River belt and Wallowa terrane: Implications for terrane accretion in northeastern Oregon and west-central Idaho

2005 ◽  
Vol 117 (5) ◽  
pp. 687 ◽  
Author(s):  
Keith D. Gray ◽  
John S. Oldow
Keyword(s):  
Salmon River ◽  
West Central ◽  
Wallowa Terrane ◽  
Terrane Accretion ◽  
Central Idaho

Middle Jurassic corals from the Wallowa terrane, west-central Idaho

1990 ◽  
Vol 64 (3) ◽  
pp. 352-362 ◽  
Author(s):  
George D. Stanley ◽  
Louise Beauvais
Keyword(s):  
North American ◽  
Middle Jurassic ◽  
The North ◽  
Western Cordillera ◽  
West Central ◽  
Wallowa Terrane ◽  
North American Craton ◽  
Central Idaho

New colonial corals from near Pittsburg Landing, Idaho, are clearly dated as Middle Jurassic (Bajocian) in age. They consist of Coenastraea hyatti (Wells) and Thecomeandra vallieri n. sp., and occur abundantly with molluscan fossils in thin, biostromal limestone beds in the Coon Hollow Formation. These fossils are the youngest shelly faunas yet known from the Wallowa terrane. The similarity of the coral and bivalve fauna to endemic faunas of the Western Interior suggests that during Middle Jurassic time, the Wallowa terrane was close enough to the North American craton for faunal exchange with the Western Interior Embayment. The Pittsburg Landing corals appear dissimilar from Middle Jurassic corals known from other terranes of the western Cordillera.

Intracontinental subduction and hinged unroofing along the Salmon River Suture Zone, west central Idaho

Tectonics ◽  
1992 ◽  
Vol 11 (1) ◽  
pp. 124-144 ◽  
Author(s):  
Jane Selverstone ◽  
Brian P. Wernicke ◽  
Elaine A. Aliberti
Keyword(s):  
Suture Zone ◽  
Salmon River ◽  
West Central ◽  
Intracontinental Subduction ◽  
Salmon River Suture Zone ◽  
Central Idaho

Age and structure of the Crevice pluton: overlapping orogens in west-central Idaho?

2012 ◽  
Vol 49 (6) ◽  
pp. 709-731 ◽  
Author(s):  
Keith D. Gray ◽  
A. John Watkinson ◽  
Richard M. Gaschnig ◽  
Vincent H. Isakson
Keyword(s):  
Shear Zone ◽  
Inductively Coupled Plasma ◽  
Shear Zones ◽  
Ductile Deformation ◽  
North American Cordillera ◽  
Salmon River ◽  
The North ◽  
West Central ◽  
Salmon River Suture Zone ◽  
Central Idaho

New U–Pb zircon geochronology from the Riggins region of west-central Idaho refines the timing of contractional deformation across the Salmon River suture zone (SRSZ), a broad north- to northeast-striking belt (>25 km wide) of high strain recording Jura-Cretaceous island-arc–continent collision. Laser ablation – inductively coupled plasma – mass spectrometry (LA–ICP–MS) yields mid-Cretaceous crystallization ages on formerly undated plutonic rocks sampled from the Salmon River canyon. In the Crevice pluton (∼105 Ma), the development of steep to moderate northerly striking gneissic foliation (S1) was followed by tops-to-the-west slip on shallow mylonitic shear zones (S2) and brittle overprinting via systematic joints (Jn) of regional extent. Together, these structures form the pluton’s internal architecture. Subvertical gneissic foliation in the adjacent Looking Glass pluton (∼92 Ma) indicates ductile deformation was ongoing in the Late Cretaceous. Prior to this investigation, penetrative fabrics in local arc volcanogenic, plutonic, and continental rocks have been unequivocally linked to post-collisional dextral transpression on the narrow (<10 km wide) western Idaho shear zone (WISZ). As an alternative to this model which requires spatially overlapping but temporally distinct orogenic belts (WISZ–SRSZ), we consider a protracted history whereby regional synmetamorphic structures accumulated over a pre-118 Ma to post-92 Ma interval without an overprinting orogen-scale ductile shear zone. In our view, a progressive deformation history more accurately accounts for the time-transgressive nature and structural continuity of fabrics observed across the arc–continent transition. This tectonic history proposed for western Idaho may be analogous to other long-lived accretionary margins in the North American Cordillera (e.g., Omineca Belt of southeastern British Columbia).

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