Two-phase evolution of accretionary margins: examples from the North American Cordillera

McClelland, William C.; Tikoff, Basil; Manduca, Cathryn A.

doi:10.1016/s0040-1951(00)00145-1

Cited by 80 publications

(91 citation statements)

References 73 publications

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“…2 (west-central Idaho) indicated by bold outline. Modified from McClelland et al (2000). Sr i , initial Sr. led to formation of the Salmon River suture zone (SRSZ: Lund and Snee 1988), a broad north-to northeast-striking deformed belt (>25 km wide) straddling the arc-craton juncture (Fig.…”

Section: Jura-cretaceous Tectonismmentioning

confidence: 99%

“…1). According to McClelland et al (2000), suturing was followed by mid-Cretaceous transpressional deformation on the narrower (<10 km wide) WISZ. Although the superposition of mylonitic fabric on suture zone structures is not documented, the WISZ and SRSZ are viewed as spatially overlapping but temporally distinct tectonic elements in west-central Idaho (McClelland et al 2000;Tikoff et al 2001;Giorgis et al 2007;Blake et al 2009).…”

Section: Jura-cretaceous Tectonismmentioning

confidence: 99%

“…According to McClelland et al (2000), suturing was followed by mid-Cretaceous transpressional deformation on the narrower (<10 km wide) WISZ. Although the superposition of mylonitic fabric on suture zone structures is not documented, the WISZ and SRSZ are viewed as spatially overlapping but temporally distinct tectonic elements in west-central Idaho (McClelland et al 2000;Tikoff et al 2001;Giorgis et al 2007;Blake et al 2009). This concept of "overlapping Jura-Cretaceous orogens" follows the early premise of Hamilton (1963a) and plays a fundamental role in tectonic models proposed along central portions of the North American Cordillera (e.g., Gray and Oldow 2005;Giorgis et al 2008).…”

Section: Jura-cretaceous Tectonismmentioning

confidence: 99%

“…Between Heavens Gate Ridge and the Crevice pluton area (Fig. 2), we do not observe structural elements supporting temporally distinct orogenic events -i.e., an initial suturing event followed by deformation on a post-accretionary mylonitic shear zone (McClelland et al 2000).…”

Section: Progressive Deformationmentioning

confidence: 99%

“…Near the alpine village of McCall (Fig. 2), mid-Cretaceous calcalkaline plutons recording the arc-craton transition ( 87 Sr/ 86 Sr i ratios <0.7045 to >0.707; e.g., Manduca et al 1992) are deformed by steep mylonitic fabrics attributed to dextral transpression on the post-accretionary western Idaho shear zone (WISZ;McClelland et al 2000;Tikoff et al 2001;Giorgis et al 2005). The timing of deformation in this area (ca.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2012

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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).Résumé : Une nouvelle géochronologie par U-Pb sur zircon pour la région Riggins du centre-ouest de l'Idaho précise le moment de la déformation par contraction à travers la zone de suture de Salmon River (SRSZ), une large ceinture (>25 km) de direction nord à nord-est de grandes contraintes enregistrant des collisions au Jurassique-Crétacé entre des îles d'arcs et le continent. La spectrométrie de masse à source plasma à couplage inductif avec ablation laser (LA-ICP-MS) a donné des âges de cristallisation au Crétacé moyen à partir de roches plutoniques prélevées dans le canyon de la rivière Salmon non datées antérieurement. Dans le pluton Crevice (∼105 Ma), le développement de foliation gneissique (S1) à direction nord et à pendage fort à modéré a été suivi par un décrochement « sommet vers l'ouest » sur des zones de cisaillement mylonitiques à faible profondeur (S2) et une surimpression cassante par des joints (Jn) systématiques d'étendue régionale. Ensemble, ces structures forment l'architecture interne du pluton. Une foliation subverticale des gneiss dans le pluton adjacent de Looking Glass (∼92 Ma) indique qu'une déformation ductile était en cours au Crétac...

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Section: Jura-cretaceous Tectonismmentioning

confidence: 99%

Section: Jura-cretaceous Tectonismmentioning

confidence: 99%

Section: Jura-cretaceous Tectonismmentioning

confidence: 99%

Section: Progressive Deformationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

et al. 2012

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Simultaneous batholith emplacement, terrane/continent collision, and oroclinal bending in the Blue Mountains Province, North American Cordillera

et al. 2015

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The North American Cordillera is a classic example of accretionary orogen, consisting of multiple oceanic terranes attached to the western margin of Laurentia during the Mesozoic times. Although the Cordillera is linear for most parts, terrane boundaries are at a high angle to the overall structural grain in several segments of the orogen, which has been a matter of longstanding controversy as to how and when these orogenic curvatures formed. This paper discusses mechanisms, kinematics, and timing of initiation of one of these major curvatures, the Blue Mountains Province in northeastern Oregon. Here magmatic fabric patterns and anisotropy of magnetic susceptibility in the Wallowa batholith record three phases of progressive deformation of the host Wallowa terrane during Early Cretaceous. First is terrane-oblique~NE-SW shortening, interpreted as recording attachment of the amalgamated oceanic and fringing terranes to the continental margin during dextral convergence at~140 Ma. Deformation subsequently switched to pure shear-dominated NNE-SSW shortening associated with crustal thickening, caused by continued impingement of the amalgamated Blue Mountains superterrane into a presumed westward concave reentrant in the continental margin at 135-128 Ma. Upon impingement (at~126 Ma), the northern portion of the superterrane became "locked," leading to reorientation of the principal shortening direction to~NNW-SSE while its still deformable southern portion rotated clockwise about a vertical axis. We thus propose oblique bending as the main mechanism of the orocline formation whereby horizontal compressive forces resulting from plate convergence acted at an angle to the terrane boundaries.

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Crustal structure beneath the Blue Mountains terranes and cratonic North America, eastern Oregon, and Idaho, from teleseismic receiver functions

et al. 2016

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We present new images of lithospheric structure obtained from P‐to‐S conversions defined by receiver functions at the 85 broadband seismic stations of the EarthScope IDaho‐ORegon experiment. We resolve the crustal thickness beneath the Blue Mountains province and the former western margin of cratonic North America, the geometry of the western Idaho shear zone (WISZ), and the boundary between the Grouse Creek and Farmington provinces. We calculated P‐to‐S receiver functions using the iterative time domain deconvolution method, and we used the H‐k grid search method and common conversion point stacking to image the lithospheric structure. Moho depths beneath the Blue Mountains terranes range from 24 to 34 km, whereas the crust is 32–40 km thick beneath the Idaho batholith and the regions of extended crust of east‐central Idaho. The Blue Mountains group Olds Ferry terrane is characterized by the thinnest crust in the study area, ~24 km thick. There is a clear break in the continuity of the Moho across the WISZ, with depths increasing from 28 km west of the shear zone to 36 km just east of its surface expression. The presence of a strong midcrustal converting interface at ~18 km depth beneath the Idaho batholith extending ~20 km east of the WISZ indicates tectonic wedging in this region. A north striking ~7 km offset in Moho depth, thinning to the east, is present beneath the Lost River Range and Pahsimeroi Valley; we identify this sharp offset as the boundary that juxtaposes the Archean Grouse Creek block with the Paleoproterozoic Farmington zone.

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Two-phase evolution of accretionary margins: examples from the North American Cordillera

Cited by 80 publications

References 73 publications

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

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

Simultaneous batholith emplacement, terrane/continent collision, and oroclinal bending in the Blue Mountains Province, North American Cordillera

Crustal structure beneath the Blue Mountains terranes and cratonic North America, eastern Oregon, and Idaho, from teleseismic receiver functions

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