Database for the geologic map of the Sauk River 30-minute by 60-minute quadrangle, Washington (I-2592)

Tabor, R.W.; Booth, Derek B.; Vance, Joseph A.; Ford, A. B.

doi:10.3133/ds188

Cited by 16 publications

(31 citation statements)

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“…The Boulder River and Finney Creek are underlain by Cretaceous metamorphic rocks (folded and foliated phyllite, greenschist, and argillitic mélanges) and glacial sediments derived from Pleistocene ice-sheet advances (Tabor et al 2002). In contrast, the Willapa River is incised into Tertiary marine sediments (sandstones, siltstones, and mudstones) and Eocene marine basalts (Massong and Montgomery 2000).…”

Section: Study Sites and Analysismentioning

confidence: 98%

Basin-scale availability of salmonid spawning gravel as influenced by channel type and hydraulic roughness in mountain catchments

Buffington¹,

Montgomery²,

Greenberg³

2004

Can. J. Fish. Aquat. Sci.

125

177

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A general framework is presented for examining the effects of channel type and associated hydraulic roughness on salmonid spawning-gravel availability in mountain catchments. Digital elevation models are coupled with grain-size predictions to provide basin-scale assessments of the potential extent and spatial pattern of spawning gravels. To demonstrate both the model and the significance of hydraulic roughness, we present a scenario for optimizing the spatial extent of spawning gravels as a function of channel type in Pacific Northwest catchments. Predictions indicate that hydraulic roughness could control more than 65% of the potential available spawning habitat at our study sites. Results further indicate that bar roughness can be important for maintaining spawning gravels in lower mainstem reaches, while wood roughness may be required for spawning-gravel maintenance in steeper, upper mainstem channels. Our analysis indicates that wood loss and consequent textural coarsening could deplete up to one third of the potentially usable spawning area at our study sites.Résumé : Nous présentons ici un cadre général pour l'examen des effets du type de chenal et de la rugosité hydraulique associée sur la disponibilité de graviers pour la fraye des saumons dans les bassins versants de montagne. Le couplage de modèles digitaux d'altitude et de prédictions des tailles des particules fournit une évaluation à l'échelle du bassin versant de l'étendue potentielle et de la répartition spatiale des graviers de fraye. Comme illustration du fonctionnement du modèle et de l'importance de la rugosité hydraulique, nous présentons un scénario pour l'optimisation de l'étendue spatiale des graviers de fraye en fonction du type de chenal dans les bassins versants de la région pacifique du nord-ouest. Les prédictions indiquent que la rugosité hydraulique peut contrôler plus de 65 % des habitats de fraye potentiellement disponibles dans nos sites d'étude. Les résultats indiquent de plus que la rugosité due aux seuils peut être importante pour le maintien des graviers de fraye dans les sections d'aval du cours principal, alors que la rugosité due au bois est nécessaire pour le maintien des graviers de fraye dans les cours principaux d'amont à pente plus forte. Notre analyse montre que la perte du bois et la texture plus grossière qui en résulterait pourraient éliminer jusqu'à un tiers de la surface utilisable potentielle de fraye dans nos sites d'étude.[Traduit par la Rédaction] Buffington et al. 2096

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Section: Study Sites and Analysismentioning

confidence: 98%

Basin-scale availability of salmonid spawning gravel as influenced by channel type and hydraulic roughness in mountain catchments

Buffington¹,

Montgomery²,

Greenberg³

2004

Can. J. Fish. Aquat. Sci.

125

177

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“…The eastern mélange consists mainly of mafic volcanic rocks and chert and argillite, with lesser argillite, graywacke and limestone-marble, some of which bears Permian Tethyan fusulinids (Danner 1977;Frizzell et al 1987), and scattered blocks of ultramafic rock and metamorphosed gabbros and tonalites. The western mélange belt is predominantly argillite and graywacke, with lesser chert, mafic volcanic rock, plutonic rock and arkosic sandstone; fossils are of Late Jurassic to Early Cretaceous age (Frizzell et al 1987;Jett and Heller 1988;Tabor et al 2002). Blocks of metamorphosed gabbro, tonalite, and diabase in both eastern and western mélange belts yield U-Pb zircon ages in the range of 150-170 Ma (Frizzell et al 1987;Tabor et al 2002).…”

Section: Details Of the Haystack Nappementioning

confidence: 97%

“…The western mélange belt is predominantly argillite and graywacke, with lesser chert, mafic volcanic rock, plutonic rock and arkosic sandstone; fossils are of Late Jurassic to Early Cretaceous age (Frizzell et al 1987;Jett and Heller 1988;Tabor et al 2002). Blocks of metamorphosed gabbro, tonalite, and diabase in both eastern and western mélange belts yield U-Pb zircon ages in the range of 150-170 Ma (Frizzell et al 1987;Tabor et al 2002). Three sandstone petrofacies are recognized in the western mélange by Jett and Heller (1988) based on point count analyses: arkosic, cherty, and lithic.…”

Section: Details Of the Haystack Nappementioning

confidence: 98%

“…The eastern and western mélange belts (Frizzell et al 1987;Tabor et al 1993) are characterized by matrix of scaly argillite or phyllite and blocks or phacoids ranging from centimetres to mountainside in scale. The scaly foliation and phacoid shapes define a generally steep northeasterly dipping internal fabric to the belts (Tabor et al 2002); on the large scale, however, a low-dip structural framework is indicated by a mapped thrust fault separating the eastern and western mélange belts (Fig. 2).…”

Section: Details Of the Haystack Nappementioning

confidence: 99%

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Obducted nappe sequence in the San Juan Islands – northwest Cascades thrust system, Washington and British Columbia

Brown

2012

Can. J. Earth Sci.

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The San Juan Islands -northwest Cascades thrust system in Washington and British Columbia is composed of previously accreted terranes now assembled as four broadly defined composite nappes stacked on a continental footwall of Wrangellia and the Coast Plutonic Complex. Emplacement ages of the nappe sequence are interpreted from zircon ages, field relations, and lithlogies, to young upward. The basal nappe was emplaced prior to early Turonian time (∼93 Ma), indicated by the occurrence of age-distinctive zircons from this nappe in the Sidney Island Formation of the Nanaimo Group. The emplacement age of the highest nappe in the thrust system postdates 87 Ma detrital zircons within the nappe. The nappes bear high-pressure -low-temperature (HP-LT) mineral assemblages indicative of deep burial in a thrust wedge; however, several features indicate that metamorphism occurred prior to nappe assembly: metamorphic discontinuities at nappe boundaries, absence of HP-LT assemblages in the footwall to the nappe pile, and absence of significant unroofing detritus in the Nanaimo Group. A synorogenic relationship of the thrust system to the Nanaimo Group is evident from mutually overlapping ages and by conglomerates of Nanaimo affinity that lie within the nappe pile. From the foregoing relations, and broader Cordilleran geology, the tectonic history of the nappe terranes is interpreted to involve initial accretion and subduction-zone metamorphism south of the present locality, uplift and exhumation, orogen-parallel northward transport of the nappes as part of a forearc sliver, and finally obduction at the present site over the truncated south end of Wrangellia and the Coast Plutonic Complex.Résumé : Le système de chevauchement formé par l'archipel San Juan et le nord-ouest de la chaîne des Cascades dans l'état de Washington et la province de la Colombie-Britannique est composé de terranes anciennement accrétés et qui sont maintenant assemblés, au sens large, en quatre nappes composites empilées sur l'éponte inférieure continentale de la Wrangellie et du complexe plutonique côtier. Les âges de la mise en place de la séquence des nappes ont été détermi-nés à partir d'âges de zircons, de relations sur le terrain et des lithologies; ils sont plus jeunes vers le haut. La nappe à la base a été mise en place avant le Turonien précoce (∼93 Ma), ce qui est indiqué par la présence de zircons à âge distinctif provenant de cette nappe dans la Formation de Sidney Island du Groupe de Nanaimo. L'âge de la mise en place de la nappe supérieure dans le système de chevauchement est plus tardif que les zircons détritiques âgés de 87 Ma dans cette nappe. Les nappes comportent des assemblages de minéraux de haute pression -basse température (HP-BT) indiquant un enfouissement profond dans un prisme de chevauchement; toutefois, plusieurs caractéristiques indiquent que le métamorphisme est survenu avant l'assemblage de la nappe : des discordances métamorphiques à la limite des nappes, l'absence d'assemblages HP-BT dans l'éponte inférieure de l'empilement d...

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“…The Darrington-Devils Mountain fault zone is thought to have formed in the early Eocene, and it juxtaposes Mesozoic accreted terranes (Trafton sequence, and Western and Eastern mélange belts) to the south against Upper Mesozoic terranes (Helena-Haystack mélange and Easton metamorphic suite) to the north ( Fig. 2; Whetten et al, 1988;Tabor, 1994;Johnson et al, 1996;Tabor et al, 2002;Dragovich and DeOme, 2006). In our area of investigation, the Darrington-Devils Mountain fault zone is coincident with the northern margin of the Tertiary Everett Basin, and it juxtaposes a thick section of Eocene to Oligocene continental sedimentary rocks (Rocks of Bulson Creek) to the south against similar Eocene rocks (Chuckanut Formation) to the north.…”

Section: Introductionmentioning

confidence: 94%

Holocene earthquakes and right-lateral slip on the left-lateral Darrington–Devils Mountain fault zone, northern Puget Sound, Washington

et al. 2014

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Sources of seismic hazard in the PugetSound region of northwestern Washington include deep earthquakes associated with the Cascadia subduction zone, and shallow earthquakes associated with some of the numerous crustal (upper-plate) faults that crisscross the region. Our paleoseismic investigations on one of the more prominent crustal faults, the Darrington-Devils Mountain fault zone, included trenching of fault scarps developed on latest Pleistocene glacial sediments and analysis of cores from an adjacent wetland near Lake Creek, 14 km southeast of Mount Vernon, Washington. Trench excavations revealed evidence of a single earthquake, radiocarbon dated to ca. 2 ka, but extensive burrowing and root mixing of sediments within 50-100 cm of the ground surface may have destroyed evidence of other earthquakes. Cores in a small wetland adjacent to our trench site provided stratigraphic evidence (formation of a laterally extensive, prograding wedge of hillslope colluvium) of an earthquake ca. 2 ka, which we interpret to be the same earthquake documented in the trenches. A similar colluvial wedge lower in the wetland section provides possible evidence for a second earthquake dated to ca. 8 ka. Three-dimensional trenching techniques revealed evidence for 2.2 ± 1.1 m of right-lateral offset of a glacial outwash channel margin, and 45-70 cm of north-side-up vertical separation across the fault zone. These offsets indicate a net slip vector of 2.3 ± 1.1 m, plunging 14° west on a 286°-striking, 90°-dipping fault plane. The dominant right-lateral sense of slip is supported by the presence of numerous Riedel R shears preserved in two of our trenches, and probable right-lateral offset of a distinctive bedrock fault zone in a third trench. Holocene northside-up, right-lateral oblique slip is opposite the south-side-up, left-lateral oblique sense of slip inferred from geologic mapping of Eocene and older rocks along the fault zone. The cause of this slip reversal is unknown but may be related to clockwise rotation of the Darrington-Devils Mountain fault zone into a position more favorable to right-lateral slip in the modern N-S compressional stress fi eld.

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Database for the geologic map of the Sauk River 30-minute by 60-minute quadrangle, Washington (I-2592)

Cited by 16 publications

References 0 publications

Basin-scale availability of salmonid spawning gravel as influenced by channel type and hydraulic roughness in mountain catchments

Basin-scale availability of salmonid spawning gravel as influenced by channel type and hydraulic roughness in mountain catchments

Obducted nappe sequence in the San Juan Islands – northwest Cascades thrust system, Washington and British Columbia

Holocene earthquakes and right-lateral slip on the left-lateral Darrington–Devils Mountain fault zone, northern Puget Sound, Washington

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