Reconnaissance geology and U-Pb geochronology of the west flank of the Coast Mountains between Juneau and Skagway, southeastern Alaska

Gehrels, George E.

doi:10.1130/0-8137-2343-4.213

Cited by 31 publications

(32 citation statements)

References 45 publications

(129 reference statements)

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“…63 and ca. 57 Ma (Gehrels , 2000b). As described later, the recognition of dextral slip along the Coast shear zone is also consistent with models that interpret much larger amounts of dextral displacement.…”

Section: Coast Shear Zonesupporting

confidence: 80%

U-Th-Pb geochronology of the Coast Mountains batholith in north-coastal British Columbia: Constraints on age and tectonic evolution

Gehrels

Rusmore

Woodsworth

et al. 2009

Geological Society of America Bulletin

271

384

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Section: Coast Shear Zonesupporting

confidence: 80%

U-Th-Pb geochronology of the Coast Mountains batholith in north-coastal British Columbia: Constraints on age and tectonic evolution

Gehrels

Rusmore

Woodsworth

et al. 2009

Geological Society of America Bulletin

271

384

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“…Gehrels et al (1991) report Cambrian zircon grains in a quartzite near Port Haughton and Archean zircon grains in quartzites from Tracy and Endicott Arms. Recent studies by Gehrels (2000) and Gehrels and Boghossian (2000) report other occurrences of detrital zircons with similar ages throughout the Coast Mountains from Bella Coola, British Columbia, to Skagway, Alaska. The presence of inherited zircons with ages similar to those in the Coast Mountains supports the hypothesis that this was the source area for on May 28, 2015 specialpapers.gsapubs.org Downloaded from the Valdez Group and that these zircons were inherited during the Eocene magmatism.…”

Section: Geochronologymentioning

confidence: 89%

Geochemical and geochronologic constraints for genesis of a tonalite-trondhjemite suite and associated mafic intrusive rocks in the eastern Chugach Mountains, Alaska: A record of ridge-transform subduction

Sisson

Poole²,

Harris

et al. 2003

Geology of a Transpressional Orogen Developed During Ridge-Trench Interaction Along the North Pacific Margin

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Igneous rocks in the Chugach metamorphic complex of southern Alaska form part of the Sanak-Baranof belt, a series of forearc plutons believed to have been formed by subduction of a spreading ridge. The intrusives are predominantly tonalite-trondhjemite-granodiorite suite. There are some associated mafi c plutonics close to the eastern end of the belt near Yakutat and Glacier Bay National Park. Trace element and Nd-Sr isotopic data suggest that tonalitic magmas were derived from the mixing of two sources: melted accretionary wedge sedimentary rocks and mafi c material underplated at the base of the wedge as the ridge was subducted. The mafi c material could include metabasaltic amphibolites at Nunatak Fjord that have a midocean ridge basalt-composition protolith.Early Tertiary ridge migration along the Alaskan margin was generally toward the east. New U-Pb and 40 Ar/ 39 Ar geochronology data indicate synchronous magmatism at 54 Ma in the western Chugach metamorphic complex and Nunatak Fjord region. There is also a younger 49 Ma intrusive at Nunatak Fjord. The Nunatak Fjord region is subdivided into two blocks: (1) Chugach block has young amphibole cooling ages of 20 Ma, whereas (2) Boundary-Fairweather block has older cooling ages of ca. 53 Ma, which are contemporaneous with an U-Pb age on an adjacent tonalitic pluton.

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“…The lower reaches of the watershed are uplifted marine terraces with some colluvial and alluvial sediments. The underlying bedrock is marine graywacke sandstone and mudstone turbidites (Gehrels 2000). Streamflow in Peterson Creek typically peaks during the autumn rainy season and reaches a minimum during the early spring (March-April).…”

Section: Methodsmentioning

confidence: 99%

Salmon influences on dissolved organic matter in a coastal temperate brownwater stream: An application of fluorescence spectroscopy

Hood

Fellman

Edwards

2007

Limnology & Oceanography

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We examined how spawning Pacific salmon (genus Oncorhynchus) affect streamwater concentrations of inorganic nitrogen and phosphorus and dissolved organic matter in Peterson Creek, a stream in southeast Alaska. When spawning salmon were present, concentrations of ammonium (NH 4 -N) increased by more than 100 times over prespawning levels and concentrations of soluble reactive phosphorus increased by more than an order of magnitude. In contrast, concentrations of nitrate (NO 3 -N) increased by only two to three times during spawning and were not significantly higher than at an upstream reference site with no salmon. During spawning, concentrations of dissolved organic carbon and dissolved organic nitrogen were significantly higher in the spawning reach compared with the upstream reference site. The influx of salmon-derived dissolved organic matter (DOM) altered the fluorescence index (FI), which has previously been used to distinguish between terrestrial and aquatic sources of DOM, with the FI increasing significantly during the salmon run. Salmon DOM was rich in protein compared with the DOM derived from the terrestrial portion of the watershed. Spawning salmon may be an important source of labile DOM in Peterson Creek.

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Reconnaissance geology and U-Pb geochronology of the west flank of the Coast Mountains between Juneau and Skagway, southeastern Alaska

Cited by 31 publications

References 45 publications

U-Th-Pb geochronology of the Coast Mountains batholith in north-coastal British Columbia: Constraints on age and tectonic evolution

U-Th-Pb geochronology of the Coast Mountains batholith in north-coastal British Columbia: Constraints on age and tectonic evolution

Geochemical and geochronologic constraints for genesis of a tonalite-trondhjemite suite and associated mafic intrusive rocks in the eastern Chugach Mountains, Alaska: A record of ridge-transform subduction

Salmon influences on dissolved organic matter in a coastal temperate brownwater stream: An application of fluorescence spectroscopy

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