Macrofossil and conodont data from: SW Kluane Lake (115G &amp;amp; F[E 1/2]), Mount St. Elias (115B &amp;amp; C[E 1/2]), SW Dezadeash (115A), NE Yakutat (114O) and Tatshenshini River (114P) map areas, southwestern Yukon and northwestern British Columbia

Dodds, C J; Campbell, R B; Read, P B; Orchard, Michael J.; Tozer, E. T.; Bamber, E W; Pedder, A E H; Norford, B S; McLaren, D. J.; Harker, P.; McIver, E. E.; Norris, A W; Ross, C. Elizabeth; Chatterton, Brian D. E.; Cooper, G.A.; Flower, Rousseau H.; Haggart, J W; Uyeno, T T; Irwin, S E B

doi:10.4095/193494

Cited by 5 publications

(1 citation statement)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The Duke River fault is a high‐angle reverse fault that forms the boundary between the Alexander and Wrangellia terranes (Cobbett et al., 2016) and today connects the Totschunda fault to the southern segment of the Eastern Denali fault (Figure 1a; Dodds & Campbell, 1992). Studies of the Duke River fault show that it is predominately a thrust fault that has accommodated deformation as far back as the Cretaceous and still accommodates brittle‐regime deformation (Cobbett et al., 2016).…”

Section: Tectonic Settingmentioning

confidence: 99%

Earthquake Relocations Delineate a Discrete Fault Network and Deformation Corridor Throughout Southeast Alaska and Southwest Yukon

Biegel,

Gosselin,

Dettmer

et al. 2024

Tectonics

View full text Add to dashboard Cite

Deformation in southeastern Alaska and southwest Yukon is governed by the subduction and translation of the Pacific‐Yakutat plates relative to the North American plate in the St. Elias region. Despite notable historical seismicity and major regional faults, studies of the region between the Fairweather and Denali faults are complicated by glacial coverage and the remote setting. In the last decade, significant improvements have been made to the density of regional broadband seismometer networks. We relocate more than 5,000 earthquakes between 2010 and 2021 in the region of southeastern Alaska and southwestern Yukon utilizing these improved seismic networks. With reductions in catalog uncertainty, particularly in depth, we quantify the thickness of the seismogenic layer in the crust throughout the region and locate seismicity on a shallow network of upper‐crustal faults. Relocated earthquakes, combined with an updated focal‐mechanism catalog, permit estimating and classifying motion of active faults. This includes mapping the Totschunda‐Fairweather “Connector” fault, which plays an important role in explaining regional deformation, and identifying new faults like the Kathleen Lake fault. We draw similarities between our seismic observations and simplified conceptual models of regional tectonics, which describe a dominant transpressional regime and localized slip partitioning. Our results support a hypothesis where current deformation is taking place on a well‐defined and evolved network of shallow faults in the corridor between the Totschunda‐Fairweather “Connector” and Denali faults.

show abstract

Section: Tectonic Settingmentioning

confidence: 99%

Earthquake Relocations Delineate a Discrete Fault Network and Deformation Corridor Throughout Southeast Alaska and Southwest Yukon

Biegel,

Gosselin,

Dettmer

et al. 2024

Tectonics

View full text Add to dashboard Cite

show abstract

Late Paleozoic assembly of the Alexander-Wrangellia-Peninsular composite terrane, Canadian and Alaskan Cordillera

Beranek

Staal

McClelland

et al. 2014

Geological Society of America Bulletin

View full text Add to dashboard Cite

Late Paleozoic assembly of the Alexander-Wrangellia-Peninsular composite terrane is recorded by two phases of regional deformation, metamorphism, and magmatism within basement complexes of the Alexander (Craig and Admiralty subterranes), Wrangellia, and Peninsular terranes in the Canadian and Alaskan Cordillera. New secondary ion mass spectrometry (SIMS) and chemical abrasionisotope dilution-thermal ionization mass spectrometry (CA-ID-TIMS) zircon U-Pb ages, whole-rock major-and trace-element and Nd-Sr isotope geochemical compositions, and geological fi eld observations of late Paleozoic igneous rocks were used to identify the precise timing and signifi cance of this tectonism in the Saint Elias Mountains region of southwestern Yukon and eastern Alaska. Middle to Late Pennsylvanian (301-307 Ma) igneous rocks, herein assigned to the Barnard Glacier suite, were preferentially emplaced along the Wrangellia-Craig subterrane boundary and mainly comprise syenitic plutons that intrude Paleozoic country rocks with evidence of Pennsylvanian or older (D1) deformation. We propose that Barnard Glacier suite magmatism was produced by a slab breakoff event after the consumption of a narrow backarc ocean basin and early Pennsylvanian collision between the Wrangellia-Peninsular arc and Craig subterrane passive margin. Early Permian (284-291 Ma) dioritic to granodioritic rocks, herein assigned to the Donjek Glacier suite, comprise the vestiges of an extensive magmatic system within the Craig subterrane of southwestern Yukon and southeastern Alaska. The available data sug-gest that the Donjek Glacier suite represents part of a short-lived, Early Permian arc that initiated along the outboard margin of the Craig subterrane-Wrangellia-Peninsular block after Pennsylvanian collision and slab breakoff. At two fi eld localities in southwestern Yukon, Paleozoic country rocks with D1 fabrics are also intruded by sills and dikes of the Donjek Glacier suite that show evidence of ca. 285 Ma regional deformation and metamorphism (D2). Field evidence for Early Permian tectonism in the Saint Elias Mountains implies direct connections with coeval deformation and metamorphism in the Admiralty subterrane, a microcontinent in the Admiralty Island region of southeastern Alaska that developed separately from the Craig subterrane prior to the Early Per mian. D2 tectonism was likely related to the entry of the Admiralty subterrane margin into the Early Permian subduction zone, which resulted in collision and fi nal amalgamation of the Alexander-Wrangellia-Peninsular composite terrane. Our tectonic scenarios require the currently accepted confi guration of the Alexander terrane (com posite of the Craig and Admiralty subterranes) to have only existed after the Early Permian collision between the Admiralty subterrane and the previously assembled Craig subterrane-Wrangellia-Peninsular terrane. Biogeographic and other geological data suggest that the two-part assembly of the Alexander-Wrangellia-Peninsular composite terrane took place along a convergent marg...

show abstract

Orogen transplant: Taconic–Caledonian arc magmatism in the central Brooks Range of Alaska

Strauss¹,

Hoiland²,

Ward³

et al. 2017

Geological Society of America Bulletin

View full text Add to dashboard Cite

Macrofossil and conodont data from: SW Kluane Lake (115G & F[E 1/2]), Mount St. Elias (115B & C[E 1/2]), SW Dezadeash (115A), NE Yakutat (114O) and Tatshenshini River (114P) map areas, southwestern Yukon and northwestern British Columbia

Cited by 5 publications

References 0 publications

Earthquake Relocations Delineate a Discrete Fault Network and Deformation Corridor Throughout Southeast Alaska and Southwest Yukon

Earthquake Relocations Delineate a Discrete Fault Network and Deformation Corridor Throughout Southeast Alaska and Southwest Yukon

Late Paleozoic assembly of the Alexander-Wrangellia-Peninsular composite terrane, Canadian and Alaskan Cordillera

Orogen transplant: Taconic–Caledonian arc magmatism in the central Brooks Range of Alaska

Contact Info

Product

Resources

About