Geologic maps of the Livengood SW C-3 and SE C-4 quadrangles, Tolovana mining district, Alaska

Athey, J. E.; Craw, P. A.

doi:10.14509/3308

Cited by 3 publications

(3 citation statements)

References 9 publications

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“…Gastropods are most like those from coeval Farewell terrane units to the southwest and have Siberian paleogeographic affinities (Blodgett et al, 2002), but trilobites resemble species from the Canadian Arctic Islands (Weber et al, 1994). Conglomerate clasts include chert, mudstone, sandstone, and felsic to intermediate igneous rocks (Athey and Craw, 2004). Petrographic analysis of graywacke suggests a collision orogen source, with some local input from the underlying Ordovician Livengood Dome Chert (Gergen et al, 1988).…”

Section: Lithologies and Fossil Datamentioning

confidence: 99%

The Mystic subterrane (partly) demystified: New data from the Farewell terrane and adjacent rocks, interior Alaska

et al. 2018

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The youngest part of the Farewell terrane in interior Alaska (USA) is the enigmatic Devonian-Cretaceous Mystic subterrane. New U-Pb detrital zircon, fossil, geochemical, neodymium isotopic, and petrographic data illuminate the origin of the rocks of this subterrane. The Devonian-Permian Sheep Creek Formation yielded youngest detrital zircons of Devonian age, major detrital zircon age probability peaks between ca. 460 and 405 Ma, and overall age spectra like those from the underlying Dillinger subterrane. Samples are sandstones rich in sedimentary lithic clasts, and differ from approximately coeval strata to the east that have abundant volcanic lithic clasts and late Paleozoic detrital zircons. The Permian Mount Dall conglomerate has mainly carbonate and chert clasts and yielded youngest detrital zircons of latest Pennsylvanian age. Permian quartz-carbonate sandstone in the northern Farewell terrane yielded abundant middle to late Permian detrital zircons. Late Triassic-Early Jurassic mafic igneous rocks occur in the central and eastern Mystic subterrane. New whole-rock geochemical and isotopic data indicate that magmas were rift related and derived from subcontinental mantle. Triassic and Jurassic strata have detrital zircon age spectra much like those of the Sheep Creek Formation, with major age populations between ca. 430 and 410 Ma. These rocks include conglomerate with clasts of carbonate ± chert and youngest detrital zircons of Late Triassic age and quartz-carbonate sandstone with youngest detrital zircons of Early Jurassic age. Lithofacies indicating highly productive oceanographic conditions (upwelling?) bracket the main part of the Mystic succession: Upper Devonian bedded barite and phosphatic Upper Devonian and Lower Jurassic rocks. The youngest part of the Mystic subterrane consists of Lower Cretaceous (Valanginian-Aptian) limestone, calcareous sandstone, and related strata. These rocks are partly coeval with the oldest parts of the Kahiltna assemblage, an overlap succession exposed along the southern margin of the Farewell terrane. Our findings support previous models suggesting that the Farewell terrane was proximal to the Alexander-Wrangellia-Peninsular composite terrane during the late Paleozoic, and further suggest that such proximity continued into (or recurred during) the Late Triassic-Early Jurassic. But middle to late Permian detrital zircons in northern Farewell require another source; the Yukon-Tanana terrane is one possibility.

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Section: Lithologies and Fossil Datamentioning

confidence: 99%

The Mystic subterrane (partly) demystified: New data from the Farewell terrane and adjacent rocks, interior Alaska

et al. 2018

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“…Altered volcanic rocks belonging to this unit were previously mapped as the Ruth Creek and Olive Creek plutons by Athey and Craw (2004). Subsequent exploration drilling at Money Knob showed that these rocks have volcanic textures and comprise a stratiform layer approximately 10-75 m thick (Klipfel and others, 2009).…”

Section: Kwcs DCmentioning

confidence: 97%

“…The Cambrian assemblage displays a mid-ocean ridge basalt (MORB) trace-element signature (Athey and others, 2004c) and may represent a differentiated sill complex (Cady and Morin, 1990) or an obducted slab of oceanic crust. This assemblage is metamorphosed to prehnite-pumpellyite facies (Foster, 1966;Athey and Craw, 2004).…”

Section: Mafic and Ultramafic Assemblagementioning

confidence: 99%

Geologic map of portions of the Livengood B-3, B-4, C-3, and C-4 quadrangles, Tolovana mining district, Alaska

Twelker¹,

Athey²,

Newberry³

et al. 2016

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Ordovician geology of Alaska

Dumoulin

Strauss

Repetski

2022

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Ordovician rocks, found in northern, east-central, interior, and southern Alaska, formed in a variety of depositional and paleogeographic settings. Shallow- and deep-water strata deposited along the northwestern Laurentian margin occur in east-central Alaska (Yukon River area) and probably correlative rocks crop out to the north in the Porcupine River area. Ordovician strata elsewhere in Alaska are parts of continental or island arc fragments that, as indicated by faunal and detrital zircon data, have been variously displaced. In northern Alaska, Ordovician rocks are included in the Arctic Alaska-Chukotka Microplate (AACM), a composite tectonic entity with a complex history. Some Ordovician strata in the AACM (parts of the North Slope subterrane) represent displaced fragments of the northern Laurentian margin. Coeval strata in southwestern parts of the AACM (York and Seward terranes, Hammond subterrane) share distinctive lithologic and biotic features with Ordovician rocks in interior Alaska (Farewell and related terranes). Ordovician strata in southeastern Alaska (Alexander terrane) also likely compose a composite crustal fragment that accumulated in a complex arc system. Shared features between many of these units suggest similar origins as part of one or more crustal fragments situated in the paleo-Arctic between Laurentia, Baltica, and Siberia during early Paleozoic time.

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Geologic maps of the Livengood SW C-3 and SE C-4 quadrangles, Tolovana mining district, Alaska

Cited by 3 publications

References 9 publications

The Mystic subterrane (partly) demystified: New data from the Farewell terrane and adjacent rocks, interior Alaska

The Mystic subterrane (partly) demystified: New data from the Farewell terrane and adjacent rocks, interior Alaska

Geologic map of portions of the Livengood B-3, B-4, C-3, and C-4 quadrangles, Tolovana mining district, Alaska

Ordovician geology of Alaska

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