{
"USGS Publications Warehouse": { "@context": "https://schema.org", "@type": "Article", "additionalType": "Journal Article", "name": "Cretaceous to Oligocene magmatic and tectonic evolution of the western Alaska Range: Insights from U-Pb and 40Ar/39Ar geochronology", "identifier": [ { "@type": "PropertyValue", "propertyID": "USGS Publications Warehouse IndexID", "value": "70216894", "url": "https://pubs.usgs.gov/publication/70216894" }, { "@type": "PropertyValue", "propertyID": "USGS Publications Warehouse Internal ID", "value": 70216894 }, { "@type": "PropertyValue", "propertyID": "DOI", "value": "10.1130/GES02303.1", "url": "https://doi.org/10.1130/GES02303.1" } ], "journal": { "@type": "Periodical", "name": "Geosphere", "volumeNumber": "17", "issueNumber": "1" }, "inLanguage": "en", "isPartOf": [ { "@type": "CreativeWorkSeries", "name": "Geosphere" } ], "datePublished": "2020", "dateModified": "2024-01-04", "abstract": "New U-Pb and\u00a040Ar/39Ar ages integrated with geologic mapping and observations across the western Alaska Range constrain the distribution and tectonic setting of Cretaceous to Oligocene magmatism along an evolving accretionary plate margin in south-central Alaska. These rocks were emplaced across basement domains that include Neoproterozoic to Jurassic carbonate and siliciclastic strata of the Farewell terrane, Triassic and Jurassic plutonic and volcanic rocks of the Peninsular terrane, and Jurassic and Cretaceous siliciclastic strata of the Kahiltna assemblage. Plutonic rocks of different ages also host economic mineralization including intrusion-related Au, porphyry Cu-Mo-Au, polymetallic veins and skarns, and peralkaline intrusion-related rare-earth elements. The oldest intrusive suites were emplaced ca. 104\u201380 Ma into the Peninsular terrane only prior to final accretion. Deformation of the northern Kahiltna succession and underlying Farewell terrane occurred at ca. 97 Ma, and more widespread deformation ca. 80 Ma involved south-vergent folding and thrusting of the Kahiltna assemblage that records collisional accretion of the Peninsular-Wrangellia terrane and juxtaposition of sediment wedges formed on the inboard and outboard terranes. More widespread magmatism ca. 75\u201355 Ma occurred in two general pulses, each having distinct styles of localized deformation. Circa 75\u201365 Ma plutons were emplaced in a transpressional setting and stitch the accreted Peninsular and Wrangellia terranes to the Farewell terrane. Circa 65\u201355 Ma magmatism occurred across the entire range and extends for more than 200 km inboard from the inferred position of the continental margin. The Paleocene plutonic suite generally reflects shallower emplacement depths relative to older suites and is associated with more abundant andesitic to rhyolitic volcanic rocks. Deformation ca. 58\u201356 Ma was concentrated along two high-strain zones, the most prominent of which is 1 km wide, strikes east-northeast, and accommodated dextral oblique motion. Emplacement of widespread intermediate to mafic dikes ca. 59\u201351 Ma occurred before a notable magmatic lull from ca. 51\u201344 Ma reflecting a late Paleocene to early Eocene slab window. Magmatism resumed ca. 44 Ma, recording the transition from slab window to renewed subduction that formed the Aleutian-Meshik arc to the southwest. In the western Alaska Range, Eocene magmatism included emplacement of the elongate north-south Merrill Pass pluton and large volumes of ca. 44\u201337 Ma andesitic flows, tuffs, and lahar deposits. Finally, a latest Eocene to Oligocene magmatic pulse involved emplacement of a compositionally variable but spatially concentrated suite of magmas ranging from gabbro to peralkaline granite ca. 35\u201326 Ma, followed by waning magmatism that coincided with initiation of Yakutat shallow-slab subduction. Cretaceous to Oligocene magmatism throughout the western Alaska Range collectively records terrane accretion, translation, and integration together with evolving subduction dynamics that have shaped the southern Alaska margin since the middle Mesozoic.", "description": "36 p.; 3 Data Releases", "publisher": { "@type": "Organization", "name": "Geological Society of America" }, "author": [ { "@type": "Person", "name": "Jones, James V. III jvjones@usgs.gov", "givenName": "James V.", "familyName": "Jones", "email": "jvjones@usgs.gov", "identifier": { "@type": "PropertyValue", "propertyID": "ORCID", "value": "0000-0002-6602-5935", "url": "https://orcid.org/0000-0002-6602-5935" }, "affiliation": [ { "@type": "Organization", "name": "Alaska Science Center Geology Minerals", "url": "https://www.usgs.gov/centers/alaska-science-center" } ] }, { "@type": "Person", "name": "Todd, Erin etodd@usgs.gov", "givenName": "Erin", "familyName": "Todd", "email": "etodd@usgs.gov", "identifier": { "@type": "PropertyValue", "propertyID": "ORCID", "value": "0000-0002-4871-9730", "url": "https://orcid.org/0000-0002-4871-9730" }, "affiliation": [ { "@type": "Organization", "name": "Alaska Science Center Geology Minerals", "url": "https://www.usgs.gov/centers/alaska-science-center" } ] }, { "@type": "Person", "name": "Box, Stephen E. sbox@usgs.gov", "givenName": "Stephen E.", "familyName": "Box", "email": "sbox@usgs.gov", "identifier": { "@type": "PropertyValue", "propertyID": "ORCID", "value": "0000-0002-5268-8375", "url": "https://orcid.org/0000-0002-5268-8375" }, "affiliation": [ { "@type": "Organization", "name": "Geology, Minerals, Energy, and Geophysics Science Center", "url": "https://www.usgs.gov/centers/gmeg" } ] }, { "@type": "Person", "name": "Haeussler, Peter J.", "givenName": "Peter J.", "familyName": "Haeussler", "identifier": { "@type": "PropertyValue", "propertyID": "ORCID", "value": "0000-0002-1503-6247", "url": "https://orcid.org/0000-0002-1503-6247" }, "affiliation": [ { "@type": "Organization", "name": "Alaska Science Center", "url": "https://www.usgs.gov/centers/alaska-science-center" }, { "@type": "Organization", "name": "Alaska Science Center Geology Minerals", "url": "https://www.usgs.gov/centers/alaska-science-center" } ] }, { "@type": "Person", "name": "Karl, Susan M.", "givenName": "Susan M.", "familyName": "Karl", "identifier": { "@type": "PropertyValue", "propertyID": "ORCID", "value": "0000-0003-1559-7826", "url": "https://orcid.org/0000-0003-1559-7826" }, "affiliation": [ { "@type": "Organization", "name": "Alaska Science Center Geology Minerals", "url": "https://www.usgs.gov/centers/alaska-science-center" } ] }, { "@type": "Person", "name": "Holm-Denoma, Christopher", "givenName": "Christopher", "familyName": "Holm-Denoma", "identifier": { "@type": "PropertyValue", "propertyID": "ORCID", "value": "0000-0003-3229-5440", "url": "https://orcid.org/0000-0003-3229-5440" }, "affiliation": [ { "@type": "Organization", "name": "Geology, Geophysics, and Geochemistry Science Center", "url": "https://www.usgs.gov/centers/gggsc" } ] }, { "@type": "Person", "name": "Graham, Garth E. ggraham@usgs.gov", "givenName": "Garth E.", "familyName": "Graham", "email": "ggraham@usgs.gov", "identifier": { "@type": "PropertyValue", "propertyID": "ORCID", "value": "0000-0003-0657-0365", "url": "https://orcid.org/0000-0003-0657-0365" }, "affiliation": [ { "@type": "Organization", "name": "Geology, Geophysics, and Geochemistry Science Center", "url": "https://www.usgs.gov/centers/gggsc" }, { "@type": "Organization", "name": "Central Mineral and Environmental Resources Science Center", "url": "https://www.usgs.gov/centers/gggsc" } ] }, { "@type": "Person", "name": "Bradley, Dwight bradleyorchard2@gmail.com", "givenName": "Dwight", "familyName": "Bradley", "email": "bradleyorchard2@gmail.com", "identifier": { "@type": "PropertyValue", "propertyID": "ORCID", "value": "0000-0001-9116-5289", "url": "https://orcid.org/0000-0001-9116-5289" }, "affiliation": [ { "@type": "Organization", "name": "Alaska Science Center", "url": "https://www.usgs.gov/centers/alaska-science-center" }, { "@type": "Organization", "name": "Alaska Science Center Geology Minerals", "url": "https://www.usgs.gov/centers/alaska-science-center" }, { "@type": "Organization", "name": "Central Mineral and Environmental Resources Science Center", "url": "https://www.usgs.gov/centers/gggsc" } ] }, { "@type": 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