Matches in SemOpenAlex for { <https://semopenalex.org/work/W1988174467> ?p ?o ?g. }
Showing items 1 to 89 of
89
with 100 items per page.
- W1988174467 endingPage "96" @default.
- W1988174467 startingPage "85" @default.
- W1988174467 abstract "Gneisses within an Archean basement terrane adjacent to the southwestern portion of the Labrador Trough were variably retrograded during a regional metamorphism of Grenville age (ca. 1000 Ma). Biotites from non-retrograded segments of the gneiss terrane record40Ar/39Ar plateau and isochron ages which date times of cooling following an episode of the Kenoran orogeny (2376–2391 Ma). A suite of gneiss samples displaying varying degrees of retrograde alteration was collected across the Grenville metamorphic gradient. Biotites in these samples show no petrographic evidence of retrograde alteration, however they do record internally discordant40Ar/39Ar age spectra. Although the extent of internal discordance is variable, the overall character of the release patterns is similar with younger apparent ages recorded in intermediate-temperature gas fractions. The total-gas dates range from 2257±27 Ma (northwest) to 1751±23 Ma (southeast), suggesting that variable quantities of radiogenic argon were lost from the Archean biotites during Grenville metamorphism. The “saddle-shaped” nature of the discordant spectra indicates that argon loss was not accomplished through single-stage, volume diffusion processes. Biotites in portions of the gneiss terrane which were completely recrystallized during Grenville metamorphism are petrographically and texturally distinct. A representative of this phase records a40Ar/39Ar plateau age of 2674±28 Ma. This date is markedly inconsistent with regional constraints on the timing of Grenville metamorphism, and indicates the presence of extraneous argon components. Both the extraneous and radiogenic argon components must have been liberated in constant proportions during experimental heating because the argon isotopic data yield a well-defined40Ar/36Ar vs.39Ar/36Ar isochron corresponding to an age (2658±23 Ma) similar to that defined by the plateau portion of the spectrum. The40Ar/39Ar biotite dates suggest that the effects of Grenville metamorphism extent 15–20 km northward into the Superior Province. The limit of this overprint is approximately coincident with the northernmost development of Grenville age thrust faults in the Archean terrane. Therefore, it is proposed that the northern margin of the Grenville Province in southwestern Labrador should be located along the northernmost Grenville thrust fault because this represents both a structural and a thermal discontinuity." @default.
- W1988174467 created "2016-06-24" @default.
- W1988174467 creator A5053179781 @default.
- W1988174467 date "1982-11-01" @default.
- W1988174467 modified "2023-09-26" @default.
- W1988174467 title "40Ar/39Ar incremental-release ages of biotite from a progressively remetamorphosed Archean basement terrane in southwestern Labrador" @default.
- W1988174467 cites W1596950208 @default.
- W1988174467 cites W1973238180 @default.
- W1988174467 cites W1974724228 @default.
- W1988174467 cites W1983522510 @default.
- W1988174467 cites W1998076168 @default.
- W1988174467 cites W2022223654 @default.
- W1988174467 cites W2031475474 @default.
- W1988174467 cites W2035558641 @default.
- W1988174467 cites W2038599233 @default.
- W1988174467 cites W2039933887 @default.
- W1988174467 cites W2041348481 @default.
- W1988174467 cites W2041452259 @default.
- W1988174467 cites W2044181360 @default.
- W1988174467 cites W2049200271 @default.
- W1988174467 cites W2050731913 @default.
- W1988174467 cites W2074785392 @default.
- W1988174467 cites W2097328061 @default.
- W1988174467 cites W2109608271 @default.
- W1988174467 cites W2137128965 @default.
- W1988174467 cites W2145604970 @default.
- W1988174467 cites W2314927865 @default.
- W1988174467 cites W2908783666 @default.
- W1988174467 cites W2910348137 @default.
- W1988174467 cites W2911016076 @default.
- W1988174467 cites W3010251339 @default.
- W1988174467 cites W934267857 @default.
- W1988174467 doi "https://doi.org/10.1016/0012-821x(82)90041-3" @default.
- W1988174467 hasPublicationYear "1982" @default.
- W1988174467 type Work @default.
- W1988174467 sameAs 1988174467 @default.
- W1988174467 citedByCount "9" @default.
- W1988174467 countsByYear W19881744672013 @default.
- W1988174467 crossrefType "journal-article" @default.
- W1988174467 hasAuthorship W1988174467A5053179781 @default.
- W1988174467 hasConcept C112764850 @default.
- W1988174467 hasConcept C127313418 @default.
- W1988174467 hasConcept C149347711 @default.
- W1988174467 hasConcept C150999391 @default.
- W1988174467 hasConcept C151730666 @default.
- W1988174467 hasConcept C171701179 @default.
- W1988174467 hasConcept C17409809 @default.
- W1988174467 hasConcept C180785854 @default.
- W1988174467 hasConcept C26687426 @default.
- W1988174467 hasConcept C2777241186 @default.
- W1988174467 hasConcept C57016615 @default.
- W1988174467 hasConcept C59235061 @default.
- W1988174467 hasConcept C67236022 @default.
- W1988174467 hasConcept C77928131 @default.
- W1988174467 hasConceptScore W1988174467C112764850 @default.
- W1988174467 hasConceptScore W1988174467C127313418 @default.
- W1988174467 hasConceptScore W1988174467C149347711 @default.
- W1988174467 hasConceptScore W1988174467C150999391 @default.
- W1988174467 hasConceptScore W1988174467C151730666 @default.
- W1988174467 hasConceptScore W1988174467C171701179 @default.
- W1988174467 hasConceptScore W1988174467C17409809 @default.
- W1988174467 hasConceptScore W1988174467C180785854 @default.
- W1988174467 hasConceptScore W1988174467C26687426 @default.
- W1988174467 hasConceptScore W1988174467C2777241186 @default.
- W1988174467 hasConceptScore W1988174467C57016615 @default.
- W1988174467 hasConceptScore W1988174467C59235061 @default.
- W1988174467 hasConceptScore W1988174467C67236022 @default.
- W1988174467 hasConceptScore W1988174467C77928131 @default.
- W1988174467 hasIssue "1" @default.
- W1988174467 hasLocation W19881744671 @default.
- W1988174467 hasOpenAccess W1988174467 @default.
- W1988174467 hasPrimaryLocation W19881744671 @default.
- W1988174467 hasRelatedWork W2009612684 @default.
- W1988174467 hasRelatedWork W2012258136 @default.
- W1988174467 hasRelatedWork W2014344272 @default.
- W1988174467 hasRelatedWork W2058753091 @default.
- W1988174467 hasRelatedWork W2068891498 @default.
- W1988174467 hasRelatedWork W2383926153 @default.
- W1988174467 hasRelatedWork W2391232661 @default.
- W1988174467 hasRelatedWork W2394267470 @default.
- W1988174467 hasRelatedWork W2495767126 @default.
- W1988174467 hasRelatedWork W3184018226 @default.
- W1988174467 hasVolume "61" @default.
- W1988174467 isParatext "false" @default.
- W1988174467 isRetracted "false" @default.
- W1988174467 magId "1988174467" @default.
- W1988174467 workType "article" @default.