FRINK Linked Data Fragments server

Matches in SemOpenAlex for { <https://semopenalex.org/work/W4246479887> ?p ?o ?g. }

• W4246479887 endingPage "41" @default.
• W4246479887 startingPage "19" @default.
• W4246479887 abstract "The rapid change in 207Pb/206Pb ratio during early Earth history provides a powerful constraint for temporal resolution of Archaean crustal evolution. New and published data for Amı̂tsoq gneiss feldspars and whole rocks define the Earth's least radiogenic silicate Pb known until now. The most important feature of the data is that independent of the exact slope of the regression in a common Pb diagram, a very well-defined intercept with plausible terrestrial Pb evolution lines is obtained between 3.63 and 3.66 Ga, identical to a combined Pb/Pb regression age of 3654±73 Ma (MSWD=17.6). We conclude that the magmatic precursors of the Amı̂tsoq orthogneisses separated from a depleted mantle-like source at ca. 3.65 Ga. This contrasts sharply with claims based on ion-probe U–Pb zircon dating that the Amı̂tsoq gneisses had a prolonged, episodic, magmatic evolution extending from ca. 3.87 to 3.60 Ga. Pb isotopes offer no evidence that any Amı̂tsoq gneiss analysed until now began its evolution in the crust as long ago as 3.85 Ga. We propose that zircons significantly older than 3.65 Ga were inherited from chemically evolved rocks as old as ca. 3.85 Ga. Geochemical arguments are presented to support this proposal. New feldspar and whole rock Pb isotope data are also reported for sheets of quartz-dioritic gneiss on Akilia Island that yield the oldest zircon U–Pb age clusters in the range 3.84–3.87 Ga. These sheets are discordant to a metasedimentary enclave containing accessory apatite with graphite inclusions whose C-isotope ratios are regarded as biogenic in origin. As above, Pb-isotopes in the sheets are consistent with a magmatic age of 3.65 Ga, which we regard as the true minimum age for these waterlain sediments and their possibly biogenic markers. Additional Pb-isotope data, as well as limited published Sm–Nd and U–Pb zircon data on the Akilia enclaves themselves, suggest an age between ca. 3.65 and 3.70 Ga for their original deposition, some 150–200 Ma younger than proposed previously. Thus the question of overlap of earliest life with a bolide impact scenario terminating ≥3.80 Ga (as on the moon) becomes irrelevant." @default.
• W4246479887 created "2022-05-12" @default.
• W4246479887 creator A5009733994 @default.
• W4246479887 creator A5082781738 @default.
• W4246479887 date "1998-08-01" @default.
• W4246479887 modified "2023-09-26" @default.
• W4246479887 title "Initial Pb of the Amı̂tsoq gneiss revisited: implication for the timing of early Archaean crustal evolution in West Greenland" @default.
• W4246479887 cites W1615451124 @default.
• W4246479887 cites W1967347520 @default.
• W4246479887 cites W1977795491 @default.
• W4246479887 cites W1978095121 @default.
• W4246479887 cites W1980343879 @default.
• W4246479887 cites W1984901263 @default.
• W4246479887 cites W1987420581 @default.
• W4246479887 cites W1991569889 @default.
• W4246479887 cites W1994361828 @default.
• W4246479887 cites W199436490 @default.
• W4246479887 cites W1995891161 @default.
• W4246479887 cites W1996146659 @default.
• W4246479887 cites W1997462210 @default.
• W4246479887 cites W1998225068 @default.
• W4246479887 cites W1998674367 @default.
• W4246479887 cites W2007105153 @default.
• W4246479887 cites W2010084304 @default.
• W4246479887 cites W2010431068 @default.
• W4246479887 cites W2010626609 @default.
• W4246479887 cites W2011636272 @default.
• W4246479887 cites W2017175357 @default.
• W4246479887 cites W2018245819 @default.
• W4246479887 cites W2022904951 @default.
• W4246479887 cites W2031312028 @default.
• W4246479887 cites W2031535992 @default.
• W4246479887 cites W2032456215 @default.
• W4246479887 cites W2034370530 @default.
• W4246479887 cites W2044590283 @default.
• W4246479887 cites W2045746543 @default.
• W4246479887 cites W2046961523 @default.
• W4246479887 cites W2047379211 @default.
• W4246479887 cites W2049065847 @default.
• W4246479887 cites W2051919739 @default.
• W4246479887 cites W2054000451 @default.
• W4246479887 cites W2055274306 @default.
• W4246479887 cites W2057709663 @default.
• W4246479887 cites W2063015921 @default.
• W4246479887 cites W2065250459 @default.
• W4246479887 cites W2065371877 @default.
• W4246479887 cites W2066697768 @default.
• W4246479887 cites W2070066501 @default.
• W4246479887 cites W2076774944 @default.
• W4246479887 cites W2077085454 @default.
• W4246479887 cites W2082164816 @default.
• W4246479887 cites W2088337974 @default.
• W4246479887 cites W2088934812 @default.
• W4246479887 cites W2095172979 @default.
• W4246479887 cites W2124896017 @default.
• W4246479887 cites W2141236028 @default.
• W4246479887 cites W2153601941 @default.
• W4246479887 cites W2325860424 @default.
• W4246479887 cites W4251358869 @default.
• W4246479887 cites W50052442 @default.
• W4246479887 doi "https://doi.org/10.1016/s0009-2541(98)00059-x" @default.
• W4246479887 hasPublicationYear "1998" @default.
• W4246479887 type Work @default.
• W4246479887 citedByCount "83" @default.
• W4246479887 countsByYear W42464798872012 @default.
• W4246479887 countsByYear W42464798872014 @default.
• W4246479887 countsByYear W42464798872015 @default.
• W4246479887 countsByYear W42464798872018 @default.
• W4246479887 countsByYear W42464798872019 @default.
• W4246479887 countsByYear W42464798872021 @default.
• W4246479887 countsByYear W42464798872022 @default.
• W4246479887 countsByYear W42464798872023 @default.
• W4246479887 crossrefType "journal-article" @default.
• W4246479887 hasAuthorship W4246479887A5009733994 @default.
• W4246479887 hasAuthorship W4246479887A5082781738 @default.
• W4246479887 hasConcept C127313418 @default.
• W4246479887 hasConcept C149347711 @default.
• W4246479887 hasConcept C171701179 @default.
• W4246479887 hasConcept C17409809 @default.
• W4246479887 hasConcept C202746551 @default.
• W4246479887 hasConcept C26687426 @default.
• W4246479887 hasConcept C2776698055 @default.
• W4246479887 hasConcept C2778849375 @default.
• W4246479887 hasConcept C37523158 @default.
• W4246479887 hasConcept C57016615 @default.
• W4246479887 hasConcept C67236022 @default.
• W4246479887 hasConceptScore W4246479887C127313418 @default.
• W4246479887 hasConceptScore W4246479887C149347711 @default.
• W4246479887 hasConceptScore W4246479887C171701179 @default.
• W4246479887 hasConceptScore W4246479887C17409809 @default.
• W4246479887 hasConceptScore W4246479887C202746551 @default.
• W4246479887 hasConceptScore W4246479887C26687426 @default.
• W4246479887 hasConceptScore W4246479887C2776698055 @default.
• W4246479887 hasConceptScore W4246479887C2778849375 @default.
• W4246479887 hasConceptScore W4246479887C37523158 @default.
• W4246479887 hasConceptScore W4246479887C57016615 @default.
• W4246479887 hasConceptScore W4246479887C67236022 @default.
• W4246479887 hasIssue "1-2" @default.

• next