Matches in SemOpenAlex for { <https://semopenalex.org/work/W2775889104> ?p ?o ?g. }
- W2775889104 endingPage "80" @default.
- W2775889104 startingPage "67" @default.
- W2775889104 abstract "Metasediments of the Jack Hills contain the oldest known terrestrial minerals in the form of zircons nearly 4.4 billion years old. Paleointensity data from these zircons provide evidence for a Hadean geodynamo as old as 4.2 billion years old. Given the importance of these zircons for constraining the earliest history of the core, it is vital to understand the fidelity of the zircon record. A fundamental aspect providing context for the preservation of primary magnetic signals is the nature of overprints predicted to have been imparted on rocks of the Jack Hills due to Archean to Proterozoic metamorphic events. To be viable magnetic records of a Hadean geodynamo, zircon magnetization directions should differ from these secondary magnetizations. To evaluate these secondary magnetizations, we report paleomagnetic analyses of a comprehensive sampling of 68 quartzite cobble-sized clasts from the Jack Hills metasediments ∼0.5 to 1.0 km from the Discovery Site (which has yielded the oldest zircons and paleofield estimates). While application of standard paleomagnetic tests suggests that the ensemble of cobble directions cannot be distinguished from those drawn from a random distribution, a new cluster analysis of directions on a sphere and non-parametric resampling approaches reveal significant directions amongst subsets of the data. One, isolated at the lowest temperature analyzed [200 to 300 °C, Declination (Dec.) = 316.8°, Inclination (Inc.) =−51.1°] appears to be dominated by the present day field. Another, isolated at higher (but still relatively low unblocking temperatures that we call “intermediate”, of ∼350–500 °C, Dec. = 243.8°, Inc. = 9.5°) agrees with a magnetic overprint isolated from the secondary Cr–Fe mica fuchsite isolated from the Jack Hills Discovery site, passing a field test at the 80% confidence level. No evidence is found in our data, or in the data of others collected on similar Jack Hills lithologies, for a widespread 1 Ga remagnetization event. Instead, we interpret the most prevalent secondary magnetization of the quartzite (i.e., intermediate unblocking) and the fuchsite characteristic remanent magnetization to be ∼2.65 Ga in age, coincident with peak metamorphism (as high as ca. 475 °C) of the Jack Hills. The presence of this distinct secondary magnetization, its difference from that recorded by Jack Hills zircons at high unblocking temperatures, and the lack of a dominant remagnetization direction at high unblocking temperatures in the cobble data (the expected result for a primary magnetization), lends further support to the fidelity of the Hadean geomagnetic record. The presence of the secondary magnetization also lends support to the conclusion that most of the Jack Hills metasediments were deposited in the Archean, with only minor reworking and potential tectonic interleaving of Proterozoic components. Overall, the application of the new directional cluster analysis presented here has the potential to reveal magnetic directions in highly scattered data sets, typical of weakly magnetized coarse-grained sedimentary rocks" @default.
- W2775889104 created "2018-01-05" @default.
- W2775889104 creator A5068938126 @default.
- W2775889104 creator A5070063998 @default.
- W2775889104 creator A5071860732 @default.
- W2775889104 creator A5076142110 @default.
- W2775889104 creator A5083883713 @default.
- W2775889104 date "2018-02-01" @default.
- W2775889104 modified "2023-10-17" @default.
- W2775889104 title "Cluster analysis on a sphere: Application to magnetizations from metasediments of the Jack Hills, Western Australia" @default.
- W2775889104 cites W1160060274 @default.
- W2775889104 cites W1541988658 @default.
- W2775889104 cites W1615737483 @default.
- W2775889104 cites W1990368529 @default.
- W2775889104 cites W1996832375 @default.
- W2775889104 cites W2008738611 @default.
- W2775889104 cites W2012363050 @default.
- W2775889104 cites W2015245929 @default.
- W2775889104 cites W2021564878 @default.
- W2775889104 cites W2025732410 @default.
- W2775889104 cites W2036328877 @default.
- W2775889104 cites W2052636445 @default.
- W2775889104 cites W2059277213 @default.
- W2775889104 cites W2074857191 @default.
- W2775889104 cites W2077208327 @default.
- W2775889104 cites W2083819548 @default.
- W2775889104 cites W2095800081 @default.
- W2775889104 cites W2096391343 @default.
- W2775889104 cites W2112688502 @default.
- W2775889104 cites W2124915259 @default.
- W2775889104 cites W2147199686 @default.
- W2775889104 cites W2152423430 @default.
- W2775889104 cites W2266521699 @default.
- W2775889104 cites W2286975898 @default.
- W2775889104 cites W2338208045 @default.
- W2775889104 cites W2475087122 @default.
- W2775889104 cites W2495522451 @default.
- W2775889104 cites W2514340137 @default.
- W2775889104 cites W2577149531 @default.
- W2775889104 cites W2617338718 @default.
- W2775889104 cites W2738169223 @default.
- W2775889104 cites W3124604814 @default.
- W2775889104 doi "https://doi.org/10.1016/j.epsl.2017.12.007" @default.
- W2775889104 hasPublicationYear "2018" @default.
- W2775889104 type Work @default.
- W2775889104 sameAs 2775889104 @default.
- W2775889104 citedByCount "8" @default.
- W2775889104 countsByYear W27758891042018 @default.
- W2775889104 countsByYear W27758891042020 @default.
- W2775889104 countsByYear W27758891042022 @default.
- W2775889104 countsByYear W27758891042023 @default.
- W2775889104 crossrefType "journal-article" @default.
- W2775889104 hasAuthorship W2775889104A5068938126 @default.
- W2775889104 hasAuthorship W2775889104A5070063998 @default.
- W2775889104 hasAuthorship W2775889104A5071860732 @default.
- W2775889104 hasAuthorship W2775889104A5076142110 @default.
- W2775889104 hasAuthorship W2775889104A5083883713 @default.
- W2775889104 hasBestOaLocation W27758891041 @default.
- W2775889104 hasConcept C109007969 @default.
- W2775889104 hasConcept C127313418 @default.
- W2775889104 hasConcept C149347711 @default.
- W2775889104 hasConcept C151730666 @default.
- W2775889104 hasConcept C173776410 @default.
- W2775889104 hasConcept C17409809 @default.
- W2775889104 hasConcept C189479680 @default.
- W2775889104 hasConcept C202746551 @default.
- W2775889104 hasConcept C26687426 @default.
- W2775889104 hasConcept C2778660078 @default.
- W2775889104 hasConcept C2778849375 @default.
- W2775889104 hasConcept C2779343474 @default.
- W2775889104 hasConcept C2779614968 @default.
- W2775889104 hasConcept C37523158 @default.
- W2775889104 hasConcept C77928131 @default.
- W2775889104 hasConcept C83365034 @default.
- W2775889104 hasConcept C93033518 @default.
- W2775889104 hasConceptScore W2775889104C109007969 @default.
- W2775889104 hasConceptScore W2775889104C127313418 @default.
- W2775889104 hasConceptScore W2775889104C149347711 @default.
- W2775889104 hasConceptScore W2775889104C151730666 @default.
- W2775889104 hasConceptScore W2775889104C173776410 @default.
- W2775889104 hasConceptScore W2775889104C17409809 @default.
- W2775889104 hasConceptScore W2775889104C189479680 @default.
- W2775889104 hasConceptScore W2775889104C202746551 @default.
- W2775889104 hasConceptScore W2775889104C26687426 @default.
- W2775889104 hasConceptScore W2775889104C2778660078 @default.
- W2775889104 hasConceptScore W2775889104C2778849375 @default.
- W2775889104 hasConceptScore W2775889104C2779343474 @default.
- W2775889104 hasConceptScore W2775889104C2779614968 @default.
- W2775889104 hasConceptScore W2775889104C37523158 @default.
- W2775889104 hasConceptScore W2775889104C77928131 @default.
- W2775889104 hasConceptScore W2775889104C83365034 @default.
- W2775889104 hasConceptScore W2775889104C93033518 @default.
- W2775889104 hasFunder F4320306076 @default.
- W2775889104 hasLocation W27758891041 @default.
- W2775889104 hasOpenAccess W2775889104 @default.
- W2775889104 hasPrimaryLocation W27758891041 @default.
- W2775889104 hasRelatedWork W1984858595 @default.
- W2775889104 hasRelatedWork W2008043020 @default.