Matches in SemOpenAlex for { <https://semopenalex.org/work/W2022962879> ?p ?o ?g. }
- W2022962879 endingPage "142" @default.
- W2022962879 startingPage "111" @default.
- W2022962879 abstract "The intensity of the geomagnetic field during Archean is an important source of information about the evolution of the Earth’s core. Hale [Earth Planet. Sci. Lett. 86 (1987b) 354] reported a very low equatorial paleointensity of 5 μT at ca. 3.5 Ga obtained from komatiites of the Barberton greenstone belt, South Africa, and regarded their remanences as thermal overprints due to a metamorphic event. However, this result has a major drawback since remanences of the Barberton komatiites are carried by magnetites formed during serpentinization that typically results in acquisition of chemical remanent magnetization (CRM). We report the results of detailed paleomagnetic, rock magnetic, and paleointensity investigations using komatiite samples from the Barberton (ca. 3.5 Ga) and Belingwe (ca. 2.7 Ga) greenstone belts in South Africa and Zimbabwe, respectively. Paleodirectional data for Barberton are consistent with results of previous work, and the characteristic remanent magnetization (ChRM) of the Belingwe samples reveals a positive fold test, suggesting that samples from both areas record the Archean geomagnetic field. The main carriers of ChRM are Ti-free magnetites presumed to be akin to single domain grains, and their rock magnetic properties are very stable when subjected to laboratory heating up to 600–700 °C. Our microscopic observations provide support that these are secondary minerals formed during serpentinization. Thellier–Thellier paleointensity experiments for the Barberton and Belingwe samples yielded very low mean virtual dipole moment (VDM) estimates of (1.8±1.3)×1022 A m2 and (1.1±0.9)×1022 A m2, respectively. These correspond to about 24 and 15% of the present day value. Considering the low metamorphic grade for the sampling areas, however, it seems to be somewhat difficult to regard the entire ranges of komatiite ChRM as thermal overprints acquired by reheating during metamorphic events. We hence propose as the most likely scenario the possibility that most fractions of ChRM are survivors of primary grain growth CRM. Taking the theoretical and experimental estimates of the ratio of CRM to thermoremanent magnetization (TRM) into account, this suggests that these low mean VDM values can provide constraints on the lower limits of the geomagnetic field intensities in both greenstone belts at ca. 3.5 and 2.7 Ga." @default.
- W2022962879 created "2016-06-24" @default.
- W2022962879 creator A5008238015 @default.
- W2022962879 creator A5013109536 @default.
- W2022962879 date "2004-05-01" @default.
- W2022962879 modified "2023-10-06" @default.
- W2022962879 title "Paleomagnetic constraints on the Archean geomagnetic field intensity obtained from komatiites of the Barberton and Belingwe greenstone belts, South Africa and Zimbabwe" @default.
- W2022962879 cites W1964730198 @default.
- W2022962879 cites W1965960661 @default.
- W2022962879 cites W1966765391 @default.
- W2022962879 cites W1969247505 @default.
- W2022962879 cites W1969846781 @default.
- W2022962879 cites W1971513400 @default.
- W2022962879 cites W1974405492 @default.
- W2022962879 cites W1974553802 @default.
- W2022962879 cites W1982066092 @default.
- W2022962879 cites W1995484521 @default.
- W2022962879 cites W1999185112 @default.
- W2022962879 cites W1999673370 @default.
- W2022962879 cites W2015133676 @default.
- W2022962879 cites W2018467900 @default.
- W2022962879 cites W2019704178 @default.
- W2022962879 cites W2020859337 @default.
- W2022962879 cites W2035380088 @default.
- W2022962879 cites W2042582115 @default.
- W2022962879 cites W2043144038 @default.
- W2022962879 cites W2048225026 @default.
- W2022962879 cites W2050426306 @default.
- W2022962879 cites W2050756326 @default.
- W2022962879 cites W2052128667 @default.
- W2022962879 cites W2058750287 @default.
- W2022962879 cites W2080767331 @default.
- W2022962879 cites W2082048561 @default.
- W2022962879 cites W2082241110 @default.
- W2022962879 cites W2082737776 @default.
- W2022962879 cites W2086225362 @default.
- W2022962879 cites W2088100278 @default.
- W2022962879 cites W2089351169 @default.
- W2022962879 cites W2091795225 @default.
- W2022962879 cites W2093975809 @default.
- W2022962879 cites W2106981356 @default.
- W2022962879 cites W2127145395 @default.
- W2022962879 cites W2144031821 @default.
- W2022962879 cites W2147067250 @default.
- W2022962879 cites W2154101512 @default.
- W2022962879 cites W2154707884 @default.
- W2022962879 cites W2158222249 @default.
- W2022962879 cites W2158350227 @default.
- W2022962879 cites W2158500713 @default.
- W2022962879 cites W2159154761 @default.
- W2022962879 cites W2169115796 @default.
- W2022962879 cites W2175772604 @default.
- W2022962879 cites W2536115877 @default.
- W2022962879 cites W3020934278 @default.
- W2022962879 cites W3044058298 @default.
- W2022962879 cites W3044499890 @default.
- W2022962879 cites W3045022628 @default.
- W2022962879 cites W4242249832 @default.
- W2022962879 cites W836961161 @default.
- W2022962879 doi "https://doi.org/10.1016/j.precamres.2004.01.003" @default.
- W2022962879 hasPublicationYear "2004" @default.
- W2022962879 type Work @default.
- W2022962879 sameAs 2022962879 @default.
- W2022962879 citedByCount "56" @default.
- W2022962879 countsByYear W20229628792012 @default.
- W2022962879 countsByYear W20229628792013 @default.
- W2022962879 countsByYear W20229628792014 @default.
- W2022962879 countsByYear W20229628792015 @default.
- W2022962879 countsByYear W20229628792016 @default.
- W2022962879 countsByYear W20229628792017 @default.
- W2022962879 countsByYear W20229628792019 @default.
- W2022962879 countsByYear W20229628792020 @default.
- W2022962879 countsByYear W20229628792021 @default.
- W2022962879 countsByYear W20229628792022 @default.
- W2022962879 countsByYear W20229628792023 @default.
- W2022962879 crossrefType "journal-article" @default.
- W2022962879 hasAuthorship W2022962879A5008238015 @default.
- W2022962879 hasAuthorship W2022962879A5013109536 @default.
- W2022962879 hasConcept C115260700 @default.
- W2022962879 hasConcept C121332964 @default.
- W2022962879 hasConcept C127313418 @default.
- W2022962879 hasConcept C149347711 @default.
- W2022962879 hasConcept C155058782 @default.
- W2022962879 hasConcept C165205528 @default.
- W2022962879 hasConcept C171782412 @default.
- W2022962879 hasConcept C17409809 @default.
- W2022962879 hasConcept C189479680 @default.
- W2022962879 hasConcept C199635899 @default.
- W2022962879 hasConcept C2780733770 @default.
- W2022962879 hasConcept C32546565 @default.
- W2022962879 hasConcept C62520636 @default.
- W2022962879 hasConcept C8058405 @default.
- W2022962879 hasConceptScore W2022962879C115260700 @default.
- W2022962879 hasConceptScore W2022962879C121332964 @default.
- W2022962879 hasConceptScore W2022962879C127313418 @default.
- W2022962879 hasConceptScore W2022962879C149347711 @default.
- W2022962879 hasConceptScore W2022962879C155058782 @default.
- W2022962879 hasConceptScore W2022962879C165205528 @default.