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Return to Rodinia? ...
Return to Rodinia? Moderate to high palaeolatitude of the São Francisco/Congo craton at 920 Ma
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- Evans, D. A D (författare)
- Yale University
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- Trindade, R. I F (författare)
- University of São Paulo
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- Catelani, E. L. (författare)
- University of São Paulo
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- D'Agrella-Filho, M. S. (författare)
- University of São Paulo
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- Heaman, L. M. (författare)
- University of Alberta
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- Oliveira, E. P. (författare)
- University of Campinas
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- Söderlund, U. (författare)
- Lund University,Lunds universitet,Geologiska institutionen,Naturvetenskapliga fakulteten,Department of Geology,Faculty of Science
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- Ernst, R. E. (författare)
- Carleton University
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- Smirnov, A. V. (författare)
- Michigan Technological University
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- Salminen, J. M. (författare)
- University of Helsinki
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(creator_code:org_t)
- 1
- 2015
- 2015
- Engelska 24 s.
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Ingår i: Geological Society Special Publication. - 0305-8719. ; 424:1, s. 167-190
- Relaterad länk:
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http://dx.doi.org/10...
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https://lup.lub.lu.s...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- Moderate to high palaeolatitudes recorded in mafic dykes, exposed along the coast of Bahia, Brazil, are partly responsible for some interpretations that the São Francisco/Congo craton was separate from the low-latitude Rodinia supercontinent at about 1050 Ma. We report new palaeomagnetic data that replicate the previous results. However, we obtain substantially younger U-Pb baddeleyite ages from five dykes previously thought to be 1.02-1.01 Ga according to the 40Ar/39Ar method. Specifically, the so-called «A-normal» remanence direction from Salvador is dated at 924.2±3.8 Ma, within error of the age for the «C» remanence direction at 921.5±4.3 Ma. An «A-normal» dyke at Ilh»us is dated at 926.1±4.6 Ma, and two «A-normal» dykes at Olivença have indistinguishable ages with best estimate of emplacement at 918.2±6.7 Ma. We attribute the palaeomagnetic variance of the «A-normal» and «C» directions to lack of averaging of geomagnetic palaeosecular variation in some regions. Our results render previous 40Ar/39Ar ages from the dykes suspect, leaving late Mesoproterozoic palaeolatitudes of the São Francisco/Congo craton unconstrained. The combined «A-normal» palaeomagnetic pole from coastal Bahia places the São Francisco/Congo craton in moderate to high palaeolatitudes at c. 920 Ma, allowing various possible positions of that block within Rodinia.
Ämnesord
- NATURVETENSKAP -- Geovetenskap och miljövetenskap -- Geologi (hsv//swe)
- NATURAL SCIENCES -- Earth and Related Environmental Sciences -- Geology (hsv//eng)
Publikations- och innehållstyp
- kap (ämneskategori)
- ref (ämneskategori)
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Evans, D. A D
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Trindade, R. I F
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Catelani, E. L.
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D'Agrella-Filho, ...
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Heaman, L. M.
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Oliveira, E. P.
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visa fler...
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Söderlund, U.
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Ernst, R. E.
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Smirnov, A. V.
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Salminen, J. M.
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visa färre...
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