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Columbia revisited :
Columbia revisited : paleomagnetic results from the 1790 Ma colider volcanics (SW Amazonian Craton, Brazil)
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- Bispo-Santos, Franklin (författare)
- Universidade de São Paulo
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- D’Agrella-Filho, Manoel S. (författare)
- Universidade de São Paulo
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- Pacca, Igor I.G. (författare)
- Universidade de São Paulo
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- Janikian, Liliane (författare)
- Universidade de São Paulo
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- Trindade, Ricardo I.F. (författare)
- Universidade de São Paulo
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- Elming, Sten-åke (författare)
- Luleå tekniska universitet,Geovetenskap och miljöteknik
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- Silva, Jesué A. (författare)
- METAMAT
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- Barros, Márcia A.S. (författare)
- Department of Mineral Resources, UFMT
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- Pinho, Francisco E.C. (författare)
- Department of Mineral Resources, UFMT
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(creator_code:org_t)
- Elsevier BV, 2008
- 2008
- Engelska.
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Ingår i: Precambrian Research. - : Elsevier BV. - 0301-9268 .- 1872-7433. ; 164:1-2, s. 40-49
- Relaterad länk:
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- In an attempt to improve our understanding of the Paleoproterozoic geodynamic evolution, a paleomagnetic study was performed on 10 sites of acid volcanic rocks of the Colider Suite, southwestern Amazonian Craton. These rocks have a well-dated zircon U-Pb mean age of 1789 +/- 7 Ma. Alternating field and thermal demagnetization revealed northern (southern) directions with moderate to high upward (downward) inclinations. Rock magnetism experiments and magnetic mineralogy show that this characteristic magnetization is carried by Ti-poor magnetite or by hematite that replaces magnetite by late-magmatic cleuteric alteration. Both magnetite and hematite carry the same characteristic component. The mean direction (Dm = 183.0 degrees, Im = 53.5 degrees, N = 10, alpha(95) = 9.8 degrees, K = 25.2) yielded a paleomagnetic pole located at 298.8 degrees E, 63.3 degrees S (alpha(95) = 10.2 degrees, K = 23.6), which is classified with a quality factor Q = 5. Paleogeographic reconstructions using this pole and other reliable Paleoproterozoic poles suggest that Laurentia, Baltica, North China Craton and Amazonian Craton were located in laterally contiguous positions forming a large continental mass at 1790 Ma ago. This is reinforced by geological evidence which support the existence of the supercontinent Columbia in Paleoproterozoic times.
Ämnesord
- NATURVETENSKAP -- Geovetenskap och miljövetenskap -- Geofysik (hsv//swe)
- NATURAL SCIENCES -- Earth and Related Environmental Sciences -- Geophysics (hsv//eng)
Nyckelord
- Applied Geophysics
- Tillämpad geofysik
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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