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Mapping of Surface Radioactive Heat Production from in situ Gamma Spectrometry and Chemical Data of Exhumed Mantle Peridotites from St. Peter and St. Paul Archipelago (Equatorial Atlantic)
  • +9
  • Thomas Campos,
  • Jose Humberto Araujo,
  • Susanna Sichel,
  • Valeria Pastura,
  • Kenji Motoki,
  • Leonardo Barao,
  • Marcia Maia,
  • Daniele Brunelli,
  • Estefano Fonseca,
  • Joaquim Das Virgens Neto,
  • Thais Vargas,
  • Peter Szatmari
Thomas Campos
Federal University of Rio Grande do Norte

Corresponding Author:[email protected]

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Jose Humberto Araujo
Federal University of Rio Grande do Norte
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Susanna Sichel
Federal Fluminense University
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Valeria Pastura
Nuclear Engineering Institute
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Kenji Motoki
Federal Fluminense University
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Leonardo Barao
Federal University of Parana
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Marcia Maia
Universite de Bretagne Occidentale
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Daniele Brunelli
Università degli Studi di Modena e Reggio Emilia
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Estefano Fonseca
Federal Fluminense University
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Joaquim Das Virgens Neto
Geological Survey of Brazil
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Thais Vargas
Rio de Janeiro State University
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Peter Szatmari
Petrobras
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Abstract

The mapping of radioactive heat production (RHP) and the respective radioactive heat flow (RHF) of Saint Peter and Saint Paul Archipelago (SPSPA), based on radioactive heat-producing elements (RPE) data from whole-rock chemical analysis and in situ Gamma radiation spectrometry. The SPSPA show a radioactive heat production that ranging from 0.08 to 0.68 μW/m3 (Median: 0.21 μW/m3 and Geometric mean: 0.25 μW/m3) by whole-rock chemical analysis and among 0.08 to 0.48 μW/m3 (Median: 0.19 μW/m3; Geometric mean: 0.19 μW/m3) by in situ Gamma radiation spectrometry. The mean of radioactive heat production of mylonite rocks from SPSPA (0.22 μW/m3) is significantly high concerning those predicted for ultrabasic rocks due to the geological alteration process. The respective average surface radioactive heat flow (49.7 mW/m2) is to lower in relation to those predicted for the oceanic lithosphere, which indicates that the additional heat flow from the upper mantle is also low in the SPSPA area. Our date and another geological feature suggest that lithospheric mantle around the SPSPA area is colder than the upper mantle outside the Equatorial Atlantic area.