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)
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.