Variation of Icelandic and Hawaiian magmatism: evidence for co-pulsation of mantle plumes? |
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| Authors: | R Mjelde J I Faleide |
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| Institution: | (1) Department of Earth Science, University of Bergen, Allegt. 41, 5007 Bergen, Norway;(2) Department of Geosciences, University of Oslo, Blindern, P.O. Box 1047, 0316 Oslo, Norway |
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| Abstract: | Based on published estimates of areal extent, thickness and dating of igneous rocks related to formation of the North Atlantic
Volcanic Province, we calculate the magmatic production since the first reported magmatism at 70 Ma until present. We relate
the magmatism to the Icelandic Plume and estimate the total volumetric production to 22.1 × 106 km3. The magmatic production varied significantly with time, with a clear maximum of 55.5 m3/s around continental break-up at ca. 54 Ma. The lowest production is estimated at 4 m3/s, increasing to 7 m3/s at ca. 23 Ma. Two other pulses with increased activity are found around 40 Ma and in the late Miocene (10–5 Ma). The variations
in productivity are consistent with a plume pulsing with a periodicity of ca. 15 million years. The same periodicity and relative
timing is found for the Hawaiian Plume. If confirmed, these observations suggest that both plumes originate within the thin
boundary layer near the Core-Mantle Boundary. This hypothesis may imply periodic heating of the earth’s core with subsequent
heat-release to the mantle and increased global plume activity. |
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| Keywords: | Icelandic Plume Hawaiian Plume Plume productivity Plume pulsation |
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