Geochemistry, geology, education in a digital world

The trace element and Sr-Nd-Pb isotope geochemistry of Juan Fernandez lavas reveal variable contributions from a high-3He/4He mantle plume

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Trace element, Sr-Nd-Pb isotope geochemistry of Juan Fernandez lavas

Slide with histogram showing number of analyses for 3He/4He in units of RA. One island, Alexander Selkirk has lower values between 8-10, while the other, Robinson Crusoe has higher values between 11-18. Bottom shows Yellow banner text of phrase formatted like equation: Age-progressive volcanism (check-mark) + High 3He/4He (over 9 RA) (check-mark) = Mantle plume (??). Slide text: Situating Juan Fernandez in Global OIB Studies. Juan Fernandez notable among other high-3He/4He OIBs for range in ratios. Despite this range, has relatively limited, nearly homogeneous range of Sr-Nd isotopic signature. Natland (2003) proposed shallow-level disequilibrium, complex history of magmatic differentiation with “xenocryst” olivines decoupled 3He/4He. Juan Fernandez is an important case study for Helium isotopic variations.

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Convened and presented in session: “Geophysical and geochemical insights into volcanic hotspots and large igneous provinces”. Day 1 of Oregon student-organized conference about volcanology