Noble gas variation along the Mid-Atlantic Ridge (24-30°N): A unique window into volatile cycling and a heterogeneous mantle by Michael Huh

Michael Huh

UC Davis

The history of the Earth is recorded in the mantle. To read this history, I measure the noble gases trapped in mid ocean ridge basalts which provides a window into the deep Earth.


The noble gases trapped in oceanic basalts are excellent tools for studying heterogeneities in the mantle. Presented here are isotopic noble gas data measured along a section of the Mid-Atlantic Ridge (MAR, 24-30 °N) which show extreme heterogeneity in the mid ocean ridge basalt (MORB) source. This is interesting because this segment of the MAR is devoid of geophysical or lithophile geochemical anomalies that are expected in an area that is “contaminated” by mantle rocks of another flavor, such as deeper-sourced plume material (like Hawaiian volcanic rocks) or rocks that have been reintroduced into the mantle by subduction processes. The traditional lithophile geochemistry used to interpret the rocks is not able to fully read the recorded history. Questions that motivate this study are: 1) How dispersed is plume-like material in the upper mantle? 2) What is the length scale of heterogeneity in the upper mantle? 3) Are the noble gases recycled back into the mantle by subduction?


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