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Showing 1 to 4 of 4 for “"Atlantis II (Ship : 1963-) Cruise AII107"”.
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Helium isotope geochemistry of oceanic volcanic rocks : implications for mantle heterogeneity and degassing
The concentrations and isotopic compositions of helium have been measured in a number of mantle derived oceanic basalts. The goal of this research is to use the helium isotopic systematics to constrain the nature and origin of mantle heterogeneity in the oceanic mantle. Studies of helium …
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Helium and lead isotope geochemistry of oceanic volcanic rocks from the East Pacific and South Atlantic
… precise reconstruction of He-Pb isotope relationships in volcanic source regions is complicated by post-eruptive radiogenic ingrowth of 4He in non-zero age basalts, by pre-eruptive radiogenic ingrowth of 4He in magmas with elevated (U+Th)/He, by multi-stage fractionation processes involving …
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Trace element geochemistry of oceanic peridotites and silicate melt inclusions : implications for mantle melting and ocean ridge magmagenesis
… non-steady state mantle melting at the Atlantis II Fracture Zone cutting the very slow spreading Southwest Indian Ridge. Trace element compositions of peridotite clinopyroxenes from fracture zones along the American-Antarctic and Southwest Indian Ridges vary as a function of proximity to …
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Temporal evolution of tritium-³He age in the North Atlantic : implications for thermocline ventilation
This thesis is a study of the physical mechanisms that ventilate the subtropical thermocline of the eastern North Atlantic. The starting point is an analysis of the existent historical database of natural and anthropogenic tracers, with special emphasis on 3He and tritium, that can be used to infer …