Oxygen isotope evidence for chemical interaction of Kilauea historical magmas with basement rocks
Garcia MO, Ito E, Eiler JM. 2008. Oxygen isotope evidence for chemical interaction of Kilauea historical magmas with basement rocks. Journal of Petrology. 49(4):757-769
Kilauea historical summit lavas have a wide range in matrix (oxygen isotope) values with lower values in rocks erupted following a major summit collapse or eruptive hiatus. In contrast, d18O values for olivines in most of these lavas are nearly constant.The disequilibrium between matrix and olivine d18O values in many samples indicates that the lower matrix values were acquired by the magma after olivine growth, probably just before or during eruption. Both Mauna Loa and Kilauea basement rocks are the likely sources of the contamination, based on O, Pb and Sr isotope data. However, the extent of crustal contamination of Kilauea historical magmas is probably minor (512%, depending on the assumed contaminant) and it is superimposed on a longer-term, cyclic geochemical variation that reflects source heterogeneity. Kilauea’s heterogeneous source, which is well represented by the historical summit lavas, probably has magma d18O values within the normal mid-ocean ridge basalt mantle range based on the new olivine d18O values.
- Type
- Journal Article
- Authors
- Garcia, Michael; Ito, Emi; Eiler, John
- Units
- HAVO
- Keywords
- Basalt, crustal contamination, Geology, Hawaii, Kilauea, Oxygen Isotopes, Physical Sciences