No abstract

No abstract

Introduction ______________________________ 1 Acknowledgments ____________________________ 2 Previous work ___________________________ 2 The eruption of March 5-15, 1965 __________________ 2 Chronology ________________________ 2 Initial conditions following formation of a permanent crust __________________________________ 3 Definition of "crust" and "melt" __ ___ _ _ __ _____ __ 4 Methods of study __ ___ _ ___ __ __ ____ _ __ _ _ _ 5 Measurement of surface altitude changes _________ 5 Core drilling-_____________________________ 5 Sampling of melt and casing drill holes below the crust-melt interface ________________________ 8 Measurement of temperature _______________ 8 Additional field studies ________________________ 9 Observations _______________________________ 10 Thermal history ______________________^__10 Temperature of the crust-melt interface ___ _ ___16 Cooling of the crust (T<1,070°C) _____________16 Cooling of the melt (T>1,070°C)______________18 Page Observations-Continued Oxygen fugacity measurements ______________ 18 Changes in surface altitude_________-____ 24 Chemical and petrographic studies ____________-25 Major element chemistry ______________-25 Petrography ______________________-31 Distribution of olivine ________________ 36 Variation in grain size ____-_________ 36 Core density and vesicle distribution ______ 36 Discussion__________________________-37 Chemical differentiation in the lava lake _________-40 Gravitative settling of olivine ________________-40 Flow differentiation of olivine-augite-plagioclase-47 Segregation veins ____-_______-_________ 42 Convective cooling in the lava lake _____________-44 High-temperature oxidation of basalt _____ ___ _ ___-45 Interpretation of surface altitude changes __________-46 Summary: Cooling and solidification history of Makaopuhi lava lake__________________________________46 References cited

No abstract