Cooling and crystallization of tholeiitic basalt, 1965 Makaopuhi Lava Lake, Hawaii

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

Melt migration in basalt columns driven by crystallization-induced pressure gradients

“…Cooling of thick lava flows has been shown to be dominated by conductive heat loss 25,26 . This occurs simultaneously from the top and base of the lava flow [25][26][27] and to the column-bounding fractures.…”

On some fundamentals of igneous petrology

“…3; Richter et al 1970). The subsequent drilling of this and especially Makaopuhi lava lake (Wright and Okamura 1977) gave the impetus for the establishment of the solidification front concept (Marsh 1981(Marsh , 1996. Much of the incoming lava for Kilauea Iki was picritic with MgO as high as 25 wt% and forsteritic olivine crystals as large as 2 mm.…”

“…They are thin (14-125 m) strongly differentiated, layered sheets that have been extensively studied by direct sampling during the course of filling and solidification (e.g., Wright and Okamura 1977). They furnish an invaluable and indisputable connection between volcanism and the vast family of bodies known as differentiated sills (e.g., Upton and Wadsworth 1967;Gunn 1966;Gunn and Warren 1962) that have been so aptly generalized by Simkin 1967).…”

Geochemistry of ilmenite from the Asama ultramafic-mafic layered igneous complex, Mikabu greenstone belt, Sambagawa metamorphic terrane, central Japan.

“…9). Although the Ti02 and MgO estimates in the Asama complex are approximate, the Asama (Wright and Okamura, 1977;Wright and Peck, 1978;Nicholls and Stout, 1988;Wilkinson, 1991); MORB: mid-oceanic ridge basalts (Bryan, 1979;Walker et al, 1979;le Roex et al, 1982le Roex et al, , 1996Fornari et al, 1983;Allan et al, 1989); IAT: island-arc tholeiites including andesites (Barsdell, 1988;Ikeda and Agata, 1988;Defant et al, 1991;Kersting and Arculus, 1994 (Agata, 1994). The Asama igneous complex is considered to have formed in an oceanic island.…”