Olivine-liquid relations of lava erupted by Kilauea volcano from 1994 to 1998: Implications for shallow magmatic processes associated with the ongoing east-rift-zone eruption
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Abstract
From 1994 through 1998, the eruption of Kîlauea, in Hawai’i, was dominated by steady-state effusion at Pu‘u ‘Ô‘ô that was briefly disrupted by an eruption 4 km uprift at Nāpau Crater on January 30, 1997. In this paper, I describe the systematic relations of whole-rock, glass, olivine, and olivine-inclusion compositions of lava samples collected throughout this interval. This suite comprises vent samples and tube-contained flows collected at variable distances from the vent. The glass composition of tube lava varies systematically with distance and allows for the “vent-correction” of glass thermometry and olivine–liquid KD as a function of tube-transport distance. Combined olivine–liquid data for vent samples and “vent-corrected” lava-tube samples are used to document pre-eruptive magmatic conditions. KD values determined for matrix glasses and forsterite cores define three types of olivine phenocrysts: type A (in equilibrium with host glass), type B (Mg-rich relative to host glass) and type C (Mg-poor relative to host glass). All three types of olivine have a cognate association with melts that are present within the shallow magmatic plumbing system during this interval. During steady-state eruptive activity, the compositions of whole-rock, glass and most olivine phenocrysts (type A) all vary sympathetically over time and as influenced by changes of magmatic pressure within the summit-rift-zone plumbing system. Type-A olivine is interpreted as having grown during passage from the summit magma-chamber along the east-rift-zone conduit. Type-B olivine (high Fo) is consistent with equilibrium crystallization from bulk-rock compositions and is likely to have grown within the summit magma-chamber. Lower-temperature, fractionated lava was erupted during non-steady-state activity of the Nāpau Crater eruption. Type-A and type-B olivine–liquid relations indicate that this lava is a mixture of rift-stored and summit-derived magmas. Post- Nāpau lava (at Pu‘u ‘Ô‘ô) gradually increases in temperature and MgO content, and contains type-C olivine with complex zoning, indicating magma hybridization associated with the flushing of rift-stored components through the eruption conduit.
Study Area
Publication type | Article |
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Publication Subtype | Journal Article |
Title | Olivine-liquid relations of lava erupted by Kilauea volcano from 1994 to 1998: Implications for shallow magmatic processes associated with the ongoing east-rift-zone eruption |
Series title | Canadian Mineralogist |
DOI | 10.2113/gscanmin.39.2.239 |
Volume | 39 |
Issue | 2 |
Year Published | 2001 |
Language | English |
Publisher | Mineralogical Association of Canada |
Description | 28 p. |
First page | 239 |
Last page | 266 |
Country | United States |
State | Hawaii |
Other Geospatial | Kilauea Volcano |
Google Analytic Metrics | Metrics page |