Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6428597 | Earth and Planetary Science Letters | 2015 | 11 Pages |
â¢KÄ«lauea's summit magma storage reservoir comprised two magma bodies since at least 1971.â¢The summit reservoir contained only â¼0.1-0.5 km3 of magma during the late 20th century.â¢At least four distinct mantle-derived magma batches were delivered to KÄ«lauea since 1959.â¢The eruptive behavior of the volcano is partly tied to the delivery of magma batches from the mantle.
The summit magma storage reservoir of KÄ«lauea Volcano is one of the most important components of the magmatic plumbing system of this frequently active basaltic shield-building volcano. Here we use new high-precision Pb isotopic analyses of KÄ«lauea summit lavas-from 1959 to the active Halema'uma'u lava lake-to infer the number, size, and interconnectedness of magma bodies within the volcano's summit reservoir. From 1971 to 1982, the 206Pb/204Pb ratios of the lavas define two separate magma mixing trends that correlate with differences in vent location and/or pre-eruptive magma temperature. These relationships, which contrast with a single magma mixing trend for lavas from 1959 to 1968, indicate that KÄ«lauea summit eruptions since at least 1971 were supplied from two distinct magma bodies. The locations of these magma bodies are inferred to coincide with two major deformation centers identified by geodetic monitoring of the volcano's summit region: (1) the main locus of the summit reservoir â¼2-4 km below the southern rim of KÄ«lauea Caldera and (2) a shallower magma body <2 km below the eastern rim of Halema'uma'u pit crater. Residence time modeling suggests that the total volume of magma within KÄ«lauea's summit reservoir during the late 20th century (1959-1982) was exceedingly small (â¼0.1-0.5 km3). Voluminous KÄ«lauea eruptions, such as the ongoing, 32-yr old Pu'u 'Å'Å rift eruption (>4 km3 of lava erupted), must therefore be sustained by a nearly continuous supply of new melt from the mantle. The model results show that a minimum of four compositionally distinct, mantle-derived magma batches were delivered to the volcano (at least three directly to the summit reservoir) since 1959. These melt inputs correlate with the initiation of energetic (1959 KÄ«lauea Iki) and/or sustained (1969-1974 Mauna Ulu, 1983-present Pu'u 'Å'Å and 2008-present Halema'uma'u) eruptions. Thus, KÄ«lauea's eruptive behavior is partly tied to the delivery of new magma batches from the volcano's source region within the Hawaiian mantle plume.