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Detailed Reference Information |
Chen, C.Y., Frey, F.A. and Garcia, M.O. (1990). Evolution of alkalic lavas at Haleakala Volcano, East Maui, Hawaii; major, trace element and isotopic constraints. Contributions to Mineralogy and Petrology 105(2): 197-218. |
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The postshield and posterosional stages of Haleakala Volcano contain intercalated alkalic basalt and evolved alkalic lavas. Isotopic and incompatible element abundance ratios in the Haleakala postshield basalts changed systematically with time, providing evidence for significant temporal changes in the mantle components contributing to the magmatic sources. Specifically, a depleted, i.e. low 87Sr/86Sr and high 143Nd/144Nd, mantle component is more abundant in younger lavas. However, as magma-production rates decreased during the postshield and posterosional stages, basaltic melts in magma reservoirs cooled and fractionated, leading to evolved residual melts such as hawaiite. Because primary basalt compositions changed with time, the evolved Haleakala lavas formed from a range of parental compositions. However, basalts and evolved lavas of similar age and isotopic ratios (Sr and Nd) have major and trace element contents that are consistent with a crystal-fractionation model. Although alkalic basalt and hawaiite are the dominant lavas of the postshield stages of both Haleakala and Mauna Kea volcanoes, there are important differences between their lavas. For example, compositional differences between the hawaiite suites at Haleakala and Mauna Kea indicate that, on average, the evolved lavas at Haleakala formed at lower pressures. Also, at Haleakala, basalts are intercalated with hawaiites, whereas at Mauna Kea basalts and hawaiites are separated by a sharp boundary. These differences probably reflect a higher magma supply rate to the Haleakala volcano. |
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Keywords
alkali basalts; alkalic composition; alkaline earth metals;, basalts; chemical composition; composition; differentiation; East, Pacific Ocean Islands; fractional crystallization; Haleakala;, Hawaii; hawaiite; igneous rocks; isotope ratios; isotopes; lava;, magmas; Maui; Maui County Hawaii; metals; mineral composition;, mugearite; Nd-144/Nd-143; neodymium; Oceania; partition, coefficients; petrography; petrology; Polynesia; rare earths;, ratios; Sr-87/Sr-86; stable isotopes; strontium; trace elements;, United States; volcanic rocks; Western U.S., 05A Igneous and metamorphic petrology; 02C Geochemistry of rocks,, soils, and sediments |
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Publisher
Springer-Verlag New York Inc. 175 Fifth Avenue New York, NY 10010 USA 1-800-777-4643 1-348-4505 orders@springer-ny.com |
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