The origin and evolution of lavas from Haleakala Crater, Hawaii
Sr, Nd, and Pb isotope systematics of lavas from the Maui Volcanic Complex (MVC) are consistent with a three-component petrogenetic mixing model. MVC shield-building (SB) lavas define linear trends on isotope-isotope plots, consistent with two-component mixing between primitive (PM) and enriched (EM) mantle components. The two-component (PM-EM) Hawaiian plume source is variable in composition during production of tholeiite magmas even within a single shield. Sr and Pb isotopic ratios of Haleakala post shield-building (PSB) lavas define a strong positively correlated array that deviates from the SB array towards an unradiogenic end-member. The PSB array may therefore result from time- and volume-dependent binary mixing between Hawaiian plume melts and a depleted (DM) mantle (i.e. MORB source) component. Several trace element ratios in Haleakala PSB lavas are correlated with isotopic compositions but not with major and trace element contents, and therefore appear to reflect changes in source composition. Trace element mixing systematics for these lavas indicate that the DM component must be a melt. The inferred PM component has chondritic ratios for several trace elements, consistent with it representing primitive mantle. The EM component may represent apart of the Hawaiian plume source that was either metasomatized or metasomatically scavenged. Alkalic cap lavas exposed in the northwest wall of Haleakala Crater display systematic, upsection geochemical variations indicative of the repetitive intrusion of discrete magma batches. In contrast, lava compositions within magma batches vary upsection progressively, and geochemical variations are opposite to those observed for interbatch discontinuities.
- Research Organization:
- Rice Univ., Houston, TX (USA)
- OSTI ID:
- 7164477
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
580000* -- Geosciences
ALKALINE EARTH METALS
CHEMICAL COMPOSITION
CHEMISTRY
CORRELATIONS
EARTH MANTLE
ELEMENTS
FEDERAL REGION IX
GEOCHEMISTRY
GEOLOGIC HISTORY
GEOLOGIC MODELS
HAWAII
ISOTOPE RATIO
LAVA
LEAD
MAGMA
METALS
MIXING
NEODYMIUM
NORTH AMERICA
ORIGIN
RARE EARTHS
STRONTIUM
TRACE AMOUNTS
USA
VARIATIONS
VOLCANIC REGIONS