The origin and evolution of lavas from Haleakala Crater, Hawaii

Thesis/Dissertation · Fri Jan 01 00:00:00 EST 1988

OSTI ID:7164477

West, H B

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
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
HAWAII
VOLCANIC REGIONS
LAVA
ORIGIN
GEOCHEMISTRY
CHEMICAL COMPOSITION
CORRELATIONS
EARTH MANTLE
ELEMENTS
GEOLOGIC HISTORY
GEOLOGIC MODELS
ISOTOPE RATIO
LEAD
MAGMA
MIXING
NEODYMIUM
STRONTIUM
TRACE AMOUNTS
VARIATIONS
ALKALINE EARTH METALS
CHEMISTRY
FEDERAL REGION IX
METALS
NORTH AMERICA
RARE EARTHS
USA
580000* - Geosciences