The evolution of Mauna Kea volcano, Hawaii: petrogenesis of tholeiitic and alkalic basalts

Author:

Frey, F. A., Garcia, M.O., Wise, W.S., Kennedy, A., Gurriet, P., Albarede, F.

Title:

The evolution of Mauna Kea volcano, Hawaii: petrogenesis of tholeiitic and alkalic basalts

Periodical:

Journal of Geophysical Research

Year:

1991

Volume:

96

Pages:

14,347-14,375

Subject:

Mauna Kea volcano Lava analysis

Summary:

Hawaiian volcanoes evolve through well-defined stages: preshield, postshield, and posterosional. The shield stage forms the bulk of each volcano that is dominantly composed of tholeiitic basalt. However, the eruption of alkalic basalt precedes and postdates the formation of the shield. This compositional variation correlates with magma supply rates which seem to be initially low but increase to high rates during shield formation. These rates then decrease sharply during the postshield state. Magma supply rate is presumed to be controlled by the location of the volcano relative to the focus of melting, i.e., "hotspot". In order to understand the processes controlling the compositional variations of basalts during the transition from shield to postshield volcanism, Mauna Kea, the youngest of the Hawaiian volcanoes that has essentially completed its postshield volcanism, was selected for a detailed mapping and geochemical study. As a result, one of the objectives of this paper was to document the temporal geochemical trends that are defined by basaltic lavas that were erupted during the late shield and postshield stages of Mauna Kea. Understanding the processes that created the diversity of basalt compositions was also an objective of this study.

Label:

Geology

Collection:

Periodicals