In search of ancestral Kilauea volcano
- 1U.S. Geological Survey, Menlo Park, California 94025, USA
- 2Graduate School of Science, Hokkaido University, Japan
- 3Japan Marine Science and Technology Center, Yokosuka, Japan
Abstract
Submersible observations and samples show that the lower south flank of Hawaii, offshore from Kilauea volcano and the active Hilina slump system, consists entirely of compositionally diverse volcaniclastic rocks; pillow lavas are confined to shallow slopes. Submarine-erupted basalt clasts have strongly variable alkalic and transitional basalt compositions (to 41% SiO2, 10.8% alkalies), contrasting with present-day Kilauea tholeiites. The volcaniclastic rocks provide a unique record of ancestral alkalic growth of an archetypal hotspot volcano, including transition to its tholeiitic shield stage, and associated slope-failure events.
Footnotes
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- Accepted September 14, 2000.
- Received May 9, 2000.
- Revision received September 1, 2000.
- Geological Society of America
