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| Detailed Reference Information |
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Dalrymple, G.B., Lanphere, M.A. and Jackson, E.D. (1974). Contributions to the Petrography and Geochronology of Volcanic Rocks from the Leeward Hawaiian Islands. Geological Society of America, Bulletin 85(5): 727-738. |
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Petrographic and chemical analyses of basalt from Nihoa Island, Necker Island, French Frigate Shoals, and Midway Atoll, all in the leeward part of the Hawaiian chain, confirm that these islands are subaerial remnants of tholeiitic shield volcanoes similar to those that form the principal Hawaiian Islands. Chemistry suggests that Gardner Pinnacles may be part of the alkalic cap on a tholeiitic shield. Weighted mean potassium-argon ages of 7.0+0.3 m.y. for Nihoa, 10.0+0.4 m.y. for Necker, 11.7+0.4 m.y. for French Frigate, and 17.9+0.6 m.y. for Midway demonstrate that the ages of these volcanoes increase northwestward, continuing the trend of increasing age away from the active volcano of Kilauea shown by the main islands. The increase in age with distance along the chain, however, appear to be nonlinear. The results support the general hypothesis that the volcanoes of the Hawaiian chain have a common origin and were formed as the Pacific plate moved northwestward over a melting spot in the mantle. |
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| BACKGROUND DATA FILES |
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Abstract |
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Appendix 1: Localities of Analyzed Samples |
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Table 1 |
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Table 2 |
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Table 3 |
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Keywords
absolute age; basalts; Cenozoic; chemical analyses; East Pacific, Ocean Islands; French Frigate Shoals; geochronology; Hawaii;, igneous rocks; interpretation; K/Ar; Midway; movement; Necker, Island; Nihoa Island; Oceania; Pacific Ocean; Pacific Plate;, petrography; petrology; plate tectonics; Polynesia; shield;, tectonophysics; Tertiary; tholeiite; United States; upper, Tertiary; volcanic; volcanic rocks; volcanoes; volcanology, 03, Geochronology |
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Publisher
The Geological Society of America
P.O. Box 9140
Boulder, CO 80301
1-303-447-2020
1-303-357-1071
member@geosociety.org |
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