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USGS · 70010851

Age of the Hawaiian-Emperor bend

G. B. Dalrymple·D.A. Clague
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Abstract

40 Ar/ 39 Ar age data on alkalic and tholeiitic basalts from Diakakuji and Kinmei Seamounts in the vicinity of the Hawaiian-Emperor bend indicate that these volcanoes are about 41 and 39 m.y. old, respectively. Combined with previously published age data on Yuryaku and Ko¯ko Seamounts, the new data indicate that the best age for the bend is 42.0 ± 1.4 m.y. Petrochemical data indicate that the volcanic rocks recovered from bend seamounts are indistinguishable from Hawaiian volcanic rocks, strengthening the hypothesis that the Hawaiian-Emperor bend is part of the Hawaiian volcanic chain. 40 Ar/ 39 Ar total fusion ages on altered whole-rock basalt samples are consistent with feldspar ages and with 40 Ar/ 39 Ar incremental heating data and appear to reflect the crystallization ages of the samples even though conventional K-Ar ages are significantly younger. The cause of this effect is not known but it may be due to low-temperature loss of 39 Ar from nonretentive montmorillonite clays that have also lost 40 Ar.

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G. B. Dalrymple, D.A. Clague. 1976. Age of the Hawaiian-Emperor bend. https://doi.org/10.1016/0012-821x(76)90113-8

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