Combined U–Th/He and 40Ar/39Ar geochronology of post-shield lavas from the Mauna Kea and Kohala volcanoes, Hawaii

Aciego, S.; Jourdan, Fred; DePaolo, Donald J.; Kennedy, B. Mack; Renne, Paul R.; Sims, K. W. W.

doi:10.1016/j.gca.2009.11.020

Cited by 9 publications

(9 citation statements)

References 65 publications

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“…To assume that these samples in question are derived from Kohala implies that ~680 kyr ago, this volcano was reaching the end of its evolution. This is not supported by growth models for Kohala, which at this time should have been in its vigorous tholeiitic shield‐building stage [ Moore and Clague , ; Lipman and Calvert , ], nor it is supported by the ages of sub‐aerially exposed Kohala post‐shield lavas (~175–450 ka) [ Clague and Dalrymple , ; Aciego et al ., ]. Although little is known about the history and interactions between Hawaiian volcanoes [ Stolper et al ., ], it is difficult to geometrically reconcile the existence of an unknown volcano older than Mauna Kea [e.g., Baker et al ., ].…”

Section: Discussionmentioning

confidence: 99%

Isotopic systematics of the early Mauna Kea shield phase and insight into the deep mantle beneath the Pacific Ocean

Silva

Weis

Scoates

2013

Geochem Geophys Geosyst

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[1] The 3500 m deep Hawai`i Scientific Drilling Project core provides a~680 kyr record of the magmatic history and source components of Mauna Kea volcano. We report high-precision Pb-Sr-Nd isotopic compositions of 40 basalts from the last 408 m of the final drilling phase (HSDP2-B and HSDP2-C) and show that these lowermost basalts represent the early shield stage of Mauna Kea's growth history. Two sample groups are distinguished based on their isotopic variability compared to the rest of the core. Over a depth interval of 210 m (3098.2-3308.2 mbsl), the basalts show very restricted isotopic variation and represent sampling of a relatively homogeneous source. Samples from the bottom 192 m record the largest range of 206 Pb/ 204 Pb and 208 Pb/ 204 Pb in the core, reflecting the greater isotopic variability of the earlier stages of volcanism compared to subsequent stages. The heterogeneity of Mauna Kea lavas is explained by mixing variable proportions of four distinct components intrinsic to the Hawaiian mantle plume. One of these components, Kea, is a prevalent and long-lived composition within the Hawaiian plume, whereas the other three components are involved at different stages of the volcano's history and contribute to the short-term isotopic variability of Mauna Kea. The compositional similarity of the Kea component to "C" and to the super-chondritic bulk-silicate Earth suggests that Kea may be part of the primitive mantle of a non-chondritic Earth. Other Pacific oceanic island basalts share Kea-like compositions, indicating that the Kea component is a common, widespread composition within the Pacific deep mantle.

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Section: Discussionmentioning

confidence: 99%

Isotopic systematics of the early Mauna Kea shield phase and insight into the deep mantle beneath the Pacific Ocean

Silva

Weis

Scoates

2013

Geochem Geophys Geosyst

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“…The collected samples are fresh; olivine phenocrysts are unaltered and there is only rare minor alteration of the groundmass. The bottom left inset in Figure 1 shows the age distribution of the postshield lavas and their relative timing compared to shield basalts [ Aciego et al , 2009].…”

Section: Samplesmentioning

confidence: 99%

“…The Loa (blue) and Kea (red) trends and the summits of the studied volcanoes (stars) are also indicated. The bottom left inset shows the age range for the four volcanoes studied (see compilation in the work by Clague and Dalrymple [1987]) as well as for the studied samples [ Aciego et al , 2009].…”

Section: Samplesmentioning

confidence: 99%

“…At Kohala, the oldest and most extensively eroded volcano on the island of Hawaii, seven samples were collected, including three late shield lavas (Polulu Volcanics) that range in age from 450 ± 40 ka to 375 ± 22 ka. The four samples belonging to Kohala's postshield stage (Hawi Volcanics) are significantly younger, with ages ranging from 190 ± 20 ka [ Aciego et al , 2009] to 137 ± 5 ka [ McDougall , 1969]. For Mauna Kea, where postshield volcanism is divided into an earlier basaltic substage (Hamakua Volcanics) and a later hawaiitic substage (Laupahoehoe Volcanics) [ Wolfe et al , 1997], 12 samples were collected (six from each substage).…”

Section: Samplesmentioning

confidence: 99%

“…For Mauna Kea, where postshield volcanism is divided into an earlier basaltic substage (Hamakua Volcanics) and a later hawaiitic substage (Laupahoehoe Volcanics) [ Wolfe et al , 1997], 12 samples were collected (six from each substage). The basaltic samples range in age from 239 ± 84 ka to 123 ± 5 ka, and the hawaiitic samples are as young as 19 ± 4 ka [ Aciego et al , 2009]. Thirteen samples were selected from Hualalai, which is almost completely covered by a thin veneer of postshield lavas (Hualalai Volcanics).…”

Section: Samplesmentioning

confidence: 99%

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Horizontal and vertical zoning of heterogeneities in the Hawaiian mantle plume from the geochemistry of consecutive postshield volcano pairs: Kohala‐Mahukona and Mauna Kea–Hualalai

Hanano

Weis

Scoates

et al. 2010

Geochem Geophys Geosyst

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[1] Sr-Nd-Pb-Hf isotopic compositions of postshield lavas from two pairs of Hawaiian volcanoes, Mauna Kea and Kohala (Kea trend) and Hualalai and Mahukona (Loa trend), allow for identification of smallscale (tens of kilometers) heterogeneities in the Hawaiian mantle plume and provide constraints on their distribution. The postshield lavas range from transitional/alkalic basalt to trachyte and are enriched in incompatible trace elements (e.g., La N /Yb N = 6.0-16.2 Pb/ 204 Pb = 17.89-18.01) of recent Hawaiian volcanoes. In contrast, comparison of Kohala with the adjacent Mahukona volcano shows that these older postshield lavas become more radiogenic in Pb during the late stages of volcanism. The isotope systematics of the postshield lavas cannot be explained by mixing between Hawaiian plume end-members (e.g., Kea, Koolau, and Loihi) or by assimilation of Pacific lithosphere and are consistent with the presence of ancient recycled lower oceanic crust (±sediments) in their source. More than one depleted component is sampled by the postshield lavas and these components are long-lived features of the Hawaiian plume that are present in both the Kea and Loa source regions. The depleted components in the postshield lavas, particularly as sampled at Hualalai, are different from the much more homogeneous component present in rejuvenated lavas. The geochemistry of the postshield lavas provides evidence for a bilateral symmetry to the plume where the compositional boundary between the Kea and Loa sources is complex and vertical components of heterogeneity are significant.

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Ultra-high precision 40Ar/39Ar ages for Fish Canyon Tuff and Alder Creek Rhyolite sanidine: New dating standards required?

Phillips

Matchan

2013

Geochimica et Cosmochimica Acta

143

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Combined U–Th/He and 40Ar/39Ar geochronology of post-shield lavas from the Mauna Kea and Kohala volcanoes, Hawaii

Cited by 9 publications

References 65 publications

Isotopic systematics of the early Mauna Kea shield phase and insight into the deep mantle beneath the Pacific Ocean

Isotopic systematics of the early Mauna Kea shield phase and insight into the deep mantle beneath the Pacific Ocean

Horizontal and vertical zoning of heterogeneities in the Hawaiian mantle plume from the geochemistry of consecutive postshield volcano pairs: Kohala‐Mahukona and Mauna Kea–Hualalai

Ultra-high precision 40Ar/39Ar ages for Fish Canyon Tuff and Alder Creek Rhyolite sanidine: New dating standards required?

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