Defining Pre-eruptive Conditions of the Havre 2012 Submarine Rhyolite Eruption Using Crystal Archives

Knafelc, Joseph; Bryan, Scott; Gust, David; Cathey, Henrietta E.

doi:10.3389/feart.2020.00310

Cited by 12 publications

(27 citation statements)

References 61 publications

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“…Given these limitations in determining what might be appropriate crustal materials and compositions to partially melt, we test the viability of a model that invokes extensive fractional crystallization. We have previously shown that the 2012 Havre medium-K rhyolite can be generated by limited fractional crystallization (7%) from a starting composition represented by a dredged Havre flank dacite (~67 wt% SiO 2 ; Knafelc et al, 2020). Herein, we explore the idea that this dacite composition is ultimately derived from a basaltic parent.…”

Section: Introductionmentioning

confidence: 93%

“…An effusive exit velocity of approximately 14 ms −1 was estimated to produce the pumice raft based on magma ascent models inputting seafloor pumice properties (Manga et al, 2018). However, more recent work has shown that when only utilizing seafloor pumice properties, eruption rates of the associated pumice rafts could be considerably underestimated (Knafelc et al, 2020;Mitchell et al, 2021;Knafelc et al, 2022). Most recently, the Havre 2012 eruption model has been expanded to include a shortlived, violent explosive eruption, capable of ejecting hot pyroclasts through the 900 m water column into the atmosphere, which then air-cooled to be deposited at the ocean surface, producing the pumice raft (Knafelc et al, 2022).…”

Section: The Havre 2012 Eruptionmentioning

confidence: 99%

“…Pumice collection, desalination of pumice samples prior to all chemical analysis, XRF whole-rock composition, and electron microprobe analysis (EMPA) of clinopyroxene within embedded rock fragments follow the methods presented in Knafelc et al (2020). In order to desalinate the pumice samples prior to any bulk analysis (XRF & Solution ICP-MS), the pumice was crushed to roughly 1 mm in size fragments and placed in a forced convection hot bath (~50 °C) of DI water for 2-3 weeks with the water replaced daily (further details described in Knafelc et al, 2020). Major and trace element data are presented for all types of pumice in the Havre 2012 pumice raft, a fraction of which were presented in Knafelc et al (2020).…”

Section: Sample Collection Xrf and Epmamentioning

confidence: 99%

“…One of the challenges in understanding the petrogenesis of submarine island arc rhyolite magmas is the general lack of information on the longer-term magmatic systems of island arc volcanoes, where sampling may be restricted to small islands where the volcano has breached the surface (e.g., Raoul, Macauley; Smith et al, 2003a,b;Barker et al, 2012), where dredge surveys and sampling have been undertaken of the summit regions and flanks (Wright et al, 2006), or where products from recent eruptions have been sampled (Havre, Carey et al, 2018;Knafelc et al, 2020;.…”

Section: Introductionmentioning

confidence: 99%

“…We present new major and trace element data on the full range of pumice types found in the Havre raft. Knafelc et al (2020) first reported that a number of distinct pumice types occur in the raft deposits that differ in color, texture, and vesicularity. Further, the entire eruption had both explosive (Knafelc et al, 2022) and effusive phases (Carey et al, 2018;Ikegami et al, 2018;Manga et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

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Petrogenesis of Havre Volcano in the Kermadec Arc: 2012 Eruption of a Chemically Homogeneous Rhyolite

et al. 2022

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The 2012 Havre submarine eruption produced a 1.5 km3 bulk rock volume or 0.52 km3 dense rock equivalent volume of rhyolite emplaced as minor lava flows, a field of sunken seafloor pumice, and a volumetrically dominant pumice raft. This moderately large volume of medium-K (1.4–1.6 wt% K2O) rhyolite pumice is relatively chemically homogeneous (71.5–73.0 wt% SiO2), and no trace element variation or cryptic zoning has been detected despite the textural diversity of pumice material. Radiogenic isotope ratios (87Sr/86Sr 0.703693–0.703744; 206Pb/204Pb 18.7648–18.7781; 208Pb/204Pb 38.587–38.605; 143Nd/144Nd 0.513001–0.513020) demonstrate the Havre rhyolite is sourced from mantle similar to regional eruptive products of the Kermadec arc volcanic front. Providing some further insight into the Havre magmatic system is an abundance of diverse volcanic rock fragments primarily embedded in the banded raft pumice. Embedded rock fragments represent a variety of fresh to hydrothermally altered lavas ranging in composition from basaltic to rhyolitic (50.6–72.3 wt% SiO2) and are likely sourced from varying depths within the volcanic conduit during explosive fragmentation. The diverse embedded volcanic rock fragments, therefore, represent earlier erupted lavas that constructed Havre volcano and are snapshots of the petrogenetic history of Havre. Magnesian augite in basaltic to basaltic andesite embedded rock fragments has a similar compositional range (En55Fs12Wo33 to En39Fs26Wo35) to the previously documented antecrystic clinopyroxene observed in the 2012 rhyolite pumice raft. Herein, we explain how this large volume of chemically homogeneous crystal-poor rhyolite can be generated in an oceanic arc setting based on major and trace element petrogenetic models. Rhyolite-MELTS crystal fractionation models indicate the antecrystic mineral compositions within the Havre pumice of plagioclase (An55–78), and magnesian augites (En53Fs10Wo37 to En40Fs26Wo34) are the primary phases that would crystallize in basaltic to andesitic melt compositions. Modeling indicates that the forerunner basaltic magma must be a relatively dry (∼1 wt% H20) low-K tholeiitic basalt in composition and would require ∼78% crystallization at different pressures to ultimately generate the Havre 2012 rhyolite.

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Section: Introductionmentioning

confidence: 93%