Maxim Gavrilenko | Washington University in St. Louis (original) (raw)

Papers by Maxim Gavrilenko

Research paper thumbnail of Major and trace element composition of melts from the Gorely volcanic center, southern Kamchatka

Melt inclusions in olivine and plagioclase phenocrysts from rocks (magnesian basalt, basaltic and... more Melt inclusions in olivine and plagioclase phenocrysts from rocks (magnesian basalt, basaltic andesite, andesite, ignimbrite, and dacite) of various age from the Gorely volcanic center, southern Kamchatka, were studied by means of their homogenization and by analyzing the glasses in 100 melt inclusions on an electron microprobe and 24 inclusions on an ion probe. The SiO2 concentrations of the melts vary within a broad range of 45-74 wt%, as also are the concentrations of other major components. According to their SiO2, Na2O, K2O, TiO2, and P2O5 concentrations, the melts are classified into seven groups. The mafic melts (45-53 wt% SiO2) comprise the following varieties: potassic (on average 4.2 wt% K2O, 1.7 wt% Na2O, 1.0 wt% TiO2, and 0.20 wt% P2O5), sodic (3.2% Na2O, 1.1% K2O, 1.1% TiO2, and 0.40% P2O5), and titaniferous with high P2O5 concentrations (2.2% TiO2, 1.1% P2O5, 3.8% Na2O, and 3.0% K2O). The melts of intermediate composition (53-64% SiO2) also include potassic (5.6% K2O, 3.4% Na2O, 1.0% TiO2, and 0.4% P2O5) and sodic (4.3% Na2O, 2.8% K2O, 1.3% TiO2, and 0.4% P2O5) varieties. The acid melts (64-74% SiO2) are either potassic (4.5% K2O, 3.6% Na2O, 0.7% TiO2, and 0.15% P2O5) or sodic (4.5% Na2O, 3.1% K2O, 0.7% TiO2, and 0.13% P2O5). A distinctive feature of the Gorely volcanic center is the pervasive occurrence of K-rich compositions throughout the whole compositional range (silicity) of the melts. Melt inclusions of various types were sometimes found not only in a single sample but also in the same phenocrysts. The sodic and potassic types of the melts contain different Cl and F concentrations: the sodic melts are richer in Cl, whereas the potassic melts are enriched in F. We are the first to discover potassic melts with very high F concentrations (up to 2.7 wt%, 1.19 wt% on average, 17 analyses) in the Kuriles and Kamchatka. The average F concentration in the sodic melts is 0.16 wt% (37 analyses). The melts are distinguished for their richness in various groups of trace elements: LILE, REE (particularly [...]

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Research paper thumbnail of Petrological And Geochemical Characteristics Of Magmatic Melts At Gorely Volcano, Kamchatka, Russia

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Research paper thumbnail of Table 3) Major element oxides of plagioclase in rocks obtained from the Gorely volcanic center

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Research paper thumbnail of Trace elements in olivine grains from volcanic rocks: magma chamber processes, magma water content, and primary melt generation

OF THE DISSERTATION........................................................................ ii PR... more OF THE DISSERTATION........................................................................ ii PREFACE ......................................................................................................................... iv ACKNOWLEDGMENTS ............................................................................................. viii TABLE OF CONTENTS ................................................................................................. x Chapter 1: Seismically active subcrustal magma source of the Klyuchevskoy volcano in Kamchatka, Russia ......................................................................................... 1 Abstract ........................................................................................................................... 1

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Research paper thumbnail of EPMA analyses of olivine near the boundary with a basaltic glass – the secondary fluorescence effect quantification

Goldschmidt2021 abstracts, 2021

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Research paper thumbnail of The quench control of water estimates in convergent margin magmas

American Mineralogist, 2019

Here we present a study on the quenchability of hydrous mafic melts. We show via hydrothermal exp... more Here we present a study on the quenchability of hydrous mafic melts. We show via hydrothermal experiments that the ability to quench a mafic hydrous melt to a homogeneous glass at cooling rates relevant to natural samples has a limit of no more than 9 ± 1 wt% of dissolved H2O in the melt. We performed supra-liquidus experiments on a mafic starting composition at 1–1.5 GPa spanning H2O-undersaturated to H2O-saturated conditions (from ~1 to ~21 wt%). After dissolving H2O and equilibrating, the hydrous mafic melt experiments were quenched. Quenching rates of 20 to 90 K/s at the glass transition temperature were achieved, and some experiments were allowed to decompress from thermal contraction while others were held at an isobaric condition during quench. We found that quenching of a hydrous melt to a homogeneous glass at quench rates comparable to natural conditions is possible at water contents up to 6 wt%. Melts containing 6–9 wt% of H2O are partially quenched to a glass, and always ...

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Research paper thumbnail of A Calcium-in-Olivine Geohygrometer and its Application to Subduction Zone Magmatism

Journal of Petrology, 2016

High-precision electron microprobe analyses were obtained on olivine grains from Klyuchevskoy, Sh... more High-precision electron microprobe analyses were obtained on olivine grains from Klyuchevskoy, Shiveluch and Gorely volcanoes in the Kamchatka Arc; Irazú, Platanar and Barva volcanoes of the Central American Arc; and mid-ocean ridge basalt (MORB) from the Siqueiros Transform. Calcium contents of these subduction zone olivines are lower than those for olivines from modern MORB, Archean komatiite and Hawaii. A role for magmatic H2O is likely for subduction zone olivines, and we have explored the suggestion of earlier workers that it has affected the partitioning of CaO between olivine and silicate melt. We provide a provisional calibration of DCaOOl/L as a function of magmatic MgO and H2O, based on nominally anhydrous experiments and minimally degassed H2O contents of olivine-hosted melt inclusions. Application of our geohygrometer typically yields 3–4 wt % magmatic H2O at the Kamchatka and Central American arcs for olivines having ∼1000 ppm Ca, which agrees with H2O maxima from melt ...

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Research paper thumbnail of Abrupt transition from fractional crystallization to magma mixing at Gorely volcano (Kamchatka) after caldera collapse

Bulletin of Volcanology, 2016

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Research paper thumbnail of Tephrochronological research in KALMAR Project and its implications to the temporal and compositional evolution of volcanism in Kamchatka

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Research paper thumbnail of Chemical composition, volatile components, and trace elements in the melts of the Gorely volcanic center, southern Kamchatka: Evidence from inclusions in minerals

Geochemistry International, 2012

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Research paper thumbnail of Secondary fluorescence effect quantification of EPMA analyses of olivine grains embedded in basaltic glass

Chemical Geology

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Research paper thumbnail of Seismically active subcrustal magma source of the Klyuchevskoy volcano in Kamchatka, Russia

Geology, 2014

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Research paper thumbnail of Evidence for superhydrous primitive arc magmas from mafic enclaves at Shiveluch volcano, Kamchatka

Contributions to Mineralogy and Petrology

Mafic enclaves preserve a record of deep differentiation of primitive magmas in arc settings. We ... more Mafic enclaves preserve a record of deep differentiation of primitive magmas in arc settings. We analyze the petrology and geochemistry of mafic enclaves from Shiveluch volcano in the Kamchatka peninsula to determine the differentiation histories of primitive magmas and to estimate their pressures, temperatures, and water contents. Amphibole inclusions in high forsterite olivine suggest that the primitive melt was superhydrous (i.e., > 8 wt% H 2 O) and was fractionating amphibole and olivine early on its liquid line of descent. We find that the hydrous primitive melt had liquidus temperatures of 1062 ± 48 °C and crystallized high Mg# amphibole at depths of 23.6-28.8 km and water contents of 10-14 wt% H 2 O. The major and trace element whole-rock chemistry of enclaves and of published analyses of andesites suggest that they are related through fractionation of amphibole-bearing assemblages. Quantitative models fractionating olivine, clinopyroxene, and amphibole reproduce geochemical trends defined by enclaves and andesites in variation diagrams. These models estimate 0.2-12.2% amphibole fractionated from the melt to reproduce the full range of enclave compositions, which overlaps with estimates of the amount of amphibole fractionated from parental melts based on whole-rock dysprosium contents. This contribution extends the published model of shallow processes at Shiveluch to greater depths. It provides evidence that primitive magmas feeding arc volcanoes may be more hydrous than estimated from other methods, and that amphibole is an important early fractionating phase on the liquid line of descent of superhydrous, primitive mantle-derived melts.

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Research paper thumbnail of Evidence for Eruption of a Superhydrous Magma from Shiveluch Volcano, Kamchatka

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Research paper thumbnail of Evidence for superhydrous primitive arc magmas from mafic enclaves at Shiveluch volcano, Kamchatka

Contributions to Mineralogy and Petrology, 2020

Mafic enclaves preserve a record of deep differentiation of primitive magmas in arc settings. We ... more Mafic enclaves preserve a record of deep differentiation of primitive magmas in arc settings. We analyze the petrology and geochemistry of mafic enclaves from Shiveluch volcano in the Kamchatka peninsula to determine the differentiation histories of primitive magmas and to estimate their pressures, temperatures, and water contents. Amphibole inclusions in high forsterite olivine suggest that the primitive melt was superhydrous (i.e., > 8 wt% H 2 O) and was fractionating amphibole and olivine early on its liquid line of descent. We find that the hydrous primitive melt had liquidus temperatures of 1062 ± 48 °C and crystallized high Mg# amphibole at depths of 23.6-28.8 km and water contents of 10-14 wt% H 2 O. The major and trace element whole-rock chemistry of enclaves and of published analyses of andesites suggest that they are related through fractionation of amphibole-bearing assemblages. Quantitative models fractionating olivine, clinopyroxene, and amphibole reproduce geochemical trends defined by enclaves and andesites in variation diagrams. These models estimate 0.2-12.2% amphibole fractionated from the melt to reproduce the full range of enclave compositions, which overlaps with estimates of the amount of amphibole fractionated from parental melts based on whole-rock dysprosium contents. This contribution extends the published model of shallow processes at Shiveluch to greater depths. It provides evidence that primitive magmas feeding arc volcanoes may be more hydrous than estimated from other methods, and that amphibole is an important early fractionating phase on the liquid line of descent of superhydrous, primitive mantle-derived melts.

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Research paper thumbnail of The quench control of water estimates in convergent margin magmas

American Mineralogist, 2019

Here we present a study on the quenchability of hydrous mafic melts. We show via hydrothermal exp... more Here we present a study on the quenchability of hydrous mafic melts. We show via hydrothermal experiments that the ability to quench a mafic hydrous melt to a homogeneous glass at cooling rates relevant to natural samples has a limit of no more than 9 ± 1 wt% of dissolved H2O in the melt. We performed supra-liquidus experiments on a mafic starting composition at 1–1.5 GPa spanning H2O-undersaturated to H2O-saturated conditions (from ~1 to ~21 wt%). After dissolving H2O and equilibrating, the hydrous mafic melt experiments were quenched. Quenching rates of 20 to 90 K/s at the glass transition temperature were achieved, and some experiments were allowed to decompress from thermal contraction while others were held at an isobaric condition during quench. We found that quenching of a hydrous melt to a homogeneous glass at quench rates comparable to natural conditions is possible at water contents up to 6 wt%. Melts containing 6–9 wt% of H2O are partially quenched to a glass, and always contain significant fractions of quench crystals and glass alteration/devitrification products. Experiments with water contents greater than 9 wt% have no optically clear glass after quench and result in fine-grained mixtures of alteration/devitrification products (minerals and amorphous materials). Our limit of 9 ± 1 wt% agrees well with the maximum of dissolved H2O contents found in natural glassy melt inclusions (8.5 wt% H2O). Other techniques for estimating pre-eruptive dissolved H2O content using petrologic and geochemical modeling have been used to argue that some arc magmas are as hydrous as 16 wt% H2O. Thus, our results raise the question of whether the observed record of glassy melt inclusions has an upper limit that is partially controlled by the quenching process. This potentially leads to underestimating the maximum amount of H2O recycled at arcs when results from glassy melt inclusions are predominantly used to estimate water fluxes from the mantle.

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Research paper thumbnail of A Calcium-in-Olivine Geohygrometer and its Application to Subduction Zone Magmatism

High-precision electron microprobe analyses were obtained on olivine grains from Klyuchevskoy, Sh... more High-precision electron microprobe analyses were obtained on olivine grains from Klyuchevskoy, Shiveluch and Gorely volcanoes in the Kamchatka Arc; Iraz u, Platanar and Barva volcanoes of the Central American Arc; and mid-ocean ridge basalt (MORB) from the Siqueiros Transform. Calcium contents of these subduction zone olivines are lower than those for olivines from modern MORB, Archean komatiite and Hawaii. A role for magmatic H 2 O is likely for subduction zone olivines, and we have explored the suggestion of earlier workers that it has affected the partitioning of CaO between olivine and silicate melt. We provide a provisional calibration of D CaO Ol/L as a function of magmatic MgO and H 2 O, based on nominally anhydrous experiments and minimally degassed H 2 O contents of olivine-hosted melt inclusions. Application of our geohygrometer typically yields 3–4 wt % magmatic H 2 O at the Kamchatka and Central American arcs for olivines having $1000 ppm Ca, which agrees with H 2 O maxima from melt inclusion studies; Cerro Negro and Shiveluch volcanoes are exceptions, with about 6% H 2 O. High-precision electron microprobe analyses with 10–20 lm spatial resolution on some olivine grains from Klyuchevskoy and Shiveluch show a decrease in Ca content from the core centers to the rim contacts, and a sharp increase in Ca in olivine rims. We suggest that the zoning of Ca in olivine from subduction zone lavas may provide the first petrological record of temporal changes that occur during hydration of the mantle wedge and dehydration during ascent, and we predict olivine H 2 O contents that can be tested by secondary ionization mass spectrometry analysis.

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Research paper thumbnail of Geochemical precursors of the 2000 eruption of Mutnovsky Volcano, Kamchatka

The Mutnovsky Volcano is one of the biggest and most active volcanoes of South Kamchatka. The mos... more The Mutnovsky Volcano is one of the biggest and most active volcanoes of South Kamchatka. The most recent explosive eruption of the volcano was 1960. After that time the volcano is in a stage of weak eruption that has already been continuing for more than 40 years. The analysis of seismologic data and visual observations confirmed an eruption in March 2000. Within sev-eral hours of the eruption a steam-gas outburst reaching 2500 m was observed. It disappeared the next day. During the observations from a helicopter it was determined that the eruption took place in the northern ex-plosive funnel of the volcano's South-Western crater which was active until middle 1950s. Hydrochemical sampling demonstrated that the eruption of March 2000 was preceded by a continuing annual increase in SO 4 -2 / Cl -and SO 4 -2 / F -in waters of Vulkannaya River, which drains Mutnovsky's active craters. Possibly, one of the surface events led to the March 2000 Mutnovsky Volcano eruption was the g...

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Research paper thumbnail of Provenance of olivine in volcanic rocks

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Research paper thumbnail of Mineralogical and Geochemical Characteristics of Magmatic Series Evolution at Gorely Volcano (Southern Kamchatka)

... Marijan KOVAČIĆ & Anita GRIZELJ ... Žumberak (Fig. 1). They consist of various silici... more ... Marijan KOVAČIĆ & Anita GRIZELJ ... Žumberak (Fig. 1). They consist of various siliciclastic and carbonate rocks that are grouped into six informal lithostratigraphic units: Croatica, MedvedskiBreg, Ozalj, Andraševec, Hum Zabočki and Pluska (KOVAČIĆ & GRIZELJ 2006). ...

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Research paper thumbnail of Major and trace element composition of melts from the Gorely volcanic center, southern Kamchatka

Melt inclusions in olivine and plagioclase phenocrysts from rocks (magnesian basalt, basaltic and... more Melt inclusions in olivine and plagioclase phenocrysts from rocks (magnesian basalt, basaltic andesite, andesite, ignimbrite, and dacite) of various age from the Gorely volcanic center, southern Kamchatka, were studied by means of their homogenization and by analyzing the glasses in 100 melt inclusions on an electron microprobe and 24 inclusions on an ion probe. The SiO2 concentrations of the melts vary within a broad range of 45-74 wt%, as also are the concentrations of other major components. According to their SiO2, Na2O, K2O, TiO2, and P2O5 concentrations, the melts are classified into seven groups. The mafic melts (45-53 wt% SiO2) comprise the following varieties: potassic (on average 4.2 wt% K2O, 1.7 wt% Na2O, 1.0 wt% TiO2, and 0.20 wt% P2O5), sodic (3.2% Na2O, 1.1% K2O, 1.1% TiO2, and 0.40% P2O5), and titaniferous with high P2O5 concentrations (2.2% TiO2, 1.1% P2O5, 3.8% Na2O, and 3.0% K2O). The melts of intermediate composition (53-64% SiO2) also include potassic (5.6% K2O, 3.4% Na2O, 1.0% TiO2, and 0.4% P2O5) and sodic (4.3% Na2O, 2.8% K2O, 1.3% TiO2, and 0.4% P2O5) varieties. The acid melts (64-74% SiO2) are either potassic (4.5% K2O, 3.6% Na2O, 0.7% TiO2, and 0.15% P2O5) or sodic (4.5% Na2O, 3.1% K2O, 0.7% TiO2, and 0.13% P2O5). A distinctive feature of the Gorely volcanic center is the pervasive occurrence of K-rich compositions throughout the whole compositional range (silicity) of the melts. Melt inclusions of various types were sometimes found not only in a single sample but also in the same phenocrysts. The sodic and potassic types of the melts contain different Cl and F concentrations: the sodic melts are richer in Cl, whereas the potassic melts are enriched in F. We are the first to discover potassic melts with very high F concentrations (up to 2.7 wt%, 1.19 wt% on average, 17 analyses) in the Kuriles and Kamchatka. The average F concentration in the sodic melts is 0.16 wt% (37 analyses). The melts are distinguished for their richness in various groups of trace elements: LILE, REE (particularly [...]

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Research paper thumbnail of Petrological And Geochemical Characteristics Of Magmatic Melts At Gorely Volcano, Kamchatka, Russia

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Research paper thumbnail of Table 3) Major element oxides of plagioclase in rocks obtained from the Gorely volcanic center

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Research paper thumbnail of Trace elements in olivine grains from volcanic rocks: magma chamber processes, magma water content, and primary melt generation

OF THE DISSERTATION........................................................................ ii PR... more OF THE DISSERTATION........................................................................ ii PREFACE ......................................................................................................................... iv ACKNOWLEDGMENTS ............................................................................................. viii TABLE OF CONTENTS ................................................................................................. x Chapter 1: Seismically active subcrustal magma source of the Klyuchevskoy volcano in Kamchatka, Russia ......................................................................................... 1 Abstract ........................................................................................................................... 1

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Research paper thumbnail of EPMA analyses of olivine near the boundary with a basaltic glass – the secondary fluorescence effect quantification

Goldschmidt2021 abstracts, 2021

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Research paper thumbnail of The quench control of water estimates in convergent margin magmas

American Mineralogist, 2019

Here we present a study on the quenchability of hydrous mafic melts. We show via hydrothermal exp... more Here we present a study on the quenchability of hydrous mafic melts. We show via hydrothermal experiments that the ability to quench a mafic hydrous melt to a homogeneous glass at cooling rates relevant to natural samples has a limit of no more than 9 ± 1 wt% of dissolved H2O in the melt. We performed supra-liquidus experiments on a mafic starting composition at 1–1.5 GPa spanning H2O-undersaturated to H2O-saturated conditions (from ~1 to ~21 wt%). After dissolving H2O and equilibrating, the hydrous mafic melt experiments were quenched. Quenching rates of 20 to 90 K/s at the glass transition temperature were achieved, and some experiments were allowed to decompress from thermal contraction while others were held at an isobaric condition during quench. We found that quenching of a hydrous melt to a homogeneous glass at quench rates comparable to natural conditions is possible at water contents up to 6 wt%. Melts containing 6–9 wt% of H2O are partially quenched to a glass, and always ...

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Research paper thumbnail of A Calcium-in-Olivine Geohygrometer and its Application to Subduction Zone Magmatism

Journal of Petrology, 2016

High-precision electron microprobe analyses were obtained on olivine grains from Klyuchevskoy, Sh... more High-precision electron microprobe analyses were obtained on olivine grains from Klyuchevskoy, Shiveluch and Gorely volcanoes in the Kamchatka Arc; Irazú, Platanar and Barva volcanoes of the Central American Arc; and mid-ocean ridge basalt (MORB) from the Siqueiros Transform. Calcium contents of these subduction zone olivines are lower than those for olivines from modern MORB, Archean komatiite and Hawaii. A role for magmatic H2O is likely for subduction zone olivines, and we have explored the suggestion of earlier workers that it has affected the partitioning of CaO between olivine and silicate melt. We provide a provisional calibration of DCaOOl/L as a function of magmatic MgO and H2O, based on nominally anhydrous experiments and minimally degassed H2O contents of olivine-hosted melt inclusions. Application of our geohygrometer typically yields 3–4 wt % magmatic H2O at the Kamchatka and Central American arcs for olivines having ∼1000 ppm Ca, which agrees with H2O maxima from melt ...

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Research paper thumbnail of Abrupt transition from fractional crystallization to magma mixing at Gorely volcano (Kamchatka) after caldera collapse

Bulletin of Volcanology, 2016

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Research paper thumbnail of Tephrochronological research in KALMAR Project and its implications to the temporal and compositional evolution of volcanism in Kamchatka

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Research paper thumbnail of Chemical composition, volatile components, and trace elements in the melts of the Gorely volcanic center, southern Kamchatka: Evidence from inclusions in minerals

Geochemistry International, 2012

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Research paper thumbnail of Secondary fluorescence effect quantification of EPMA analyses of olivine grains embedded in basaltic glass

Chemical Geology

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Research paper thumbnail of Seismically active subcrustal magma source of the Klyuchevskoy volcano in Kamchatka, Russia

Geology, 2014

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Research paper thumbnail of Evidence for superhydrous primitive arc magmas from mafic enclaves at Shiveluch volcano, Kamchatka

Contributions to Mineralogy and Petrology

Mafic enclaves preserve a record of deep differentiation of primitive magmas in arc settings. We ... more Mafic enclaves preserve a record of deep differentiation of primitive magmas in arc settings. We analyze the petrology and geochemistry of mafic enclaves from Shiveluch volcano in the Kamchatka peninsula to determine the differentiation histories of primitive magmas and to estimate their pressures, temperatures, and water contents. Amphibole inclusions in high forsterite olivine suggest that the primitive melt was superhydrous (i.e., > 8 wt% H 2 O) and was fractionating amphibole and olivine early on its liquid line of descent. We find that the hydrous primitive melt had liquidus temperatures of 1062 ± 48 °C and crystallized high Mg# amphibole at depths of 23.6-28.8 km and water contents of 10-14 wt% H 2 O. The major and trace element whole-rock chemistry of enclaves and of published analyses of andesites suggest that they are related through fractionation of amphibole-bearing assemblages. Quantitative models fractionating olivine, clinopyroxene, and amphibole reproduce geochemical trends defined by enclaves and andesites in variation diagrams. These models estimate 0.2-12.2% amphibole fractionated from the melt to reproduce the full range of enclave compositions, which overlaps with estimates of the amount of amphibole fractionated from parental melts based on whole-rock dysprosium contents. This contribution extends the published model of shallow processes at Shiveluch to greater depths. It provides evidence that primitive magmas feeding arc volcanoes may be more hydrous than estimated from other methods, and that amphibole is an important early fractionating phase on the liquid line of descent of superhydrous, primitive mantle-derived melts.

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Research paper thumbnail of Evidence for Eruption of a Superhydrous Magma from Shiveluch Volcano, Kamchatka

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Research paper thumbnail of Evidence for superhydrous primitive arc magmas from mafic enclaves at Shiveluch volcano, Kamchatka

Contributions to Mineralogy and Petrology, 2020

Mafic enclaves preserve a record of deep differentiation of primitive magmas in arc settings. We ... more Mafic enclaves preserve a record of deep differentiation of primitive magmas in arc settings. We analyze the petrology and geochemistry of mafic enclaves from Shiveluch volcano in the Kamchatka peninsula to determine the differentiation histories of primitive magmas and to estimate their pressures, temperatures, and water contents. Amphibole inclusions in high forsterite olivine suggest that the primitive melt was superhydrous (i.e., > 8 wt% H 2 O) and was fractionating amphibole and olivine early on its liquid line of descent. We find that the hydrous primitive melt had liquidus temperatures of 1062 ± 48 °C and crystallized high Mg# amphibole at depths of 23.6-28.8 km and water contents of 10-14 wt% H 2 O. The major and trace element whole-rock chemistry of enclaves and of published analyses of andesites suggest that they are related through fractionation of amphibole-bearing assemblages. Quantitative models fractionating olivine, clinopyroxene, and amphibole reproduce geochemical trends defined by enclaves and andesites in variation diagrams. These models estimate 0.2-12.2% amphibole fractionated from the melt to reproduce the full range of enclave compositions, which overlaps with estimates of the amount of amphibole fractionated from parental melts based on whole-rock dysprosium contents. This contribution extends the published model of shallow processes at Shiveluch to greater depths. It provides evidence that primitive magmas feeding arc volcanoes may be more hydrous than estimated from other methods, and that amphibole is an important early fractionating phase on the liquid line of descent of superhydrous, primitive mantle-derived melts.

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Research paper thumbnail of The quench control of water estimates in convergent margin magmas

American Mineralogist, 2019

Here we present a study on the quenchability of hydrous mafic melts. We show via hydrothermal exp... more Here we present a study on the quenchability of hydrous mafic melts. We show via hydrothermal experiments that the ability to quench a mafic hydrous melt to a homogeneous glass at cooling rates relevant to natural samples has a limit of no more than 9 ± 1 wt% of dissolved H2O in the melt. We performed supra-liquidus experiments on a mafic starting composition at 1–1.5 GPa spanning H2O-undersaturated to H2O-saturated conditions (from ~1 to ~21 wt%). After dissolving H2O and equilibrating, the hydrous mafic melt experiments were quenched. Quenching rates of 20 to 90 K/s at the glass transition temperature were achieved, and some experiments were allowed to decompress from thermal contraction while others were held at an isobaric condition during quench. We found that quenching of a hydrous melt to a homogeneous glass at quench rates comparable to natural conditions is possible at water contents up to 6 wt%. Melts containing 6–9 wt% of H2O are partially quenched to a glass, and always contain significant fractions of quench crystals and glass alteration/devitrification products. Experiments with water contents greater than 9 wt% have no optically clear glass after quench and result in fine-grained mixtures of alteration/devitrification products (minerals and amorphous materials). Our limit of 9 ± 1 wt% agrees well with the maximum of dissolved H2O contents found in natural glassy melt inclusions (8.5 wt% H2O). Other techniques for estimating pre-eruptive dissolved H2O content using petrologic and geochemical modeling have been used to argue that some arc magmas are as hydrous as 16 wt% H2O. Thus, our results raise the question of whether the observed record of glassy melt inclusions has an upper limit that is partially controlled by the quenching process. This potentially leads to underestimating the maximum amount of H2O recycled at arcs when results from glassy melt inclusions are predominantly used to estimate water fluxes from the mantle.

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Research paper thumbnail of A Calcium-in-Olivine Geohygrometer and its Application to Subduction Zone Magmatism

High-precision electron microprobe analyses were obtained on olivine grains from Klyuchevskoy, Sh... more High-precision electron microprobe analyses were obtained on olivine grains from Klyuchevskoy, Shiveluch and Gorely volcanoes in the Kamchatka Arc; Iraz u, Platanar and Barva volcanoes of the Central American Arc; and mid-ocean ridge basalt (MORB) from the Siqueiros Transform. Calcium contents of these subduction zone olivines are lower than those for olivines from modern MORB, Archean komatiite and Hawaii. A role for magmatic H 2 O is likely for subduction zone olivines, and we have explored the suggestion of earlier workers that it has affected the partitioning of CaO between olivine and silicate melt. We provide a provisional calibration of D CaO Ol/L as a function of magmatic MgO and H 2 O, based on nominally anhydrous experiments and minimally degassed H 2 O contents of olivine-hosted melt inclusions. Application of our geohygrometer typically yields 3–4 wt % magmatic H 2 O at the Kamchatka and Central American arcs for olivines having $1000 ppm Ca, which agrees with H 2 O maxima from melt inclusion studies; Cerro Negro and Shiveluch volcanoes are exceptions, with about 6% H 2 O. High-precision electron microprobe analyses with 10–20 lm spatial resolution on some olivine grains from Klyuchevskoy and Shiveluch show a decrease in Ca content from the core centers to the rim contacts, and a sharp increase in Ca in olivine rims. We suggest that the zoning of Ca in olivine from subduction zone lavas may provide the first petrological record of temporal changes that occur during hydration of the mantle wedge and dehydration during ascent, and we predict olivine H 2 O contents that can be tested by secondary ionization mass spectrometry analysis.

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Research paper thumbnail of Geochemical precursors of the 2000 eruption of Mutnovsky Volcano, Kamchatka

The Mutnovsky Volcano is one of the biggest and most active volcanoes of South Kamchatka. The mos... more The Mutnovsky Volcano is one of the biggest and most active volcanoes of South Kamchatka. The most recent explosive eruption of the volcano was 1960. After that time the volcano is in a stage of weak eruption that has already been continuing for more than 40 years. The analysis of seismologic data and visual observations confirmed an eruption in March 2000. Within sev-eral hours of the eruption a steam-gas outburst reaching 2500 m was observed. It disappeared the next day. During the observations from a helicopter it was determined that the eruption took place in the northern ex-plosive funnel of the volcano's South-Western crater which was active until middle 1950s. Hydrochemical sampling demonstrated that the eruption of March 2000 was preceded by a continuing annual increase in SO 4 -2 / Cl -and SO 4 -2 / F -in waters of Vulkannaya River, which drains Mutnovsky's active craters. Possibly, one of the surface events led to the March 2000 Mutnovsky Volcano eruption was the g...

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Research paper thumbnail of Provenance of olivine in volcanic rocks

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Research paper thumbnail of Mineralogical and Geochemical Characteristics of Magmatic Series Evolution at Gorely Volcano (Southern Kamchatka)

... Marijan KOVAČIĆ & Anita GRIZELJ ... Žumberak (Fig. 1). They consist of various silici... more ... Marijan KOVAČIĆ & Anita GRIZELJ ... Žumberak (Fig. 1). They consist of various siliciclastic and carbonate rocks that are grouped into six informal lithostratigraphic units: Croatica, MedvedskiBreg, Ozalj, Andraševec, Hum Zabočki and Pluska (KOVAČIĆ & GRIZELJ 2006). ...

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Research paper thumbnail of Possible existence of deep super-hydrous arc magmas: implications from high-Mg amphibole

The importance of quantifying the amount of H2O dissolved in magmas is obvious. However, pre-er... more The importance of quantifying the amount of H2O dissolved in magmas is obvious. However, pre-eruptive dissolved H2O in magmas is difficult to estimate due to nearly complete degassing of magmas during ascent, eruption, and cooling. Currently, magmatic H2O content estimations are based mostly on two methods: 1) measurements of water dissolved in melt inclusions; 2) plagioclase chemistry ‘hygrometers’ that are thermodyanmically derived models which use composition and/or phase stability as a function of dissolved water content. There is compelling evidence that these methods are only applicable to magmas in the upper-most part of the Earth's crust. Thus, the tools, which are commonly used for magmatic pre-eruptive H2O estimations are not able to provide information about deep/primitive arc magmas, which may contain much larger amounts of water than normally recognized.
In many ways amphibole may be complementary to plagioclase in its potential use as a hygrometer-type phase. In water-bearing magmas plagioclase crystallization gets suppressed, but amphibole crystallization does not. This leads to amphibole being an early crystallizing phase in deep-crustal hydrous systems, and in particular it crystallizes before plagioclase, and under certain circumstances, coeval with olivine. Primitive amphiboles crystallizing with or possibly even before olivine is a rare but globally ubiquitous assemblege, and has a lot to reveal about just how hydrous are subduction zone magmas when they leave the mantle. The primitive setting for amphibole discussed here is very different from the more typical use of amphibole as a baramoter in evolved acidic rocks. Here we present a survey of published data from plutonic and volcanic rocks that shows magma processing in the lower to middle crust often involves dissolved H2O contents >12 wt%. We also outline how petrologic investigations of primitive igneous amphibole could be carried out to highlight the importance and ubiquity of amphibole as an early crystallizing phase. Amphibole’s lack of a stability field at low pressure and the positive correlation between pressure and H2O solubility are likely major contributing factors to the underestimation of the global significance of H2O-rich primitive melts that are processed through volcanic arc systems. Ongoing and future experiments will help to better interpret the global array of primitive amphibole samples.

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Research paper thumbnail of Are melt inclusions a robust tool for understanding H2O content of deep hydrous arc magmas?

Dissolved in magma, H2O plays a significant role in generation, evolution, and eruption of arc ma... more Dissolved in magma, H2O plays a significant role in generation, evolution, and eruption of arc magmas. Estimating pre-eruptive H2O content is challenged by near surface H2O degassing during ascent and eruption. Currently, the ‘gold-standard’ for determining pre-eruptive volatile contents in magmas is the study of mineral-hosted glassy melt inclusions (MIs). They act as tiny pressure capsules potentially preserving maximum dissolved water contents, while the matrix melt degasses on ascent and gets modified by mixing and differentiation processes. Despite the widespread use of glassy MIs, it has yet to be tested whether they underlie a systematic maximum limit resulting in potentially biasing the inferred magmatic H2O budget in subduction zones. Natural glassy MIs have been found to contain no more than ~8-9 wt.% of dissolved H2O, and the question remains, is this limit representing a natural limit or a preservation limit? Here we explore the limits of mineral hosted glassy MIs as hydrous magma recorders based on an experimental study of quenching water-bearing silicate melts and show that 9 wt.% of dissolved H2O is a physical limit that quenched melt inclusions cannot exceed, while still quenching to a single-phase glass. Our results demonstrate that the maxima of 8-9 wt.% H2O from glassy MIs studies is linked to the ability of quenched glass to incorporate H2O/OH– in its structure, while excess water exsolves as bubbles and/or promotes devitrification through crystallization of quench crystals or hydrous alteration of the glass. Hydrous melts with H2O >9% will not form glassy MIs. As a result glassy MIs are only faithfully recording magmatic pre-eruptive H2O contents in the upper-most part of the Earth’s crust where H2O-solubility is below 9 wt.%. They have no sensitivity to estimate volatile budgets neither in deep/primitive arc magmas nor in midcrustal evolved magmas. Such magmas may contain much larger amounts of water than currently recognized imparting also additional buoyancy on ascent. For dense primitive magmas this may solve a conundrum often found in convergent margins; the fact that such magmas can reach the surface despite a low-density filter in the form of evolved magmas and crust in their path. These results show that we might be drastically underestimating the volatile budgets in subduction zones and they highlight the necessity of using and developing alternative methods for estimating pre-eruptive H2O contents.

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