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Blythe, Lara
Alternative names
Publications (10 of 18) Show all publications
Burchardt, S., Troll, V. R., Schmeling, H., Koyi, H. & Blythe, L. (2016). Erupted frothy xenoliths may explain lack of country-rock fragments in plutons. Scientific Reports, 6, Article ID 34566.
Open this publication in new window or tab >>Erupted frothy xenoliths may explain lack of country-rock fragments in plutons
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2016 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, article id 34566Article in journal (Refereed) Published
Abstract [en]

Magmatic stoping is discussed to be a main mechanism of magma emplacement. As a consequence of stoping, abundant country-rock fragments should occur within, and at the bottom of, magma reservoirs as "xenolith graveyards", or become assimilated. However, the common absence of sufficient amounts of both xenoliths and crustal contamination have led to intense controversy about the efficiency of stoping. Here, we present new evidence that may explain the absence of abundant country-rock fragments in plutons. We report on vesiculated crustal xenoliths in volcanic rocks that experienced devolatilisation during heating and partial melting when entrained in magma. We hypothesise that the consequential inflation and density decrease of the xenoliths allowed them to rise and become erupted instead of being preserved in the plutonic record. Our thermomechanical simulations of this process demonstrate that early-stage xenolith sinking can be followed by the rise of a heated, partially-molten xenolith towards the top of the reservoir. There, remnants may disintegrate and mix with resident magma or erupt. Shallow-crustal plutons emplaced into hydrous country rocks may therefore not necessarily contain evidence of the true amount of magmatic stoping during their emplacement. Further studies are needed to quantify the importance of frothy xenolith in removing stoped material.

National Category
Geophysics
Identifiers
urn:nbn:se:uu:diva-308894 (URN)10.1038/srep34566 (DOI)000386722700001 ()27804996 (PubMedID)
Funder
Swedish Research Council
Available from: 2016-12-01 Created: 2016-12-01 Last updated: 2017-11-29Bibliographically approved
Blythe, L., Deegan, F., Freda, C., Jolis, E. M., Masotta, M., Misiti, V., . . . Troll, V. (2015). CO2 bubble generation and migration during magma–carbonate interaction. Contributions to Mineralogy and Petrology, 169(4), Article ID 42.
Open this publication in new window or tab >>CO2 bubble generation and migration during magma–carbonate interaction
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2015 (English)In: Contributions to Mineralogy and Petrology, ISSN 0010-7999, E-ISSN 1432-0967, Vol. 169, no 4, article id 42Article in journal (Refereed) Published
Abstract [en]

We conducted quantitative textural analysis of vesicles in high temperature and pressure carbonate assimilation experiments (1200 °C, 0.5 GPa) to investigate CO2 generation and subsequent bubble migration from carbonate into magma. We employed Mt. Merapi (Indonesia) and Mt. Vesuvius (Italy) compositions as magmatic starting materials and present three experimental series using (1) a dry basaltic-andesite, (2) a hydrous basaltic-andesite (2 wt% H2O), and (3) a hydrous shoshonite (2 wt% H2O). The duration of the experiments was varied from 0 to 300 s, and carbonate assimilation produced a CO2-rich fluid and CaO-enriched melts in all cases. The rate of carbonate assimilation, however, changed as a function of melt viscosity, which affected the 2D vesicle number, vesicle volume, and vesicle size distribution within each experiment. Relatively low-viscosity melts (i.e. Vesuvius experiments) facilitated efficient removal of bubbles from the reaction site. This allowed carbonate assimilation to continue unhindered and large volumes of CO2 to be liberated, a scenario thought to fuel sustained CO2-driven eruptions at the surface. Conversely, at higher viscosity (i.e. Merapi experiments), bubble migration became progressively inhibited and bubble concentration at the reaction site caused localised volatile over-pressure that can eventually trigger short-lived explosive outbursts. Melt viscosity therefore exerts a fundamental control on carbonate assimilation rates and, by consequence, the style of CO2-fuelled eruptions.

Keywords
CO2, Carbonate assimilation, Melt viscosity, Bubble size distribution, Eruption style
National Category
Geology
Research subject
Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
Identifiers
urn:nbn:se:uu:diva-271088 (URN)10.1007/s00410-015-1137-4 (DOI)000367847900001 ()
Funder
Swedish Research Council
Available from: 2016-01-05 Created: 2016-01-05 Last updated: 2017-12-01Bibliographically approved
Troll, V., Deegan, F., Jolis, E. M., Dahrén, B., Blythe, L., Harris, C., . . . Freda, C. (2014). Magma storage at Krakatau volcanic complex. In: : . Paper presented at City On volcanoes.
Open this publication in new window or tab >>Magma storage at Krakatau volcanic complex
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2014 (English)Conference paper, Oral presentation only (Refereed)
National Category
Geology Geosciences, Multidisciplinary
Research subject
Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
Identifiers
urn:nbn:se:uu:diva-240897 (URN)
Conference
City On volcanoes
Available from: 2015-01-08 Created: 2015-01-08 Last updated: 2015-01-08
Troll, V., Dahrén, B., Deegan, F., Jolis, E. M., Blythe, L., Harris, C., . . . Freda, C. (2014). Reconstructing the plumbing system of Krakatau volcano. In: : . Paper presented at EGU General Assembly, 2014, Vienna.
Open this publication in new window or tab >>Reconstructing the plumbing system of Krakatau volcano
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2014 (English)Conference paper, Oral presentation with published abstract (Refereed)
National Category
Geosciences, Multidisciplinary Geology
Research subject
Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
Identifiers
urn:nbn:se:uu:diva-240945 (URN)
Conference
EGU General Assembly, 2014, Vienna
Available from: 2015-01-08 Created: 2015-01-08 Last updated: 2015-01-08
Deegan, F., Troll, V., Jolis, E. M., Freda, C., Hilton, D., Budd, D., . . . Zimmer, M. (2014). The role of CO2-rich basement at Merapi; perspectives from petrology, geochemistry, and experiments. In: : . Paper presented at City on volcanoes.
Open this publication in new window or tab >>The role of CO2-rich basement at Merapi; perspectives from petrology, geochemistry, and experiments
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2014 (English)Conference paper, Oral presentation only (Refereed)
National Category
Geology Geosciences, Multidisciplinary
Research subject
Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
Identifiers
urn:nbn:se:uu:diva-240866 (URN)
Conference
City on volcanoes
Available from: 2015-01-08 Created: 2015-01-08 Last updated: 2015-01-08
Blythe, L., Deegan, F., Freda, C., Jolis, E. M., Masotta, M., Misiti, V., . . . Troll, V. (2014). Time-monitored vesiculation processes in magma-carbonate interaction experiments. Contributions to Mineralogy and Petrology
Open this publication in new window or tab >>Time-monitored vesiculation processes in magma-carbonate interaction experiments
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2014 (English)In: Contributions to Mineralogy and Petrology, ISSN 0010-7999, E-ISSN 1432-0967Article in journal (Other academic) Submitted
National Category
Geosciences, Multidisciplinary
Research subject
Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
Identifiers
urn:nbn:se:uu:diva-240817 (URN)
Available from: 2015-01-08 Created: 2015-01-08 Last updated: 2017-12-05
Troll, V. R., Chadwick, J. P., Jolis, E. M., Deegan, F. M., Hilton, D., Schwarzkopf, L. M., . . . Zimmer, M. (2013). Crustal volatile release at Merapi volcano; the 2006 earthquake and eruption events. Geology Today, 29(3), 96-101
Open this publication in new window or tab >>Crustal volatile release at Merapi volcano; the 2006 earthquake and eruption events
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2013 (English)In: Geology Today, ISSN 0266-6979, E-ISSN 1365-2451, Vol. 29, no 3, p. 96-101Article in journal (Other (popular science, discussion, etc.)) Published
National Category
Geosciences, Multidisciplinary
Identifiers
urn:nbn:se:uu:diva-198051 (URN)10.1111/gto.12008 (DOI)
Available from: 2013-04-08 Created: 2013-04-08 Last updated: 2017-12-06Bibliographically approved
Jolis, E. M., Freda, C., Troll, V. R., Deegan, F. M., Blythe, L. S., McLeod, C. L. & Davidson, J. P. (2013). Experimental simulation of magma-carbonate interaction beneath Mt. Vesuvius, Italy. Contributions to Mineralogy and Petrology, 166(5), 1335-1353
Open this publication in new window or tab >>Experimental simulation of magma-carbonate interaction beneath Mt. Vesuvius, Italy
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2013 (English)In: Contributions to Mineralogy and Petrology, ISSN 0010-7999, E-ISSN 1432-0967, Vol. 166, no 5, p. 1335-1353Article in journal (Refereed) Published
Abstract [en]

We simulated the process of magma-carbonate interaction beneath Mt. Vesuvius in short duration piston-cylinder experiments under controlled magmatic conditions (from 0 to 300 s at 0.5 GPa and 1,200 A degrees C), using a Vesuvius shoshonite composition and upper crustal limestone and dolostone as starting materials. Backscattered electron images and chemical analysis (major and trace elements and Sr isotopes) of sequential experimental products allow us to identify the textural and chemical evolution of carbonated products during the assimilation process. We demonstrate that melt-carbonate interaction can be extremely fast (minutes), and results in dynamic contamination of the host melt with respect to Ca, Mg and Sr-87/Sr-86, coupled with intense CO2 vesiculation at the melt-carbonate interface. Binary mixing between carbonate and uncontaminated melt cannot explain the geochemical variations of the experimental charges in full and convection and diffusion likely also operated in the charges. Physical mixing and mingling driven by exsolving volatiles seems to be a key process to promote melt homogenisation. Our results reinforce hypotheses that magma-carbonate interaction is a relevant and ongoing process at Mt. Vesuvius and one that may operate not only on a geological, but on a human timescale.

Keywords
Mt. Vesuvius, Magma-carbonate interaction, Crustal assimilation, CO2 liberation, Experimental petrology
National Category
Geochemistry Geology
Research subject
Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
Identifiers
urn:nbn:se:uu:diva-211007 (URN)10.1007/s00410-013-0931-0 (DOI)000325625500005 ()
Available from: 2013-11-20 Created: 2013-11-19 Last updated: 2017-12-06Bibliographically approved
Troll, V. R., Hilton, D. R., Jolis, E. M., Chadwick, J. P., Blythe, L. S., Deegan, F. M., . . . Zimmer, M. (2012). Crustal CO2 liberation during the 2006 eruption and earthquake events at Merapi volcano, Indonesia. Geophysical Research Letters, 39, L11302
Open this publication in new window or tab >>Crustal CO2 liberation during the 2006 eruption and earthquake events at Merapi volcano, Indonesia
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2012 (English)In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 39, p. L11302-Article in journal (Refereed) Published
Abstract [en]

High-temperature volcanic gas is widely considered to originate from ascending, mantle-derived magma. In volcanic arc systems, crustal inputs to magmatic gases mainly occur via subducted sediments in the mantle source region. Our data from Merapi volcano, Indonesia imply, however, that during the April-October 2006 eruption significant quantities of CO2 were added from shallow crustal sources. We show that prior to the 2006 events, summit fumarole gas delta C-13((CO2)) is virtually constant (delta C-13(1994-2005) = -4.1 +/- 0.3 parts per thousand), but during the 2006 eruption and after the shallow Yogyakarta earthquake of late May, 2006 (M6.4; hypocentres at 10-15 km depth), carbon isotope ratios increased to -2.4 +/- 0.2 parts per thousand. This rise in delta C-13 is consistent with considerable addition of crustal CO2 and coincided with an increase in eruptive intensity by a factor of similar to 3 to 5. We postulate that this shallow crustal volatile input supplemented the mantle-derived volatile flux at Merapi, intensifying and sustaining the 2006 eruption. Late-stage volatile additions from crustal contamination may thus provide a trigger for explosive eruptions independently of conventional magmatic processes.

National Category
Earth and Related Environmental Sciences
Research subject
Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
Identifiers
urn:nbn:se:uu:diva-176812 (URN)10.1029/2012GL051307 (DOI)000304772800002 ()
Available from: 2012-06-27 Created: 2012-06-26 Last updated: 2017-12-07Bibliographically approved
Berg, S., Troll, V., Freda, C., Mancini, L., Masotta, M., Brun, F., . . . Barker, A. (2012). Experimental simulation of crustal volatile release in magmatic conduits. In: : . Paper presented at 1st European Mineralogical Conference in Frankfurt, Germany, 2012.
Open this publication in new window or tab >>Experimental simulation of crustal volatile release in magmatic conduits
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2012 (English)Conference paper, Poster (with or without abstract) (Other academic)
National Category
Geology
Identifiers
urn:nbn:se:uu:diva-191132 (URN)
Conference
1st European Mineralogical Conference in Frankfurt, Germany, 2012
Note

Vol. 1, EMC2012-202

Available from: 2013-01-09 Created: 2013-01-09 Last updated: 2013-09-23Bibliographically approved
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