Abstract
High-temperature decompression experiments demonstrate that crystal textures preserve a record of the style and rate of magmatic ascent. To reinforce this link, we performed a suite of isothermal decompression experiments using starting material from the climactic 1991 Pinatubo eruption. We decompressed experiments from 220 MPa to final, quench pressures of 75 or 30 MPa using continuous decompression rates of 100, 30, 10, 3, 1, and 0.3 MPa h−1. Amphibole, clinopyroxene, and plagioclase crystallized during the experiments, with plagioclase microlites dominating the assemblage. Total microlite number densities range from 107.6±0.4 up to 108.2±0.2 cm−3, with plagioclase accounting for up to 65% of the total number. Plagioclase microlite area increased systematically from 19 ± 8 to 937 ± 487 µm2 with increasing experiment duration. Our textures provide time-integrated records of crystal kinetics. Average nucleation and areal growth rates of plagioclase are highest in the fastest decompressions (~ 107.5 cm−3 h−1 and 10.1 ± 4.1 µm2 h−1, respectively) and more than an order of magnitude lower in the slowest experiments (~ 105.5 cm−3 h−1 and 0.8 ± 0.2 µm2 h−1, respectively). Both nucleation and growth rates are highest at high degrees of disequilibrium. We find that peak supersaturation-dependent instantaneous rates are generally more than an order of magnitude faster than average rates. We use those instantaneous nucleation and growth rates to introduce an iterative model to evaluate the effects of different decompression rates, decompression paths (continuous, single-step or multistep), and the presence of phenocrysts on final crystallinity and microlite size distribution.
Similar content being viewed by others
References
Andrews BJ, Gardner JE (2010) Effects of caldera collapse on magma decompression rate: an example from the 1800 14 C yr BP eruption of Ksudach Volcano, Kamchatka, Russia. J Volcanol Geotherm Res 198(1):205–216
Arzilli F, Carroll MR (2013) Crystallization kinetics of alkali feldspars in cooling and decompression-induced crystallization experiments in trachytic melt. Contrib Mineral Petrol 166(4):1011–1027
Befus KS, Manga M, Gardner JE, Williams M (2015) Ascent and emplacement dynamics of obsidian lavas inferred from microlite textures. Bull Volcanol 77(10):1–17
Blundy J, Cashman K (2001) Ascent-driven crystallisation of dacite magmas at Mount St Helens, 1980–1986. Contrib Mineral Petrol 140(6):631–650
Browne B, Szramek L (2015) Rates of magma ascent and storage. In: Sigurdsson H, Houghton B, McNutt S, Rymer H, Stix J (eds) Encyclopedia of volcanoes, 2nd edn. Academic Press, London, pp 203–214
Brugger CR, Hammer JE (2010a) Crystal size distribution analysis of plagioclase in experimentally decompressed hydrous rhyodacite magma. Earth Planet Sci Lett 300(3):246–254
Brugger CR, Hammer JE (2010b) Crystallization kinetics in continuous decompression experiments: implications for interpreting natural magma ascent processes. J Petrol 51(9):1941–1965
Cashman KV (1992) Groundmass crystallization of Mount St. Helens dacite, 1980–1986: a tool for interpreting shallow magmatic processes. Contrib Mineral Petrol 109(4):431–449. https://doi.org/10.1007/BF00306547
Castro JM, Dingwell DB (2009) Rapid ascent of rhyolitic magma at Chaitén volcano, Chile. Nature 461(7265):780
Cichy SB, Botcharnikov RE, Holtz F, Behrens H (2010) Vesiculation and microlite crystallization induced by decompression: a case study of the 1991–1995 Mt Unzen eruption (Japan). J Petrol 52(7–8):1469–1492
Couch S, Sparks R, Carroll M (2003) The kinetics of degassing-induced crystallization at Soufriere Hills Volcano, Montserrat. J Petrol 44(8):1477–1502
Gardner J, Rutherford M, Carey S, Sigurdsson H (1995) Experimental constraints on pre-eruptive water contents and changing magma storage prior to explosive eruptions of Mount St Helens volcano. Bull Volcanol 57(1):1–17
Gardner JE, Hilton M, Carroll MR (1999) Experimental constraints on degassing of magma: isothermal bubble growth during continuous decompression from high pressure. Earth Planet Sci Lett 168(1–2):201–218
Geschwind C-H, Rutherford MJ (1995) Crystallization of microlites during magma ascent: the fluid mechanics of 1980–1986 eruptions at Mount St Helens. Bull Volcanol 57(5):356–370
Gonnermann HM, Manga M (2003) Explosive volcanism may not be an inevitable consequence of magma fragmentation. Nature 426(6965):432–435. https://doi.org/10.1038/nature02138
Gualda GA, Ghiorso MS, Lemons RV, Carley TL (2012) Rhyolite-MELTS: a modified calibration of MELTS optimized for silica-rich, fluid-bearing magmatic systems. J Petrol 53(5):875–890
Hammer JE (2004) Crystal nucleation in hydrous rhyolite: Experimental data applied to classical theory. Am Mineral 89(11–12):1673–1679
Hammer JE (2008) Experimental studies of the kinetics and energetics of magma crystallization. Rev Mineral Geochem 69(1):9–59
Hammer JE, Rutherford MJ (2002) An experimental study of the kinetics of decompression-induced crystallization in silicic melt. J Geophys Res 107(B1):ECV-8-1. https://doi.org/10.1029/2001JB000281
Hammer J, Cashman K, Hoblitt R, Newman S (1999) Degassing and microlite crystallization during pre-climactic events of the 1991 eruption of Mt. Pinatubo, Philippines. Bull Volcanol 60(5):355–380
Humphreys MC, Menand T, Blundy JD, Klimm K (2008) Magma ascent rates in explosive eruptions: constraints from H2O diffusion in melt inclusions. Earth Planet Sci Lett 270(1):25–40
James PF (1985) Kinetics of crystal nucleation in silicate glasses. J Non Cryst Solids 73(1–3):517–540
Kirkpatrick RJ (1981) Kinetics of crystallization of igneous rocks. Rev Mineral (United States) 8:1
La Spina G, Burton M, Vitturi MdM, Arzilli F (2016) Role of syn-eruptive plagioclase disequilibrium crystallization in basaltic magma ascent dynamics. Nat Commun 7:13402
Lasaga AC (2014) Kinetic theory in the earth sciences, vol 402. Princeton University Press, Princeton
Martel C (2012) Eruption dynamics inferred from microlite crystallization experiments: application to Plinian and dome-forming eruptions of Mt. Pelée (Martinique, Lesser Antilles). J Petrol 53(4):699–725
Martel C, Schmidt BC (2003) Decompression experiments as an insight into ascent rates of silicic magmas. Contrib Mineral Petrol 144(4):397–415
Marxer H, Bellucci P, Nowak M (2015) Degassing of H2O in a phonolitic melt: a closer look at decompression experiments. J Volcanol Geotherm Res 297:109–124
Melnik O, Sparks R (2002) Dynamics of magma ascent and lava extrusion at Soufriere Hills Volcano, Montserrat. Geological Society, London, Memoirs, vol 21(1), pp 153–171
Mollard E, Martel C, Bourdier J-L (2012) Decompression-induced crystallization in hydrated silica-rich melts: empirical models of experimental plagioclase nucleation and growth kinetics. J Petrol 53(8):1743–1766
Mollo S, Hammer J (2017) Dynamic crystallization in magmas. EMU Notes Mineral 16:373–418
Nielsen CH, Sigurdsson HR (1981) Quantitative methods of electron microprobe analysis of sodium in natural and synthetic glasses. Am Min 66:547–552
Patanè D, De Gori P, Chiarabba C, Bonaccorso A (2003) Magma ascent and the pressurization of Mount Etna’s volcanic system. Science 299(5615):2061–2063
Peslier AH, Bizimis M, Matney M (2015) Water disequilibrium in olivines from Hawaiian peridotites: recent metasomatism, H diffusion and magma ascent rates. Geochim Cosmochim Acta 154:98–117
Polacci M, Papale P, Rosi M (2001) Textural heterogeneities in pumices from the climactic eruption of Mount Pinatubo, 15 June 1991, and implications for magma ascent dynamics. Bull Volcanol 63(2):83–97
Riker JM, Cashman KV, Rust AC, Blundy JD (2015) Experimental constraints on plagioclase crystallization during H2O- and H2O–CO2-saturated magma decompression. J Petrol 56(10):1967–1998
Rutherford MJ (2008) Magma ascent rates. Rev Mineral Geochem 69(1):241–271
Rutherford MJ, Devine JD (1996) Preeruption pressure-temperature conditions and volatiles in the 1991 dacitic magma of Mount Pinatubo. Fire and mud: eruptions and lahars of Mount Pinatubo, Philippines. University of Washington Press, Washington, pp 751–766
Rutherford MJ, Hill PM (1993) Magma ascent rates from amphibole breakdown: an experimental study applied to the 1980–1986 Mount St. Helens eruptions. J Geophys Res 98(B11):19667–19685
Scaillet B, Evans BW (1999) The 15 June 1991 eruption of Mount Pinatubo. I. Phase equilibria and pre-eruption P–T–fO2–fH2O conditions of the dacite magma. J Petrol 40(3):381–411
Scandone R, Cashman KV, Malone SD (2007) Magma supply, magma ascent and the style of volcanic eruptions. Earth Planet Sci Lett 253(3–4):513–529
Shea T, Hammer JE (2013) Kinetics of cooling-and decompression-induced crystallization in hydrous mafic-intermediate magmas. J Volcanol Geotherm Res 260:127–145
Shea T, Larsen JF, Gurioli L, Hammer JE, Houghton BF, Cioni R (2009) Leucite crystals: surviving witnesses of magmatic processes preceding the 79AD eruption at Vesuvius, Italy. Earth Planet Sci Lett 281(1–2):88–98
Suzuki Y, Gardner JE, Larsen JF (2007) Experimental constraints on syneruptive magma ascent related to the phreatomagmatic phase of the 2000 AD eruption of Usu volcano, Japan. Bull Volcanol 69(4):423–444
Swanson SE (1977) Relation of nucleation and crystal-growth rate to the development of granitic textures. Am Mineral 62(9–10):966–978
Swanson SE, Naney MT, Westrich HR, Eichelberger JC (1989) Crystallization history of Obsidian Dome, Inyo Domes, California. Bull Volcanol 51(3):161–176. https://doi.org/10.1007/BF01067953
Toramaru A, Noguchi S, Oyoshihara S, Tsune A (2008) MND (microlite number density) water exsolution rate meter. J Volcanol Geotherm Res 175(1–2):156–167. https://doi.org/10.1016/j.jvolgeores.2008.03.035
Waters LE, Andrews BJ, Lange RA (2015) Rapid crystallization of plagioclase phenocrysts in silicic melts during fluid-saturated ascent: Phase equilibrium and decompression experiments. J Petrol 56(5):981–1006
Acknowledgements
We thank Smithsonian for sample NMNH 116563-1. Helpful reviews from Jenny Riker and an anonymous reviewer improved this manuscript.
Author information
Authors and Affiliations
Corresponding author
Additional information
Communicated by Mark S Ghiorso.
Rights and permissions
About this article
Cite this article
Befus, K.S., Andrews, B.J. Crystal nucleation and growth produced by continuous decompression of Pinatubo magma. Contrib Mineral Petrol 173, 92 (2018). https://doi.org/10.1007/s00410-018-1519-5
Received:
Accepted:
Published:
DOI: https://doi.org/10.1007/s00410-018-1519-5