Understanding active volcanism through geology and geochemistry of eruption products:
Understanding the relationships between volcanic eruptions (style, duration, size, intensity) and the magmatic processes that lead to them (source composition, melting style and extent, magma transport, crustal processes and magma storage) is a long term goal of volcanology in general, and a focus of my group's research. We use petrological and compositional variations in space and time, in erupted products, and deposit morphology and distribution, to decipher how and when magma is formed, delivered to active volcanoes, stored, and erupted. Our ongoing work with both US and international partners unites high-spatial-resolution sampling of modern/recent volcanic products, compositional analyses, and deposit mapping to link spatiotemporal patterns of composition to variations in magma formation, supply, and eruption style within single eruptions and between successive eruptions. We work on both subaerial and submarine systems. In the latter we use deep submergence methods for geological observations/sampling coupled to high-resolution temporal records from disequilibria amongst short-lived U-series daughters.
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Figure 1 Images of the first molten lava sampled in the deep sea by the remotely operated vehicle Jason2 during the 2009 Northeast Lau event response cruise on R/V TG Thompson. The Jason team skillfully inserted a T-handled rod into a glowing portion of an advancing pillow lobe and pulled out a cantaloupe-sized piece of lava, subsequently shown to be a rare magma type known as boninite (Resing et al., 2011). This sample, taken from West Mata Volcano near Tonga, is one of many we are using to reconstruct the dynamics of boninite magmatism at the site (Figure is from Rubin et al., 2012) |
Here I am taking a sample of lava from erupted late in the historical eruption of Paricutin volcano, in Michoacan, Mexico. The eruption was from 1943 to 1952. Study of how the magma changed during eruption here, as well as in an early eruption from El Jorullo Volcano (18th century) give us insights into monogenetic volcanism (a type of activity where there is a volcanism is restricted to a single event, or sequence of closely related events in space and time, at a site that had not previously had a volcano, and has not reactivated since). This work in Mexico has not yet been published, although similar sorts of work, coupling lava distribution and type with compositona analysis and natural radioactive signatures ("U-series") appear in many of the papers below.
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Figure 2 Lava sampling in Mexico |
The temporal variability of crustal and mantle processes in magmatic systems is key for understanding the dynamics of magma formation and storage, and its link to eruption size, style, intensity and duration. Figure 3 Diagram illustrating the decay of radioactive disequilibria in 4 parent-daughter pairs within the U-series decay chain that we apply for timescale reconstructions in this research. The different half-lives involved cause the signals to decay over different timescales. "A" stands for "activity", and "o" stands for "initial". In this case daughter excesses are depicted, and only the excess part of the disequilibria changes with time. Note the log scale on the x-axis | |
The methods we utilize focus on radioactive disequlibria amongst naturally occuring isotopes in the Uranium decay series, which as a group cover a wide range of chemistries and half-lives. Focus applications of my research group include:
Selected recent publications: Rubin KH. (2014) Mid-Ocean Ridge Magmatism and Volcanism. In: Harff J., Meschede M., Petersen S., Thiede J. (Ed.) Encyclopedia of Marine Geosciences. pp.1-21 Springer-Verlag Berlin Heidelberg. DOI: 10.1007/978-94-007-6644-0_28-3 KH Rubin, SA Soule, WW Chadwick, DJ Fornari, DS Clague, RW. Embley, ET Baker, MR Perfit, DW Caress, RP Dziak (2012) Volcanic Eruptions in the Deep Sea, Oceanography, 25(1), 142–157, http://dx.doi.org/10.5670/oceanog.2012.12. Resing, KH Rubin, R Embley, J Lupton, E Baker, R Dziak, T Baumberger, M Lilley, J Huber, T Shank, D Butterfield, D Clague, N Keller, S Merle, N Buck, P Michael, S.A Soule, D Caress, S Walker, R Davis, J Cowen, A-L Reysenbach, H Thomas (2011) Active Submarine Eruption of Boninite in the north-eastern Lau Basin, Nature Geoscience, 4, DOI: 10.1038/NGEO1275 AK Schmitt, MR Perfit, KH Rubin, DF Stockli, MC Smith, LA Cotsonika, GF Zellmer, WI Ridley, OM Lovera (2011) Rapid cooling rates at an active mid-ocean ridge from zircon thermochronology, Earth Planet. Sci. Lett., 302, 349-358, doi: 10.1016/j.epsl.2010.12.022 GF Zellmer, KH Rubin, P Dulski, Y Iizuka, SL Goldstein, MR Perfit (2011) Crystal growth during dike injection of MOR basaltic melts: evidence from preservation of local Sr disequilibria in plagioclase Contributions to Mineralogy and Petrology, 161, 153-173, doi: 10.1007/s00410-010-0518-y GF Zellmer, KH Rubin, K Grönvold, Z Jurado-Chichay (2008) On the recent bimodal magmatic processes and their rates in the Torfajökull-Veidivötn area, Iceland Earth Planet. Sci. Lett., 269, 387-397, doi:10.1016/j.epsl.2008.02.026. KH Rubin and JM Sinton (2007), Inferences on mid-ocean ridge thermal and magmatic structure from MORB compositions, Earth Planet. Sci. Lett., 26, 257–276, doi:10.1016/j.epsl.2007.05.035. EC Bergmanis, J Sinton, KH Rubin (2007) Recent Eruptive History and Magma Reservoir Dynamics on the Southern East Pacific Rise at 17.5°S, Geochem. Geophys. Geosyst., 8, Q12O06, doi:10.1029/2007GC001742 S.A. Soule, D.J. Fornari, M.R. Perfit and K.H. Rubin (2007), New insights into mid-ocean ridge volcanic processes from the 2005-06 eruption of the East Pacific Rise, 9° 46'-56'N, Geology, 35 (12), 1079–1082, doi: 10.1130/G23924A.1. RP Dziak, DR Bohnenstiehl, JP Cowen, ET Baker, KH Rubin, JH Haxel, MJ, Fowler (2007) Rapid dike emplacement leads to dramatic hydrothermal plume release during seafloor spreading events, Geology, 35, 579-582, doi: 10.1130/G23476A.1 M Tolstoy, J P Cowen, E T Baker, DJ Fornari, KH Rubin, TM Shank, F Waldhauser, DR Bohnenstiehl, DW Forsyth, RC Holmes, B Love, MR Perfit, RT Weekly, SA Soule, B. Glazer (2006) A Seafloor Spreading Event Captured by Seismometers, Science, 314, 1920-1922. RW Embley, WW Chadwick, Jr., ET Baker, DA Butterfield, JA Resing, CEJ de Ronde, V Tunniclife, JE Lupton, KS Juniper, KH Rubin, RJ Stern, GT Lebon, K Nakamura, SG Merle, JR Hein, DP Wiens, & Y. Tamura (2006) Long-Term Eruptive Activity at a Submarine Arc Volcano, Nature, 441, 494-497 doi:10.1038/nature04762. KH Rubin, I. van der Zander, MC Smith and EC Bergmanis (2005) Minimum speed limit for ocean ridge magmatism from 210Pb-226Ra-230Th disequilibria, Nature, 437, 534-538, doi:10.1038/nature03993. KH Rubin & I van der Zander (2005) Obtaining High-Resolution Chronologies of Submarine Lava Eruptions: Better Dating Through Radiochemistry, Ridge 2000 Events, 3 (Spring 2005), 28-30. J Sinton, E Bergmanis, KH Rubin, R Batiza, TKP Gregg, K Grönvold, K Macdonald, and S White (2002) Volcanic eruptions on mid-ocean ridges: New evidence from the superfast-spreading East Pacific Rise, 17°-19°S, J. Geophys. Res..107, (p ECV3-1 to 3-19) doi:10.1029/2000JB000090 Rubin, KH, Smith, MC, Bergmanis, EC, Perfit, MR, Sinton, JM and Batiza R (2001) Geochemical heterogeneity within mid-ocean ridge lava flows: insights into eruption, emplacement and global variations in magma generation Earth Planet. Sci. Lett., 188, 349-367. Pietruszka, AJ, Rubin, KH and Garcia, MO (2001) 226Ra-230Th-238U disequilibria of historical Kilauea lavas (1790-1982) and the dynamics of mantle melting within the hawaiian plume. Earth Planet. Sci. Lett. , 186, 15-31.
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