Authigenic Mineral Texture in Submarine 1979 Basalt Drill Core, Surtsey Volcano, Iceland

M. D. Jackson*, S. Couper, C. V. Stan, M. Ivarsson, M. W. Czabaj, N. Tamura, D. Parkinson, L. M. Miyagi, J. G. Moore

*Corresponding author for this work

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Abstract

Micrometer-scale maps of authigenic microstructures in submarine basaltic tuff from a 1979 Surtsey volcano, Iceland, drill core acquired 15 years after eruptions terminated describe the initial alteration of oceanic basalt in a low-temperature hydrothermal system. An integrative investigative approach uses synchrotron source X-ray microdiffraction, microfluoresence, micro-computed tomography, and scanning transmission electron microscopy coupled with Raman spectroscopy to create finely resolved spatial frameworks that record a continuum of alteration in glass and olivine. Microanalytical maps of vesicular and fractured lapilli in specimens from 157.1-, 137.9-, and 102.6-m depths and borehole temperatures of 83, 93.9, and 141.3 °C measured in 1980, respectively, describe the production of nanocrystalline clay mineral, zeolites, and Al-tobermorite in diverse microenvironments. Irregular alteration fronts at 157.1-m depth resemble microchannels associated with biological activity in older basalts. By contrast, linear microstructures with little resemblance to previously described alteration features have nanocrystalline clay mineral (nontronite) and zeolite (amicite) texture. The crystallographic preferred orientation rotates around an axis parallel to the linear feature. Raman spectra indicating degraded and poorly ordered carbonaceous matter of possible biological origin are associated with nanocrystalline clay mineral in a crystallographically oriented linear microstructure in altered olivine at 102.6 m and with subcircular nanoscale cavities in altered glass at 137.9-m depth. Although evidence for biotic processes is inconclusive, the integrated analyses describe the complex organization of previously unrecognized mineral texture in very young basalt. They provide a foundational mineralogical reference for longitudinal, time-lapse characterizations of palagonitized basalt in oceanic environments.

Original languageEnglish
JournalGeochemistry, Geophysics, Geosystems
Volume20
Issue number7
Pages (from-to)3751-3773
Number of pages23
ISSN1525-2027
DOIs
Publication statusPublished - 31. Jul 2019

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Keywords

  • glass alteration
  • micrometer-scale maps
  • Raman spectroscopy
  • submarine basalt
  • Surtsey volcano
  • X-ray microdiffraction

Cite this

Jackson, M. D., Couper, S., Stan, C. V., Ivarsson, M., Czabaj, M. W., Tamura, N., Parkinson, D., Miyagi, L. M., & Moore, J. G. (2019). Authigenic Mineral Texture in Submarine 1979 Basalt Drill Core, Surtsey Volcano, Iceland. Geochemistry, Geophysics, Geosystems, 20(7), 3751-3773. https://doi.org/10.1029/2019GC008304