Cristobalite in volcanic ash of the Soufriere Hills volcano, Montserrat, British West Indies

Science

Volumn 283, Issue 5405, 1999, Pages 1142-1145

  Baxter, P J ^a   Bonadonna, C ^b   Dupree, R ^c   Hards, V L ^d   Kohn, S C ^b   Murphy, M D ^b   Nichols, A ^e   Nicholson, R A ^d   Norton, G ^d   Searl, A ^e   Sparks, R S J ^b   Vickers, B P ^d  

^a UNIVERSITY OF CAMBRIDGE   (United Kingdom)

^b UNIVERSITY OF BRISTOL   (United Kingdom)

^c UNIVERSITY OF WARWICK   (United Kingdom)

^d BRITISH GEOLOGICAL SURVEY   (United Kingdom)

^e INSTITUTE OF OCCUPATIONAL MEDICINE   (United Kingdom)

Author keywords

[No Author keywords available]

Indexed keywords

SILICON DIOXIDE;

CRISTOBALITE; SILICA; VOLCANIC ASH;

AIR SAMPLING; ARTICLE; ATMOSPHERIC DISPERSION; CHEMICAL ANALYSIS; ENVIRONMENTAL EXPOSURE; GEOGRAPHY; GEOLOGY; HEALTH HAZARD; HUMAN; MONTSERRAT; PRIORITY JOURNAL; VOLCANIC ASH;

MONTSERRAT;

EID: 0033582794     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.283.5405.1142     Document Type: Article

References (19)

1. S. R. Young et al., Geophys. Res. Lett. 25, 3389 (1998).
2. M. D. Murphy et al., ibid., p. 3433.
3. XRD was performed with a Phillips PW1700 diffractometer by using Co-Kα radiation generated at 45 kV and 40 mA, a step size of 0.02° 2θ, and sampling time of 1.5 s per step. A zero background Si substrate was used, and the sample was mounted by using a drop of acetone. NMR spectra were collected with a Bruker MSL 360 operating at 71.535 MHz with a 2-μs pulse length and 180-s recycle delay. Samples were analyzed on a JEOL JXA-8600 electron microprobe by energy-dispersive spectral analysis to identify the phases. Run conditions were 15-kV accelerating voltage, 15-nA beam current, and 1-μm probe diameter. The proportions of different phases in the sub-10-μm fraction were estimated by counting 200 grains per sample.
4. N. A. Talvitie, Am. Ind. Hydrol. Assoc. J. 25, 169 (1964).
5. Opaline silica typically can be identified as a broad peak on XRD, but our XRD traces show no evidence of its presence (Fig. 1). Opaline silica is also formed in low-temperature environments and would not be expected in a high-temperature lava dome.
6. R. L. Hay, J. Geol. 67, 540 (1959); G. P. L. Walker, Contrib. Mineral. Petrol. 36, 135 (1972); R. S. J. Sparks and G. P. L. Walker, J. Volcanol. Geotherm. Res. 2, 329 (1997).
7. R. L. Hay, J. Geol. 67, 540 (1959); G. P. L. Walker, Contrib. Mineral. Petrol. 36, 135 (1972); R. S. J. Sparks and G. P. L. Walker, J. Volcanol. Geotherm. Res. 2, 329 (1997).
8. R. L. Hay, J. Geol. 67, 540 (1959); G. P. L. Walker, Contrib. Mineral. Petrol. 36, 135 (1972); R. S. J. Sparks and G. P. L. Walker, J. Volcanol. Geotherm. Res. 2, 329 (1997).
9. Health and Safety Executive (UK), Methods for the Determination of Hazardous Substances 14/2 (1997).
10. _, ibid. 76 (1994).
11. Expert Panel on Air Quality Standards, Particles (Department of the Environment Expert Panel for Air Quality Standards, Her Majesty's Government, 1995).
12. Health and Safety Executive, Occupational Exposure Limits EH40/97 (1997); American Conference of Government Hygenists, Threshold Limit Values for Chemical Substances and Physical Agents: Biological Exposure Indices (American Conference of Government Hygenists, Cincinnati, OH, 1997).
13. Health and Safety Executive, Occupational Exposure Limits EH40/97 (1997); American Conference of Government Hygenists, Threshold Limit Values for Chemical Substances and Physical Agents: Biological Exposure Indices (American Conference of Government Hygenists, Cincinnati, OH, 1997).
14. R. K. Soren, J. Volcanol. Geotherm. Res. 13, 63 (1982).
15. World Health Organization, Monographs on the Evaluation of Carcinogenic Risks to Humans 68 (1997).
16. P. J. Heaney and J. A. Banfield, in G. D. Guthrie and B. T. Mossman, Eds., Rev. Mineral. Min. Soc. Am. 28, 185 (1993).
17. D. D. Dollberg, M. L. Bolyard, D. L. Smith, Am. J. Public Health 76 (suppl.), 53 (1986).
18. A. S. Buist, R. S. Bernstein, L. R. Johnson, W. M. Vollmer, ibid., p. 66.
19. Work on Montserrat was supported by the Department for International Development and Natural Environmental Research Council. The cooperation of the people of Montserrat and staff of the Montserrat Volcano Observatory is acknowledged. We thank T. S. Brewer (Leicester University) for performing XRF analyses of lava samples, T. Riemer and B. Schmidt (Warwick University) for performing NMR experiments, and A. Seaton (Aberdeen University) for advice.