Volcanic ash, Spurr (Gunsight)

Practical significance

Interpretation of remote sensing data. Analogues of other planets' atmospheric dust, and dust in comets, asteroids, and circumstellar shells

Origin

Crater Peak on the south side of Mount Spurr volcano, across Cook Inlet, Alaska, USA, 125 km west of Anchorage. The particles are from the 17 September 1992 eruption and were collected 265 km east of the volcano.

Main constituent
57-78 wt% glass, plagioclase feldspar, opx, magnetite, amphibole, cpx
Color
Dark grey
Particle size Fraunhofer: reff (μm)
3.5
Particle size Fraunhofer: veff
8.2
Size distribution plot:
Size Distribution Spurr (Gunsight)
Size distribution table
size_spurrgunsight.txt
Particle shape

Irregular

SEM/TEM images:
Spurr (Gunsight) SEM Image 1
Spurr (Gunsight) SEM Image 2
All SEM/TEM images (zip file)
Spurr (Gunsight) SEM Images
Scattering matrix (1) wavelength in nm
632.80 nm
Scattering matrix (1) table
matrix_spurrgunsight_633nm.txt
Scattering matrix (1) plot:
Scattering matrix elements Spurr (Gunsight)
Refractive index

Estimated to be in the range [1.48-1.56] + i[0.0018-0.02]

Angle range (deg)
[3,174]
Reference/s
Muñoz et al., 2004