Alaska Volcano Observatory

Not a visible tephra layer: cryptotephra. 102–110 cm depth in core. Colourless, highly vesicular, bubblewall and non-vesicular angular glass shards. Their maximum measured length is 100 microns, the median being <45 microns. About 60% of the shards have characteristic feldspar microlite crystals up to 20 microns long, occurring in all types of glass shards.

Sample Location:

Great Sitkin

Spurr

+−

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Legend

	Red (Warning)
	Orange (Watch)
	Yellow (Advisory)
	Green (Normal)
	Uninstrumented

500 km

300 mi

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References Cited

[1] Linking the North Atlantic to central Europe: A high-resolution Holocene tephrochronological record from northern Germany, 2002

van den Bogaard, C., and Schmincke, H.U., 2002, Linking the North Atlantic to central Europe: A high-resolution Holocene tephrochronological record from northern Germany: Journal of Quaternary Science, v. 17, p. 3-20, doi: 10.1002/jqs.636

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