Kuehn, Stephen

Tephrochronology, the use of volcanic ash (tephra) layers to provide correlations between sites and age control – including:

– analytical methods for obtaining geochemical data (e.g. electron microprobe, ICP-OES), including the development of new procedures and new standard reference materials
-cryptotephra (locating and identifying trace volcanic ash that does not occur as visible layers), especially in glacial ice
– applications (e.g. Quaternary geology, climate change, paleolimnology, archaeology, paleoseismology)

* Volcanology & petrology, especially of pyroclastic rocks – including:

-Proximal stratigraphy and geochemistry
– Eruption and depositional mechanisms (from deposit characteristics such as particle size variations and thickness distributions)* Selected field localities:
-Newberry Volcano, Oregon
-Summer Lake and Fossil Lake, Oregon (Great Basin region)
-central Alaska
-Mt. St. Helens, Washington

Recent publications:

Kuehn, S.C., Froese, D.G., and Shane, P.A.R., 2011 (in press), The INTAV intercomparison of electron-beam microanalysis of glass by tephrochronology laboratories, results and recommendations: Quaternary International.

Kuehn, S.C. and Froese, D.G., 2010, Tephra from ice – A simple method to routinely mount, polish, and quantitatively analyze sparse fine particles: Microscopy and Microanalysis.

Kuehn, S.C. and Negrini, R.N., 2010, A 250,000-year record of Cascade Range pyroclastic volcanism from late Pleistocene lacustrine sediments near Summer Lake, Oregon, USA: Geosphere.

Lacelle, D., St-Jean, M., Lauriol, B., Clark, I.D., Froese, D., Kuehn, S.C., Zazula, G., and Lewkowicz, A., 2010, Burial history of a relict perennial snowbank body and vegetation by the Dawson tephra (25,300 14C years BP) near Red Creek, Ogilvie Mountains, central Yukon, Canada: Quaternary Science Reviews.

Microanalysis