Deformation of the Wineglass Welded Tuff and the timing of caldera collapse at Crater Lake, Oregon

Journal of Volcanology and Geothermal Research
By: , and 

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Abstract

Four types of deformation occur in the Wineglass Welded Tuff on the northeast caldera rim of Crater Lake: (a) vertical tension fractures; (b) ooze-outs of fiamme: (c) squeeze-outs of fiamme; and (d) horizontal pull-apart structures. The three types of plastic deformation (b-d) developed in the lower part of the Wineglass Welded Tuff where degree of welding and density are maximum. Deformation originated from concentric normal faulting and landsliding as the caldera collapsed. The degree of deformation of the Wineglass Welded Tuff increases toward the northeast part of the caldera, where plastic deformation occurred more easily because of a higher emplacement temperature probably due to proximity to the vent. The probable glass transition temperature of the Wineglass Welded Tuff suggests that its emplacement temperature was ???750??C where the tuff is densely welded. Calculation of the conductive cooling history of the Wineglass Welded Tuff and the preclimactic Cleetwood (lava) flow under assumptions of a initially isothermal sheet and uniform properties suggests that (a) caldera collapse occurred a maximum of 9 days after emplacement of the Wineglass Welded Tuff, and that (b) the period between effusion of the Cleetwood (lava) flow and onset of the climactic eruption was <100 years. If cooling is controlled more by precipitation during quiescent periods than by conduction, these intervals must be shorter than the calculated times.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Deformation of the Wineglass Welded Tuff and the timing of caldera collapse at Crater Lake, Oregon
Series title Journal of Volcanology and Geothermal Research
DOI 10.1016/0377-0273(93)90019-N
Volume 56
Issue 3
Year Published 1993
Language English
Contributing office(s) Volcano Science Center
Description 13 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Journal of Volcanology and Geothermal Research
First page 253
Last page 265
Country United States
State Oregon
Other Geospatial Crater Lake