Volcano List
About Alaska's Volcanoes Hazards from Alaska's Volcanoes
Map & Alphabetical List Interactive Map
Eruption Search Volcano Search
|
Text Description: The tephra is present in the upper part of a 2-m-thick gully-fill deposit, the gully being incised about 10 m into the Klondike gravel, close to the level of the highest terrace along the Klondike River. The gully-fill sediments consist of 0.5 m of matrix-supported gravel overlain by 1.5 m of massive to crudely stratified, organic-rich silt. Discontinuous pods of Jackson Hill tephra, up to 3 cm thick, occur 50 cm below the surface in this silt. The lower diamict is interpreted as a hillslope deposit derived from downslope movement of the Klondike gravel into the gully, while the overlying silt is thought to represent retransported loess. Fine grain size. Consists mostly of bubble-wall glass shards with feldspar, orthopyroxene, clinopyroxene and minor amounts of green or red amphibole, titanomagnetite, ilmenite, apatite and zircon. From Preece et al. (2011): 3 cm thick; pumice, bubble-wall shards, spheres with a small amount of brown glass; in brown organic silt overlying Klondike Gravel; field name 799a References:  The variegated (VT) tephra: A new regional marker for middle to late marine isotope stage 5 across Yukon and Alaska A catalogue of late Cenozoic tephra beds in the Klondike Goldfields and adjacent areas, Yukon Territory Glass-fission-track ages of late Cenozoic distal tephra beds in the Klondike district, Yukon Territory |
This website is supported by the U.S. Geological Survey under Cooperative Agreement Grant G22AC00137
Mention of trade names or commercial products does not constitute their endorsement by the U.S. Geological Survey.
Operations
Response
Staff
Fields of Study
Geology
Color Code Definitions
Webcams
Webicorders
RSAM
Great Sitkin
Takawangha
Glossary
Recent Images
Browse Images
