Unalaska Formation
Jump to navigation
Jump to search
| Unalaska Formation | |
|---|---|
| Stratigraphic range: Miocene Era, Neogene Period | |
| File:Dutch Harbor 1.jpg Outcrops near Dutch Harbor, Unalaska | |
| Type | Geologic formation |
| Overlies | Aleutian Ridge |
| Thickness | 900–10,000 metres (3,000–32,800 ft) |
| Location | |
| Region | Aleutian Islands, Alaska |
| Country | United States |
| Type section | |
| Named for | Unalaska Island |
The Unalaska Formation is a Miocene Era geologic formation on Amaknak Island and Unalaska Island, in the Aleutian Islands archipelago of southwestern Alaska.[1]
It consists mainly of volcanic breccia, flows, tuff, and intercalated sedimentary rocks.[1] It is exposed over about 70 percent of Unalaska Island. The Dutch Harbor Member is a 126 metres (413 ft) thick Early Miocene sequence of the formation.[1]
It preserves fossils dating back to the Miocene era of the Neogene period.[2]
See also
[edit | edit source]Lua error in mw.title.lua at line 392: bad argument #2 to 'title.new' (unrecognized namespace name 'Portal').
References
[edit | edit source]- ^ a b c USGS: Stratigraphy and depositional environment of the Dutch Harbor Member of the Unalaska Formation, Unalaska Island, Alaska
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).