| 词条 | Unalaska Formation |
| 释义 |
| name = Unalaska Formation | image = | caption = | type = Geologic formation | age = Miocene Era, Neogene Period | prilithology = | otherlithology = | namedfor = Unalaska Island | namedby = | region = Aleutian Islands, Alaska | country = United States | coordinates = | unitof = | subunits = | underlies = | overlies = Aleutian Ridge | thickness ={{convert|900|-|10000|m|ft}} | extent = | area = | map = | map_caption = }} 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 {{convert|126|m|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{{Portal|Neogene|Alaska|Paleontology|Cenozoic}}
References1. ^1 2 [https://www.sciencebase.gov/catalog/item/4f4e4b1fe4b07f02db6ab798 USGS: Stratigraphy and depositional environment of the Dutch Harbor Member of the Unalaska Formation, Unalaska Island, Alaska] {{Neogene Footer}}2. ^{{cite web|title= Fossilworks: Gateway to the Paleobiology Database|author= Various Contributors to the Paleobiology Database|url= http://www.fossilworks.org/|accessdate= 8 July 2014|deadurl= yes|archiveurl= https://web.archive.org/web/20140731140924/http://fossilworks.org/|archivedate= 31 July 2014|df= }} 7 : Miocene geology|Neogene Alaska|Amaknak Island|Unalaska Island|Miocene Series of North America|Neogene stratigraphic units of North America|Geologic formations of Alaska |
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