Earth:Tukwila Formation

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Tukwila Formation
Stratigraphic range: Bartonian
TypeGeological formation
Location
Region Washington
King County Geologic Cross Section
King County Geologic Map

The Tukwila Formation is a geological formation in King County, Washington within the Puget Group. It is named after Tukwila area, which is close to the formation. The formation consists of various fossils of marine origin.[1]

The Tukwila formation is mainly composed of andesitic to dacitic volcanic sandstone, siltstone, shale, tuff-breccia, tuff, lahar, and carbonaceous shales. The tuff-breccia has an approximate age of 42 Ma.[2]

Fauna

Vertebrate fauna

Vertebrate fauna mainly consists of just shark remains. Mainly one unnamed species of Goblin shark and one unnamed species belonging to the same genus as the Whitetip reef shark.[3][4]

Invertebrate fauna

  • ? Coeloma martinezensis
  • Zanthopsis vulgaris
  • Terebratulina washingtoniana
  • Protula sp.
  • Glycymeris saggittata
  • Venericardia clarki
  • Colwellia bretzi
  • Brisaster sp.

References