The Astoria Formation (formerly known as the Astoria shales) is a
geologic formation
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...
in
Washington state
Washington, officially the State of Washington, is a state in the Pacific Northwest region of the United States. It is often referred to as Washington State to distinguish it from the national capital, both named after George Washington ...
&
Oregon
Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...
. It preserves
fossils
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
dating back to the early to middle
Miocene
The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...
(but was formerly thought to date to the
Oligocene
The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...
).
Description
The Astoria Formation is a thick
marine formation representing a near shore, relatively shallow-water shelf deposit.
The formation spans a considerable amount of time, with its base considered to be lower boundary of Newportian Stage (late
Early Miocene
The Early Miocene (also known as Lower Miocene) is a sub-epoch of the Miocene epoch (geology), Epoch made up of two faunal stage, stages: the Aquitanian age, Aquitanian and Burdigalian stages.
The sub-epoch lasted from 23.03 ± 0.05 annum, Ma to ...
) & its top to be upper boundary of Newportian Stage (middle
Middle Miocene
The Middle Miocene is a sub-epoch of the Miocene epoch (geology), epoch made up of two Stage (stratigraphy), stages: the Langhian and Serravallian stages. The Middle Miocene is preceded by the Early Miocene.
The sub-epoch lasted from 15.97 ± 0. ...
).
Fossil content
Mammals
Carnivorans
Cetaceans
Perissodactyls
Birds
Cartilaginous fish
See also
*
List of fossiliferous stratigraphic units in Oregon
*
Paleontology in Washington (state)
Paleontology in Washington encompasses Paleontology, paleontological research occurring within or conducted by people from the United States, U.S. state of Washington (state), Washington. Washington has a rich fossil Fossil record, record spanning ...
*
List of fossiliferous stratigraphic units in Washington
*
Paleontology in Oregon
image:Map of USA OR.svg, The location of the state of Oregon
Paleontology in Oregon refers to Paleontology, paleontological research occurring within or conducted by people from the U.S. state of Oregon. Oregon's geologic record extends back app ...
References
*
*
*
Neogene geology of Washington (state)
Neogene geology of Oregon
Long stubs with short prose
Geologic formations of Washington (state)
Geologic formations of Oregon
{{Neogene-stub