Astoria Formation (UGSG 15611) - #49 (Moore, 1963) (Miocene of the United States)

Also known as Locality #49 (Moore, 1963); USGS 15611

Where: Tillamook County, Oregon (45.3° N, 123.9° W: paleocoordinates 45.1° N, 119.2° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Astoria Formation, Middle Miocene (16.0 - 11.6 Ma)

• From unknown stratigraphic position. Astoria Formation has been used as a name for almost all of the marine middle Miocene sedimentary rocks of Washington and Oregon although these correlations are poorly constrained. The formation has been divided into three members: a lower sandstone, a shale, and an upper sandstone. These rocks form the northern limb of a syncline, the asis of which is exposed east of Astoria, and the syncline trends NE and plunges to the SW. The Astoria Formation is intermittently exposed; theya re faulted and exposures are interupted by volcanic rocks and slides. The maximum thickness of any exposure is 25 feet.

• bed-level stratigraphic resolution

Environment/lithology: coastal; poorly lithified, fine-grained, concretionary, silty, carbonaceous sandstone

• Astoria Formtaion is faulted and interupted in exposure by volcanic rocks and land slides.
• Fine-grained sandstone, alternating with sandy shale in whcih coal pebbles, small round concretions, and fossils are abundant.

Size class: macrofossils

Preservation: concretion, replaced with other

Reposited in the CAS, USNM

Collection methods: quarrying,

• Collected by R.M. Grivetti, 1945. Collections reside in the Californian Academy of Sciences, the U.S. National Museum, and presumably the USGS.

Primary reference: E. J. Moore. 1963. Miocene marine mollusks from the Astoria Formation in Oregon. United States Geological Survey Professional Paper 419 [A. Miller/A. Hendy/A. Hendy]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 39690: authorized by Austin Hendy, entered by Austin Hendy on 03.06.2004

Creative Commons license: CC BY (attribution)

Taxonomic list

• Exhaustive for mollusca