McDonald (UCMP V-4828) (Miocene of the United States)
Where: Wheeler County, Oregon (44.9° N, 120.2° W: paleocoordinates 44.8° N, 115.5° W)
• coordinate based on political unit
• small collection-level geographic resolution
When: Unit 2 Member (Mascall Formation), Miocene (23.0 - 5.3 Ma)
Environment/lithology: terrestrial
Reposited in the UCMP
Primary reference: T. Downs. 1956. The Mascall fauna from the Miocene of Oregon. University of California Publications in Geological Sciences 31(5):199-354 [J. Alroy/J. Alroy/J. Marcot]more details
PaleoDB collection 18967: authorized by John Alroy, entered by John Alroy on 05.08.1996
Creative Commons license: CC BY (attribution)
Taxonomic list
• Downs suspected this belonged to Unit 2, and Fremd et al. 1994 seem to agree
this is the only substantial locality low in the section
Baksi 1974 gives an average date of 15.2 (= 15.60) +/- 0.6 Ma (whole rock KA) for 22 dates from ten samples from seven of 15 basalt flows in the Picture Gorge section; these flows are beneath the Mascall Fm. and the McDonald localities are the closest to them stratigraphically
KA 1203 of Evernden et al. 1964, dated at 15.4 (= 15.81) Ma (whole rock basalt), is from the very base of the formation more than 20 mi ("13 miles east of Dayville"); sample is said to be "probably satisfactory" despite slight alteration of plagioclase and very high atmospheric argon percentage, but their argument is not accepted by Baksi 1974
this is the only substantial locality low in the section
Baksi 1974 gives an average date of 15.2 (= 15.60) +/- 0.6 Ma (whole rock KA) for 22 dates from ten samples from seven of 15 basalt flows in the Picture Gorge section; these flows are beneath the Mascall Fm. and the McDonald localities are the closest to them stratigraphically
KA 1203 of Evernden et al. 1964, dated at 15.4 (= 15.81) Ma (whole rock basalt), is from the very base of the formation more than 20 mi ("13 miles east of Dayville"); sample is said to be "probably satisfactory" despite slight alteration of plagioclase and very high atmospheric argon percentage, but their argument is not accepted by Baksi 1974
Show authors, comments, and common names
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"Protospermophilus oregonensis" = Arctomyoides oregonensis1
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