North bank of Moose Creek (Paleocene of the United States)

Where: Alaska (61.7° N, 149.0° W: paleocoordinates 68.6° N, 123.0° W)

• coordinate stated in text

• small collection-level geographic resolution

When: Chickaloon Formation, Late/Upper Paleocene (58.7 - 55.8 Ma)

• The Chickaloon Formation was named by Martin and Katz (1912) and covers the greater part of the valley of the Chickaloon River south of Castle Mountain, southern Alaska. The formation consists of fl uviatile and alluvial carbonacous mudstone, siltstone, polymictic sandstone, conglomeratic sandstone, and numerous beds of bituminous coals at least 1500 meters thick (Barnes and Payne 1956, Winkler 1992; Wolfe et al. 1966). Martin and Katz (1912) assigned an age of Tertiary, probably Eocene. Barnes and Payne (1956:14) considered the age to be Paleocene or Eocene. Wolf et al. (1966), based on the flora, considered the Chickaloon Formation as Paleocene. Most recently, Triplehorn et al. (1984) and Winkler (1992) dated volcanic ash partings in the upper part of the Chickaloon at the Evan Jones mine, northwest of Jonesville, using fi ssion-track and radiometric data. Their assigned ages of Paleocene and early Eocene (53.3 ± 1.5 to 55.8 ± 1.7Ma) encompass the Paleocene-Eocene boundary (about 55.5 Ma fi de Berggren et al. 1998). The fossil turtle locality lies near the Matanuska Bluffs U.S. Geological Survey Paleobotany locality 5892 of Wolfe et al. (1966), who considered this section to lie entirely below the coal rich upper part of the formation and thus presumably below the dated beds of Triplehorn et al. (1984). Scott Wing (1999, pers. comm.) regards the fl ora as late Paleocene and an excellent match for Clarkforkian North American Land Mammal Age (NALMA; 56.35–55.8 Ma fi de Woodburne and Swischer 1995; 56.2–55.5 Ma fi de Prothero 1995).

• bed-level stratigraphic resolution

Environment/lithology: fluvial; carbonaceous mudstone

• carbonacous mudstone

Size class: macrofossils

Preservation: adpression

Collected by Anthony Milionta, Mike Morrison, and Veronica Cacy during a geology class fi eld trip with instructor Bjarme Holm of Service High School, Anchorage, Alaska in 1994

Primary reference: J. H. Hutchison and A. D. Pasch. 2004. First record of a turtle (Protochelydra, Chelydridae, Testudines) from the Cenozoic of Alaska (Chickaloon Formation, Paleocene–Eocene). PaleoBios 24(1):1-5 [P. Mannion/P. Mannion]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 137806: authorized by Philip Mannion, entered by Philip Mannion on 20.12.2012

Creative Commons license: CC BY (attribution)

Taxonomic list

Reptilia
 Testudines - Panchelydridae
Protochelydra cf. zangerli Erickson 1973 turtle
UAM No. AK-526-V-01 (a nearly complete but compressed carapace); UCMP 159853 (mold)
unclassified
  -
Plantae indet. Haeckel 1866
"rich in plant remains"