Kukpowruk River 96-13 (Cretaceous to of the United States)

Also known as Kukpowruk River/Cape Lisburne floras

Where: western North Slope County, Alaska (69.1° N, 162.9° W: paleocoordinates 79.0° N, 97.0° W)

• coordinate stated in text

• outcrop-level geographic resolution

When: Corwin Formation, Albian to Albian (113.0 - 93.9 Ma)

• middle Albian to Cenomanian

• group of beds-level stratigraphic resolution

Environment/lithology: mire or swamp; carbonaceous shale and brown, gray mudstone

• Description. The base of the section is composed of carbonaceous

•shales and poor coals dominated by Podozamites. Podozamites also

•occurs abundantly in ironstone concretions associated with the

•coals and carbonaceous shales. These are overlain by grey/brown

•mudstones also containing abundant fragmented Podozamites

•together with Equisetites, Pityophyllum and probably Ginkgo fragments.

•Up section (down river) grey, weathering to yellow, finegrained

•sandstones become more prevalent with wood fragments

•and impressions of logs. The sands are ripple-marked with sometimes

•two phases of rippling: large ripples asymmetrical, of approximately

•10-cm wavelength within the troughs of which are smaller,

•transverse (ladder) ripples with a wavelength of 1–2 cm. The

•sediments also contain horizontal U-shaped burrows and internal

•moulds of bivalves 4–5 cm long (inoceramids?).

•Interpretation. Going up section the sedimentary environment

•changes from a woody, Podozamites-dominated swamp to a marginal

•marine setting. The two types of ripples may indicate subaerial

•exposure with wind (or draining) ripples formed in the

•flooded troughs of the larger ripples formed by water flow (tidal or

•longshore currents?).

Size class: macrofossils

Collection methods: quarrying,

• Material stored at the Earth Sciences Department, The Open University, collection # 96 RAS.

Primary reference: R. A. Spicer and A. B. Herman. 2001. The Albian-Cenomanian flora of the Kukpowruk River, western North Slope, Alaska: stratigraphy, palaeofloristics, and plant communities. Cretaceous Research 22:1-40 [D. Royer/D. Royer/D. Royer]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 34296: authorized by Dana Royer, entered by Dana Royer on 26.08.2003

Creative Commons license: CC BY (attribution)

Taxonomic list

Gnetopsida
  -
Pinopsida
 Pinales - Podocarpaceae
Podozamites spp. Braun 1843
occurs in carbonaceous shales, poor coals, ironstone conceretions, and mudstones
Equisetopsida
 Equisetales - Equisetaceae
Equisetites ex gr. burejensis
occurs in mudstones