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Upper Colville River, Alaska

        Upper Colville Fossil Images Unassigned Fossil Images 85JTP13

 

This interactive map of part of the Colville River, Northern Alaska, shows the locations of plant fossil collections made by J.T. Parrish and R.A. Spicer in 1985 and 1989. Click on a number for more details on that site. The red outlined area links to another map showing positions of florules (plant fossil assemblages) collected by C.J. Smiley along both the Colville and Chandler Rivers.

Interactive map of the Upper Colville River Hotspot linking to 85RAS09 Hotspot linking to Smiley's Colville and Chandler River localities. Hotspot linking to 85RAS02 Hotspot linking to 85RAS01 Hotspot linking to 85RAS03 Hotspot linking to 85RAS04 Hotspot linking to 85RAS05 Hotspot linking to 85RAS06 Hotspot linking to 85RAS07  Hotspot linking to 85RAS08 Hotspot linking to 85RAS10 Hotspot linking to 85RAS11 Hotspot linking to 85RAS12 Hotspot linking to 85RAS13 Hotspot linking to 85RAS14 Hotspot linking to 85RAS13 Hotspot linking to 85RAS16 Hotspot linking to 85RAS17 Hotspot linking to 85RAS18 Hotspot linking to 85RAS19 Hotspot linking to 89RAS1_3 Hotspot linking to 89RAS04 Hotspot linking to 89RAS05 Hotspot linking to 89RAS06 Hotspot linking to 89RAS07 Hotspot linking to 89RAS09 Hotspot linking to 89RAS10 Hotspot linking to 89RAS11 Hotspot linking to 89RAS12 Hotspot linking to 89RAS164_320

Locality 85JTP13

This exposure is mapped as the Lower Killik of the Chandler Formation (Chapman et al., 1964), now the upper part of the laower half of the Nanushuk Formation of Mull et al. (2003). Here a carbonaceous siltstone is exposed near the base of the section and this underlies a coal approximately 1.3 m thick. Most of the plant fossils were collected from tabular ironstone concretions that crop out at river level. Taxa present include entire-margined cycads (Nilssonia yukonensis), ginkgos, Podozamites, and Gleichenites.

Lithologies as summarised by J.T. Parrish in July 1985.

Top of Section    
  2.4 m Thin to medium bedded very fine sandstone weathering gray and orange, some silty horizons present, rippled with finely disseminated plant material
  Approx. 1 m Cover
  1.3 m Coal with very large ironstone concretions
  4.5 - 6 m Medium dark gray siltstone and silty mudstone with black coaly paper shale in some horizons and coaly stringers (presumably compressed logs). Abundant large and small ironstone concretions containing plant fossils such as Cephalotaxopsis, Podozamites, angiosperms, cycads and ferns.
  0.6 m Pale yellow-orange concretionary layer
  2.4 m Olive gray bentonitic silty claystone excavated from what is basically cover. Abundant pale yellowish-orange concretionary lenses.
  6.1 m Bentonitic very fine medium to light gray sandstone, thin to medium bedded, with abundant ironstone lenses and concretions.
  6 m Covered by bentonitic slope wash.
  1 m Ironstone concretionary layer, yellow-weathering, cropping out at river level containing cycads, ginkgos, Podozamites etc.

 

Downstream further outcrops suggest that the basal ironstone layer is underlain by a bentonitic sandstone totalling 18 m in thickness, below which is a 3.5 m thick dark gray mudstone, a concretionary layer and a coal.

Hotspot linking to Smiley's Colville and Chandler River localities. Hotspot linking to localities along the Kukpowruk River Hotspot linking to the Kuk River Localities