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Upper Colville River, Alaska

Map of Northern Alaska       Upper Colville Fossil Images Unassigned No Fossil Images

 

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 89JTP06

Description:

Here marine units pass up into heavily rooted brown/gray nodular siltstones with abundant rooting much of which is formed by Equisetites rhizomes. The seat earths and paper shales of the coals in this section contain Podozamites, Equisetites and Cephalotaxopsis, together with woody (branch) debris and occasional logs. Pityophyllum is less abundant but present. This section was not studied in 1985 because our boat was already overloaded with samples and a suitable resupply landing site needed to be found.

The lower part of the section is poorly exposed. The well exposed part of the section begins with a claystone/siltsone with intercalated fine sandstones with invertebrate trails, burrows and flute casts. The bioturbation style is the same as that in the marine beds of 85JTP05 that contain undeniably marine fossils such as ophioroids.

Sketch of the 89JTP06 section  

These marine(?) units pass up into heavily rooted gray siltstones with abundant Equisetites rhizomes. This is overlain by mottled brown/gray nodular, poorly bedded silts and clays that are abundantly rooted. These are interpreted as overbank sediments. Above these are several meters of unconsolidated clays with small ironstone nodules capped by a 0.1m thick rooted sandstone. Bedding planes of the sandstone are covered in poorly oriented water-worn woody fragments representing transported twigs. Some Equisetites stems/rhizomes also present. This in turn is overlain by two distinct rooted coarse siltstones beneath a seat earth of a coal. The lower part of this coal is papery with remains of Equisetites, abundant Podozamites and small conifer leafy shoots probably representing Cephalotaxopsis. Pityophyllum staratchinii is present but uncommon. The coal in total is several meters thick but contains numerous clay/silt partings and is often more of a paper shale. Numerous large compressed logs > 0.3 m in diameter are present and Podozamites leaves are abundant throughout. The coal is overlain by a pedogenically modified clay preserving tree roots, which is in turn overlain by 1 m thick nodular siltstones capped by cross bedded sands overlain by a nodular siltstone containing Equisetites rhizomes. Approximately 5 m above is an inferred non-marine/marine transition.

 

 

 

Sketch of the 89JTP06 section.
Field photograph of an in situ tree base from the 89JTP06 section. The clay containing the tree base is covered by slope wash.   Field photograph of an in situ tree base

 

 

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