Sagavanirktok River - Sagwon Section
|Sagwon Coals and Floras||Section 1||Section 1.5||Section 2||Sections 3 and 4||Sagwon Fossil Images|
The most prominant lithologies in the Sagwon section are the coals. There are four coals exposed (see below) that can be traced laterally throughout the length of the section except where they are eroded out or covered. Locally the coals are disrupted by faults with throws of a just a few metres.
The thickest coal is that referred to as Coal III. Where examined in detail (Section 1.5) Coal III appears not to have a rooted base and is predominantly composed of branch wood. Charcoal (fusain) is present but not abundant in this coal.
At locality 3 the exposure is poor but immediately above Coal III siltstones contain abundant leaf material, whole leaves and fragmented, representing Metasequoia, Equisetites, and numerous angiosperms. Some leaves appear folded and suggest rapid deposition.
Photograph, looking northwest, of the bluffs at the northern end of the sagwon section showing the light gray conglomerates of the Sagwon member of the Sagavanirktok Formation unconformably overlying Coal IV that here forms the uppermost unit of the Prince Creek Formation.
|Interactive panorama of the northern end of the Sagwon section. Place the cursor on the image to see the positions of the main coal seams highlighted. For more details of the localities see the page describing Sagavanirktok geology.|
Coal IV is poorly exposed and deeply weathered but is best exposed immediately under the conglomerates that make up the Sagwon Member of the Sagavanirktok Formation. Sediments associated with coals III and IV contain locally abundant plant fossils that we refer to the Late Sagwon Phase of floral evolution.
The Early Sagwon Phase of floral evolution is represented by fossils found below Coal III and is best exemplified by the exposures at Sagwon Section 2 and in the associated stream bed leading down to the Sagavanirktok River as well as the lower part of the section at Sagwon Section 1.5.