F-3B:

Bioturbated

siltstone composed

of Cruziana ichnofacies.

・ F-3B is composed of siltstone dominated by Cruziana ichnofacies.

・ F-3B is moderately well sorted.

・ No sedimentary structures.

・ The trace fossils recorded in F-3B are rare Zoophycos? Planolites, Phycosiphon, Chondrites, Thalassinoides, Cruziana, Skolithos, Teichichnus, and Palaeophycos. In cores, these traces are not well preserved.

・ F-3B fugichnia- escape structures are present.

・ Trace fossils such as Planolites, Thalassinoides, Cruziana, and Palaeophycus are ichnocoenosis of the Cruziana ichnofacies.

・ The Cruziana ichnofacies is commonly characterized by a high diversity of trace fossils associated with a variety of ichnofauna.

・ The present of these trace fossils in F-3B are indicative of distal offshore setting.

・ Conclusion: Distal offshore depositional environment.

F-4: Dolomitic very fine-grained

sandstone

・ F-4 consist of dolomitic, thin beds (≤1 meter) of very fine-grained sandstone.

・ Thin-section petrography confirms that F-4 is quartz rich, moderately well sorted and dolomitic.

・ F-4 succession shows a coarsening upward trend.

・ The basal contact of F-4 with lithofacies F-5 is sharp and grades into coarse siltstone grade.

・ No sedimentary structures.

・ Trace fossils and bioturbation are not present in lithofacies F-4.

・ There are no body fossils preserved in F-4.

・ The coarsening-upward trend in lithofacies F-4 is interpreted as basinward shoreline shift, which often characterizes a progradational trend.

・ The coarsening upward succession of F-4 is likely to have accumulated in deepening water, particularly in areas that are not adjacent to the shoreline and are characteristic of facies that prograded basinward during a falling stage of regression.

・ Conclusion: Proximal offshore depositional environment.

F-5: Massive siltstone.

・ Dark grey to black colored, organic rich, pyritized, massive siltstone.

・ Petrographic examination of F-5 confirms that the grains are sub-angular to sub-rounded.

・ The texture of pyrite in F-5 under reflected light microscopy appears as irregularly rounded “clots” that partly coalesce with one another and partly separated by non-reflective dolomite.

・ No sedimentary structures.

・ The upper contact of F-5 with the overlying Doig Formation is reminiscent of erosional lag deposit characterized by a Glossifungites-Trypanites surface.

・ Trace fossils and bioturbation are not present in lithofacies F-5.

・ There are no body fossils pre-served in F-5.

・ The dark grey to black colored, organic carbon content of F-5 is a result of high nutrient rich sediment source and rapid sedimentation, which enhanced the preservation of organic matter.

・ The composition of detrital dolomite in F-5 is interpreted as post-depositional in origin, rather than in-situ.

・ Pyrite in F-5 is related to post-depositional emplacement caused by the dissolution of organic matter due to diagenesis.

・ The deposition of massive siltstone of F-5 may be related to transport and deposition from suspension, principally enhanced by the influence of waves mobilization of sediment by hyperpycnal, or/and clay flocculation mechanisms.

・ Conclusion: Distal offshore (outer shelf) depositional environment to ramp setting.