Facies Associations in Slope-to-Shelf Transition: Precambrian Miette to Lower Cambrian Gog Group, Kicking Horse Pass, Southern Canadian Rocky Mountains: ABSTRACT

Abstract

In the eastern Kicking Horse Pass, Miette sediments consist of End_Page 580------------------------------ feldspathic, chaotic conglomerate/slate mixtures associated with graded-stratified conglomerates, dispersed and massive pebbly sandstones, and sandstone turbidites. Paleocurrents are toward the north-northwest. Conformably overlying these beds are quartzose cross-stratified sandstones (possibly Gog Group) consisting of facies: (1) trough cross-stratified conglomerate and sandstone; (2) graded swaley-or-hummocky cross-stratified conglomerate; and (3) isolated trough cross-stratified sandstone sets in shale. Paleocurrents are toward the east-southeast. Miette beds were deposited on a slope, possibly within a submarine canyon. These beds record deposition near a shelf break, possibly with storm influence. In the western Kicking Horse Pass, quartzose Gog sediments belong to Facies 1-3, and (4) small-scale trough cross-stratified quartzite; (5) planar cross-stratified quartzite; (6) very low angle to horizontally stratified quartzite; and (7) shale. Absence of desiccation features and abundance of horizontal trace fossils suggest a shallow, sublittoral marine setting. Overall cyclicity consists of the following units upsection: (a) Facies 1, 3, 4, and 7 with unidirectional west-southwesterly paleoflows; (b) Facies 5 with bimodal paleoflows; (c) Facies 1, 4, and 3 with unidirectional westerly paleoflows; (d) large scale epsilon cross-stratified quartzites; and (e) Facies 6 with bimodal to random paleoflows. This sequence may represent shoaling-up from offshore dune and bar complexes with alternating oceanic current (sequences a and c) or tidal (sequence b) influence. Above are lateral accretion deposits due to migration of a spit or ridge (sequence d), topped by high energy nearshore deposits (sequence e). Paleoflow patterns are complex, suggesting that sediment dispersal was not simply a westerly prograding clastic wedge. End_of_Article - Last_Page 581------------