The strata of the Ski-Lodge Road map-area, near the town of Jasper, Alberta, belong to Walcott's Miette Formation. These strata, which consist of lenticular, interbedded arenaceous and argillaceous units up to 300 feet thick, are probably, Precambrian in age, and correlate lithologically, if not temporally, with the Hector Formation of the Bow Valley and the Horsethief Creek Formation of southeastern British Columbia. Graded bedding and cross-stratification are particularly common in the arenaceous units, which also contain load-casts, flow-casts, penecontemporaneous folds, and ripple marks. Heavy mineral studies of finegrained sandstones show that only the ultra-stable suite of zircon, tourmaline, apatite, and rutile, is present.

The conglomerates and sandstones of the arenaceous units have a composition similar to Pettijohn's feldspathic graywacke, are composed of poorly sorted and angular grains of quartz and feldspar, mica, patchy carbonate cement, and a recrystallized matrix of chlorite and muscovite. Some pebbles are composed of chess-board twinned feldspar. Argillite-fragments are common and sometimes form intraformational argillite-fragment conglomerates. Authigenic pyrite cubes in various stages of weathering are scattered throughout the arenaceous units. The argillaceous units consist of thinly bedded and laminated argillite composed of muscovite, chlorite, and silt- to fine-sand sized quartz.

The mineralogy and texture of the rocks suggest a close, topographically high source consisting of igneous and metamorphic rocks. Deposition was probably rapid in a subsiding deltaic area, with the arenaceous rocks representing the top-set beds, and the argillaceous rocks representing fore-set beds and interdistributary deposits. Cross-stratification studies indicate that the source of the sediments was to the northeast, possibly within the Canadian Shield.

Structural deformation probably occurred during the Laramide orogeny and is reflected by folding, fracturing, and metamorphism of the rocks. Eleven joint-sets, most of which are vein-filled, have been recognized in the arenaceous units. The rocks and the vein material, though having different mineral assemblages, are within the quartz-albite-muscovite-chlorite subfacies of the greenscrist metamorphic morphic facies.

End_of_Record - Last_Page 199-------