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Upper Devonian-Lower Mississippian siliciclastic miogeoclinal strata in the southern Canadian Rocky Mountains provide a partial record of the geographic and tectonic setting of the Paleozoic western margin. Although these marine strata (Exshaw and lower Banff formations) contain extensive shale and mudstone, and some quartzofeldspathic sandstone and siltstone, as well as volcanic ash layers, the provenance of these clastic units has, thus far, remained poorly or incompletely understood. The integration of sandstone petrofacies analysis with neodymium isotopic and trace-element (rare earth element, Th, and Sc) analyses of mudrock facies was undertaken in this study to constrain better the sedimentary provenance.Coarse siltstones and sandstones in the Exshaw and Banff formations are chiefly subfeldspathic and feldspathic (quartzose-arkosic) arenites, with a complex sedimentary history involving derivation, at least in part, from an uplifted plutonic and volcanic source, such as possible western ''Antler'' orogenic highlands. The presence of monocrystalline quartz (inclusionless and with unit extinction) and sanidine in Exshaw sandstones at some sections suggests at least a partial acidic volcanic or shallow intrusive source component. The Exshaw and Banff petrofacies reflect the possible combined effects of regional tectonic complexity (different and/or mixed source terranes), sediment transport and recycling, complex sediment dispersal paths, and weathering and diagenesis. Mudrock elemental and isotope geochemistry also support a provenance involving potentially multiple sources (mixed provenance). Chondrite-normalized REE distribution patterns and La-Th-Sc ratios for Exshaw and Banff mudrocks resemble patterns for sediments derived from old continental crust (e.g., passive margins, etc.) as well as some arc settings. Nd isotopic compositions of the Exshaw and Banff formations do not support a specific provenance, but they are consistent with addition of material younger than Archean in age.

Uppermost Devonian – lowermost Carboniferous strata in the southernmost Canadian Cordillera and adjacent Montana record the onset and termination of low-oxygen conditions in carbonate-dominated epicontinental and shelf seas. Several distinct conodont biofacies representative of shallow-ramp to deep-basin settings are recognized on the basis of conodont distribution and preservation patterns.During early and middle Famennian time, the region was the site of a westward-deepening carbonate ramp (Palliser Formation) that was bordered to the west by a deep, shale basin (Lussier syncline strata). Palliser carbonates contain low-diversity conodont faunas of indigenous to transported Palmatolepis-, Polygnathus-, and Apatognathus-dominated assemblages. Basinal deposits yield a pelagic palmatolepid biofacies. Middle to late Famennian time was marked by termination of carbonateramp sedimentation and flooding of the margin with oxygen-depleted water. Deposition of organic-rich facies began in the expansa Zone in shelf to basin environments (Exshaw Formation and correlative units). These deposits contain indigenous pelagic Palmatolepis- and (or) Bispathodus-dominated assemblages; reworked or transported fragments are primarily polygnathids and icriodontids.Sedimentation of anaerobic to aerobic, deep-water, lower Banff facies occurred intermittently until middle Tournaisian and, locally, late Tournaisian time prior to westward progradation of younger carbonate deposits. Middle Tournaisian biofacies include transported and indigenous assemblages of siphonodellids (deep–middle ramp). Late Tournaisian biofacies parallel lithofacies changes associated with shallowing of the Banff sequence and are characterized by scaliognathid–doliognathid (basin to deep ramp), polygnathid and polygnathid–bactrognathid (deep to middle ramp), and bactrognathid–hindeodid (middle to shallow ramp) indigenous and displaced biofacies. The spatial relations of these Famennian and Tournaisian biofacies are generally consistent with models developed for correlative strata elsewhere.

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