ABSTRACT

The Early Carboniferous Peace River Embayment, which opened northwestward into Prophet Trough, was a broad, fault-controlled re-entrant into the western cratonic platform. An anomalously thick succession of Lower Carboniferous siliciclastics and ramp-to-platform carbonates was deposited along the embayment's axis, which generally lay slightly north of the Late Devonian Peace River Arch. The Sukunka Uplift, extending southeastward from the western Peace River Embayment, partly restricted the embayment's connection with the Prophet Trough. Embayment development began with late Famennian to early middle Tournaisian blockfaulting during deposition of the Exshaw Formation and overlying Banff Formation. The embayment, clearly differentiated by the late Tournaisian, was probably best developed during deposition of the upper Visean and Serpukhovian Stoddart Group.

The Carboniferous succession records four principal episodes of blockfaulting: 1) after deposition of the upper Famennian Exshaw Formation, 2) during sedimentation of the middle Tournaisian Lower Banff Formation, 3) during and after deposition of the upper Visean Golata Formation, but prior to that of the upper Visean Kiskatinaw Formation, and 4) after deposition of the upper Visean to Serpukhovian Taylor Flat Formation, but prior to the early Permian. The first episode of blockfaulting rejuvinated part of the Peace River Arch and was locally accompanied by deep erosion of the Exshaw, Palliser and Wabamun formations. Throughout the Late Carboniferous, the region was subjected to blockfaulting and deep subaerial erosion.

The succession comprises several second- and third-order, transgressive-regressive sequences: 1) Exshaw Formation, 2) Banff Formation, 3) Pekisko/Shunda succession and correlatives, 4) Debolt Formation and correlatives, 5) Golata Formation, and 6) Taylor Flat Formation, and a

End_Page 177------------------------

third-order transgressive sequence (Kiskatinaw Formation). The greatest water depths were established during deposition of the Lower Banff (early middle Tournaisian) and Upper Pekisko Formation (late Tournaisian). Extensive tidal flats developed during deposition of the Upper Banff, Shunda (late Tournaisian), and Debolt (Visean) formations.

End_of_Record - Last_Page 178-------