| Popis: |
Late Albian rocks of the Upper Viking, Westgate and lower Fish Scales alloformations were deposited about 101-100 Ma in the Western Canada Foreland Basin. Sediments in the study area span the forebulge, and are dominated by mudstone which forms 5-15 m thick, siltier-or sandier-upward sucessions bounded by marine flooding surfaces. Stratification is on a mm scale and represents storm deposits and fluid muds. Viking allomember VD and Westgate allomembers WA, WB and WC all thin towards the E and S and progressively onlap the forebulge. They record relative sea-level rise and gradual drowning and subsidence of the forebulge. In contrast, Fish Scales allomember FA thins to the west because it is erosionally truncated by surface BFSM. Beveling of FA implies contemporaneous uplift and westward migration of the forebulge, which can be linked to an abrupt reorientation, and increase in subsidence rate of the foredeep to the west. |
