The role of wave reworking on the architecture of storm sandstone facies, Bell Island Group (Lower Ordovician), eastern Newfoundland

摘要: Stacked shallow marine cycles in the Lower Ordovician, Bell Island Group, of Island, Newfoundland, show upward thickening and coarsening sequences which were deposited on a storm-affected shelf. In Beach Formation each cycle has facies sequence comprised, from base to top, dark grey mudstones, light tabular sandstones lenticular thick bedded sandstones, reflecting progressive increase wave orbital velocities at sediment surface. The mudstones reflect an environment sea floor lay lower part velocity field tempestites as widespread sheets weak combined flow currents. succeeding are reworked sands, commonly lying erosional hollows having tops internal hummocky cross-stratification. Planar lamination is relatively uncommon sole marks mainly absent. this oscillatory currents dominant accumulated sand patches generally 10–30 m diameter. formed inner shelf where generated by storm waves had powerful effects also determined depositional bedforms. Mud partings second-order set boundaries within sandstone beds believed separate products individual storms so that many represent amalgamation several event beds. This interpretation important implications for attempts estimate frequency counting estimates budgets during events. The appears have been erosion mud between leading nearly complete bodies except residual partings. In overlying Redmans process progressed even further all removed, resulting formation sandstones. Sequence stratigraphic analysis cyclical suggests eustatically controlled. rising limb level curve produced only mudstone while remainder was falling limb. There gradational but rapid transition interpreted occurring inflexion point periods maximum fall. The stacked aggradational, high or parasequence bounded top boundary succeeded three aggradational parasequences Formation. The recognition with very different bed length reservoir modelling such facies.