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SUMMARY Alternative alluvial and deltaic depositional models for the topmost Scarborough and Scalby Formation are outlined. Biostratigraphical and sedimentological arguments are used to deduce that a lengthy time gap of around 9.0 m.y. existed between deposition of the shallow marine Scarborough Formation (middle Bajocian) and the fluvial Moor Grit Member of the Scalby Formation (? upper Bathonian). This rules out acceptance of the deltaic model for the successions and is taken to indicate that much of the Yorkshire Basin was uplifted or became positive during late Bajocian/Bathonian times. Uplift may have been linked to rift-related processes acting in the North Sea basin, especially on the Pennine/Mid-North Sea High which acted as the hinterland and sediment source area for the Scalby alluvium.

An exhumed Jurassic meander belt from Yorkshire, England M. NAMI Summary. Three-dimensional coastal exposures of the Middle Jurassic (Bathonian) Scalby Formation in Yorkshire, England, exhibit a complex, exhumed meander belt. The lateral accretion surfaces (epsilon-cross stratification) of individual meander loops are described. Field and aerial photograph measurements of accretion-surface dimensions have enabled direct determination of channel bankful depths and widths and meander wavelengths. Values for mean annual discharge of the channel system are derived using existing empirical equations. Palaeocurrents measured in the meander belt sandstones show a wide dispersal due to many periods of meander migration and cut off.

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