Abstract Heavy mineral assemblages in deepwater Paleocene sandstones of the Foinaven Sub-basin (west of Shetland) reflect the influence of three main provenance and dispersal systems. The Schiehallion system has relatively uniform characteristics and persisted through much of the early-mid Paleocene. Its sphere of influence was centred on the Schiehallion Field, but it progressively encroached into the Foinaven area with time. Its main source was the Triassic Foula Formation, with minor supply from Lewisian and Moine basement rocks. The Foinaven system shows marked changes in character, related to evolution of the source area. The earliest sands were derived from a heavily weathered late Cretaceous regolith, and represent the onset of uplift and exhumation of the Shetland Platform. Progressive unroofing led to the incorporation of increasing amounts of Lewisian- and Moine-sourced detritus. Following deposition of the main reservoir sandstones in Foinaven and Schiehallion, there was a progressive change in provenance, with a gradual increase in the amount of sediment shed directly from metamorphic basement. Pulsing of the proto-Icelandic plume has been proposed as the mechanism for repeated influx of sand to the basins around Scotland. However, on the basis of available geochronological data, there does not appear to be a direct link between events in the British Tertiary Igneous Province (BTIP) and changes in provenance in the Foinaven Sub-basin. The initial influx of sediment from a weathered land surface may have been coeval with the onset of magmatism in the BTIP, but the cessation of supply through the Foinaven system at c. 59 Ma does not appear to be related to magmatic events in the BTIP. The waning of magmatism in the BTIP around 58 Ma is broadly coincident with a gradual increase of first-cycle basement detritus.

Abstract Miospores demonstrate that the Walls Group of West Shetland is of early and possibly in part late Givetian age (Late Mid-Devonian age). This is both substantially younger in age and of a shorter duration than previously estimated. The correlative rocks of the Walls Group are those of southeast Shetland, Fair Isle, the Eday Group of Orkney and the John O'Groats Sandstone Group of Caithness. The two formations of the Walls Group are, at least in part, time equivalent rather than a stacked sequence. The total thickness of sediment is likely to be much less than the generally cited 12 km, given the short time duration represented by the single miospore assemblage identified throughout the succession. The low diversity of the miospore assemblage and its fluctuating dominant species is interpreted as reflecting a local vegetation source in a low preservation environment. The age and thermal maturity contrast between the Walls Group and the sedimentary successions to the west (Melby, Papa Stour and Foula) provide further constraints on the movement history along the St Magnus Bay Fault system.