The majority of Orkney’s Sedimentary Rocks are Middle Devonian in age – Eifelian and Givetian. Upper part of Hoy and Upper Eday Sands edge into the Upper Devonian Frasnian. Although indeterminate the Harra Ebb Formation at the base of the Orcadian sequence may well be Lower Devonian Emsian in age. the Yesnaby Sandstone could be late Emsian early Eifelian.
During the Devonian Period, North America and Northern Europe were joined together forming Euramerica, one of the three major continental masses on the Devonian globe, with Orkney placed south of the equator. Most of Britain formed part of this landmass with mountains in the northwest and the open marine Devonian Sea covering southwest England.
The age of the Orkney dykes is 252+/-10 million years, placing the time of intrusion in the late Permian, a period of renewed tectonic movement in the sedimentary basins to the west of Orkney.
The Petroleum System consists of four main Geologic components, source, reservoir, seal and trap plus additional processes necessary to generate and store hydrocarbons in the subsurface. Their presence is required to generate a viable EXPLORATION TARGET.
At the opening of the Tertiary chalk sedimentation continued on the northern North Sea. Starting around 63 Ma, the East Shetland Platform was uplifted and tilted towards the south-east. ...
The Quaternary deposits found on the East Shetland Platform are thin (Johnson et al., 1993). The Quaternary thickens above the Viking Graben to as much as 300m and provides a long and relatively detailed record of glaciation.
Rifting in the Northern North Sea commenced during the early Triassic, peaked during the late Jurassic, and terminated by the late Cretaceous. The Viking Graben can be seen as a failed arm of proto-Atlantic rift. Almost throughout this period, the Shetland area formed an area of positive relief.