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 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.
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.
This work is licensed under a Creative Commons License. You are welcome to copy material from this site for non-commercial use provided that you acknowledge its source or link to this site. Some material here, both text and photos, is not our own and this cannot be copied without the permission of its intellectual property owner.