Detrital zircon age constraints on basement history on the margins of the northern Rockall Basin
Andrew Morton, Dirk Frei, Martyn Stoker, David Ellis, 2014. "Detrital zircon age constraints on basement history on the margins of the northern Rockall Basin", Hydrocarbon Exploration to Exploitation West of Shetlands, S. J. C. Cannon, D. Ellis
Download citation file:
Detrital zircon dating has proven to be an effective way to constrain ages of submerged basement terranes on the margins of the northern Rockall Basin, a region where direct evidence of crustal affinities is scarce or absent. Zircons have been dated from sandstones of Paleocene–Oligocene age known to have been derived from the east (Hebridean Platform) and west (Rockall and George Bligh highs). The results show that the Hebridean Platform is a westward extension of the Lewisian Complex, with Archaean and Palaeoproterozoic ages that can be directly correlated with events identified in the Outer Hebrides and NW Scotland. The detrital zircons derived from the Hebridean Platform also provide evidence for a Mesoproterozoic thermal event and two phases of intrusions in the Palaeozoic. The Rockall High consists of a Palaeoproterozoic terrane dated as c. 1760–1800 Ma, similar to ages previously determined from both basement samples and detrital sediment. The data also provide evidence for the subsequent intrusion of alkaline igneous rocks in the Paleocene–Eocene. The George Bligh High represents an Archaean terrane heavily affected by Palaeoproterozoic tectonothermal events, and was also the site of intrusion of alkaline igneous rocks during Paleocene time.
Figures & Tables
Hydrocarbon Exploration to Exploitation West of Shetlands
This volume addresses the challenges facing explorers and developers alike in a region that is becoming a major focus of the petroleum industry in the United Kingdom, Faroes and North Norway. Several West of Shetland fields are still in the appraisal phase almost a decade after discovery. Sub-volcanic exploration risks remain high: sub-volcanic structural traps are imaged poorly, and so the geophysical community is responding with the application of latest technology. The more simple reservoirs might not be large enough to prompt informed and speedy development decisions; larger fields might have a combination of complexities, requiring a phased approach to the development. Infrastructure has been slow to arrive and planned developments have been subject to dramatic swings in fiscal regime ranging from special allowances to unexpected tax increases.
Environmental challenges are significant when moving into more remote, deeper water. The perception of these challenges by the third parties has become much more acute. To sustain its right to operate, the industry has to demonstrate safe drilling operations and appropriate response capability with government agencies.