Resumé
The geology of the Faeroe Plateau north and northwest of Scotland is described. New morphological and petrological results are provided.
The Faeroe lava pile exceeds 5 kilometres in thickness. It was poured onto a continental platform slightly before the opening of the NE Atlantic ocean floor in lower Tertiary. The 3.5 kilometre subarial sequence of the Faeroes ranges from olivine tholeiites to tholeiites and includes lavas both rich and depleted in large ionic radii lithophile (LIL) elements. Systematic changes through the pile in chemistry of the LIL-element rich tholeiites reflect steady changes in the P-T-chemical conditions of magma formation. Similar subarial basalts occur on the banks to the southwest (Faeroe Bank, Bill Bailey Bank and Lousy Bank) and among dredged erratics. However, the proportion of LIL-element poor tholeiites probably increases towards the outer oceanic edges of the.plateau. The eruption area seems gradually to have been restricted to the Faeroe Block.
In the waning phase of volcanism the plateau was probably sub merged and a "Moberg" series was produced by submarine eruptions. Dome and basin formation took place on the Faeroe Block before the end of minor intrusive activity. During continental break-up at the end of Paleocene the Faeroe Plateau was disintegrated by crustal thinning and subsidence, and the Faeroe-Shetland, Faeroe Bank Channel system was formed. Erosion began - and reworked ashes were deposited in basins on the outer Faeroe shelf - and the plateau was probably peneplaned in the lower Tertiary. The Faeroe Block was further uplifted and eroded in late Tertiary, possibly Pliocene time, and most of the block was repeately glaciated in Plio-Pleistocene time. Roughly one kilometre of sediments was deposited in the adjoining channels in the lower Tertiary, while 0-1.5 kilometres were deposited by vigorous Norwegian Sea overflow in the upper Tertiary.
The Faeroe lava pile exceeds 5 kilometres in thickness. It was poured onto a continental platform slightly before the opening of the NE Atlantic ocean floor in lower Tertiary. The 3.5 kilometre subarial sequence of the Faeroes ranges from olivine tholeiites to tholeiites and includes lavas both rich and depleted in large ionic radii lithophile (LIL) elements. Systematic changes through the pile in chemistry of the LIL-element rich tholeiites reflect steady changes in the P-T-chemical conditions of magma formation. Similar subarial basalts occur on the banks to the southwest (Faeroe Bank, Bill Bailey Bank and Lousy Bank) and among dredged erratics. However, the proportion of LIL-element poor tholeiites probably increases towards the outer oceanic edges of the.plateau. The eruption area seems gradually to have been restricted to the Faeroe Block.
In the waning phase of volcanism the plateau was probably sub merged and a "Moberg" series was produced by submarine eruptions. Dome and basin formation took place on the Faeroe Block before the end of minor intrusive activity. During continental break-up at the end of Paleocene the Faeroe Plateau was disintegrated by crustal thinning and subsidence, and the Faeroe-Shetland, Faeroe Bank Channel system was formed. Erosion began - and reworked ashes were deposited in basins on the outer Faeroe shelf - and the plateau was probably peneplaned in the lower Tertiary. The Faeroe Block was further uplifted and eroded in late Tertiary, possibly Pliocene time, and most of the block was repeately glaciated in Plio-Pleistocene time. Roughly one kilometre of sediments was deposited in the adjoining channels in the lower Tertiary, while 0-1.5 kilometres were deposited by vigorous Norwegian Sea overflow in the upper Tertiary.
Originalsprog | Engelsk |
---|---|
Udgivelsessted | Copenhagen |
Forlag | DGU |
Antal sider | 269 |
DOI | |
Status | Udgivet - 25 okt. 1977 |
Emneord
- Faroe Islands
Programområde
- Programområde 3: Energiressourcer