Ordovician to Silurian magmatism on the Utsira High, North Sea: implications for correlations between the onshore and offshore
Caledonides
A. M. Lundmark
T. Sæther
R. Sørlie
10.6084/m9.figshare.3453599.v1
https://geolsoc.figshare.com/articles/dataset/Ordovician_to_Silurian_magmatism_on_the_Utsira_High_North_Sea_implications_for_correlations_between_the_onshore_and_offshore___Caledonides/3453599
<p>The age and tectonic significance of two basement granitoids cored on the Utsira High, Viking Graben, North Sea, are constrained
by zircon LA-ICPMS data. Syenite in well 25/10-2R is dated to 482±2 Ma, with εHf<sub>(482)</sub> values from −4.4 to −5.8, and granite in well 16/1-12 yields an age of 436±3 Ma with εHf<sub>(436)</sub> values from +3.7 to −0.5. The evolved Hf-signature of the syenite demonstrates 482 Ma reworking of Palaeoproterozoic–Archaean
crust, interpreted to reflect Taconian–Grampian orogenesis. New and recently published data from the offshore Caledonides
allow a first-order correlation of the Utsira High basement with the surrounding on- and offshore Caledonides. The Utsira
High occupies a similar position with respect to Dalradian rocks as the Scottish Midland Valley terrane. Geophysical data
indicate a volcanic arc beneath the East Shetland Basin, forming a northwards continuation of the Utsira High basement. We
propose that the offshore volcanic arc segments represent the northeastern continuation of the Scottish Grampian orogen across
the Mesozoic North Sea rift. A north-striking terrane boundary fault is proposed to separate the volcanic arc from the East
Shetland Platform and merge northwards with the offshore extension of the Great Glen Fault–Møre Trøndelag Fault Complex.
</p>
2016-06-21 11:32:33
Scottish Midland Valley terrane
Utsira High
Scottish Grampian orogen
482 Ma reworking
basement granitoids cored
Caledonide
East Shetland Platform
arc
Mesozoic North Sea rift
continuation
East Shetland Basin
data
Hf
northward
North Sea
Utsira High basement
Fault
correlation
Geology