Early Neoproterozoic (Tonian) subduction-related magmatism and tectonothermal activity in Shetland and northern mainland Scotland: implications for the tectonic evolution of northeast Laurentia, and Rodinia reconstructions ...

• Main Authors: Kinny, P. D., Strachan, R. A., Fowler, M. B., Bruand, E., Millar, I. L., Hand, M., Clark, C., Cutts, K. A.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Geological Society of London 2024
• Subjects: Geology; FOS: Earth and related environmental sciences; East Greenland; Ellesmere Island; Greenland; North Atlantic; Svalbard
• Online Access: https://dx.doi.org/10.6084/m9.figshare.c.7405471.v1; https://geolsoc.figshare.com/collections/Early_Neoproterozoic_Tonian_subduction-related_magmatism_and_tectonothermal_activity_in_Shetland_and_northern_mainland_Scotland_implications_for_the_tectonic_evolution_of_northeast_Laurentia_and_Rodinia_reconstructions/7405471/1

Abstract: The tectonic setting of Tonian orogenic events recorded in the present-day circum-North Atlantic region is uncertain. U–Pb zircon geochronology shows that the Yell Sound and Westings groups (Shetland) and metasedimentary rocks of the Naver Nappe (northern mainland Scotland) were deposited between c. 1050–960 Ma and intruded by mafic, intermediate and felsic igneous rocks at c. 965–950 Ma. Chemical discrimination diagrams and Hf and Nd isotope data together suggest that the protoliths of the mafic meta-igneous rocks were emplaced as relatively juvenile crustal contributions in an active plate margin. Zircon growth at c. 920 Ma within the Yell Sound Group correlates with high-grade metamorphism documented previously in Shetland. Further zircon growth and Pb-loss at c. 470–460 Ma indicates overprinting during the Ordovician Grampian orogenic event. Similar age successions of Ellesmere Island, Svalbard and East Greenland also contain evidence for Tonian magmatism (some calc-alkaline), deformation and ...