Tectonomagmatic evolution of the Early Ordovician suprasubduction-zone ophiolites of the Trondheim Region, Mid-Norwegian Caledonides
Published:January 01, 2014
Trond Slagstad, Christian Pin, David Roberts, Christopher L. Kirkland, Tor Grenne, Greg Dunning, Simone Sauer, Tom Andersen, 2014. "Tectonomagmatic evolution of the Early Ordovician suprasubduction-zone ophiolites of the Trondheim Region, Mid-Norwegian Caledonides", New Perspectives on the Caledonides of Scandinavia and Related Areas, F. Corfu, D. Gasser, D. M. Chew
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The Trondheim Region ophiolites in the Mid-Norwegian Caledonides represent variably tectonized ophiolite fragments. We present high-precision thermal-ionization mass spectrometry and secondary-ion mass spectrometry (SIMS) U–Pb zircon dates, whole-rock geochemical and Sm–Nd data and Lu–Hf zircon analyses that permit the timing and nature of various stages in the evolution of the ophiolite to be elucidated. Plagiogranite intrusions dated at 487 and 480 Ma have relatively juvenile Nd and Hf isotopic compositions (ɛNd(t)=6.3, ɛHf(t)=8.2–12.4). Geochemical data indicate a subduction-zone influence, suggesting formation in an oceanic back-arc setting. At 481 Ma, a granitoid body...
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New Perspectives on the Caledonides of Scandinavia and Related Areas
The Caledonides are a major orogenic belt that stretches from the Arctic, through Scandinavia, East Greenland, Britain and Ireland into the Atlantic coast of North America. Following the break-up of Rodinia, the Caledonides formed in the Palaeozoic by the drifting of various continents and their eventual aggregation in the Silurian and Devonian. The orogen subsequently fragmented during the opening of the Atlantic Ocean. This volume brings together 25 papers presenting the results of modern research that investigates the orogenic processes and the provenance of specific components of the belt. The contributions reflect different lines of research, linking traditional field studies with modern analytical techniques. In addition three overview papers summarize the main features of the belts in Scandinavia, Svalbard, East Greenland, Britain and Ireland, highlighting the advances made since the last major synthesis of the Scandinavian Caledonides 30 years ago, and discussing important open questions.