The Shuram-Wonoka event recorded in a high-grade metamorphic terrane: Insight from the Scandinavian Caledonides

An approximately 250 in thick polydeformed and polymetamorphosed, isotopically unusual, variegated marble (locally termed the 'Leivset marble') shows a great lateral extent in the Scandinavian Caledonides. Its extremely C-13-depleted primary nature (-7.9 +/- 1.2 parts per thousand on average, n = 93) makes the Leivset marble unique. This, together with a high Sr content (up to 8740 ppm) that buffered Sr-87/Sr-86 ratios between 0.70802 and 0.70872, suggests correlation with the worldwide Shuram-Wonoka isotopic event occurring within the 600-550 Ma time interval during the Ediacaran (Vendian) period. Despite a high-grade deformation and metamorphism, the Leivset marble has retained its original carbon and strontium isotope ratios. A combination of the variegated colour with unusually low delta C-13(carb) can potentially be used for stratigraphic correlations in high-grade, non-fossiliferous, marble-dominated terranes across the Caledonian orogenic belt in Baltica and Laurentia. Isotope chemostratigraphy has identified a prominent cryptic stratigraphic discontinuity and suggests that the Ediacaran Leivset marble was tectonically juxtaposed above low-grade, Llandovery-age, fossiliferous marbles during the Scandian orogeny.