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

Melezhik, V.A., Roberts, D., Fallick, A.E. and Gorokhov, I.M. (2008) The Shuram-Wonoka event recorded in a high-grade metamorphic terrane: insight from the Scandinavian Caledonides. Geological Magazine, 145(2), pp. 161-172. (doi: 10.1017/S0016756807004189)

Abstract

An approximately 250 m thick polydeformed and polymetamorphosed, isotopically unusual, variegated marble (locally termed the ‘Leivset marble’) shows a great lateral extent in the Scandinavian Caledonides. Its extremely ¹³C-depleted primary nature (−7.9±1.2‰ on average, n=93) makes the Leivset marble unique. This, together with a high Sr content (up to 8740 ppm) that buffered 87Sr/86Sr 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 δ¹³Ccarb 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.

• Item Type: Articles
• Keywords: Caledonides; Ediacaran; marble; carbon; strontium; isotopes
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Fallick, Professor Anthony
• Authors: Melezhik, V.A., Roberts, D., Fallick, A.E., and Gorokhov, I.M.
• Subjects: Q Science > QE Geology
• College/School: College of Science and Engineering > Scottish Universities Environmental Research Centre
• Journal Name: Geological Magazine
• ISSN: 0016-7568