Neoproterozoic glaciation of South Norway: from continental interior to rift and pericratonic basins in western Baltica
Johan P. Nystuen, Jarkko T. Lamminen, 2011. "Neoproterozoic glaciation of South Norway: from continental interior to rift and pericratonic basins in western Baltica", The Geological Record of Neoproterozoic Glaciations, Emmanuelle Arnaud, Galen P. Halverson, Graham Shields-Zhou
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Neoproterozoic glacial deposits of South Norway comprise the Moelv and Koppang formations. The former occurs on Baltican crystalline basement in autochthonous position at the Caledonian erosional nappe front, on basement windows and basement thrust sheets in the Caledonian nappe region, and in thick sedimentary successions in the allochthonous Hedmark and Valdres rift basins. The Koppang Formation (Fm.) occurs on top of platform carbonates in the allochthonous pericratonic Engerdalen Basin. The glacial deposits are dominated by diamictite interpreted as basal till from warm-based grounded ice, whereas stratified successions of diamictite beds, sandstone and laminated siltstone with outsized stones represent local ice-margin deposits and/or subglacially infilled water bodies, and the final glaciomarine stage. Palinspastic reconstruction of Caledonian nappe complexes carrying the glacial formations indicates that the glacial deposits were deposited over a wide area by a large western Baltoscandian ice sheet, probably during the Gaskiers (c. 580 Ma) glacial event (or events), but the age of the glaciation in South Norway needs to be better constrained.
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In recent years, interest in Neoproterozoic glaciations has grown as their pivotal role in Earth system evolution has become increasingly clear. One of the main goals of the IGCP Project No. 512 was to produce a synthesis of newly available information on Neoproterozoic successions worldwide similar in format to Hambrey & Harland’s (1981) Earth’s pre-Pleistocene Glacial Record. This Memoir therefore consists of a series of overview chapters followed by site-specific chapters. The overview chapters cover key topics including the history of research on Neoproterozoic glaciations, identification of glacial deposits, chemostratigraphic techniques and datasets, palaeomagnetism, biostratigraphy, geochronology and climate modelling. The site specific chapters for 60 successions worldwide include reviews of the history of research on these rocks and up-to-date syntheses of the structural framework, tectonic setting, palaeomagnetic and geochronological constraints, physical, biological, and chemical stratigraphy, and descriptions of the glaciogenic and associated strata, including economic deposits.