Evidence for late Neoproterozoic glaciation in the central Scandinavian Caledonides
2011 (English)In: Geological Record of Neoproterozoic Glaciations / [ed] Arnaud, E; Halverson, GP; Shields Zhou, G, Avon: The Geological Society Publishing House, 2011, 623-628 p.Chapter in book (Refereed)
The Langmarkberg Formation (Fm). rests on either the Neoproterozoic rift-related Risback Group or Palaeoproterozoic basement in central Scandinavia. It is always succeeded in stratigraphy by the marine Gardsjon Fm. The Langmarkberg Fm. is a thin, generally less than 50-m-thick, discontinuous, but persistent unit, primarily in the Lower Allochthon; subordinately also in the Autochthon, and Middle Allochthon of the central Scandinavian Caledonides. The formation is composed of a lower diamictite and an upper laminated, lonestone-bearing mudstone. Criteria supporting the glaciogenic origin of the formation are (i) a large regional extension of the formation (>5000 km(2)) and (ii) its fixed position in the regional stratigraphy, (iii) the 'tillite-like' appearance of the lower part of the formation, (iv) the lonestone-bearing mudstone in the upper part, (v) the presence of striated clasts and (vi) striated pavement. It is interpreted as having formed during one single glacial-deglacial cycle. Information on chemostratigraphy and realistic geochronology from this region is missing. The Langmarkberg Fm. has commonly been correlated with the Moelv Fm. in southern Norway and the Mortensnes Fm. in northernmost Norway. The Lower Allochthon in this region also contains an older, potentially glacially influenced diamictite unit at the base of the Risback Group, which is also briefly discussed.
Place, publisher, year, edition, pages
Avon: The Geological Society Publishing House, 2011. 623-628 p.
, Geological Society Memoirs, ISSN 0435-4052 ; 36
IdentifiersURN: urn:nbn:se:su:diva-94459DOI: 10.1144/M36.60ISI: 000300897200060ISBN: 978-1-86239-334-9OAI: oai:DiVA.org:su-94459DiVA: diva2:653590