Continental-scale transport of sediments by the Baltic Ice Stream elucidated by coupled grain size and Nd provenance analyses
|Author(s)||Boswell Steven1, 2, Toucanne Samuel3, Creyts Timothy T.1, Hemming Sidney R.1, 2|
|Affiliation(s)||1 : Lamont Doherty Earth Observ, Palisades, NY USA.
2 : Columbia Univ, Dept Earth & Environm Sci, New York, NY 10025 USA.
3 : Inst Francais Rech Exploitat Mer IFREMER, Unite Rech Geosci Marines, Issy Les Moulineaux, France.
|Source||Earth And Planetary Science Letters (0012-821X) (Elsevier Science Bv), 2018-05 , Vol. 490 , P. 143-150|
|WOS© Times Cited||5|
|Keyword(s)||Fennoscandian Ice Sheet, Baltic Ice Stream, provenance, epsilon Nd, grain size, EMMA|
We introduce a methodology for determining the transport distance of subglacially comminuted and entrained sediments. We pilot this method on sediments from the terminal margin of the Baltic Ice Stream, the largest ice stream of the Fennoscandian Ice Sheet during the Last Glacial Maximum. A strong correlation (R2 = 0.83) between the εNd and latitudes of circum-Baltic river sediments enables us to use εNd as a calibrated measure of distance. The proportion of subglacially transported sediments in a sample is estimated from grain size ratios in the silt fraction (<63 μm). Coupled εNd and grain size analyses reveal a common erosion source for the Baltic Ice Stream sediments located near the Åland sill, more than 850 km upstream from the terminal moraines. This result is in agreement with both numerical modeling and geomorphological investigations of Fennoscandinavian erosion, and is consistent with rapid ice flow into the Baltic basins prior to the Last Glacial Maximum. The methodology introduced here could be used to infer the distances of glacigenic sediment transport from Late Pleistocene and earlier glaciations.