Mid‐Weichselian interstadial in Kolari, western Finnish Lapland

TY - JOUR

T1 - Mid‐Weichselian interstadial in Kolari, western Finnish Lapland

AU - Salonen, Veli-Pekka

AU - Moreau, Julien

AU - Hyttinen, Outi

AU - Eskola, Kari O.

PY - 2014/7

Y1 - 2014/7

N2 - Finnish Lapland is known as an area where numerous sites with sediments from Pleistocene glacial and interglacial periods occur. Recent sedimentological observations and dating call for reinterpretation of the record, which shows a complicated Mid-Weichselian ice-sheet evolution within the ice-divide zone. Here, a large, previously unstudied section from a former Hannukainen iron mine was investigated sedimentologically and dated with optically stimulated luminescence (OSL). Ten sedimentary units were identified displaying a variety of depositional environments (glacial, glaciolacustrine, fluvial and aeolian). They are all - except for the lowermost, deeply weathered till - interpreted to be of Mid- or Late Weichselian/Holocene age. Five OSL samples from fluvial sediments give ages ranging from 55 to 35ka, indicating two MIS 3 ice-free intervals of unknown duration. The Mid-Weichselian interstadial was interrupted by a re-advance event, which occurred later than 35ka and caused glaciotectonic deformation, folding and stacking of older sediments. This new evidence emphasizes the importance of the Kolari area when unravelling the complex Late Pleistocene glacial history of northern Finland and adjacent regions.

AB - Finnish Lapland is known as an area where numerous sites with sediments from Pleistocene glacial and interglacial periods occur. Recent sedimentological observations and dating call for reinterpretation of the record, which shows a complicated Mid-Weichselian ice-sheet evolution within the ice-divide zone. Here, a large, previously unstudied section from a former Hannukainen iron mine was investigated sedimentologically and dated with optically stimulated luminescence (OSL). Ten sedimentary units were identified displaying a variety of depositional environments (glacial, glaciolacustrine, fluvial and aeolian). They are all - except for the lowermost, deeply weathered till - interpreted to be of Mid- or Late Weichselian/Holocene age. Five OSL samples from fluvial sediments give ages ranging from 55 to 35ka, indicating two MIS 3 ice-free intervals of unknown duration. The Mid-Weichselian interstadial was interrupted by a re-advance event, which occurred later than 35ka and caused glaciotectonic deformation, folding and stacking of older sediments. This new evidence emphasizes the importance of the Kolari area when unravelling the complex Late Pleistocene glacial history of northern Finland and adjacent regions.

U2 - 10.1111/bor.12060

DO - 10.1111/bor.12060

M3 - Journal article

SN - 0300-9483

VL - 43

SP - 627

EP - 638

JO - Boreas

JF - Boreas

IS - 3

ER -