Factors affecting the dynamics of the North Karelian/Oulu Ice Lobe, Central Finland, during the last deglaciation – a LiDAR and DEM interpretation of subglacial lineation patterns

Nikarmaa, T.; Lunkka, Juha-Pekka; Putkinen, Niko

doi:10.17741/bgsf/89.2.003

Cited by 4 publications

(3 citation statements)

References 26 publications

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“…Such flow structure has also been reported from the terrestrial periphery (Nikarmaa et al . 2017; Szuman et al . 2021).…”

Section: Discussionmentioning

confidence: 99%

Footprint of the Baltic Ice Stream: geomorphic evidence for shifting ice stream pathways

Greenwood,

Avery,

Gyllencreutz

et al. 2023

Boreas

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The Baltic Ice Stream, a large fast‐flowing sector of the last Fennoscandian Ice Sheet that occupied the present‐day Baltic Sea basin, was first conceptualized in the earliest days of glacial geological research in Scandinavia. Landform and sedimentological evidence from the terrestrial margins support the concept and numerical ice‐sheet models demonstrate its existence and possible evolution. However, with evidence for the Baltic Ice Stream thus far limited to the terrestrial periphery, its true form, scale, function, and role in deglaciation have proven enigmatic. Here we present geomorphological evidence directly from the Baltic seabed that confirms the existence of and sheds light on the behaviour of the Baltic Ice Stream. Based on an extensive collection of high‐, moderate‐ and low‐resolution bathymetric terrain models covering a large proportion of the Baltic Sea floor, and complemented by LiDAR‐data for the Baltic islands, we have identified and mapped >20 000 individual subglacial bedforms, meltwater landforms and grounding line landforms. We reconstruct a six‐stage sequence of ice flow and retreat, finding that streaming was persistent in the Baltic but that pathways were variable in extent, timing and duration: different sectors of the Baltic exhibit asynchronous streaming and out‐of‐phase grounding line changes. During deglaciation, grounding line re‐advances occurred in both the southwestern and the northern Baltic Proper, and, while abundant iceberg ploughmarks attest to calving as a significant ice loss mechanism, lobate margins suggest supply to the Baltic catchment was consistently high. Our reconstruction is limited by a fragmentary geomorphic record. Here we put forward a first hypothesis for how the Baltic Ice Stream evolved, and hope it stimulates new geomorphic, stratigraphical and core data collection to extend the landform record, provide insights into subglacial and grounding line processes, and constrain the chronology for Baltic Ice Stream flow and retreat.

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“…Such flow structure has also been reported from the terrestrial periphery (Nikarmaa et al . 2017; Szuman et al . 2021).…”

Section: Discussionmentioning

confidence: 99%

Footprint of the Baltic Ice Stream: geomorphic evidence for shifting ice stream pathways

Greenwood,

Avery,

Gyllencreutz

et al. 2023

Boreas

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show abstract

“…The ice dome areas of the SIS were situated in the Scandinavian mountain range and six major ice lobes were operating timetransgressively in the eastern flank of the SIS (Boulton et al, 2001). The behaviour of these ice lobes (hosting ice streams) was complex and to date there is only a limited amount of detailed knowledge of how the ice lobes behaved in space and time (Nikarmaa et al, 2017;Putkinen et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Baltic Ice Lake levels and a LiDAR/DEM-based estimate of the glacio-isostatic uplift gradient of the Salpausselkä zone, SE Finland

Lunkka¹,

Nikarmaa²,

Putkinen³

2019

Bull Geol Soc Finland

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Glaciofluvial ice-contact deltas were mapped and altitudes of the highest shorelines defined in the eastern arc of the Salpausselkä zone, southern Finland, using Light Detection and Ranging (LiDAR)-based digital elevation models and GIS tools. Mapping of deltas and the highest shorelines in the Salpausselkä zone were undertaken in order to calculate and define the glacio-isostatic uplift palaeo-isobases, uplift gradients and equidistant diagrams (distance diagrams) for the Salpausselkä zone. The results indicate that the glacio-isostatic uplift palaeo-isobases were orientated NE-SW (50°-230°) and the uplift gradients for both the First and the Second Salpausselkä in the eastern arc, are virtually the same, namely 0.6 mkm-1. This suggests that both Salpausselkä ridge complexes, which were originally laid down in front of the Finnish Lake District Ice Lobe (FLDIL) in relatively shallow water, were deposited within a short time period during the Late Weichselian Younger Dryas Stadial. The results also suggest that the Baltic Ice Lake water level regressed 7.5 metres from Baltic Ice Lake level B I to level B III as the ice retreated in its eastern arc from the First to the Second Salpausselkä.

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“…In the third paper by Nikarmaa et al (2017) authors examine the behaviour and subglacial conditions of the North Karelian/Oulu Ice Lobe with the inversion modelling method. The method is based on the identification and interpretation of mapped glacigenic streamlined lineations that were formed during active ice flow stages.…”

mentioning

confidence: 99%

Editorial: LiDAR – rapid developments in remote sensing of geological features

Ojala¹,

Sarala²

2017

Bull Geol Soc Finland

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Factors affecting the dynamics of the North Karelian/Oulu Ice Lobe, Central Finland, during the last deglaciation – a LiDAR and DEM interpretation of subglacial lineation patterns

Cited by 4 publications

References 26 publications

Footprint of the Baltic Ice Stream: geomorphic evidence for shifting ice stream pathways

Footprint of the Baltic Ice Stream: geomorphic evidence for shifting ice stream pathways

Baltic Ice Lake levels and a LiDAR/DEM-based estimate of the glacio-isostatic uplift gradient of the Salpausselkä zone, SE Finland

Editorial: LiDAR – rapid developments in remote sensing of geological features

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