Deglaciation chronology and glaciomarine successions in the Malangen‐Målselv area, northern Norway

Abstract

The deglaciation history of the Malangen‐Målselv fjord and valley area proximally to the Tromsø‐Lyngen (Younger Dryas) moraine at Bakkejord, Malangen, northern Norway, is reconstructed based on morphostratigraphic, lithostratigraphic and geophysical evidence, and 25 radiocarbon dates from marine shells and foraminifera. The results show that following the Skarpnes event c. 12 200 14Cyr BP, and prior to the Younger Dryas readvance, the area was deglaciated at least as far as Sandmo situated 22 km proximally to the Tromsø‐Lyngen moraine. Two moraine ridges crossing the fjord at Sandmo and buried beneath thick glaciomarine sediments are correlated with this period. The area was subsequently deglaciated between 10 300 and 9200 14Cyr BP, following the Tromsø‐Lyngen (Younger Dryas) readvance. Five ice‐front accumulations post‐dating the Tromsø‐Lyngen moraine and situated 19, 27, 42, 55 and 77 km behind it are identified and dated based on radiocarbon dates and correlation of marine limits: Målsnes (c. 10 050 14Cyr BP), Kjerresnes (c. 10 000 14Cyr BP), Solli (c. 9750 14Cyr BP), Bardufoss‐Brentmoen‐Storskogmoen (c. 9600–9700 14Cyr BP) and Alapmoen (c. 9200 Cyr BP). The largest of these, at Bardufoss‐Storskogmoen, possibly accumulated as a response to an ice advance. Fourteen dates of apparent late Allerød/Younger Dryas age (11 100–10 000 14Cyr BP), obtained from fossils in glaciomarine sediments in the Målselv valley up to 77 km proximally to the Tromsø‐Lyngen moraine, are interpreted as postdating rather than predating this moraine. Several of these are considered to be too old because of uncertain reservoir age, carbon‐dating plateaus and/or contamination. This highlights uncertainties associated with radiocarbon‐dating and the profound effect such uncertainties may have on interpreting geological events.

Vegetation and climatec. 12 300–9000 cal. yr BP at Andøya, NW Norway

“… Survey of the micro‐fossil and macro‐fossil zones of the YD–early Holocene period at northern Andøya, with suggested climate characteristics. Sea surface temperatures are according to Ebbesen & Hald (2004): (a) and Hald et al (2007) (b) Marginal moraine stages from Målselv are according to Eilertsen et al (2005, 2006) and from Lyngen–Storfjord according to Corner (1980). The YD/PB limit (left column) is according to Björck et al (1996).…”

“…100 km east of Andøya, one marginal moraine stage indicates that the glacier retreated on land and deposited marginal moraines during a likely re‐advance 11 100–10 800 cal. yr BP (Eilertsen et al 2005, 2006), which is probably contemporaneous with the Stordal/Ørnes event. Rapid retreat of the fjord glaciers to grounded glaciers during late YD and early Preboreal indicates in itself a climatic amelioration.…”

“…10 400–10 300 cal. yr BP (Eilertsen et al 2005). Although thought to be due to topography, this moraine stage correlates well with the Cryptogramma crispa peak of PAZ 3 (Fig.…”

The last Eurasian ice sheets – a chronological database and time‐slice reconstruction, DATED‐1

“…(), Dzierżek & Zreda (), Eilertsen et al . (), Elverhøi et al . (, ,b), Elverhøi & Solheim (), Engstrand & Östlund (), Engstrand (, ), Evans et al .…”

Forced regressive deposits of a deglaciation sequence: Example from the Late Quaternary succession in the Lake Saint‐Jean basin (Québec, Canada)

“…Identified either from fluvio‐deltaic (e.g. Sala & Long, ; Hart & Long, ; Hansen, ; Eilertsen et al ., , ) or coastal (e.g. Boulton, ; Fraser et al ., ) deposits, comparable successions are widely investigated.…”