Faint traces of high Arctic glaciations: an early Holocene ice‐front fluctuation in Bolterdalen, Svalbard

Abstract

Lønne, I. 2005 (August): Faint traces of high Arctic glaciations: an early Holocene ice-front fluctuation in Bolterdalen, Svalbard. Boreas, Vol. 34, Raised marine beach gravel at 62 m a.s.l. in Bolterdalen indicates that the inner part of Adventfjorden, central Spitsbergen, was ice-free shortly before 10 025+160 yr BP. A glacier advanced across the regressive, frozen beach terraces and into shallow water, 58 m above the present sea level, where a small wave-influenced icecontact delta was formed, 9775+125 yr BP. Maximum ice-front position was reached 9625+95 yr BP, 7 km outside the present ice margin. The advance was climatically forced and of several decades' duration, as seen from abundant molluscs growing in the prograding foreset beds. Today, the beaches appear as a continuous regressive sequence with no geomorphic evidence of the former ice margin. Sedimentological studies show, however, that a thin (1 m) deformation till was emplaced, the substrate was subglacially sheared to a depth of 1 m, and elongated clasts in the beach gravel were reoriented in an ice-flow parallel direction. The glacial deposits and structures, formed within 200 m from the ice front, highlight some important aspects of subglacial to ice-marginal processes in permafrost terrain. As the dead ice melted, the released debris was redistributed into thin sediment sheets down to 40 m a.s.l., which means that the postglacial meltwater-controlled reworking lasted c. 500 years. Similar isolated depocentra may be a key for future identifications of former ice margins at high latitudes.

200 ka of glacial events in NW Svalbard: an emergence cycle facies model and regional correlations

“…[2]) from an extended valley glacier, or possibly a tributary to a fjord glacier. This local ice-flow signature is similar to what has been noted for other sites on Svalbard, particularly on the west coast [10,63,[69][70][71][72] and has been assumed to reflect a predominantly low-activity, possibly even frozen-bed ice-sheet cover over these inter-fjord areas [2].…”

Svalbard glaciers re‐advanced during the Pleistocene–Holocene transition

“…Additionally, shoreline studies from north central Spitsbergen partly constrain LGEH glacial deposits for several catchments (Fig. Lønne (2005) links this advance to a regional climatic Andersson et al 1999Andersson et al , 2000. More recently, stratigraphical sections near Longyearbyen ( Fig.…”

“…And in this model, a mid-fjord tributary like Bolterdalen (Lønne 2005) may have re-advanced at some point in between the timing of the other two glaciers' re-advances. Thus, a re-advance located near the mouth of the fjord (i.e.…”

“…In a review of the deglaciation of Svalbard, Hormes et al (2013) suggested that one of the key research questions still remaining is whether there is any evidence of YD climatic cooling seen in Svalbard. Additionally, a couple of early Holocene glacier re-advances (following deglaciation) have been inferred from stratigraphical data of geological sections (Lønne 2005) or lake sediments (van der Bilt et al 2015). Additionally, a couple of early Holocene glacier re-advances (following deglaciation) have been inferred from stratigraphical data of geological sections (Lønne 2005) or lake sediments (van der Bilt et al 2015).…”

“…ka BP(Salvigsen et al 1990;Lønne 2005). Glacier deposits labelled A-F corresponding to the T abreen, Albertbreen, Lyckholmdalen, Flowerbreen, Heftybreen and Richterbreen glaciers/valleys, respectively.…”