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Structural glaciological maps can be used to study the structural evolution and past dynamics of glaciers. The map described here documents the glacier-wide structural characteristics of Austre Brøggerbreen, ac. 12 km2predominantly cold-based valley glacier in northwest Svalbard. The structural map reveals that the glacier is dominated by deep-penetrating fractures that are now relict (crevasse traces). These structures indicate that, despite being relatively inactive at present, the glacier was once much more dynamic, presumably during its last advance in the Neoglacial (c. 1900 AD). Contemporary glacier structures (i.e. those that are actively forming) include primary stratification, longitudinal foliation and rare surface fracturing (crevasses and water-healed crevasses). Relict fracture sets become increasingly re-orientated and folded down-glacier as a result of ductile flow. Individual flow units show large differences in the evolution of structures, indicating that the flow units have been subject to different flow histories and dynamics. The map will also be useful for future change-detection studies on this rapidly receding glacier. [ABSTRACT FROM PUBLISHER]

Roberson, S., Hubbard, B., Coulson, H. and Boomer, I. Physical properties and formation of flutes at a polythermal valley glacier: Midre Lovénbreen, Svalbard. Geografika Annaler: Series A, Physical Geography, 93, 71–88. DOI: 10.1111/j.1468‐0459.2011.00420.x Flutes are widespread across the forefield of a polythermal valley glacier Midre Lovénbreen, Svalbard, where they consistently form on the downglacier face of cobble to boulder‐sized subglacially‐transported clasts ploughed into proglacial till. The width of flutes at Midre Lovénbreen is constant along their long‐axes and proportional to the size of their associated subglacially‐transported boulders. Frozen flutes are observed subglacially where they protrude into the debris‐rich basal ice layer of the glacier. Particle‐size analysis shows that flutes are depleted in gravel‐sized particles relative to adjacent subglacial till. Ice sampled from flutes is enriched in δ18O relative to overlying glacier ice and debris‐rich basal ice. These properties are interpreted to reflect the formation of flutes by the squeezing of till into basal cavities associated with boulders beneath warm‐based ice in the interior of the glacier. It is hypothesized that localized freeze‐on of flute sediments, within a broader zone of warm‐based ice, occurs within cavities due to either (i) a 'heat‐pump' effect operating across these boulders leading to the development of a cold patch within the cavity, and/or (ii) fluctuations in cavity length caused by slip‐stick glacial motion. Once incorporated into the basal ice layer, the frozen flute sediment would then be transported away from the boulder by ice flow, allowing the cavity to remain continuously open and the flute to propagate downflow. [ABSTRACT FROM AUTHOR]

The diversity of highly active bacterial communities in cryoconite holes on three Arctic glaciers in Svalbard was investigated using terminal restriction fragment length polymorphism (T-RFLP) of the 16S rRNA locus. Construction and sequencing of clone libraries allowed several members of these communities to be identified, with Proteobacteria being the dominant one, followed by Cyanobacteria and Bacteroidetes. T-RFLP data revealed significantly different communities in holes on the (cold) valley glacier Austre Brøggerbreen relative to two adjacent (polythermal) valley glaciers, Midtre Lovénbreen and Vestre Brøggerbreen. These population compositions correlate with differences in organic matter content, temperature and the metabolic activity of microbial communities concerned. No within-glacier spatial patterns were observed in the communities identified over the 2-year period and with the 1 km-spaced sampling. We infer that surface hydrology is an important factor in the development of cryoconite bacterial communities. [ABSTRACT FROM AUTHOR]

The article discusses the study which evaluates the technique of Digital optical televiewing (OPTV) of the hot-water-drilled boreholes englacial ice and debris structures in the terminus region of midre Lovénbreen, Svalbard, Norway. It notes that the resulting OPTV logs successfully reveal several visually distinctive englacial ice properties and deformation structures It adds that the combination of the OPTV logs with surface mapping result in the identification of eight separate structural elements can be interpolated into grids with sediment layers intercalated in primary stratification.