Fine-grained quartz from cryoconite holes of the Russell Glacier, southwest Greenland – a scanning electron microscopy study

Abstract

The western ablation zone of the Greenland ice sheet is darker than the surrounding ice, because a higher amount of fine-grained particles, known as a cryoconite, occur. To date, biotic cryoconite components have gained a lot of attention, in contrast with mineral components, which have been studied to a limited extent. In this study, fine-grained quartz grains from the cryoconite holes of the Russell Glacier, southwest Greenland are, therefore, examined. Authors use scanning electron microscope to elucidate shape, surface character and origin of these mineral quartz particles. Triangular-faceted, sharp-edged grains dominate in most of the investigated samples, and originate from local sources, where grain-to-grain contact in the ice prevail. Grains with smooth corners and edges result from chemical weathering in meltwater of alkaline pH, in which quartz solubility significantly increases. However, part of these rounded grains is due to mechanical abrasion by wind action. Postsedimentary frost action is visible through grains entirely or partially covered by scaly-grained encrustation. Local processes and sources are largely responsible for aforementioned grain outlines. However, few grains with bulbous silica precipitation argue for a dry and warm climate, and distant, out-of-Greenland origin.

Spheroidal carbonaceous particles in cryoconite sediment on the Russell glacier, Southwest Greenland

“…Wientjes et al (2011) found that inorganic mineral material or dust in the GrIS is of local origin, i.e., from the outcropping dust in the ice-free area next to the ice margin. Similar findings were brought by the Kalińska-Nartiša et al (2017) who showed that fine-grained quartz particles in cryoconite holes on the Russell glacier are mostly of local origin, although few originate from distant sources, where dry and warm climate prevail. As the climate warms, the transport of dust from snow-free areas in the Arctic that are experiencing earlier melting of seasonal snow is a contributing source of cryoconite (Stibal et al 2012;Dumont et al 2014).…”

Mūsdienu ledāji

“…Ar atlūzām pārklātā ledāja sānu daļa (attēla vidusdaļā) pietuvinājumā redzama nākamajā attēlā. Foto: K. Lamsters, 2017. reti pārsniedz 1 km 2 . Kā novērots Tjanšanā, kur akmeņu ledājiem kopumā raksturīgas salīdzinoši lielākas dimensijas un ātrums, ledāja virsas kustības ātrums ir tikai daži centimetri līdz 10 m gadā.…”

“…Kalińska-Nartiša et al, 2017) daudzveidīgo smilts graudu izcelsmi un pārvietošanas aģentus: ledāju, ūdens straumes, vēju. Dažiem graudiem atrastas pazīmes, kas liecina par to tālo izcelsmi Zemes tuksnešos.…”

High-Resolution Surface and Bed Topography Mapping of Russell Glacier (Sw Greenland) Using Uav and GPR

“…This marginal part of the glacier is particularly dark and rich in cryoconite material (e.g. Kalińska-Nartiša et al, 2017a;Stivrins et al, 2018) that is a major contributor to the darkening of the west GIS as well. Proglacial streams flowing from the Russell Glacier create the Sandflugtdalen valley-sandur, which is a large source for wind-transported dust (Kalińska-Nartiša et al, 2017b).…”