Field observations of Mars analogue subglacial drainage systems in Kangerlussuaq - Greenland ice sheet western margin.

Abstract

Glacial erosion on Mars, and specifically the presence and role of basal meltwater on glacial processes, is a matter of long-standing debate. Whereas observations of glacial landforms related to warm-based glaciation exist both for early Mars (e.g., the Dorsa Argentea ridges) as well as for Amazonian Mars (esker ridges in Phlegra Montes), the inventory of glacial landforms seems to be largely limited to that of subglacial drainage. Here we present results from an analogue study comparing interlinked subglacial cavity systems located on the central-western portion of the Greenland Ice Sheet (GIS), specifically in the region around Kangerlussuaq, with potential subglacial interlinked cavities identified on Batson crater, located northeast of the Hellas basin on Mars. The GIS near Kangerlussuaq is known for subglacial drainage systems consisting on meltwater-filled cavities on a hard bed (Harper et al., 2017), which may become interconnected following episodes of increased discharge. Episodes of connectivity following high pressure subglacial meltwater events may lead to enhanced sliding followed by channelization, and emplacement of subglacial floods (Harper et al., 2017).We present preliminary field and remote sensing observations describing the morphology, topology, organization, and other field characteristics of recently exposed elements of the glacial hydrology system in this analogue site, which were emplaced by the western margin of the GIS. Our field site is located by the Europlanet Transnational Access TA1 Facility 4: Greenland-Kangerlussaq, which offers a unique opportunity to study the subglacial drainage patterns in this region (Carrivick et al., 2016). Few regions in the world offer the opportunity to study recently emplaced, well exposed subglacial morphologies at the level of accessibility of this site. Field data includes in situ-imagery, observations of glacial sliding directions, description of sedimentary deposits, morphology, scale and characteristics of subglacial cavities, and nature of the connection passages. Data acquired in the field is complimented with remote sensing data from the ArcticDEM and Maxar imagery. We then discuss the morphology and geometry of observed interconnected subglacial cavities to morphologically and topologically similar systems located at the Batson crater site on Mars (Grau Galofre et al., 2024), and present a morphometric comparison as well as a qualitative description of similarities and differences with the terrestrial analogue site. We finally discuss the implications for the presence of subglacial interconnected drainage patterns on Mars, and the lessons learned from the Kangerlussuaq analogues to derive identification guidelines, which can assist the community in identifying this somewhat obscure subglacial landforms.