{'fraction_non_alphanumeric': 0.03821196827685652, 'fraction_numerical': 0.023071377072819033, 'mean_word_length': 4.957081545064377, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Long continuous dendritic eskers offshore of Southampton Island, northern Hudson Bay

Eskers are long and sinuous ridges of glacifluvial sand and gravel formed subglacially or englacially in meltwater tunnels (e.g. Brennand 2000; Storrar et al. 2014). Eskers have been mapped in many formerly glaciated regions of Canada (e.g. Prest et al. 1968; Lajeunesse 2008; Storrar et al. 2014). They reveal pathways of meltwater drainage underneath the Laurentide Ice Sheet. The original geomorphology of eskers observed on land in air photos and satellite images is generally never perfectly preserved due to erosion by postglacial sub-aerial processes or to partial flooding in lakes and ponds. For this reason, eskers commonly emerge to form discontinuous ridges. Multibeam-bathymetric data collected in South Bay, Southampton Island (northern Hudson Bay; Fig. 1a–d) reveal remarkably well-preserved esker systems. The pristine state of preservation of these eskers is attributed to: (1) their occurrence in a subaqueous environment, where glacial landforms are generally better preserved than in a terrestrial setting (Ottesen & Dowdeswell 2006); and (2) the weak seafloor currents and low sedimentation rates that have prevailed in South Bay since deglaciation (Josenhans et al. 1988).



 Fig. 1. 
Long dendritic eskers in South Bay, Southampton Island, northern Hudson Bay. ( a ) Location …