Krüger's Final Camp in Arctic Canada?

On 3 July 1999, John England, Art Dyke, and undergraduate student Michelle Laurie were surveying raised marine shorelines on Axel Heiberg Island halfway between Cape Southwest and the mouth of Surprise Fiord. During this work, they discovered a site with objects that appeared to be "of considerable antiquity." ... Only the compass and the transit were collected for preservation and identification. Protruding through the surface sand was evidence of additional material, including what appeared to be tent canvas, as well as printed material and a shirt (or long underwear) with label of German origin. ... As both England and Dyke are well acquainted with the history of Arctic exploration, they began to consider who might have left the instrument, and under what circumstances, given its evident value. ... The abandoned samples clearly identified the site as a geological camp. The abandonment of specimens would be consistent with a team in some difficulty. ... The 1999 find described here now provides the best evidence concerning the probable fate of Hans Krüger and his team. The German label on the partially buried clothing, the fragment that appears to be tent canvas, the old-style canister, the small pile of rock samples, and most significantly, the evidence gleaned from the small transit, point to new evidence concerning this 70-year-old Arctic mystery. Why would one abandon such easily transported and important possessions that would constitute the very heart of the scientific expedition? The overriding impression that one is left with at this sparse site is its abandonment under duress. The fact that so few provisions remained, and that the tent itself many have been destroyed, suggests that the camp may have suffered a late spring snowstorm that buried what remained, and the explorers had no time or energy left to excavate it before escaping eastward. Regardless, if the site is Krüger's, then his team made it several hundred kilometres farther back on their return journey than was previously thought. Sadly, Krüger's fiancé and mother never had conclusive evidence of their loss, and their anguish is revealed in letters sent to Krüger via the RCMP in 1931, now preserved in the Library and Archives Canada. His fiancé never married and tragically committed suicide in 1946. We hope that the planned archeological survey of the subsurface and the snow-filled gullies adjacent to the site will help clarify what we have presented here, further confirming that this is Krüger's final camp. Since scientific surveys, including ours, have been so widely conducted along the coastlines to the east that lead into and through Eureka Sound, it is unlikely that any subsequent camp will be found

Geological controls on the geometry of incised-valley fills: Insights from a global dataset of late-Quaternary examples

Incised valleys that develop due to relative sea-level change are common features of continental shelves and coastal plains. Assessment of the factors that control the geometry of incised-valley fills has hitherto largely relied on conceptual, experimental or numerical models, else has been grounded on case studies of individual depositional systems. Here, a database-driven statistical analysis of 151 late-Quaternary incised-valley fills has been performed, the aim being to investigate the geological controls on their geometry. Results of this analysis have been interpreted with consideration of the role of different processes in determining the geometry of incised-valley fills through their effect on the degree and rate of river incision, and on river size and mobility. The studied incised-valley fills developed along active margins are thicker and wider, on average, than those along passive margins, suggesting that tectonic setting exerts a control on the geometry of incised-valley fills, likely through effects on relative sea-level change and river behaviour, and in relation to distinct characteristics of basin physiography, water discharge and modes of sediment delivery. Valley-fill geometry is positively correlated with the associated drainage-basin size, confirming the dominant role of water discharge. Climate is also inferred to exert a potential control on valley-fill dimensions, possibly through modulations of temperature, peak precipitation, vegetation and permafrost, which would in turn affect water discharge, rates of sediment supply and valley-margin stability. Shelves with slope breaks that are currently deeper than 120 m contain incised-valley fills that are thicker and wider, on average, than those hosted on shelves with breaks shallower than 120 m. No correlation exists between valley-fill thickness and present-day coastal-prism convexity, which is measured as the difference in gradient between lower coastal plains and inner shelves. These findings challenge some concepts embedded in sequence stratigraphic thinking, and have significant implications for analysis and improved understanding of source-to-sink sediment route-ways, and for attempting predictions of the occurrence and characteristics of hydrocarbon reservoirs

An updated radiocarbon-based ice margin chronology for the last deglaciation of the North American Ice Sheet Complex

The North American Ice Sheet Complex (NAISC; consisting of the Laurentide, Cordilleran and Innuitian ice sheets) was the largest ice mass to repeatedly grow and decay in the Northern Hemisphere during the Quaternary. Understanding its pattern of retreat following the Last Glacial Maximum is critical for studying many facets of the Late Quaternary, including ice sheet behaviour, the evolution of Holocene landscapes, sea level, atmospheric circulation, and the peopling of the Americas. Currently, the most up-to-date and authoritative margin chronology for the entire ice sheet complex is featured in two publications (Geological Survey of Canada Open File 1574 [Dyke et al., 2003]; ‘Quaternary Glaciations – Extent and Chronology, Part II’ [Dyke, 2004]). These often-cited datasets track ice margin recession in 36 time slices spanning 18 ka to 1 ka (all ages in uncalibrated radiocarbon years) using a combination of geomorphology, stratigraphy and radiocarbon dating. However, by virtue of being over 15 years old, the ice margin chronology requires updating to reflect new work and important revisions. This paper updates the aforementioned 36 ice margin maps to reflect new data from regional studies. We also update the original radiocarbon dataset from the 2003/2004 papers with 1541 new ages to reflect work up to and including 2018. A major revision is made to the 18 ka ice margin, where Banks and Eglinton islands (once considered to be glacial refugia) are now shown to be fully glaciated. Our updated 18 ka ice sheet increased in areal extent from 17.81 to 18.37 million km2, which is an increase of 3.1% in spatial coverage of the NAISC at that time. Elsewhere, we also summarize, region-by-region, significant changes to the deglaciation sequence. This paper integrates new information provided by regional experts and radiocarbon data into the deglaciation sequence while maintaining consistency with the original ice margin positions of Dyke et al. (2003) and Dyke (2004) where new information is lacking; this is a pragmatic solution to satisfy the needs of a Quaternary research community that requires up-to-date knowledge of the pattern of ice margin recession of what was once the world’s largest ice mass. The 36 updated isochrones are available in PDF and shapefile format, together with a spreadsheet of the expanded radiocarbon dataset (n = 5195 ages) and estimates of uncertainty for each interval

Bird remains from the Maastrichtian type area (Late Cretaceous)

Remains of Late Cretaceous birds are rare, which is especially true for Europe and the type area of the Maastrichtian Stage (southeast Netherlands, northeast Belgium) in particular. In the present paper, we record new remains (isolated tarsometatarsus and radius) that document the presence of both enantiornithine and ornithurine birds in the Maastrichtian area. These fossils, although fragmentary, are important in view of their stratigraphic age: all bird remains discovered to date in the Maastricht area are amongst the youngest ‘non-modern’ avians known, originating from strata deposited less than 500,000 years prior to the end of the Cretaceous Period

Dynamics of the North American Ice Sheet complex during its inception and build-up to the Last Glacial Maximum

The North American Ice Sheet Complex played a major role in global sea level fluctuations during the Late Quaternary but our knowledge of its dynamics is based mostly on its demise from the Last Glacial Maximum (LGM), a period characterised by non-linear behaviour in the form of punctuated ice margin recession, episodic ice streaming and major shifts in the location of ice divides. In comparison, knowledge of the pre-LGM ice complex is poorly constrained, largely because of the fragmentary nature of the evidence relating to ice sheet build-up. In this paper, we explore the inception and growth of ice (120–20 ka) using a glacial systems model which has been calibrated against a large and diverse set of data relating to the deglacial interval. We make use of calibration data prior to the LGM but its scarcity introduces greater uncertainty, which is partly alleviated by our large ensemble analysis. Results suggest that, following the last interglaciation (Oxygen Isotope Stage: OIS 5e), the ice complex initiated over the north-eastern Canadian Arctic and in the Cordillera within a few thousand years. It then underwent rapid growth to an OIS 5 maximum at ∼110 ka (5d) and covered ∼70% of the area occupied by the LGM ice cover (although only 30% by volume). An OIS 5 minimum is modelled at ∼80 ka (5a), before a second phase of rapid growth at the start of OIS 4, which culminated in a large ice complex at ∼65 ka (almost as large as at the LGM). Subsequent deglaciation was rapid (maximum modelled sea level contribution of >16 cm per century) and resulted in an OIS 3 minimum between ca 55–60 ka. Thereafter, the ice complex grew towards its LGM configuration, interrupted by several phases of successively less significant mass loss. Our results support and extend previous inferences based on geological evidence and reinforce the notion of a highly dynamic pre-LGM ice complex (e.g. with episodes of ±10 s m of eustatic sea level equivalent in 50%, but even the thin OIS 5 ice sheets exhibit fast flow features (several 1000 m a−1) in major topographic troughs. Notwithstanding the severe limitations imposed by the use of the ‘shallow-ice approximation’, we note that most fast flow-features generated prior to the LGM correspond to the location of ‘known’ ice streams during deglaciation, i.e. in major topographic troughs and over soft sediments at the southern and western margins. Moreover, the modelled flux of these ‘ice streams’ (sensu lato), appears to be non-linearly scaled to ice sheet volume, i.e. there is no evidence that decay phases were associated with significantly increased ice stream activity. This hypothesis requires testing using a model with higher-order physics and future modelling would also benefit from additional pre-LGM constraints (e.g. dated ice free/margin positions) to help reduce and quantify uncertainties