The Retreat of the North American Ice Sheet and Shifts in Cyclone Tracks

The alternating retreats and readvances of the North American ice sheet from 18,000 years to 6000 years ago are attributed to shifts in storm tracks. According to the author's theory, proglacial lakes formed during the retreat of the ice sheet became the paths of cyclone tracks whose precipitation led to an accumulation of ice and a readvance of the ice sheet. The readvance into the proglacial lake basins resulted in a reduction or southward shift of cyclone tracks, and this in turn led to a halt of the readvance and a retreat of the ice sheet. As soon as the ice had vacated the Great Lakes basin, the cyclone tracks would once again shift northward and the process of readvance would start all over again.     

A late Devensian Nunatak on the Knoydart peninsula,NW Scotland: Implications for ice‐sheet reconstruction

Geomorphological mapping and analysis of soil mineralogy indicates that all summits on the Knoydart Peninsula were over‐ridden by the last ice sheet apart from Ladhar Bheinn (1020 m), where the ice attained a maximum altitude of c. 950 m. This figure is consistent with evidence from adjacent areas and suggests that the last ice sheet descended westwards across Knoydart from c. 1000 m to c. 900 at the west coast, implying that most theoretically‐based ice‐sheet models are substantially in error in this area.     

Landscapes at the Periphery of Glacierization – Retrospect and Prospect

This paper reviews the evolution of palaeoglaciological reconstructions in regions at the periphery of glacierization, where an improved understanding of the role of glacial thermal regime has helped refine the delimitation of ice sheet maxima. Also significant has been the recognition in numerical models that some areas, especially ice sheet marginal zones, are subject to short periods of ice occupancy and hence that glacial landsystem signatures can be extremely subtle. This is compounded wherever cold-based conditions dominate during early stages of ice sheet recession, giving rise to a landform imprint typical of peripheral regions and hence often misinterpreted as unglaciated or glaciated only by older glaciations. Subtle landform imprints include meltwater channels, thin glacigenic veneers or scattered erratics and modified tors. More substantial glacigenic landform-sediment assemblages (‘drift belts’) do not always represent ice sheet maxima but instead may record significant changes in thermal regime, possibly linked to periods of ice-marginal stabilization. Some upland areas that lie beyond the traditionally demarcated limits of glaciation (e.g. Dartmoor in SW England) may contain subtle evidence of satellite ice cap development which has been overlooked due to the strong periglacial landform signature.     

Changes in the Ice Boundary of the Vestfold Hills,East Antarctica, 1947 to 1990

The position of the ice boundary around the Vestfold Hills, East Antarctica (68°30'S, 78°00'E) was observed using a 43 year record of aerial photography from 1947 to 1990. The southern boundary, formed by Sørsdal Glacier, showed two main areas of ice retreat and no areas of advance. Stagnation and retreat of this boundary is interpreted to be contraction to former limits following the Chelnok Glaciation which occurred 7lt; 700 years BP. The eastern or continental ice sheet boundary showed five sites of rapid, localised incision and downwasting around supraglacial gullies. While no area of continental ice was noted to advance, continued accumulation and firnification of wind-drifted snow in the proglacial zone of the ice sheet in the southeastern corner of the hills may signify a locally positive ice mass balance. Until ice mass balance studies are carried out in the ablation zone surrounding the hills, evidence concerning whether the ice sheet boundary is retreating, stable or advancing will remain equivocal.     

Practical surveying in schools

Analysis of detailed geomorphological mapping enables a sequence of glacial events to be established. An ice sheet whose source was to the west of the area of study is shown, by the suites of fluvioglacial landforms produced, to have down‐wasted in situ; meltwaters escaped beneath or through the ice, moving uphill across certain areas. Finally, a sub‐aerial drainage system was established and outwash terraces were spread down valley.     

Reactive transport and thermo‐hydro‐mechanical coupling in deep sedimentary basins affected by glaciation cycles: model development,verification, and illustrative example

Deep sedimentary basins are complex systems that over long time scales may be affected by numerous interacting processes including groundwater flow, heat and mass transport, water–rock interactions, and mechanical loads induced by ice sheets. Understanding the interactions among these processes is important for the evaluation of the hydrodynamic and geochemical stability of geological CO₂ disposal sites and is equally relevant to the safety evaluation of deep geologic repositories for nuclear waste. We present a reactive transport formulation coupled to thermo‐hydrodynamic and simplified mechanical processes. The formulation determines solution density and ion activities for ionic strengths ranging from freshwater to dense brines based on solution composition and simultaneously accounts for the hydro‐mechanical effects caused by long‐term surface loading during a glaciation cycle. The formulation was implemented into the existing MIN3P reactive transport code (MIN3P‐THCm) and was used to illustrate the processes occurring in a two‐dimensional cross section of a sedimentary basin subjected to a simplified glaciation scenario consisting of a single cycle of ice‐sheet advance and retreat over a time period of 32 500 years. Although the sedimentary basin simulation is illustrative in nature, it captures the key geological features of deep Paleozoic sedimentary basins in North America, including interbedded sandstones, shales, evaporites, and carbonates in the presence of dense brines. Simulated fluid pressures are shown to increase in low hydraulic conductivity units during ice‐sheet advance due to hydro‐mechanical coupling. During the period of deglaciation, Darcy velocities increase in the shallow aquifers and to a lesser extent in deeper high‐hydraulic conductivity units (e.g., sandstones) as a result of the infiltration of glacial meltwater below the warm‐based ice sheet. Dedolomitization is predicted to be the most widespread geochemical process, focused near the freshwater/brine interface. For the illustrative sedimentary basin, the results suggest a high degree of hydrodynamic and geochemical stability.     

The last glaciers in part of the South East Grampians

In an area of 400 sq km in the south east Grampians including Glen Esk, Glen Clova and part of Glen Muick the limits of former corrie glaciers, valley glaciers and a plateau ice‐cap with associated outlet glaciers have been mapped. The limits of the former corrie and valley glaciers are often clearly defined by end moraines, boulder‐strewn ground, the down‐valley termination of hummocky moraines and/or the limits of meltwater channel systems, while in suitable locations outwash terraces usually occur. The glaciers are considered to have formed during the Loch Lomond (pollen zone III) Readvance, when new glaciers developed in upland sources following complete ice‐sheet decay. The readvance was accompanied in granite areas by the formation of large solifluction lobes, these lobes being found only outside the mapped ice limits. The interpretations presented are not in accord with those recently given by D. E. Sugden for the western Cairngorms.     

Remarks on the Retreat of the North American Ice Sheet

A reply by two North American geographers to the preceding article presents some recent results of North American studies and suggests that the role of water bodies in influencing cyclogenesis is not universal. The Black Sea is cited as an example of a large water body that does not act as a major source of cyclonic activity. Other arguments are presented questioning the significance of the large proglacial lakes in influencing storm tracks near the margin of the ice sheet.     

Would North American Paleoindians have Noticed Younger Dryas Age Climate Changes?

Paleoindian groups occupied North America throughout the Younger Dryas Chronozone. It is often assumed that cooling temperatures during this interval, and the impact these would have had on biotic communities, posed significant adaptive challenges to those groups. That assessment of the nature, severity and abruptness of Younger Dryas changes is largely based on ice core records from the Greenland ice sheet where changes were indeed dramatic. This paper reviews climatic and environmental records from this time period in continental North America. We conclude that, on the Great Plains and in the Rocky Mountains, conditions were in reality less extreme. It therefore follows that conditions during the Younger Dryas interval may not have measurably added to the challenge routinely faced by Paleoindian groups who, during this interval, successfully (and perhaps rapidly) dispersed across the diverse habitats of Late Glacial North America.     

The other cold war: the United States and Greenland’s ice sheet environment, 1948–1966

During the early Cold War, no part of the Arctic was as important to the United States’ strategic interests as Greenland: situated on the shortest straight-line route between the industrial centers of the two superpowers, Greenland was integral to North American continental security. The US desire to control Greenland, however, was complicated by the island’s isolated geography, harsh climate and barren landscape. Between 1948 and 1966, US forces in Greenland were entrenched in the ‘other cold war’: the struggle with the ice sheet environment which threatened to impede American capabilities in the region. This paper explores the ‘other cold war’ through two case studies: US scientific efforts to understand and cope with polar whiteouts and the plastic deformation of ice. These case studies illuminate a struggle between two philosophical approaches to nature: a brash, aggressive approach which aimed to conquer the Greenland environment, and a more nuanced approach which aimed to collaborate with that environment. I show that the second approach won out as Greenland’s exceptional geography and environment forced the US military to reassess its relationship with nature: rather than striving for control over the island space, US military personnel ultimately chose strategic cooperation with that space.     

Science in Antarctica Intellectual and Physical Adventure

Abstract

Antarctica is a geographical region and Antarctic science is therefore multidisciplinary, the main areas of research being concerned with the continent's geological base, the superimposed ice-cap, the atmosphere above it and their external relationship. Each of these research areas is interdisciplinary: the study of its outstanding problem – the history of the Antarctic ice sheet – requires contributions from meteorology, oceanography, glaciology, geology, chemistry and physics; and its future behaviour will he determined by external events, including the consumption of fossil fuels on other continents. Research in Antarctica is given added piquancy by the continent's unique environment and rigorous climate which retain their attractive character even though modern technological developments have removed many elements of discomfort and danger. The region is also singular in its political nature and scientist have a particularly close relationship with their governments through the Antarctic Treaty.     

Age and sedimentological features of fluvial series in the Toruń Basin and the Drwęca Valley (Poland)

The deposits of the Toruń Basin are dominated by a few-metre thick sand series which fill up buried valley-like depressions. In many cases they underlie the Weichselian till which builds up the ice marginal streamway (pradolina) terraces or they are exposed at the basin slopes. As the results of the geological and sedimentological studies, as well as of the dating of the deposits at the sites in the Toruń Basin indicate, the deposits include two fluvial series accumulated before the advancement of the Leszno Phase ice sheet, i.e. in Middle Weichselian and at the beginning of Late Weichselian. The oldest fluvial series connected with the Saalian Glaciation was found at the mouth section of the Drwęca Valley. The fluvial system of the Toruń Basin during Middle Weichselian and at the beginning of Late Weichselian developed in two phases of the sand-bed braided river. During the first one the river channel were dominated by large mid-riverbed sandbars, while during the second phase the water flow was smaller and, as a result, low transverse sandbars and two-dimensional dunes developed. Other active river channel also showed low-energy flows, more intensive meandering than in the case of the braided rivers, as well as sandy side-bars. Analysis of the rounding and frosting of the quartz grains indicate that the studied series of the Weichselian sandy deposits represent alluvia of a river which were fed from two diverse sources. The first one might have represented the alluvia of a warm river which transformed its load, while the other one might have mainly carried the underlying Quaternary deposits.     

Causes and Factors of Ground-Ice Formation

The concept of ground ice is expanded to cover all forms of ice formed at the interface between two environments—the solid state and the gaseous. Ground ice is thus defined as the product of the layer-by-layer freezing of liquid water or droplets of any origin as it passes from a zone of positive temperatures into a zone below the freezing point. Ground ice may be produced by subsurface waters (springs and groundwater), surface waters (river, lake, sea, glacier and snow meltwater) and atmospheric moisture (glaze, rime, hail). [The definition excludes ice formed within the solid-state environment of the lithosphere (segregated ice, cement ice, injection ice).] Ground ice produced by subsurface waters may be formed at the surface or in large subterranean cavities, and it may be associated with the natural discharge of water or with the freezing of aquifers. Ground ice produced by surface waters may be associated with an increase of water volume in a waterbody as the level of the ice cover remains stable; with a constriction of the discharge cross section, and with changes in heat and moisture exchange. Ground ice derived from atmospheric moisture is formed either on terrestrial objects (glaze, rime) or in the free atmosphere (hail, ice formed on aircraft).     

The IGY and the ice sheet: surveying Antarctica

This paper considers the significance of the International Geophysical Year (IGY) for the development of new knowledge of the shape of the Antarctic bed surface and the ice sheet that covers it. It also situates the Antarctic geophysical work done during the IGY within a longer history that begins in the immediate post-WWII period and extends up to the 1970s. The paper pays particular attention to the US IGY seismic traverses, which were the centrepiece of US IGY activities in Antarctica. We argue that these traverses should be understood as part of a broader set of geopolitical, military and governmental strategies that the USA pursued through the IGY and afterwards. In this sense we agree with other students of Cold War science who suggest that the IGY was far from being the beginning of the end for geopolitics in Antarctica. Instead we demonstrate that US scientific activities in Antarctica during the IGY and after were a form of geopolitics in themselves.     

南极旅游开发与设想

本文提出,随着我国南极长城站和中山站的建立、以及"极地号"和"雪龙号"破冰船的购置,更由于人民生活水平的逐步提高,我国开发南极旅游的时机已经到来。本文认为与低层次的物质享受相比,南极旅游更有助于促进国民素质提高和全国主义、国际主义精神的培养。本文对南极旅游资源作了评价.划分出南极半岛等4个旅游区。本文构思了我国未来南极旅游组织实施的规划和设想,提出可先开辟南极半岛旅游区和环南极旅行两条旅游线路,沿途可开展海外观光、远洋考察和远洋捕捞业,以促进我国旅游业、南大洋考察和远洋捕捞运输业的全面发展。     

黑龙江省冰雪旅游开发战略AHP决策分析

运用AHP层次分析法,对黑龙江省的冰雪旅游开发战略进行了定性与定量相结合的分析,并得出结论:黑龙江省应该首先实行冰雪旅游产业化战略目标,同时不可忽视冰雪旅游国际化战略目标;而争创品牌战略是第一重要的发展战略;当前亟待解决的首要问题是思想观念不够开放、经济欠发达和管理体制较落后,应该采取的措施是加大体制改革力度、根本改变"多头管理、政令不一"的现状,借鉴国内外冰雪旅游开发成功经验,大力发展滑雪旅游等。通过这些具体措施,可以确保实现"提高黑龙江省冰雪旅游的综合竞争力,把黑龙江省建设成为中国最大、世界知名的冰雪旅游胜地"的总体目标。     

Late Glacial Origin of the Sandbanks, Webb Bay, Labrador

The Sandbanks of Webb Bay, Labrador owe their origin to ice marginal conditions during the last stages of deglaciation of this section of the Labrador coast. Several phases in their evolution are recognized. Phase 1 was characterized by disintegration of the remnants of Webb Bay and Ado's Brook valley ice masses into separate local bodies with ice marginal runoff in an eastern direction. During Phase 2 the first and highest ice-dammed lake formed. Eastward ice marginal flow continued into Phase 3, when a large system of kame terraces (altitude 360 feet) formed beside the receding Webb Bay Ice. They led to new and lower ice marginal lakes in the eastern part of the Sandbanks. Phase 4 was dominated by the construction of a more extensive system of kame terraces almost 100 feet lower than those formed in Phase 3. Locally, minor moraines helped to direct runoff and control development of these newer kame terraces. In Phase 5, meltwater from the ice and runoff from the deglaciated highlands filled a large marginal lake (altitude 230 feet), which may have contributed to subglacial drainage down Port Manvers Run. Phase 6, the last of the glacial conditions associated with formation of the Sandbanks, was introduced by withdrawal of ice far enough so that the eustatically rising sea level was able to reach part of the Sandbanks. A terrace at 135 feet above sea level is believed to be the local upper marine limit. Stagnant ice still covered the floor of Hummock Valley at the western end of the Sandbanks at this time. Subsequently isostatic adjustment has lifted the last glacio-fluvial and some of the glacio-marine features above sea level.     

PALEOGEOGRAPHY,TOPONYMY AND ETHNOGENESIS

An attempt is made by a Lithuanian physical geographer to combine the findings of paleogeography and place-name studies in shedding light on the time and place of the original settlement of the Indo-European peoples. The author also suggests that plausible elements in folk legend are susceptible to paleogeographic analysis, and he illustrates the point by relating Lithuanian folk legends about the origin of lakes to known thermokarstic processes giving rise to cave-in lakes. On the basis of a paleogeographic analysis of Lithuanian place names resembling the name Dunojus (Danube), the author suggests that the name of the Danube River is derived from an Indo-European root word such as duna, signifying an inlet or estuary of Late Pleistocene waterbodies with a sandy, dunelike shoreline. The vocabulary of Indo-European languages relating to features in the natural environment is used in establishing the time and location of the settlement of Indo-European peoples. On the basis of correspondences for tree names in the various Indo-European languages, the author concludes that the original Indo-European proto-ethnos sought refuge in the Pomeranian substage of the Late Pleistocene (about 20,000 years ago) in the mountain caves of central Europe. With the retreat of the ice sheet, the original Indo-Europeans began to migrate northward, and it was in the new areas of settlement in the plains of northern Europe that the Germanic, Slavic and Baltic branches of the Indo-Europeans were formed.     

Osteometric scoring of adult residual rickets skeletal plasticity in two archaeological populations from southeastern England: Relationship to sunshine and calcium deficits and demographic stress

An osteometric scoring technique is developed for the quantification of rickets deformational effects persisting in the healed adult skeleton. Termed RR-15 scoring (for residual rickets estimate, based on 15 main diagnostic osteometric traits), the method is first validated for sunshine deficit, and is then tested in a comparison of three climatically distinct archaeological populations from southeastern England. Two well-dated cemetery series were sampled: the Saint Bride's Church columbarium collection (SBC) from London at the time of the Industrial Revolution, for which the sex, age, and calender year at death of each individual are known; and the early Anglo-Saxons from Abingdon, near Oxford (AAS). Estimates of insolation in the past were developed indirectly by reference to δ¹⁸O mass spectrometer analyses of dated layers of the Greenland ice sheet. In SBC and AAS, the RR-15 score varies primarily as a direct function of computed sunshine deficit, but is also incremented by deficits of bioavailable calcium in their reconstructed diets, and by demographic stress in AAS, the inferred result of a high birth rate. The amounts of interglobular dentine present in the permanent first and third molar crowns of SBC and AAS have been shown to correlate similarly with sunshine and calcium deficits. The relatively high RR-15 score obtained in a small sample of northwestern European neanderthals lends quantitative support to the bioenvironmental hypothesis that sunshine-deficit rickets accounts for much of their paranormal gross morphology.     

Model tuning and its impact on modelled climate change response: Hudson Bay sea ice, a case study

The impact of climate model parameterization is examined using Hudson Bay sea ice as a case study. The implicit diffusion of an upstream scheme used in a three dimensional ocean general circulation model is locally determined by using a one dimension proxy model of Hudson Bay with atmospheric, cryospheric and oceanic components. Using this proxy model, distinct pairs of values for the thermal conductivity of sea ice and thermal diffusivity of sea water are found that reproduce the current climatology of sea ice thickness in Hudson Bay. These pairs of values are subsequently used in a 3°C warming scenario. The resulting ice thicknesses are shown to be highly dependent on the choice of these pairs of values as well as the seasonal distribution of the warming.