Glacial Stratigraphy of the Upper Mersey Valley,Tasmania

The upper Mersey Valley was glaciated on three occasions during the Pleistocene. The youngest, Rowallan Claciation, probably commenced after 28000 years B.P. The maximum ice limit was attained before 13500 years B.P., and retreat occurred before 10000years B.P. Deposits associated with Rowallan Glaciation are weakly weathered chemically. They overlie moderately weathered deposits that were formed during the Arm Glaciation, which is inferred from relative dating data to have occurred before the Last Interglacial Stage. North of the deposits and ice limits of the Arm Glaciation extremely weathered tills and rhythmites occur. They were formed by ice of the Croesus Glaciation which is inferred to be of Early Pleistocene age or older.     

Mountains

Glacier ice from the south and west invaded upper Strathspey forming an ice sheet not less than 700m thick as it submerged the entire landscape. When the ice sheet wasted away, its meltwaters created complex sequences of fluvioglacial landforms. During the final stages of deglaciation, deposits left by the wasting ice mass were eroded by water, terraces spread out, gorges cut and the broad, low‐lying corridor on both sides of the River Spey was formed. There is evidence of a later, local readvance of the glaciers in three of the tributary valleys.     

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.     

Subglacial Meltwater Channels at Cape Jones,Obruchev Hills,Antarctica

Subglacial curved and winding meltwater channels, and Sichelwannen are recorded from Cape Jones in the Obruchev Hills. Such channels, sometimes referred to as P-forms, may have a variety of origins. After briefly considering the origins, it is deduced that those at Cape Jones were formed subglacially while the ice surface of the Denman Glacier became lower and bedrock was exposed The presence of water-laid glacial deposits on the summit of Cape Jones, and lakes on and adjacent to the eastern margin of the Denman Glacier suggests that the sudden release of impounded meltwater was important     

Contemporary Sorted Patterned Ground in Low Altitude Areas of Tasmania

This paper summarises the distribution of patterned ground phenomena in Tasmania. It presents observations of low altitude sorted stone circles forming on glacial and alluvial deposits in the vicinity of Queenstown, Western Tasmania. Evidence suggests that freeze‐thaw derived patterned ground could develop in most inland valleys in Tasmania where cold air drainage causes sub‐zero ground temperatures in winter and permits the formation of ground and segregation ice to low elevations. Field observations suggest that patterned ground can only develop where freeze‐thaw processes are not inhibited by vegetation. The occurrence of patterned ground below altitudes of 900 m asl in Tasmania is largely a result of anthropogenic disturbance.     

The Impact of Climate Change on an Archaeological Site in the Arctic

Climate change may accelerate the degradation of archaeological sites in the Arctic and lead to a loss of important historical information. This study assesses the current preservation conditions and the processes controlling the physical and chemical stability of the Qajaa kitchen midden in western Greenland. Currently, the site is well protected by low ground temperatures, permafrost and a high water/ice content, keeping the deposits anoxic. Based on 5 years of monitoring data, degradation experiments and model simulation, our results suggest that the combined effects of permafrost thaw, thermal and hydrological erosion and oxygen exposure may lead to substantial loss of archaeological evidence before the end of the 21st century.     

Dating the Trollesgave site and the Bromme culture – chronological fix-points for the Lateglacial settlement of Southern Scandinavia

The Bromme culture belongs to the Lateglacial, the period when people settled in the recently deglaciated Southern Scandinavia. Until now there have been only a few imprecise fix-points relating to the chronological position of this archaeological culture. This situation can now be improved with the aid of research results from a Bromme culture settlement at Trollesgave in SE Denmark. Using pollen and plant macrofossil data, Lateglacial lacustrine deposits containing waste material from the settlement can be assigned to the end of the climatically mild Allerød period. A series of ¹⁴C dates establishes the age of the settlement as c. 10 826 ± 49 ¹⁴C years BP (12 871–12 590 cal yr BP). By correlation with climate data from the Greenland ice cores, the occupation can be assigned to the early part of the cold climatic zone GS-1, thus demonstrating that the global ice-core climate zones are not absolutely synchronous with the regional division into biozones.     

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.     

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.     

The diffraction of VLF radio waves by the Antarctic ice cap

Measurements of the amplitude and phase of VLF radio signals from the Omega transmitters on La Reunion Island and in Argentina have been made on routine Antarctic re-supply nights from Christchurch, New Zealand. It has been found that when the propagation paths to the transmitters cross the Antarctic ice cap, the direct path signals are very rapidly attenuated below the receiver noise level, the dominant signal source then being provided by the radio waves diffracting around the edge of the ice cap. These results have been made possible by the simultaneous use of the phase and amplitude data in a synthetic aperture antenna type analysis.     

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).     

Thunderstorm charging: calculations of the effect of ice crystal size and graupel velocity

A one-dimensional model of a developing thunderstorm has been adapted in order to test the importance of various charge transfer parameters to the electrical development of the storm. The charge transfer data are taken from laboratory measurements obtained when ice crystals rebound off soft-hail particles in the presence of supercooled water droplets. The experiments showed that the charge transfer depends on ice crystal size and impact velocity, so a range of size and velocity dependences have been tested in the model. The calculations have been performed using initial conditions from three storm cases having a range of storm severities. The charging rates calculated were found to be affected more by the initial storm conditions than by the specific size and velocity dependencies chosen.     

SOIL TONGUES IN THE LEAMINGTON MORAINE, ONTARIO

W edge -shaped soil structures occur in many parts of southern Canada and the northern United States. These have usually been interpreted as being ice-wedge casts. Yehle (1954), however, has expressed concern over the confusion of fossil ice wedges with features he termed soil tongues, but also referred to as soil pendants (Wright 1961) or podsolschornsteine (Johnsonn 1959). Not only are soil tongues superficially similar to ice-wedge casts, but they also occur in temperate latitudes which may have experienced periglacial conditions during the Pleistocene. Soil tongues, however, are solutional features, formed by rainwater percolating through unconsolidated calcareous deposits. They may be distinguished from ice-wedge casts and other wedge-shaped structures by: (a) the presence of pebble or other marker beds extending unbroken across the wedges; (b) the absence of bed contortions or pressure features in the materials adjacent to the wedges; (c) their conical three-dimensional shape; and (d) the lower carbonate content in the sediments of the wedges than in the surrounding materials.     

Multiple Glaciation of the Upper Franklin Valley,Western Tasmania Wilderness World Heritage Area

Part of an extensive ice cap that developed in the Tasmanian Central Highlands during the late Cainozoic discharged southwards into the valley of the Franklin River and its upper tributaries where it merged with smaller glaciers that accumulated behind local snowfences. Glacial landforms and sediments in the now heavily forested valleys indicate that at least three and possibly as many as six glaciations took place. The earliest and most extensive glaciation occurred during the Pliocene or earliest Pleistocene. At this time ice extended at least 27km down the Franklin Valley and covered at least 326km² of the study area. This ice was confluent with glaciers in the West Coast Range to the west and in the Derwent Valley to the east Such confluence offers the possibility of better correlation of glacial events between western Tasmania and the Central Highlands. The smallest and most recent glaciation occurred during the late Last Glacial Stage when the Franklin Glacier did not exceed 12km in length. The glaciers were characterised by high rates of mass throughput and were of temperate maritime type.     

Making Better Use of Monitoring Data

This paper addresses the knowledge gap that exists in relation to understanding and quantifying the sensitivity of organic-rich archaeological deposits with respect to changes in the soil environment. Based on two case studies we demonstrate that it is possible to quantify the current decay rate in unsaturated archaeological deposits by combining decay rates measured in the laboratory with on-site monitoring data in a simple decay model. The decay of organic archaeological deposits is highly sensitive to variations in soil temperatures and soil water content. Measurements of soil water content cannot always stand alone as a representative measurement of oxygen availability; which suggests that in situ measurements of oxygen content or redox potential are needed in order to understand the preservation conditions at a site. The results of this study emphasize the advantage of combining monitoring data with laboratory studies, in order to document in more detail where and when degradation takes place.     

翠华山水湫池及其附近崩塌堆积形成年代探疑

通过对相关史料的分析,论证了翠华山主景区崩塌堆积不可能是唐天宝年间地震诱发山崩形成的。通过实地考察,认为这些崩塌堆积不是同时发生,而是多期崩塌活动的结果,并且崩塌活动又都发生在水湫池被堰塞成湖之后。因此,水湫池不可能是唐代的地震山崩形成的。     

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.     

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.     

“One Man's Foolishness Led to the Death of 14 Men”. Norwegian Reactions to Umberto Nobile and the “Italia” Disaster

In the summer of 1928, the dirigible “Italia” with the Italian navigator and constructor Umberto Nobile and his crew crashed in the polar ice north of Spitzbergen. The accident triggered not only the then most extensive rescue operation ever, it also resulted in a national grievance in Norway, when the national hero Roald Amundsen vanished in the sea on his way from Norway to Spitzbergen. Amundsen was flying north to help to find his old companion. With his disappearance the Norwegian attitude towards Nobile and his fellow Italians turned from bad to worse. This unkind attitude was also strengthened when Nobile came out of the ice safe and sound after 1 month. One Norwegian paper called Nobile “a goldgallooned fascist fool”, whose “insane venture had caused the whole tragedy” (Friheten 8 June 1928). Now Nobile was in safety, while Amundsen was gone forever. When the Italian shipwrecked men came to the coastal town of Narvik in Norway to dock for the waiting train to Italy, the locals met them with hostility. Why had the usually friendly and calm Norwegians suddenly become so hostile and unkind?     

The Formation of Beds of Ground ICE

The chemical composition of beds of segregated ice in the pingos of northern Siberia is analyzed with particular reference to the origin of this type of ground ice and the heaving mechanism. A regular change in chemical composition with depth and a low mineral content are found to correspond to the distribution of dissolved substances in the upper horizons of groundwater and point to a segregated rather than an injected origin. A relatively high content of organic matter in the ice, corresponding to the maximum summer concentration of organic matter in groundwater, suggests that the beds of ice grow mainly in the summer. The growth of the ice masses, combining the drawing up of interstitial water from below with the thawing of the upper horizons, produces a steady upward movement of frozen soil, including buried mammoth tusks that are usually found in the vicinity of North Siberian pingos. When the ice content is so high that even a growing bed of ice is no longer adequate to replenish the seasonal frozen ground layer with thawed upward moving bands of frozen soil, then the thermokarstic process begins to operate, producing a thaw depression, often filled with a lake.