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Characteristics of large-scalefluting and hummocky terrain on the Canadian Prairies test glacial and meltwater hypotheses for landform genesis. These tests defend the meltwater model. Neither sedimentary nor glaciotectonic processes can fully explain such erosional landforms. Province-scale flow paths, which mark palaeo-ice streams and subglacial flood routes, contain large-scale fluting with flanking hummock terrain. Antecedent relief causes these paths to differ from other flood landscapes such as the Scablands. Proponents of the glacial hypothesis use an invalid analogy between Icelandic and Prairie landsystems. They suggest that groove-ploughing formed large- scale fluting, and that ice pushing created hummocky terrain. However, landform location, form, and extent, surface lags, truncated architecture, and landform associations favour the meltwater hypoth- esis. A simple thought experiment and clear understanding of the principle of least number of assumptions answer the criticisms that meltwater forms cannot cross-cut and that the meltwater hypothesis disregards proper hypothesis testing. An example of cross-cutting erosional marks supports this theory. No narrow tract of smoothed terrain with fluting terminates at the glacially thrust Neutral Hills, negating an important point in the glacial hypothesis. While neither the glacial hypothesis nor postglacial winnowing explain boulder and cobble lags with percussion marks, meltwater processes explain them well. Copyright # 2009 John Wiley & Sons, Ltd.

Shaw, John 1979 1201: Genesis of the Sveg tills and Rogen moraines of central Sweden: a model of basal melt out. Boreas, Vol. 8, pp. 409–426. Oslo. ISSN 0300–9483. Climatic amelioration in permafrozen regions causes basal melting of Polar glaciers. Supraglacial debris concentrated at the ice surface by ablation at first inhibits the ablation process. When the surface debris is equal in thickness to the active layer no further surface melting occurs. Till deposition processes in permafrozen areas are consequently dominated by melt out from a basal isothermal zone at melting point. The basal melt-out process is influenced by englacial structures and forms which are also largely responsible for the resultant landforms and deposits. Such basal melt out may also occur in areas with less severe climate. A model for deposition largely by basal melt out is documented by field observations in central Sweden. Melt-out tills in areas of former extending or uniform glacier flow show an upward facies change corresponding to poorly attenuated and highly attenuated englacial facies. The till facies are recognised in terms of stratigraphic position, surface form, internal structure, and clast lithology, size, shape, and long-axis orientation and dip. Areas of former compressive flow are characterised by basal melt out of folded and dislocated englacial debris zones in which the stacking of debris produced transverse moraine ridges. The internal structure of the ridges includes folded till bodies dislocated by thrust planes, horizontal, stratified layers cross-cutting the tectonic structures, and characteristic distributions of clast long-axis orientation and dip. The morphology of the ridges at both the macro and micro scales is in accord with the proposed model of formation. The morphological and sedimentological associations produced largely by basal melt out are summarized. An additional implication of the proposed model is that gradual lowering of the supraglacial sediment surface by bottom melting of regionally stagnant ice may be the cause of widespread marine or lacustrine transgression.

Tills are described which occur in ridges and mounds arranged both parallel and transverse to the flow direction of the depositing glacier. Field localities are drawn from the English Midlands, Western Canada, and South Victoria Land, Antarctica. The tills retain textural and structural properties associated with glacial transport, and have suffered a minimum of redistribution suhsequent to their release from glacier ice. It is shown that ridges and mounds cannot he explained in terms of preferential till accretion. An alternative mechanism is presented in which form and structurc are a result of redistribution of debris in transport by secondary flows in ice. Flutings are longitudinal forms which are related to helicoidal flow cells. Fabric distributions, patterns of till thickness, and internal structure support the helicoidal flow hypothesis. Debris entrainment by Antarctic cold-based glaciers is explained by consideration of the morphology and sedimentology of the ice margin and the pattern of glacier flow. Deposition by sublimation and melt-out produces an upwards succession of (1) undisturbed proglacial deposits; (2) a complex of poorly sorted flow deposits intercalated with sorted and stratified water-lain deposits; (3) foliated till with sub-horizantal jointing and isolated clasts. A section shobbing this succession is described from Taylor Valley, Antarctica. Transverse asymmetric ridges are related to till stacking by over-folding in the marginal compressive zone of cold-based glaciers. Plastic deformation of the debris-laden ice may be enhanced by incorporated salts. The folding process is illustrated by structures within Taylor glacier, and is used to explain Pleistocene landforms and structures in Shropshirc, England and Taylor Valley, Antarctica.

Gas-agitated liquid-liquid dispersions arise in applications as diverse as direct hydrogenation processes for bitumen and coal, and the manufacture of iron and steel. The transfer of gas-phase constitutents to the dispersed liquid phase and/or elution of dispersed-phase drops have been identified as potential limiting phenomena in these processes. Consequently, mean drop size and drop size distribution are key design variables. In this paper, the impact of gas flux and the physical properties of dispersed-phase constitutents on the steady-state size distribution of liquid drops in lean liquid-liquid dispersions is quantified. The physical properties of the dispersed phase are shown to have a significant impact on drop size and drop-size distribution at low gas fluxes. Sauter mean drop size is correlated using theoretical models for drop break-up and coalescence. All results are compared with stirred tank analogues.

Coal particle size is considered to be a variable of secondary importance in coal/oil co-processing and coal liquefaction. This finding is inconsistent with the proposed mechanism for coal particle disintegration, and product yields realized in previous large scale dissolution experiments. Coal particles are shown to break up as a consequence of hydrogen-coal interactions occurring during preheating. The proposed mechano-chemical mechanism for coal particle disintegration was identified through direct observation of disintegrating coal particles at elevated temperatures and pressures. Implications for the design of preheaters for coal/oil co-processing and coal liquefaction are discussed. La taille des particules de charbon est consideree comme une variable d'importance secondaire dans la co-transformation charbon/huile et la liquefaction du charbon. Cette constation n'est pas compatible avec le mecanisme propose pour la desintegration des particules de charbon ni avec les rendements de produits realises dans des experiences anterieures de dissolution a grande echelle. On montre que les particules de charbon se brisent a la suite des interactions entre l'hydrogene et le charbon survenant lors du pre-chauffage. Le mecanisme mecanico-chimique propose pour la desintegration des particules de charbon a ete identifie par observation directe des particules de charbon en train de se briser a des temperatures et des pressions elevees. On analyse les implications pour la conception de systeme de pre-chauffage pour la co-transformation charbon/huile et la liquefaction du charbon.

A correlation for hydrogen solubility in aromatic, alicyclic, and heterocyclic hydrocarbon solvents is presented. This correlation, employing corresponding state theory, provides reliable estimates for hydrogen solubility, in simple and multicomponent solvents, over the temperature interval 0.45 ≤ Tr ≤ 0.97, and for pressures from 0.1 to 30.0 MPa. The correlation was found to have an average absolute error of 5.9% for 14 simple solvents, and 6.8% for 11 multicomponent solvents which include coal liquids and bitumen. Solvent specific coefficients are not employed, and the correlation is well suited for predicting hydrogen solubility in multicomponent ill defned solvents, or in simple solvents where experimental data are unavailable.

ALTHOUGH MANY STUDIES have been made of so-called ice-moulded landforms, drumlins, drumlinoids, and flutings, their mode of genesis remains unsolved. The form of drumlins is quite distinctive; a quotation from Alden (1905) used by Chorley (1959) clearly sets down their salient features: “We may regard as a typical drumlin a hill of glacial drift which approximates the form of a segment of an elongated ovoid, of which the widest part of the basal outline and the highest point of the crest are not more distant from the stoss-end than one-third the length of the major axis and whose major axis is oriented parallel to the direction of movement of the glacier which formed it.” With extension of the length of the characteristic drumlin a gradation occurs into extensive linear features known as flutings. The longitudinal profile of flutings differs from that of drumlins in that the maximum crest elevation is maintained for large distances. However, flutings show the same parallelism with ice-flow direction and general streamlined form as drumlins. In this paper flutings refer to both the ridges and the adjacent grooves that make up the total landform. Generally this paper will be confined to larger-scale flutings as described by Smith (1948), Gravenor and Meneley (1958), Lemke (1958), and Freschauf (1971). The large-scale features range in scale from two to three metres high and several kilometres in length. Such flutings appear to be confined to North America. Smaller-scale features have been described from a variety of recently deglaciated areas (Hoppe and Schytt 1953; McPherson and Gardner 1969; Baranowski 1970), but these are not analogous with the large-scale features. Drumlins and flutings clearly differ in form, and it is pertinent to consider other properties which may provide information on their mode of origin. A wide variety of internal composition has been noted. Till is most commonly observed, but stratified drift is often found in both drumlins and flutings. The influence of bedrock may also be important; drumlins with bedrock cores have been widely described (Chamberlin 1883; Crosby 1934), and flutings in Alberta, Saskatchewan and the Northwest Territories, Canada, may also be developed in crystalline bedrock (Smith 1948). Long-axis orientation of stones in drumlins has been shown to parallel drumlin axes approximately (Hoppe 1951; Donner and West 1955; Wright, 1957). Hill (1971) shows similar results but emphasizes a significant scatter in mean directions obtained from different samples from a single drumlin. Andrews and King (1968) show increasing deviation between stone and drumlin orientations in samples taken from successively higher positions in a drumlin section. However, micro-fabric analysis on samples from glacial flutings (Gravenor and Meneley 1958) gave orientations of silt and sand particles parallel to the fluting crest to a depth of three metres. Below three metres particle long axes were found to deviate from the fluting crest. Some authors have proposed that there is a relationship between the occurrence of drumlins