Sedimentology and geomorphology of drumlins in western Allgäu, South Germany

Form, lithological composition, geomorphological situation and internal structure of three different drumlins belonging to the Pleistocene Rhine and Iller glacial systems in South Germany are described: one consisting almost completely of subglacial till, another consisting of ice-marginal deposits with an incomplete mantle of till, the third consisting of delta deposits. It is concluded that no precise limits should be drawn between accumulation and erosion drumlins.     

Subglacial and subaqueous processes near a glacier grounding line: sedimentological evidence from a former ice-dammed lake, Achnasheen Scotland

Subglacial and subaqueous sediments deposited near the margin of a Late-glacial ice-dammed lake near Achnasheen, northern Scotland, are described and interpreted. The subglacial sediments consist of deformation tills and glacitectonites derived from pre-existing glaciolacustrine deposits, and the subaqueous sediments consist of ice-proximal outwash and sediment flow deposits, and distal turbidites. Sediment was delivered from the glacier to the lake by two main processes: (1) subglacial till deformation, which fed debris flows at the grounding line; and (2) meltwater transport, which fed sediment-gravity flows on prograding outwash fans. Beyond the ice-marginal environment, deposition was from turbidity currents, ice-rafting and settling of suspended sediments. The exposures support the conclusion that the presence of a subglacial deforming layer can exert an important influence on sedimentation at the grounding lines of calving glaciers.     

Microstructural interpretations of modern and Pleistocene subglacially deformed sediments: the relative role of parent material and subglacial processes

Analysis of till micromorphology represents a relatively new technique that has been used most frequently to infer the importance of subglacial shear in till genesis. This study aims to calibrate the technique by comparing Pleistocene tills from United Kingdom with a modern till (the UpB till) from beneath Ice Stream B, West Antarctica. Despite the fact that all of the tills examined have been interpreted as deforming‐bed deposits, the modern till has significantly less abundant and diverse microstructures than those found in the Pleistocene tills. Seventeen examined thin‐sections of the UpB till contain recognisable microstructures over only 0–30% of individual thin‐section area. The most common microstructures are: (i) birefringent clay patterns that are interpreted as shear zones and (ii) adherent matrix structures, which we interpret as uncomminuted remnants of the parent glacial/glaciomarine diamictons. Fourteen thin‐sections of the Pleistocene tills were covered by microstructures in 10–95% of their area. The Pleistocene microstructures include birefringent clays and adherent matrix structures, as in the UpB till, but also laminations and deformed pods made of chalk and sorted sediments. We conclude that the same till‐forming process, i.e. subglacial deformation, may result in distinctly different till micromorphology. This is a consequence of the fact that microstructural characteristics are strongly influenced by factors other than shear deformation. We identify three controls that may be important for forming contrasting microstructural assemblages: (i) strain magnitude, (ii) the degree of heterogeneity of parent material, and (iii) relative importance of sediment sorting by flowing water in the subglacial environment. Thus till micromorphology is sensitive to multiple factors, which with proper calibration may enhance the existing capability to interpret past subglacial conditions from microstructures. Copyright © 2001 John Wiley & Sons, Ltd.     

The lower Jyllandselv succession: evidence for three Weichselian glacier advances over coastal Jameson Land, East Greenland

Detailed investigations of sediments exposed along river sections in the coastal part of Jameson Land have revealed a Saalian to Holocene glacial history. Eleven sedimentary units have been distinguished. most of which are found in superposition at one single large section. Four subglacially formed till beds are recognized; three of which are of Weichselian age. All the tills are considered to have been deposited at the base of fjord glaciers restricted to the Scoresby Sund basin. The tills are separated by marine, fluvial or deltaic sediments, and demonstrate changes in the depositional environnient considered to represent changes in relative sea level during the ice-free periods. The fossil content. supported by a series of luminescence dates, suggest that most of the succession is of Eemian and Early Weichselian age. From the luminescence dates, a short duration of <10ka is suggested for the Early Weichselian glacial stades. Sedimentation during this period was partly controlled by glacio-isostatic subsidence caused by net growth of the Greenland Ice Sheet. The Middle Weichselian is represented by a large hiatus. whereas the Late Weichselian is represented by a subglacial till.     

Characterization of pebble fabrics in modern terrestrial glacigenic sediments

ABSTRACT Pebble fabric data are available from several facies of glacigenic sediments deposited by modern glaciers, where sedimentary processes can be observed or inferred with relatively little ambiguity. Over 100 samples from contemporary environments illustrate fabrics characterizing melt-out till, deformed and undeformed lodgement till, sediment flow deposits and ice slope colluvium. Lodgement till fabric variability is related to the two-layer structure of these sediments; a structureless, friable upper layer with low shear strength and high consolidation coefficient, overlying a very compact material of horizontal platy structure. Fabric strength (assessed by eigenvalue analysis) is weaker and pebble dip is more dispersed in the upper structureless horizon. Stronger fabrics in the lower platy horizon may be primary depositional fabrics which are destroyed by subglacial shearing to give weaker fabrics in the upper horizon. Alternatively, upper horizon fabrics may be characteristic of all recently-deposited lodgement tills, with stronger fabrics developing at depth by dewatering and consolidation. There is a general reduction in fabric strength and an increase in particle dip associated with the transition from melt-out tills, through undeformed and deformed lodgement tills, to sediment flow deposits and ice slope colluvium. There is, however, considerable overlap in the fabric strengths characteristic of sediment flow deposits and deformed lodgement tills. Fabric data from modern glacial sedimentary facies are used to assist in interpreting the mode of deposition of some Quaternary glacial sediments. Relatively strong fabrics characteristic of melt-out tills and undeformed lodgement tills are more likely to be diagnostic of genesis than weaker fabrics associated with deformed sediments.     

希夏邦马峰东南富曲河谷的冰川沉积和冰川构造

在希夏邦马峰（海拔８０１２ｍ）东南富曲河谷，中更新世以来有三次冰期；即聂拉木、富曲和普罗冰期。它们均可再分为两个亚阶段。聂拉木南的高冰碛平台长３.５ｍ，宽１.５ｋｍ，厚２００ｍ。属于中更新世聂拉木冰期（聂聂雄拉冰期）的巨大山谷冰川沉积，中尼公路从高冰碛平台尾端通过，形成数公里长的冰碛剖面，呈现出美丽多姿的冰川成因类型沉积和冰川构造现象，包括冰下，冰上融出碛，冰内.冰下河道沉积，冰湖沉积，坠碛，流磺等。冰川运动时造成的冰川构造，如断层、滑动面-…等也很清楚，代表了海洋型（暖冰川）冰川沉积和冰川构造特征，是中国目前研究冰川构造最理想的场所。     

Deforming bed conditions on the Dánischer Wohld Peninsula, northern Germany

At the Dänischer Wohld Peninsula coastal sections (North West Germany), subglacial deformation was found at three scales. At the smallest scale, features typical of deforming bed tills were found, i.e. small boudins, tectonic laminations and low fabric strength till. At an intermediate scale, large lenses of glaciolacustrine sediments were found within subglacially deformed till. At the largest scale, there were large (over 5 m high) subglacial folds. We suggest that these styles of sedimentation/deformation were associated with a series of readvances during overall glacial retreat: subglacial deformation occurred during each advance and glaciolacus trine sedimentation occurred during each retreat. This led to glaciolacustrine sediments and deforming bed tills being folded together during subsequent readvances. Where the rheology was relatively weak, the lacustrine sediments were totally incorporated into the diamicton and lost their previous identity. However, where the glaciolacustrine sediments were relatively strong, they survived. We suggest that this style of deformation is typical of the conditions just upglacier from the ice margin and is associated with a relatively thick deforming layer and a high input of subglacial sediment. We conclude that the evidence found at this site provides further indications that the southern margins of the Fenno-Scandinavian ice sheet were coupled with the glacier bed and underwent deforming bed conditions.     

Microsedimentology of ice stream tills from the Eastern Alps,Austria – a new perspective on till microstructures

This study of tills from the Eastern Alps, Austria, illustrates the insights obtained using microsedimentology on subglacial tills in the context of palaeogeographical reconstructions of glacier advances. Investigations of several sites with tills derived from both local glaciers and the ice‐sheet streaming of the Inn Glacier during the Last Glacial Maximum and its termination reveal a detailed picture of subglacial sedimentology that provides evidence of soft sediment subglacial deformation under polythermal conditions. All the tills exhibit microstructures that are proxy evidence of significant changes in till rheology. The tills originate from multiple sources, incorporating older tills and other deposits picked up by the subglacial deformation within a polythermal but dominantly warm temperate subglacial thermal regime. The analyses of till microstructures reveal a direct relationship between basal ice strain conditions and their development. A hypothesis is derived, from the various microstructures observed in these Austrian tills formed under soft sediment deforming basal ice conditions, that suggests that with basal thermal changes and fluctuations in clay content, pore‐water content and pressure, microstructures form in a non‐random manner. It is postulated that in clay‐deficient sediments, edge‐to‐edge events are most likely to occur first; and where clay content increases, grain stacks, rotation structures, deformation bands and, finally, shear zones are likely to evolve in an approximate sequential manner. After repeated transport, emplacement, reworking and, probably, further shearing and deformation events, an emplaced ‘till’, as observed in these Austrian tills, will form that carries most, if not all of these microstructures, in varying percentages. Finally, the impact of the Inn Glacier Ice Stream on these tills is not easily detected and/or differentiated, but indications of high pore water and probable dilatant events leading to reductions in the number of edge‐to‐edge events point to the impact of fast or thick ice upon these subglacial tills.     

Microstructural analyses of a Middle Pliocene till from the James Bay Lowlands,Canada—evidence of “potential” fast ice streaming

Sediment from the Attawapiskat area near James Bay, Northern Ontario was sampled for micromorphological analyses. The sediment is a glacial diamicton (till) of subglacial origin. The till contains entrained and scavenged sediments of proglacial and/or subglacial glaciofluvial/glaciolacustrine origin from a subglacial deforming layer that was emplaced due to both stress reduction and/or porewater dissipation. Evidence of porewater escape, clay translocation and other microstructures all point to emplacement under active subglacial bed deformation. The limited number of edge to edge (ee) grain crushing events, however, point to lower stress levels than might anticipated under a thin fast ice lobe of the James Bay during the Middle Pliocene. Microstructures of Pleistocene tills were quantitatively compared with the Attawapiskat till and the limited number of ee events at Attawapiskat further highlighted that grain to grain contact was curtailed possibly due to high till porosity, high porewater pressures and low strain rates or alternatively due to a high clay matrix component reducing grain crushing contact events. It is suggested that this Middle Pliocene till may be indicative of sediments emplaced under ice lobe surging conditions or fast ice stream subglacial environments. This proposal has significant implications for the glaciodynamics of this part of the Middle Pliocene James Bay lobe. This research highlights a crucial link between subglacial conditions, till microstructural analyses and glaciodynamics.     

Glacial deposits and Late Weichselian ice-sheet dynamics in the northeastern Baltic Sea

Glacial deposits and landforms, interpreted from the continuous seismic reflection data, have been used to reconstruct the Late Weichselian ice-sheet dynamics and the sedimentary environments in the northeastern Baltic Sea. The bedrock geology and topography played an important role in the glacial dynamics and subglacial meltwater drainage in the area. Drumlins suggest a south-southeasterly flow direction of the last ice sheet on the Ordovician Plateau. Eskers demonstrate that subglacial meltwater flow was focused mostly within bedrock valleys. The eskers have locally been overlain by a thin layer of till. Thick proximal outwash deposits occupy elongated depressions in the substratum, which often occur along the sides of esker ridges. Ice-marginal grounding-line deposit in the southern part of the area has a continuation on the adjacent Island of Saaremaa. Therefore, we assume that its formation took place during Palivere Stadial of the last deglaciation, whereas the moraine bank extending southwestward from the Serve Peninsula is tentatively correlated with the Pandivere Stadial. The wedge-shaped ice-marginal grounding-line deposit was locally fed by subglacial meltwater streams during a standstill or slight readvance of the ice margin. The thickness of the glacier at the grounding-line was estimated to reach approximately 180 m. In the western part of the area, terrace-like morphology of the ice-marginal deposit and series of small retreat moraines 10–20 km north of it suggest stepwise retreat of the ice margin. Therefore, a rather thin and mobile ice stream was probably covering the northeastern Baltic Sea during the last deglaciation.     

Ice-marginal sedimentary, glacitectonic, and morphologic features of Pleistocene drift: An example from Newfoundland

A Pleistocene drift sequence in hummocky terrain along part of the southern Avalon Peninsula of Newfoundland is interpreted to comprise complexly interrelated lodgement till, melt-out till, flow till, supraglacial and proglacial outwash, and supraglacial rhythmites. The gray and tan melt-out tills are stacked in imbricate fashion, giving rise to exceptionally thick stratigraphic sections. Contacts between melt-out tills are interpreted as remnants of shear planes because they are sharp, they dip in the up-ice direction, and they converge toward valley margins. Overlying flow tills interdigitate with supraglacial outwash. The drift sequence was deposited during a single episode of glaciation, rather than by repeated glacier advance, as previously proposed. It is the product of thrusting of englacial debris along ice-marginal shear planes, subsequent melting-out of englacial debris, and formation of supraglacial flow till and outwash. Preservation of this sequence probably is due to high content of englacial debris within the Wisconsinan ice. The sedimentary, glacitectonic, and morphologic features of this sequence are similar to those found at the margins of certain Arctic glaciers of subpolar thermal regime which have recently been the subject of Pleistocene glacial sedimentation models for west-central Canada and Great Britain. Recognition of these distinct elements indicates wisconsinan glacier lobes were of the cold Arctic type in southeastern Newfoundland. Alternative explanations for this sequence, such as deposition by glaciers of temperate thermal regime or by surging glaciers, are discounted. Because the features described here are complex and difficult to recognize, they may be more widespread in Pleistocene drift than has previously been interpreted.     

Depositional evidence for marginal oscillations of the Irish Sea ice stream in southeast Ireland during the last glaciation

Late Devensian/Midlandian glacial deposits on the southeast Irish coast contain a record of sedimentation at the margins of the Irish Sea ice stream (ISIS). Exposures through the Screen Hills reveal a stratigraphy that documents the initial onshore flow of the ISIS ('Irish Sea Till') followed by ice stream recession and readvances that constructed glacitectonic ridges. Ice-contact fans (Screen Member) were deposited in association with subglacial deformation tills and supraglacial/subaqueous mass flow diamicts. In SE Ireland, the ISIS moved onshore over proglacial lake sediments which were intensely folded, thrust and cannibalized producing a glacitectonite over which laminated and massive diamictons were deposited as glacitectonic slices. Ice marginal recession and oscillations are documented by: (a) ice-proximal, subaqueous diamict-rich facies; (b) isolated ice-contact glacilacustrine deltas; (c) syn-depositional glacitectonic disturbance of glacilacustrine sediments and overthrusting of ice-contact outwash; (d) offshore moraine ridges; and (e) changing ice flow directions and facies transitions. Diagnostic criteria for the identification of dynamic, possibly surging, ice-stream margins onshore include thrust-block moraines, tectonized pitted outwash and stacked sequences of glacitectonites, deformation tills and intervening stratified deposits. In addition, the widespread occurrence of hydrofracture fills in sediments overridden and locally reworked by the ISIS indicate that groundwater pressures were considerably elevated during glacier advance. The glacigenic sediments and landforms located around the terrestrial margins of the ISIS are explained as the products of onshore glacier flow that cannibalized and tectonically stacked pre-existing marine and glacilacustrine sediments. Localized tectonic thickening of subglacially deformed materials at the former margins of glaciers results in zones of net erosion immediately up-ice of submarginal zones of net accretion of subglacial till. The more stable the ice-stream margin the thicker and more complex the submarginal sedimentary stack.     

Development of a subglacial drainage system and its effect on glacitectonism within the polydeformed Middle Pleistocene (Anglian) glacigenic sequence of north Norfolk,Eastern England

The efficiency of subglacial drainage is known to have a profound influence on subglacial deformation and glacier dynamics with, in particular, high meltwater contents and/or pressures aiding glacier motion. The complex sequence of Middle Pleistocene tills and glacial outwash sediments exposed along the north Norfolk coast (Eastern England) were deposited in the ice-marginal zone of the British Ice Sheet and contain widespread evidence for subglacial deformation during repeated phases of ice advance and retreat. During a phase of easterly directed ice advance, the glacial and pre-glacial sequences were pervasively deformed leading to the development of a thick unit of glacitectonic mélange. Although the role of pressurised meltwater has been recognised in facilitating deformation and mélange formation, this paper provides evidence for the subsequent development of a channelised subglacial drainage system beneath this part of the British Ice Sheet filled by a complex assemblage of sands, gravels and mass flow deposits. The channels are relatively undeformed when compared to the host mélange, forming elongate, lenticular to U-shaped, flat-topped bodies (up to 20–30 m thick) located within the upper part of this highly deformed unit. This relatively stable channelised system led to an increase in the efficiency of subglacial drainage from beneath the British Ice Sheet and the collapse of the subglacial shear zone, potentially slowing or even arresting the easterly directed advance of the ice sheet.     

Provenance of Des Moines lobe till records ice‐stream catchment evolution during Laurentide deglaciation

Lusardi, B. A., Jennings, C. E. & Harris, K. L. 2011: Provenance of Des Moines lobe till records ice‐stream catchment evolution during Laurentide deglaciation. Boreas, 10.1111/j.1502‐3885.2011.00208.x. ISSN 0300‐9483. Mapping and analysis of deposits of the Des Moines lobe of the Laurentide Ice Sheet, active after the Last Glacial Maximum (LGM), reveal several texturally and lithologically distinct tills within what had been considered to be a homogeneous deposit. Although the differences between tills are subtle, minor distinctions are predictable and mappable, and till sheets within the area covered by the lobe can be correlated for hundreds of kilometres parallel to ice flow. Lateral till‐sheet contacts are abrupt or overlap in a narrow zone, coincident with a geomorphic discontinuity interpreted to be a shear margin. Till sheets 10 to 20 m thick show mixing in their lower 2 to 3 m. We suggest that: (i) lithologically distinct till sheets correspond to unique ice‐stream source areas; (ii) the sequence of tills deposited by the Des Moines lobe was the result of the evolution and varying dominance of nearby and competing ice streams and their tributaries; and (iii) in at least one instance, more than one ice stream simultaneously contributed to the lobe. Therefore the complex sequence of tills of subtly different provenances, and the unconformities between them record the evolution of an ice‐catchment area during Laurentide Ice Sheet drawdown. Till provenance data suggest that, after till is created in the ice‐stream source area, the subglacial conditions required for transporting till decline and incorporation of new material is limited.     

Stratigraphy and sedimentology of Devensian (Dimlington Stadial) glacial deposits,east Yorkshire,England

The stratigraphy and sedimentology of the glacial deposits exposed along the coast of east Yorkshire are reviewed. Critical sections at Filey Brigg, Barmston and Skipsea are examined to reassess the stratigraphy of Devensian Dimlington Stadial glacial deposits in the light of recent developments in glacial sedimentology. Sedimentary and glaciotectonic structures studied in the field and by using scanning electron microscopy are emphasised. Two hypotheses are considered for the genesis of the interbedded diamictons and stratified sediments. The first involves the deposition of lodgement till and/or deformation till followed by meltout till, which was overridden to produce more deformation till, reflecting periods of ice stagnation punctuated by glacier thickening. The second hypothesis, which is favoured on the basis of field evidence and micromorphology, involves the vertical accretion of a deforming till layer associated with cavity/channel or tunnel valley fills, beneath active ice. At Barmston the upper part of the diamicton contains elongate pendant structures containing gravels, indicating that the diamicton was saturated and able to flow. The diamictons, therefore, represent a complex sequence of tills deposited and deformed by active ice during the Dimlington Stadial. Previously published stratigraphical schemes involving classifications of multiple tills in east Yorkshire should be simplified and it is more appropriate to assign these to a single formation, the Skipsea Till Formation. Rhythmic glaciolacustrine and proglacial glaciofluvial sediments overlie the tills at Barmston and Skipsea. These were deposited in sag basins during deglaciation as the tills settled and deformed under thickening sediment and as buried ice melted out. Extensive sands and gravels cap the succession and were deposited on a sandur during the later stages of deglaciation.     

Glacial deposits and ice-sheet dynamics in the north-central Baltic Sea during the last deglaciation

Nine seismic stratigraphic units were distinguished, and their distribution mapped, in an 80 × 130 km submeridionally oriented area in the north-central Baltic Sea, east of Gotska Sandön and Farö. Analysis of these units revealed a great influence of the bedrock topography on the structure and distribution of the glacial deposits. Major glacially eroded valleys in the Baltic Clint, connecting the Faro Deep and the North Central Baltic Basin (Harff & Winterhalter 1996) across a narrow sill, form an extensive submeridional bedrock depression. The concentration of ice flow into this depression is reflected in the drumlinized surface of the till near the Baltic Clint. Large eskers in the elongated bedrock depressions and on the Ordovician Plateau mark the locations of former subglacial meltwater conduits. Termination of the eskers with extensive glacio fluvial outwash fans at the northern limit of the Farö Deep, the presence of subaquatic melt-out till in the bottom of it, and wedge-shaped ice-marginal grounding-line deposit on the Silurian Plateau suggest floating ice margin conditions in the low-lying areas and a local ice shelf confined to the Frö Deep during the deglaciation.     

Glacial retreat sedimentation in the Smalfjord Formation, Late Precambrian, North Norway

Tillites, conglomerates and sandstones occurring in the basal part of the Smalfjord Formation along the Varangerfjord, East Finnmark, North Norway are believed to have formed during the retreat of a glacier. At Kvalnes, on the south side of the fjord, the following sequence, up to 20 m thick, is found: (1) massive monomict tillite interpreted as a subglacial till, (2) massive polymict tillite with lenticular intercalations of stratified sandstone and tillite, interpreted as supraglacial/proglacial drift, (3) polymict conglomerate interstratified with laminated sandstones, interpreted as braided stream deposits. The last named interfingers laterally and is overlain by marine sandstones. At Bigganjargga, near the head of the fjord, a lens of tillite about 3 m thick rests on a striated pavement and is overlain by sandstones and shales. Part of the tillite, containing irregular patches of slightly winnowed tillite, is interpreted as a melt-out till, while a marginal part consisting of inclined tillite beds is interpreted as a series of flow till deposits. The lens is believed to be an oblique section through what was originally an ice-cored moraine ridge. During a subsequent transgression, the moraine was partially eroded, a lag conglomerate was formed, and overlying marine sediments were deposited. Bedded flow tills formed in a supraglacial/proglacial environment may be preserved where the extent of current reworking is very low (such as an isolated end moraine). Stratified conglomerate and sandstone, intimately intercalated with tillite, is to be expected at a glacier margin where glacial meltwater is locally and occasionally abundant, and glacier ablation permits downslope flowage of mobilized supraglacial fluid till.     

Salt-induced crestal faults control the formation of Quaternary tunnel valleys in the southern North Sea

Tunnel valleys are major features of glaciated margins and they enable meltwater expulsion from underneath a thick ice cover. Their formation is related to the erosion of subglacial sediments by overpressured meltwater and direct glacial erosion. Yet, the impact of pre-existing structures on their formation and morphology remains poorly known. High-quality 3D seismic data allowed the mapping of a large tunnel valley that eroded underlying preglacial delta deposits in the southern North Sea. The valley follows the N–S strike of crestal faults related to a Zechstein salt wall. A change in downstream tunnel valley orientation towards the SE accompanies a change in the strike direction of salt-induced faults. Fault offsets indicate important activity of crestal faults during the deposition of preglacial deltaic sediments. We propose that crestal faults facilitated tunnel valley erosion by acting as high-permeability pathways and allowing subglacial meltwater to reach low-permeability sediments in the underlying Neogene deltaic sequences, ultimately resulting in meltwater overpressure build-up and tunnel valley excavation. Active faults probably also weakened the near-surface sediment to allow a more efficient erosion of the glacial substrate. This control of substrate structures on tunnel valley morphology is considered as a primary factor in subglacial drainage pattern development in the study area.     

Stratigraphy and sedimentation of the stratotype sections of the Catfish Creek Drift Formation between Bradtville and Plum Point, north shore, Lake Erie, southwestern Ontario, Canada

The Catfish Creek Drift Formation is a significant and extensive lithostratigraphical marker unit in SW Ontario. Here the stratotype, exposed in the Lake Erie bluffs of the Plum Point-Bradtville (Grandview) area south of London, Ontario, Canada, is proposed. It consists of subglacial and proglacial sediments deposited at the beginning of the Nissouri Phase of the Wisconsinan glaciation. In the 2.5-km-long stratotype section, the Catfish Creek Drift consists of 9 members. Five of them, the Dunwich and Grandview I-IV members, mainly consist of till, with minor components of stratified drift. The Dunwich till was deposited by the Huron-Georgian Bay lobe, but the Grandview I-IV tills by the Erie lobe. The Zettler Farm Member consists of co-lobal till in the central part of the section and of a proglacial waterlain flow diamicton and a subglacial undermelt diamicton in the SW part. Three members consist entirely of stratified drift; the glaciolacustrine silty and clayey Waite Farm Member, the ice-marginal deltaic Oosprink Farm Member and the Boy Scout Camp Member - deposited by meltwater streams in subglacial channels. The sequence of interbedded till and stratified drift represents the oscillating advance of the Laurentide Ice Sheet in the Lake Erie basin.     

A sedimentation pattern in Anglian marginal meltwater channels from Suffolk, England

Several infilled glacial meltwater channels of Anglian age are described from SE Suffolk, U.K. These channels are up to 4km long, 150m wide and 8m deep. They possess a consistent pattern of infill comprising glacifluvial sands and gravels overlain by subglacial water-lain fine sands and silts; these pass conformably upwards through thinly interstratified tills and sands into basal tills. The channels were formed at the ice-margin. Their sedimentary infill indicates overriding by the ice-sheet and subsequent subglacial deposition.