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The article contains detailed petrographic studies, which covered a coarse and medium-grain gravel fraction of two layers of glacial till (units ŁS II and ŁS IV) and two layers of sand-gravelly outwash deposits (units ŁS I and ŁS III) related to the Odranian Glaciation (MIS6, Saalian) in Łubienica-Superunki, North Mazovian Lowland, central Poland. Additionally, the indicator erratics were identified to indicate their Scandinavian source areas and the directions of the ice sheet transgressions. This case study is discussed against the background of similar sediments and forms from the same age but from other places in the Polish Lowlands. Regardless of the facies types and fractions, crystalline rocks dominated over all other petrographic groups in all samples. The most common were the indicator erratics derived from the Åland Islands, followed by those from the south-eastern area of Sweden (Småland) and from Dalarna in central Sweden. Amongst the erratics of limited indicative significance, the most common were Lower Palaeozoic limestones and the Jotnian red sandstones. The complex petrographic analyses point to the dipartite nature of the studied profile. This separateness was confirmed by the TBC: 59.1–59.2° N and 18.0–18.2° E for the lower units and 58.8–59.4° N and 17.3–17.9° E for the upper ones.

Glaciofluvial and glaciolacustrine sediments were discovered in a small sandpit situated 800 m SE from Vindava (the Polský kopec Site). Sediments fill two channels located in superposition. Three facies associations (FA) were distinguished in this sedimentary section. The base of the lower channel is formed by gravel lag overlain by gravel-sandy sediments of 3-D dunes and a side bar (FA1). The upper channel infill begins also by basal lag and grades to a fining-upwards sequence from sand to silt (FA2). The sequence is formed from the base up by sediments of small 3-D dunes, A-type ripples, B-type ripples, C-type ripples, and horizontally laminated sediments. The sequence reveals a vertical transition from glaciofluvial (sand) to glaciolacustrine (silt) sedimentation. The sedimentary section is terminated by flat glaciofluvial bedforms (FA3) deposited under upper plane bed conditions. These bedforms arose after the restoration of glaciofluvial conditions. The base of the glaciolacustrine sequence is located at an altitude of ~ 275 m as well as the Old Kaolin Mine Site (850 m SW from the Polský kopec Site) where very similar sediments have been already described. The sediments of both localities represent a proglacial outwash plain in front of the retreating ice sheet (FA1 consists of ~ 23% of erratic rocks), where a relatively large lake, or a system of smaller lakes evolved at the same time.

The favorable overall conditions for the utilization of groundwater in fluvioglacial aquifers are impacted by significant heterogeneity in the hydraulic conductivity, which is related to small-scale facies changes. Knowledge of the spatial distribution of hydraulically relevant hydrofacies types (HF-types), derived by sedimentological analysis, helps to determine the hydraulic conductivity distribution and thus contribute to understanding the hydraulic dynamics in fluvioglacial aquifers. In particular, the HF-type “open framework gravel (OW)”, which occurs with the HF-type “bimodal gravel (BM)” in BM/OW couplings, has an intrinsically high hydraulic conductivity and significantly impacts hydrogeological challenges such as planning excavation-pit drainage or the prognosis of plumes. The present study investigates the properties and spatial occurrence of HF-types in fluvioglacial deposits at regional scale to derive spatial distribution trends of HF-types, by analyzing 12 gravel pits in the Munich gravel plain (southern Germany) as analogues for outwash plains. The results are compared to the reevaluation of 542 pumping tests. Analysis of the HF-types and the pumping test data shows similar small-scale heterogeneities of the hydraulic conductivity, superimposing large-scale trends. High-permeability BM/OW couples and their dependence on recognizable discharge types in the sedimentary deposits explain sharp-bounded small-scale heterogeneities in the hydraulic conductivity distribution from 9.1 × 10−3 to 2.2 × 10−4 m/s. It is also shown that high values of hydraulic conductivity can be interpolated on shorter distance compared to lower values. While the results of the HF-analysis can be transferred to other fluvioglacial settings (e.g. braided rivers), regional trends must be examined with respect to the surrounding topography., Bayerisches Staatsministerium für Umwelt und Verbraucherschutz http://dx.doi.org/10.13039/501100010219

The Fiskarheden quarry, situated in NW Dalarna, central Sweden, reveals thick coarse-grained sediments of Scott type facies association representing a sandur deposited in an ice-proximal proglacial environment. Optically Stimulated Luminescence (OSL) dating of the sandur sediments suggests a pre-Last Glacial Maximum (LGM) age. Most acquired ages are pre-Saalian (>200 ka) and we regard each of these ages to represent non/poorly bleached sediment except for one small-aliquot OSL age of 98±6 ka. This age comes from the top surface of an arguably well-bleached sand bed deposited on the lee-side of a braid-bar, putting the sandur build-up into the Early Weichselian. Large-scale glaciotectonic structures show an imbricate thrust fan involving both ductile and brittle deformation. The deformation was from the WNW, which largely coincides with the formative trend of the predominating streamlined terrain and Rogen moraine tracts surrounding Fiskarheden. It is suggested that the deformation of the sandur sediments took place when the advancing glacier approached and pushed its own proglacial outwash sediment, during an ice-marginal oscillation either at the inception of one of the Early Weichselian glaciations in the area, or during a general ice retreat amid a deglacial phase. The Fiskarheden sandur deposits are covered by a subglacial traction till deposited from the NE/NNE. This direction corresponds with younger streamlined terrain flowsets cross-cutting the older NNW–SSE system and probably represents deglaciation in the area following the LGM. This study will add to the understanding of the formation and deformation of Pleistocene sandur successions and their relationship to past ice-sheet behaviour. (Less)

The Kingston Peak Formation is an archetypal Cryogenian succession that crops out across the Death Valley region of eastern California. Above pre-glacial strata (KP1), two distinct glacial phases have been recognized and are interpreted to be allied to the panglacial Sturtian (KP2 and KP3) and Marinoan (KP4) icehouse events. The thickest and most extensive unit, KP3, forms the entire exposed section at Sperry Wash. At this locality, ice-distal turbidites are succeeded in turn by ice-medial and ice-proximal facies, comprising a spectrum of ice-rafted debris-bearing turbidites, debrites and shales. These are overlain by ice-marginal grounding-line fan deposits interbedded with glacitectonically deformed heterolithics, supporting local advance to an ice-contact position. The succession records accumulation within a glacier-fed subaqueous shelf, wherein the clear progradational signature is driven by ice advance towards the south-east. Evolution of the subaqueous complex is five-fold, comprising: (i) ice-distal outwash; (ii) build-out of ice-medial depositional lobes; (iii) ice-proximal deposition and increased calving; (iv) resumed ice-margin advance; and (v) growth of ice-contact grounding-line fan. This sequence is unique in the Death Valley region for recording the first evidence of advance to ice-marginal and ice-contact settings, thereby enabling the location of the glacier terminus to be documented for the first time.

Deglacial sequences typically include backstepping grounding zone wedges and prevailing glaciomarine depositional facies. However, in coastal domains, deglacial sequences are dominated by depositional systems ranging from turbiditic to fluvial facies. Such deglacial sequences are strongly impacted by glacio-isostatic rebound, the rate and amplitude of which commonly outpaces those of post-glacial eustatic sea-level rise. This results in a sustained relative sea-level fall covering the entire depositional time interval. This paper examines a Late Quaternary, forced regressive, deglacial sequence located on the North Shore of the St. Lawrence Estuary (Portneuf Peninsula, Québec, Canada) and aims to decipher the main controls that governed its stratigraphic architecture. The forced regressive deglacial sequence forms a thick (>100 m) and extensive (>100 km2) multiphased deltaic complex emplaced after the retreat of the Laurentide Ice Sheet margin from the study area ca 12 500 years ago. The sedimentary succession is composed of ice-contact, glaciomarine, turbiditic, deltaic, fluvial and coastal depositional units. A four-stage development is recognized: (i) an early ice-contact stage (esker, glaciomarine mud and outwash fan); (ii) an in-valley progradational stage (fjord head or moraine-dammed lacustrine deltas) fed by glacigenics; (iii) an open-coast deltaic progradation, when proglacial depositional systems expanded beyond the valley outlets and merged together; and (iv) a final stage of river entrenchment and shallow marine reworking that affected the previously emplaced deltaic complex. Most of the sedimentary volume (10 to 15 km3) was emplaced during the three-first stages over a ca 2 kyr interval. In spite of sustained high rates of relative sea-level fall (50 to 30 mm·year-1), delta plain accretion occurred up to the end of the proglacial open-coast progradational stage. River entrenchment only occurred later, after a significant decrease in the relative sea-level fall rates (-1), and was concurrent with the formation and preservation of extensive coastal deposits (raised beaches, spit platform and barrier sands). The turnaround from delta plain accretion to river entrenchment and coastal erosion is interpreted to be a consequence of the retreat of the ice margin from the river drainage basins that led to the drastic drop of sediment supply and the abrupt decrease in progradation rates. The main internal stratigraphic discontinuity within the forced regressive deglacial sequence does not reflect changes in relative sea-level variations.

A thick succession of Al Khlata glacio-lacustrine deposits, including diamictites, crops out in the Wadi Daiqa inlier and there are other possible Al Khlata outcrops in Wadi Amdeh and Wadi al Arabiyin. These outcrops in the Oman Mountains are 100 km north of where the Al Khlata had been thought to pinch out by non-deposition or erosion. Fossil spores and pollen from Wadi Daiqa are highly carbonized having been subject to greenschist facies metamorphism, but are still clearly identifiable as taxa from the Late Carboniferous 2159A zone of the oil-producing areas of interiorOman. This northernmost Al Khlata is sand rich and interpretedto be glacio-lacus- trine. Previously the sand-dominated Al Khlata successions north of the Central Oman High have been consideredto be glacio-fluvial outwash largely based on their context. The Al Khlata deposits in Wadi Daiqa and the underlying several-kilometre-thick Amdeh succession are preserved in Saih Hatat, probably in a continuation of the Ghaba Salt Basin that itself overlies an accreted terrane from the Pan African orogeny. Gold Open Access: This article is published under the terms of the CC-BY 3.0 license. Al Khlata glacial deposits occur widely in the sub- surface of interior Oman. They are absent along the easternmost coastal area and were believed absent from northern Oman and the Oman Moun- tains due to non-deposition. Here we describe a c. 300 m succession of Al Khlata P9 deposits from Wadi Daiqa, and other possible outcrops of Al Khlata lithologies in the Saih Hatat area. The Wadi Daiqa sections are important in being outcrop analogues of sand-prone oil-producing intervals in the subsurface of southern Oman. Unfortunately, the most easily accessible section was flooded with the filling of the Wadi Daiqa water reservoir in 2009. The better-known outcrops at Al Khlata, in the Huqf area, are of younger P5 and P1 age and are predominantly of non-reservoir facies.

This study aims to characterize the morphology and contemporary floodplain deposit dynamics within a braided sandur system in upper Erdalen, a steep U-shaped valley in western Norway. The braided sandur system is fed by two tributary valleys connected to the Jostedalsbreen Ice Field. Based on field observations, two different sub-systems can be identified within the braided sandur system: fine-grained to sandy flood sediments down-valley, and coarser, gravelly deposits in the upper part. A combination of different methods is applied for studying sediment dynamic processes within the braided sandur system (sedimentological and stratigraphic analyses, 14C dating, dendrochronology and lichenometry). The coarser deposits are interpreted as originating from the Little Ice Age advance in Erdalen. Preliminary results indicate that the floodplain sediments were deposited after the Little Ice Age advance. Different sedimentary facies types are present and different phases of flooding can be identified. Within the entire braided sandur system, multiple sub-systems characterized by different levels of process intensities exist.

Unusual development of sandur sedimentary succession, an example from the Pleistocene of S PolandAn atypical lithological development of outwash deposits in the Carpathians Foreland (S Poland) shows lower and middle parts of the sedimentary succession that are characterized by sinuous palaeochannels. This channel facies consists of laterally accreted sands derived from side bars. The sedimentary environment was a proglacial system of anabranching channels, presumably of anastomosed type. The outwash channel pattern was most probably controlled by the raising base level of the fluvial system. Both proglacial and extraglacial waters were dammed by a sandur within a small upland valley. Aggradation and progradation of the glaciofluvial deposits resulted in progressive rising of the dammed lake level. The low hydraulic gradient of the outwash streams resulted in a sinuous planform as well as a low-energy style of deposition. Afterwards, the rising lake water was drained off through a low watershed and the entire valley became filled with outwash sediments. The bedrock morphology thus became buried and a typical unconfined sandur with a braided channel network developed during the last phase of the glaciomarginal sedimentation (upper part of the sedimentary succession under study).

The Talchir Formation of Permian age is the lowermost lithostratigraphic unit of the Indian Gondwana successions preserving a record of the Late Paleozoic glaciation that affected the whole Gondwanaland. The formation unconformably overlies the Precambrian basement in all the Gondwana basins of India, and marks initiation of sedimentation after a long hiatus since the Proterozoic. The Talchir Formation of the Satpura Gondwana basin of central India shows features diagnostic of deposition under glacial regime such as the presence of diamictites, boulder pavements, bedding plane striation, faceted/striated gravels, bullet-shaped clasts, dropstone, cryoturbation, etc. The Talchir strata of the Satpura basin, in addition to tidal signatures, contain marine bivalve and trace fossils. A proglacial marine environment is thus inferred for their deposition. The dominant lithologies are conglomerate, pebbly sandstone, sandstone and shale with little limestone, which can be classified into the following major facies: • matrix-supported conglomerate, • clast-supported conglomerate, • cross-stratified, channel form pebbly sandstone, • hummocky, swaley or low-angle cross-stratified pebbly and non-pebbly sandstone, • turbidite/tempestite sheet sandstone, • massive to fissile, green to black claystone with carbonate layers and nodules. The conglomerates are interpreted as deposits of a spectrum of sub-aqueous sediment gravity flows including debris flow, hyperconcentrated/concentrated density flow and grain flow. The crossstratified pebbly sandstone bodies, on the other hand, represent braidplain delta deposits of glacial outwash origin. Hummocky, swaley, low-angle cross-stratified sediment bodies were deposited by storm-generated combined flows in a shoreface setting. In contrast, the sheet sandstone bodies are products of turbidity currents and storm-induced density currents in an inner shelf setting below fair weather wave base. The claystone facies is interpreted as a product of suspension fallout from hypopycnal sediment plumes in the outer shelf domain below storm wave base. All the lithofacies described above occur repetitively in the succession. Three facies-associations have been recognized in the Talchir Formation, representing ice-contact fandelta, outwash braidplain delta and a virtually ice-free, non-deltaic open marine realm. The different marine facies of the Talchir Formation define a number of shallowing-upward packages, which are arranged in the succession with a retrogradational trend to result in an overall fining- and deepening-upward succession. The overlying coal-bearing Barakar Formation has been interpreted to have formed in a tide-wave influenced

The lowland region of north Norfolk contains some of the best preserved evidence for glacial deposition during the Middle Pleistocene in northwest Europe. Despite the importance of these deposits, there is limited chronological control and it is debated whether they belong to a single glaciation, equated to the Anglian Glaciation (Marine Isotope Stage 12), or represent deposition over a number of Middle Pleistocene cold stages. In order to develop an improved chronology for glaciation in this region, we obtained 18 samples for optical stimulated luminescence (OSL) dating from glacial outwash facies. Samples of coarse-grained quartz sand were measured using the SAR (single aliquot regenerative-dose) protocol. The low radioactive isotope concentrations in sediments of this region enable the traditionally accepted age limit of luminescence dating to be extended. The form of the dose response curves, pre-heat plateaux tests, and dose recovery experiments also indicate that laboratory doses can be reliably measured in these samples. Age overestimation due to partial bleaching is thought to be insignificant. The OSL ages suggest that the glacial sediments studied were deposited during MIS 12 rather than in different post MIS 12 stages.

Recent studies on Neoproterozoic climate change has prompted renewed interests in Neoproterozoic glacial deposits and renewed debates over the criteria used to identify the nature of glacial influence on sedimentation. Analysis of soft sediment deformation structures have provided important clues to distinguish between competing paleoenvironmental interpretations of Quaternary glacial deposits. A similar approach is presented here in the analysis of Neoproterozoic glacial deposits of the Smalfjord Formation, northern Norway. Detailed sedimentological and structural analysis at several sites in the Varangerfjorden area reveals complex soft sediment deformation at various scales in conglomerate, sandstone and diamictite. Deformation is predominantly ductile and includes anticlinal and synclinal folding, flow noses, flame structures, recumbent folding and shear structures. The deformed sediments are predominantly associated with conglomerate and sandstone, which record glaciofluvial and deltaic depositional conditions. Some deformation can be attributed to rapid deposition and slumping, whereas others appear to record shear stress associated with overriding ice. The scale,style and range of deformation together with the coarse-grained nature of the deformed sediments and facies associations suggests these were unfrozen outwash sediments that were overridden by ice and resedimented in a dynamic ice proximal setting. Whereas recent previous studies of diamictite-bearing strata of the Smalfjord Formation had revealed no clear evidence of glacial influence on deposition, deformation structures documented here suggest that glacial conditions prevailed on the basin margin during deposition of Smalfjord Formation sediments, with sedimentary facies and deformation structures typical of temperate ice proximal settings.

The Orrisdale Outwash Member was deposited during retreat of the Late Devensian Irish Sea ice-sheet in a series of diachronous marginal sandur formed on an unstable, ice-cored supraglacial topography. Sedimentation was controlled by dead-ice ridges running parallel to the ice-margin but as buried ice melted the topographic constraints diminished and individual sandur systems widened and coalesced. The sediments are characterized by very rapid lateral and yertical facies variation caused by channel migration, abandonment, and adjustment to a rapidly-changing ice and sediment substrate. Facies assemblages consequently show marked lateral transition from high energy, laterally impersis-tent, gravel dominated longitudinal bar sequences to extensive, low-energy overbank flood basin successions.

Different methods have been used to determine the stratigraphic position of Pleistocene alluvial deposits, particularly fluvial interglacial deposits. Near-surface deposits of a meandering river, developed in point-bar and oxbow lake facies, in the Samica River valley (near Łukow, eastern Poland) have been investigated. The fossil valley is incised into the till plain and the outwash. The fluvial succession is locally overlain by solifluction deposits. All the deposits underwent sedimentological analysis. The petrographic composition of basal till occurring in the vicinity of a fossil valley was determined with the method of indicator erratics. Fluvial deposits were examined by pollen analysis and plant macrofossil analysis of oxbow lake facies. Absolute dating methods were applied to the deposits (thermoluminescence methods: TL and additionally IRSL). Lithological differences between fluvial and the surrounding glaciofluvial deposits were identified and their lithostratigraphic position assigned. Petrographic analysis of till and palaeobotanical analyses of oxbow lake facies gave compatible results. Fluvial deposits were formed after the Sanian 2/Elsterian Glaciation, during the Mazovian/Holsteinian Interglacial. Luminescence dating of the fluvial deposits by the TL MAX method yielded the most relevant results (412-445 ka), which indicate that these deposits were formed during the end of the MIS 12 and beginning of the MIS 11 stage.

Shallow seismic reflection data collected in St. George's Bay, southwest Newfoundland, reveal a complex pattern of subsurface topography and acoustic facies. Two basins in the inner bay are underlain by glacially overdeepened valleys that extend to depths in excess of 180 m. Within the thick Quaternary sequence in the inner bay we recognize eight acoustic units. Units 1 (ice contact), 2 (subaqueous outwash), and 3 (draped glaciomarine) record the presence and retreat of a major Late Wisconsinan ice margin. Unit 4 (postglacial mud) has resulted from reworking of glaciogenic sediments in response to changes in relative sea level. Unit 5 (postglacial sand) is a shoreface deposit on the seaward front of the former moraine. Unit 6 (postglacial delta) was formed by fluvial reworking of glaciogenic sediments during the postglacial lowstand of relative sea level. Unit 7 (postglacial barrier–platform) comprises seaward-fining clinoform prisms that have prograded into the basins, and underlie gravel beach-ridge plains at Stephenville and Flat Island. Unit 8 (postglacial spillover) results from entrainment of coarse sediment on the shallow sill and subsequent progradation into the basins of the inner bay.Seabed sediment in the basins is mud where sampled. The submarine platforms associated with the barriers at Stephenville and Flat Island are largely sandy. The sill is covered by a gravel veneer, with irregular patches of sand that coalesce and thicken seawards. Extensive areas of gravel ripples testify to the continued mobility of much of the coarse sediment on the sill.A major ice front in the inner bay was present prior to 13.7 ka BP. The draped glaciomarine sediments, dated at 13.7–11.2 ka BP in nearby Port au Port Bay, were deposited after withdrawal of the ice front to the vicinity of the present coast, during a readvance, and subsequently. During the postglacial lowstand of relative sea level much of the present sill area was emergent.

A nearshore sediment sampling program was undertaken in Port au Port Bay, western Newfoundland. The -objectives of the program were to map the distribution of detrital chromite in the seabed sediments and to evaluate the paleoenvironmental evolution of chromite-bearing sedimentary facies. Bottom sediments were found to be enriched in detrital chromite in an area adjacent to and parallel to the east shore of the bay, south of the mouth of the Fox Island River. During glaciation, chromite from the Lewis Hills ophiolite complex was incorporated in glacial materials. Post-glacial reworking of chromite-bearing sediments by fluvial and marine processes is observed in a number of sedimentary facies: fluvial sediments of the Fox Island River, a large outwash plain and marine-limit delta occurring near the mouth of Fox Island River, an erosional lag blanketing the outwash delta, and emergent and submergent beach terraces bordering a small coastal embayment south of Fox Island River, The relatively low wave energy of the Port au Port Bay area appears, however, to have precluded extensive placer development in all sedimentary facies. RÉSUMÉ Un programme d'éhantillonage des sédiments côtiers fut entrepris dans la baie de Port-au-Port, dans l'ouest de Terre-Neuve. Les buts de ce programme étaient de cartographier la distribution de la chromite détritique dans les sédiments de fonds marin et d'évaluer l’évolution paléo-environnementale des faciès sédimentaires porteurs de chromite. Les sédiments de fond se sont révèles être enrichis en chromite détriiique dans une zone adjacente et parallèle à la côte est de la baie, au sud de l’embouchure de la rivière de file Fox. Pendant la glaciation, la chromite du complexe ophiolitique de Lewis Hills fut incorporée dans les matériaux glaciaires. Le remaniement post-glaciaire des sédiments porteurs de chromite par des processus fluviaux et marins est observé dans un certain nombre de faciès sédimentaires: les sédiments fluviaux de la rivière de Tile Fox, unsandur étenductun delta de contact glaciaire situe près de l'embouchure de la rivière de Tile Fox, un gravier résiduel qui recouvre le sandur et des terrasses marines émergentes et submerges bordant une anse située au sud de la rivière de l'ile Fox. L'énergie relativement basse des vagues de la région de Port-au-Port semble toutefois avoir empêché la formation de placers étendus dans tous les faciès sédiment aires. [Traduit par le journal]

Despite their importance to environmental issues and mineral resources, surficial sediments are largely unmapped at depth in the United States. Full three-dimensional (3D) models of these materials are needed to support hydrologic modeling, geotechnical engineering, and mineral-resource inventory applications. The main source of information for such models in the Midwestern United States is lithology logs from public water-well records. Three-dimensional modeling of lithology was conducted to elucidate the nature and quality of spatial information sourced from water wells. The modeling was conducted on an ∼130-km 2 area near Lake Erie in northeast Ohio that contained an end moraine superimposed on a buried glacial valley. An integrated approach to 3D modeling was adopted where traditional interpretive techniques were used to define glacial stratigraphic units (glacial outwash, till, etc.) with geostatistical simulation of lithofacies conducted within the stratigraphic layers. Despite the large amount of variability and noise inherent in water-well data, there were statistical patterns in the lithology records related to glacial stratigraphy. In contrast, the well data provided only minimal information on facies geometry within these units. The spatial structure of facies in the vertical direction was based on thickness statistics from the water-well data and on geologic interpretation for the horizontal direction. Several sequential indicator simulation models were conducted to investigate the effect of grid-cell thickness, stratigraphic trimming, and length-to-thickness ratios on the reproduction of thickness statistics. This case study confirms that water wells are a viable data source for stratigraphic modeling, but better data sources (e.g., outcrops and geophysics) are needed to parameterize facies simulations.

Sampling of sediment from the fjord floor in front of tidewater glaciers in Glacier Bay, Alaska, has provided information about processes in this restricted glacimarine (Dreimanis 1979) setting. Sediment sampling, in conjunction with oceanographic and glacial dynamics data, has also enabled the discrimination of sediment types and their facies associations. Deposits are strongly controlled by: sea-water characteristics, position and sediment discharge of melt-water streams, iceberg calving, and rate of glacierfront retreat.Five distinct facies associations have been found to reflect glacier-fjord regimes. The facies associations and ice-fjord conditions responsible for them form the basis for constructing a preliminary model for glacimarine sedimentation by tidewater glaciers. The model can be used to predict (i) rapid retreat of an actively calving ice front, (ii) slow retreat or stabilization of a calving ice front at a channel constriction, (iii) stabilization of a melting (very rarely calving) ice front when the glacier base is near tidewater elevation, and (iv) large outwash delta progradation into a fjord when the ice front retreats onto land. This model can be used to interpret facies associations found in a stratigraphic record.

The Oak Ridges Moraine lies about 25 km inland from the north shore of Lake Ontario and parallels the lake for about 160 km. The width varies from less than 1.6 to 14.5 km, and the maximum relief is about 150 m. Data from boreholes indicate that the maximum thickness of sediment in the moraine is about 215 m. Previous writers considered that the moraine was formed in several stages between lobes of the Laurentide glacier during the Wisconsinan or earlier.At the western end of the moraine up to 50 m of glaciofluvial outwash has been exposed. These upper sediments were deposited during and after the Port Bruce Stadial of the Late Wisconsinan Substage (

Stratigraphic relationships indicate that late Quaternary outwash near Ottawa, Canada, was deposited close to the ice front and below wave base in the Champlain Sea and/or an earlier ice-dammed lake. Distinct sand and coarse gravel facies are present, the latter with clast long axes parallel to flow, indicating deposition from a high energy current with high clast concentration.The sand facies contain channels up to 10 m deep and 40 m wide, filled with essentially massive sand. In some cases the base and basal fill are contorted into ball-and-pillow structures, and the channels contain dish structures and scattered pebbles. Similar features occur in the channeled sands of deep sea submarine fan valleys, and are thought to indicate rapid deposition by a mass flow mechanism, with high sediment concentration and low turbulence. In the present case, deformation at the channel bases probably resulted from liquefaction due to rapid sediment loading; dewatering gave rise to dish structures at higher levels. Possible mechanisms for initiating mass flows include shock waves generated by iceberg calving, and the effects of rapid changes in water level and salinity as the Champlain Sea invaded the area.

Sea cliffs at Victoria expose submarine flow tills within an ice-contact complex of flow till – outwash proglacial cones interbedded with dinoflagellate-bearing glaciomarine fine sediments. Glacial debris flow lobes (mainly flow tills) were formed by supraglacially, englacially, and basally transported sediment slumping off an ice margin grounded in the Strait of Juan de Fuca. The structures and textures reveal that lobes formed by a conveyor mechanism. In some lobes a double sorting phenomenon apparently developed involving an outer, winnowed, layer of pseudo-plastic flow around an inner core of till that was sorted by dewatering and expulsion of fines outward from the centre during flow. Structures and fabric data indicate lobe travel was gravitationally controlled down cone flanks and independent of ice movement.A depositional model for the complex proposes the ice margin produced a proglacial apron of interdigitating cones, which accumulated on the sea floor. Sediment facies variations were probably controlled by shifts in cone development along the margin: cones formed where glacial and glaciofluvial debris discharged from the ice into the sea and glaciomarine deposits accumulated from glacial flour suspended in the seawater between the cones.Although this is the first reported example of submarine flow tills, casual observations elsewhere suggest that they are common in coastal areas.

The Foster sand pit exposes pre- to late-Champlain Sea sediments containing 4 litho/biofacies. These are, from oldest to youngest: Faciès 1- cross-stratified sand and diamicton deposited as late-glacial, ice-proximal subaqueous outwash. Faciès 2- laminated silt and clay rhythmites with a sparse Candona cf. C. subtriangulata ostracode fauna deposited in a deep, proglacial lake preceding the Champlain Sea, Fades 3- massive to rarely laminated silty clay with dominant foraminifera Elphidium bartletti, Protelphidium orbiculare and Cassidulina crassa represents the first glaciomarine deposition in Champlain Sea water 30-100 m deep with a paleosalinity of 22-33 %o. Faciès 4- mixed bedding of sand and mud, with a microfossil assemblage dominated by the Elphidium/Protelphidium complex representing an intertidal offlap sequence. Water depths during deposition of Faciès 4 dropped to 10-30 m. and paleosalinity dropped to 18-28 %o.. This study recognizes a pre-Champlain Sea proglacial lake, assigns subaqueous outwash deposits to an earlier time than previously believed and documents changes in bottom water characteristics of the early Champlain Sea based on sedimentary and microfossil evidence., La sablière Foster laisse voir des sédiments glacio-lacustres et du début de la Mer de Champlain qui comprennent quatre litho-biofaciès. Les faciès, du plus vieux au plus récent, sont les suivants: Le faciès n° 1 est composé de sable et d'un diamicton à stratification oblique qui se présente comme un épandage fluvio-glaciaire subaquatique tardiglaciaire. Le faciès n° 2 est composé de silt laminé et de rythmites d'argile comprenant une faune peu abondante d'ostracodes {Candona cf. C. subtriangulata): ce faciès a été mis en place dans un lac proglaciaire profond qui a précédé la Mer de Champlain. Le faciès n° 3 est une argile silteuse d'aspect généralement massif avec quelques rares lamines renfermant les foraminifères Elphidium bartletti, Protelphidium orbiculare et Cassidulina crassa; ce faciès représente le premier dépôt de la Mer de Champlain mis en place à 30-100 m de profondeur; la paléosalinité était de 22-33 %o. Le faciès n° 4 formé de lits de sable et de boue mélangés, comprend un assemblage de microfossiles dominé par le complexe Elphidium - Protelphidium, qui représente une séquence intertidale de régression. Au cours de sa mise en place, la profondeur d'eau s'est abaissée jusqu'à 10-30 m, et les eaux se sont progressivement dessalées jusqu'à 18-28 %o. Dans cette étude, on reconnaît l'existence d'un lac proglaciaire précédant la Mer de Champlain. on attribue aux dépôts d'épandage subaquatique un âge supérieur à ce que l'on croyait auparavant et on fournit des renseignements sur le caractère changeant des eaux plus profondes du début de la Mer de Champlain fondés sur des preuves découlant de l'étude des sédiments et des microfossiles.