Late Glacial Ontario Lobe Ice on the Niagara Peninsula: How Far Did It Go?

Burt, A K; Mulligan, R P M

doi:10.1130/abs/2017ne-290335

Cited by 3 publications

(3 citation statements)

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“…Bedforms with consistent orientations to those described here are also observed on the surface of the HT (and regional equivalents) and are associated with a series of subtle till‐cored moraine ridges to the west (Karrow ; Eyles et al . ; Burt & Mulligan ) and south of Lake Ontario (Kozlowski et al . ).…”

Section: Resultsmentioning

confidence: 99%

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Subglacial and ice‐marginal landforms in south‐central Ontario: implications for ice‐sheet reconfiguration during deglaciation

Mulligan

Eyles

Marich

2019

Boreas

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Regional‐scale, high‐resolution terrain data permit the study of landforms across south‐central Ontario, where the bed of the former Laurentide Ice Sheet is well exposed and passes downflow from irregular topography on Precambrian Shield highlands to flat‐lying Palaeozoic carbonate bedrock, and thick (50 to >200 m) unconsolidated sediment substrates. Rock drumlins and megagrooves are eroded into bedrock and mega‐scale glacial lineations (MSGL) occur on patchy streamlined till residuals in the Algonquin Highlands. Downflow, MSGL pass into juxtaposed rock and drift drumlins on Palaeozoic bedrock and predominantly till‐cored drumlins in areas of thick drift. The Lake Simcoe Moraines, now traceable for more than 80 km across the Peterborough drumlin field (PDF), form a distinct morphological boundary: downflow of the moraine system, drumlins are larger, broader and show no indication of subsequent reworking by the ice, whereas upflow of the moraines, a higher degree of complexity in bedform pattern and morphology is distinguished. Discrete radial and/or cross‐cutting flowset terminate at subtle till‐cored moraine ridges downflow of local topographic lows, indicating multiple phases of late‐stage ice flow with strong local topographic steering. More regional‐scale flow switching is evident as NW‐orientated bedforms modify drumlins south of the Oak Ridges Moraine, and radial flowset emanate from areas within the St. Lawrence and Ottawa River valleys. Most of the drumlins in the PDF formed during an early, regional drumlinization phase of NE–SW flow that followed the deposition of a thick regional till sheet. These were subsequently modified by local‐scale, topographically controlled flows that terminate at till‐cored moraines, providing evidence that the superimposed bedforms record dynamic ice (re)advances throughout the deglaciation of south‐central Ontario. The patterns and relationships of glacial landform distribution and characteristics in south‐central Ontario hold significance for many modern and palaeo‐ice sheets, where similar downflow changes in bed topography and substrate lithology are observed.

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Section: Resultsmentioning

confidence: 99%

“…Radial expansion of thicker ice along the axis of the Lake Ontario basin could be expected, producing the bedforms in the LODF consistently orientated perpendicular to the modern Lake Ontario shoreline (Eyles et al . ; Slomka ; Eyles & Doughty ; Burt & Mulligan ; Kozlowski et al . ; Sookhan et al .…”

Section: Discussionmentioning

confidence: 99%

Subglacial and ice‐marginal landforms in south‐central Ontario: implications for ice‐sheet reconfiguration during deglaciation

Mulligan

Eyles

Marich

2019

Boreas

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“…Similar, although typically thicker, packages of rhythmically bedded glaciolacustrine silt and clay separated by clay-rich diamicton have been observed in many of the 99 continuously cored boreholes drilled as part of the ongoing Niagara Peninsula 3D project (Burt 2013(Burt , 2014(Burt , 2015(Burt , 2016(Burt , 2017 and record an advance into a proglacial lake supported by the ice front (Feenstra 1981;Menzies and Taylor 1998;Burt 2016Burt , 2017Burt and Mulligan 2017).…”

Section: Pre-lgm Depositsmentioning

confidence: 99%

Three-dimensional hydrostratigraphy of the Orangeville Moraine area, southwestern Ontario, Canada

Burt

2018

Can. J. Earth Sci.

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Regional-scale three-dimensional modelling of Quaternary sediments in the Orangeville Moraine area of southwestern Ontario has been completed as part of the Ontario Geological Survey groundwater initiative and provides an improved understanding of the glacial history and conceptual hydrostratigraphic framework for that region. Older (Marine Isotope Stage (MIS) 3-5) diamicton, glaciolacustrine, glaciofluvial, and rare nonglacial deposits forming regional aquitards and local aquifers are found in the northwestern part of the area. Catfish Creek Till, deposited during the Last Glacial Maximum (LGM) (MIS 2), forms a key aquitard and stratigraphic marker at depth. Diamicton, fine-textured glaciolacustrine sediments, and the gravel, sand, and silt conduit and subaqueous fan sediments that constitute the overlying Orangeville Moraine were deposited in an ice-walled lake formed between ice lobes during retreat from the LGM. Diamicton deposited during late-glacial ice margin fluctuations forms the upper aquitard unit and buries the edges of the moraine. The Orangeville Moraine is the largest aquifer in the area, and is partially confined by the upper tills. Thick fine-textured glaciolacustrine deposits, Catfish Creek Till, and older aquitards separate the moraine from bedrock aquifers across most of the area. Depending on hydraulic gradients, buried bedrock valleys with gravel and sand fills have the potential to recharge the bedrock aquifer.Résumé : La modélisation tridimensionnelle régionale de sédiments quaternaires dans la région de la moraine d'Orangeville du sud-ouest de l'Ontario a été réalisée dans le cadre de l'initiative relative aux eaux souterraines de la Commission géologique de l'Ontario et améliore la compréhension de l'histoire glaciaire et du cadre hydrostratigraphique conceptuel pour cette région. Des diamictons, des dépôts glaciolacustres et fluvioglaciaires et de rares dépôts non glaciaires plus anciens (stades isotopiques marins (SIM) 3-5) formant des aquitards régionaux et des aquifères locaux sont présents dans la partie nord-ouest de la région. Le till de Catfish Creek, déposé durant le dernier maximum glaciaire (DMG) (SIM 2), forme un important aquitard et marqueur stratigraphique en profondeur. Des diamictons, des dépôts glaciolacustres à texture fine et les dépôts de conduit de gravier, de sable et de silt et les sédiments de cône subaquatique composant la moraine d'Orangeville sus-jacente ont été déposés dans un lac à parois de glace formé entre des lobes glaciaires durant le recul consécutif au DMG. Du diamicton déposé durant des fluctuations de la marge glaciaire associées au dernier maximum glaciaire forme l'unité d'aquitard supérieure et recouvre les bordures de la moraine. La moraine d'Orangeville constitue le plus grand aquifère dans la région et est partiellement confinée par les tills supérieurs. Des dépôts glaciolacustres à texture fine, le till de Catfish Creek et des aquitards plus anciens séparent la moraine des aquifères du socle rocheux dans la majeure partie de la régi...

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Laurentide Ice Sheet configuration in southern Ontario, Canada during the last glaciation (MIS 4 to 2) from stratigraphic drilling and LIDAR-based surficial mapping

Bukhari,

Eyles,

Mulligan

et al. 2024

Can. J. Earth Sci.

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Regional subsurface mapping of glacial depositional systems preserved in buried bedrock paleovalleys, and quantitative analysis of new LiDAR imagery of surface glacial landforms using machine learning techniques, when combined, are powerful tools for assessing the dynamics of the Laurentide Ice Sheet (LIS) during the last (Wisconsinan) glaciation in southern Ontario. While age dating of deposits preserved below Last Glacial Maximum tills (LGM: MIS 2 < c.24,000 years before present; ybp) is still sparse, newly available sedimentological data derived by cored drilling, combined with legacy outcrop data, identifies thick (100 m +) successions of glaciolacustrine sediments and a lack of till(s) indicating that the ice sheet margin did not extend beyond the Niagara Escarpment at the western end of Lake Ontario, during the earliest phases of the glaciation (MIS 4) or the ensuing mid-Wisconsinan (MIS 3). Ice was able to extend into New York State blocking the Rome outlet to the Hudson Valley ponding deep proglacial lakes in the glacio-isostatically depressed Huron-Ontario-Erie basins recorded by thick glaciolacustrine sediments in paleovalleys. These were cannibalized by an expanding Late Wisconsinan ice sheet after ~ 24,000 ybp recorded by extensive till sheets resting on a marked erosional unconformity, with drumlinized surfaces. Analysis and visualization of LiDAR data identifies discrete statistically validated flow sets of highly elongated streamlined bedforms (mega-scale glacial lineations; MSGLs). These provide key evidence of a major reorganization of the ice sheet margin during deglaciation into lobate paleo ice streams shortly after 17,400 ybp.

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Late Glacial Ontario Lobe Ice on the Niagara Peninsula: How Far Did It Go?

Cited by 3 publications

References 0 publications

Subglacial and ice‐marginal landforms in south‐central Ontario: implications for ice‐sheet reconfiguration during deglaciation

Subglacial and ice‐marginal landforms in south‐central Ontario: implications for ice‐sheet reconfiguration during deglaciation

Three-dimensional hydrostratigraphy of the Orangeville Moraine area, southwestern Ontario, Canada

Laurentide Ice Sheet configuration in southern Ontario, Canada during the last glaciation (MIS 4 to 2) from stratigraphic drilling and LIDAR-based surficial mapping

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