Palimpsest glacial dispersal trains and their significance for drift prospecting

Parent, Michel; Paradis, S J; Doiron, A

doi:10.1016/0375-6742(96)00011-8

Cited by 46 publications

(31 citation statements)

References 14 publications

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“…While Low could not provide a detailed configuration of the ice mass, his interpretation of the shifting centres of dispersion, derived from striation measurements taken along the coast only, is most remarkable, because the proposed locations of his ice divides correspond to positions south of Lake Mistassini for the oldest northwestward ice flow, and north of the lake for the second oldest west-southwestward ice flow, as proposed in the present paper. This chronology of striated surfaces and associated glacial transport was throrougly validated along the James Bay eastern coast and inland as far east as Matagami and Chibougamau Veillette, 1995Veillette, , 1997Veillette and Roy, 1995;Parent et al, 1996). Low's insightful interpretation was overlooked by glacial geoscientists for nearly a century.…”

Section: Inception Of the Labrador Sector Of The Laurentide Ice Sheetmentioning

confidence: 94%

“…Broad, regional ice flow studies, over large areas of the Canadian Shield, have largely been limited to the mapping of apparent glacial lineaments from satellite imagery or conventional airphotos, with little control from striations and glacial transport data (Boulton and Clark, 1990;Clark et al, 2000;Jansson et al, 2002). For the eastern part of the Laurentide Ice Sheet (LIS) complex sequences of shifting ice flows were proposed, particularly in Témiscamingue, Abitibi, southwest of Hudson Bay, in Labrador, to the east and to the northwest of Hudson Bay, using the dispersal of distinctive clasts or geochemical indicators, the striation record and the orientation of landforms (Veillette, 1986;Veillette and McClenaghan, 1996;Thorleifson et al, 1992;Klassen and Thompson, 1993;Parent et al, 1996;Veillette et al, 1999;McMartin and Henderson, this volume). Most detailed ice-flow reconstructions, however, have been confined to the geological provinces with the highest mineral potential.…”

Section: Introductionmentioning

confidence: 99%

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Ice-Flow Chronology and Palimpsest, Long-Distance Dispersal of Indicator Clasts, North of the St. Lawrence River Valley, Quebec

Veillette

2006

gpq

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An ice flow model, based on the distribution of distinctive Proterozoic erratics from the Lake Mistassini and Monts Otish sedimentary basins, and on the mapping of relict striations in a 230 000 km2 area located predominantly in Grenville Province, Québec, is presented to reconstruct the evolution of a large part of the Labrador Sector of the Laurentide Ice Sheet during the Wisconsinan. The results, were added to those of similar surveys carried out in the Abitibi region, and further north. Striated surfaces and indicator clasts from an early northwestward flow, overprinted by those from a widespread southeastward flow, and lastly by those from deglaciation flows toward the southwest, south, and southeast, revealed a complex sequence of events. The northwestward flow originated from a NE‑SW, early Wisconsinan, ice divide located in the Québec highlands, south of Lake Mistassini, that migrated to a position north of the lake, at the Last Glacial Maximum, to give rise to the widespread, southeastward ice flow, that left traces over a large part of Grenville Province. Deglaciation triggered a clockwise shift in ice-flow south of Lake Mistassini, and a counterclockwise shift, north of it. Inception of the northwestward flowing glacier probably results from the coalescence of ice caps formed at the highest elevations along a narrow fringe, north of and parallel to the St. Lawrence River Valley, and expansion toward the northwest suggests a similarity with the windward growth model of ice sheet expansion. The ice flow model has implications for mineral exploration methods based on the sampling of glacial sediments.Une séquence d’écoulements glaciaires est proposée pour expliquer l’évolution d’une grande partie du secteur du Labrador de la calotte laurentidienne au cours du Wisconsinien, à partir de la répartition d’erratiques distinctifs provenant des roches protérozoïques des bassins sédimentaires du lac Mistassini et des monts Otish, et de celle de stries glaciaires anciennes dans une région d’environ 230 000 km2, dont la majeure partie est située dans la province de Grenville, au Québec. Ces nouvelles données ont été ajoutées à celles provenant de levés semblables menés antérieurement en Abitibi, et plus loin au nord. Les surfaces striées et les indicateurs lithologiques de transport glaciaire, associés au premier écoulement vers le nord-ouest, recoupés par ceux d’un écoulement majeur vers le sud-est, et ensuite par ceux d’écoulements vers le sud-ouest, le sud et le sud-est, lors de la déglaciation du territoire, témoignent d’une suite complexe d’évènements glaciaires. Le mouvement initial, vers le nord-ouest, résulte d’une zone de partage des glaces d’orientation NE‑SO, située dans les hautes terres du Québec, au sud du lac Mistassini, laquelle se déplaça au nord du lac Mistassini au Pléniglaciaire, pour former l’écoulement vers le sud-est, dont les traces couvrent une grande partie de la province de Grenville. Lors de la dernière déglaciation des ajustements dans le sens d’écoulement des glaces ont engendré des ro...

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Section: Inception Of the Labrador Sector Of The Laurentide Ice Sheetmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Ice-Flow Chronology and Palimpsest, Long-Distance Dispersal of Indicator Clasts, North of the St. Lawrence River Valley, Quebec

Veillette

2006

gpq

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“…This technique has its roots in mineral prospecting where geochemistry is used to establish the provenance and dispersal pattern of valuable mineral deposits that have underwent transport by ice during glaciation (e.g. Aario & Peuraniemi, 1992;Kauranne, 1958;Klassen, 2001;Klassen & Thompson, 1993;McClenaghan, Thorleifson, & DiLabio, 2000;Parent, Paradis, & Doiron, 1996;Peuraniemi, Aario, & Pulkkinen, 1997;Sarala, Rossi, Peuraniemi, & Ojala, 2007;Veillette, 2004). The geochemical signature of the till is inherited from the bedrock parent material which allows till provenance to be established (Boston, Evans, & Ó 'Cofaigh, 2010).…”

Section: Introductionmentioning

confidence: 99%

Principal component analysis of the geochemistry of soil developed on till in Northern Ireland

et al. 2013

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This paper presents results from the first regional statistical analysis of soils developed on till in Northern Ireland, using the Geological Survey of Northern Ireland's Tellus geochemical database. Till geochemistry is largely determined by its parent bedrock and soils developed on tills are known to inherit this geochemical signature. Soil geochemistry from areas of till can therefore be used to establish sediment provenance which in turn provides information on palaeo ice flow directions and ice sheet history. In this study, we use Principal Component Analysis to establish geochemical groupings that can be related back to likely bedrock parent material for the tills in the region. The maps, presented here at 1:445,000 scale, show the results of the first regional investigation of soil geochemistry of part of the northern sector of the Irish Ice Sheet. The results indicate that the upper surface of the majority of tills in the study area have a close relationship to local bedrock with rapid geochemical changes observed at lithological boundaries. This suggests that tills in this sector of the Irish Ice Sheet are primarily local in origin, indicating rapid entrainment of bedrock and low rates of evacuation of debris to the ice margin.

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“…This re-direction of dispersed material occurred at different magnitudes across the study area and under different degrees of erosion, thus developing hybrid tills (cf. Stea and Finck 2001) and palimpsest dispersal trains modifi ed by the later event (Parent et al 1996). It may be that till was not deposited and re-eroded by the subsequent movements, but that the drift was retained in the ice mass while ice fl ow was redirected, possibly due to a change in the location of ice-growth or ice drawdown (Stumpf et al 2000).…”

Section: Discussionmentioning

confidence: 99%

“…Commonly these dispersal patterns are wedge-, amoeboid-or ribbon-shaped with concentrations elongated parallel to ice fl ow and decreasing in content inversely with distance from the source (Shilts 1976). The interpretation of two-dimensional dispersal patterns can be confused by: multiple ice-fl ow directions producing palimpsest or composite trains (Parent et al 1996;Stea and Finck 2001); topographic infl uence resulting in preferential erosion or ice streaming (Broster and Huntley 1995); or post-depositional weathering and modifi cation of geochemical content (Shilts 1976;Paulen 2001). This is particularly problematic in sub-alpine terrains such as in northern New Brunswick and other areas of Canada.…”

Section: Introductionmentioning

confidence: 99%

Comparison of clast and matrix dispersal in till: Charlo-Atholville area, north-central New Brunswick

Dickson

Broster

Parkhill³

2004

atgeol

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Striations and dispersal patterns for till clasts and matrix geochemistry are used to defi ne fl ow directions of glacial transport across an area of about 800km 2 in the Charlo-Atholville area of north-central New Brunswick. A total of 170 clast samples and 328 till matrix samples collected for geochemical analysis across the region, were analyzed for a total of 39 elements. Major lithologic contacts used here to delineate till clast provenance were based on recent bedrock mapping. Eleven known mineral occurrences and a gossan are used to defi ne point source targets for matrix geochemical dispersal trains and to estimate probable distance and direction of transport from unknown sources. Clast trains are traceable for distances of approximately 10 km, whereas till geochemical dispersal patterns are commonly lost within 5 km of transport. Most dispersal patterns refl ect more than a single direction of glacial transport.These data indicate that a single till sheet, 1-4 m thick, was deposited as the dominant ice-fl ow direction fl uctuated between southeastward, eastward, and northward over the study area. Directions of early fl ow represent changes in ice sheet dominance, fi rst from the northwest and then from the west. Locally, eastward and northward fl ow represent the maximum erosive phases. The last directions of fl ow are likely due to late glacial ice sheet drawdown towards the valley outlet at Baie des Chaleurs. RÉSUMÉL'équipe utilise les striures et les tracés de dispersion des clastes de till ainsi que les caractéristiques géochimiques de la gangue pour défi nir les orientations d'écoulement du transport glaciaire dans un secteur d'environ 800 kilomètres carrés de la région de Charlo-Atholville, dans le centre-nord du Nouveau-Brunswick. On a prélevé dans la région au total 170 échantillons de clastes et 328 échantillons de gangue du till en vue d'analyses géochimiques, et on a analysé leur teneur en 39 éléments particuliers. Les principales zones de contact lithologique utilisées dans le cadre de cet exercice pour délimiter la provenance des clastes de till ont été basées sur de récents travaux de cartographie du substrat rocheux. Onze venues minérales reconnues et un chapeau ferrugineux servent à défi nir les objectifs des sources ponctuelles des tracés de dispersion géochimique de la gangue de même qu'à estimer l'orientation et la distance probables du transport à partir des sources inconnues. Il est possible de retracer les traînées de clastes sur des distances d'une dizaine de kilomètres, tandis que les tracés de dispersion géochimique du till s'effacent généralement avant moins de cinq kilomètres. La majorité des tracés de dispersion évoquent plus d'une direction de transport glaciaire.Ces données révèlent qu'une nappe de till particulière d'une épaisseur d'un à quatre mètres s'est déposée pendant que l'orientation prédominante des écoulements de glaces a varié entre le sud-est, l'est et le nord à l'intérieur du secteur d'étude. Les orientations de l'écoulement primitif représentent les ch...

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Palimpsest glacial dispersal trains and their significance for drift prospecting

Cited by 46 publications

References 14 publications

Ice-Flow Chronology and Palimpsest, Long-Distance Dispersal of Indicator Clasts, North of the St. Lawrence River Valley, Quebec

Ice-Flow Chronology and Palimpsest, Long-Distance Dispersal of Indicator Clasts, North of the St. Lawrence River Valley, Quebec

Principal component analysis of the geochemistry of soil developed on till in Northern Ireland

Comparison of clast and matrix dispersal in till: Charlo-Atholville area, north-central New Brunswick

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