Late-Pleistocene and Holocene palynology in southeastern Québec

Mott, R J

doi:10.7202/1000060ar

Cited by 50 publications

(8 citation statements)

References 18 publications

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“…Reversals in the warming trend from late Alleröd to YD are not apparent on pollen diagrams of southern Québec, because the Saint-Narcisse Event occurred during the long tundra phase of pollen diagrams established in Appalachian sites (Mott, 1977;Richard, 1977Richard, , 1994aRichard, , 1994b and in the Laurentians south of the moraine outer limit (Labelle and Richard, 1981;Mott and Farley-Gill, 1981).…”

Section: Relation Of the Saint-narcisse Morainic Complex With Youngermentioning

confidence: 99%

The Saint-Narcisse morainic complex and early Younger Dryas events on the southeastern margin of the Laurentide Ice Sheet

Occhietti

2010

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The Saint-Narcisse morainic complex extends over 750 km along the southern margin of the Laurentian Highlands in Québec, north of the St. Lawrence Valley, between the Ottawa and Saguenay Rivers. To the east, the Laurentide Ice Sheet margin was located in the present St. Lawrence Estuary. To the west, the morainic complex is extended 235 km west of the Ottawa River to the Algonquin Highlands, in Ontario. The general outline of the morainic complex comprises large lobes and reentrants, related to major topographic features. In the lower Saint-Maurice River area, the moraine is composed of reworked clay and till and proximal glaciomarine deposits (Yamachiche Diamicton) and melt-out till and ice-marginal outwash (Charette Drift). The Saint-Narcisse Event can be subdivided in several phases: local readvance in low areas, main phase at the origin of the Saint-Narcisse Moraine s.s., melting-out of the marginal ice with compressive structures and large proglacial outwash features, and slow retreat with secondary ridges. The accuracy of the chronological data is limited by several factors: and a floating chronology is proposed. Two landmarks constrain the age and range of duration of the main Saint-Narcisse phase. The main ridge deposition occured after the onset, ca. 12.9 cal ka, of Champlain Sea in the St. Lawrence Valley, and a rapid ice retreat on the southern edge of the Laurentians. It ended before the drawdowm, in the Lake Huron basin, of Glacial Lake Algonquin ca. 12.5 cal ka. The Saint-Narcisse Event is related to the early cold phase of Younger Dryas, as evidenced by other YD ice readvances in Maine, Nova Scotia, and ice cover on the Gaspé Peninsula. It corresponds to a positive change of the budget of the Laurentide Ice Sheet as a result of climate forcing. After a slow ice front retreat during about 900-700 yr, the final phase of YD is marked by the Mars-Batiscan Moraine, located 17 to 70 km north of the Saint-Narcisse Moraine.Le complexe morainique de Saint-Narcisse s’étend sur 750 km le long de la marge méridionale des Laurentides, au Québec, au nord de la vallée du Saint-Laurent, entre l’Outaouais et le Saguenay. Vers l’est, la marge glaciaire était située dans l’estuaire actuel du Saint-Laurent. Vers l’ouest, en Ontario, les formes associées sont suivies dans le massif Algonquin, jusqu’à 235 km de l’Outaouais. Le tracé général du complexe inclut de grands lobes et rentrants liés à la topographie. Dans la basse vallée du Saint-Maurice, la Moraine de Saint-Narcisse est composée de dépôts glaciomarins proximaux, de till et d’argile marine remaniée (Diamicton de Yamachiche) et de till de fusion sur place et de dépôts fluvioglaciaires et juxtaglaciaires (Dépôts de Charette). L’Épisode de Saint-Narcisse est subdivisé en plusieurs phases non nécessairement synchrones sur toute la marge glaciaire: réavancée locale dans les dépressions importantes, phase majeure de stabilisation à l’origine de la Moraine de Saint-Narcisse, fonte sur place indiquée par des structures imbriquées et épandages proglaciaires, puis retra...

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Section: Relation Of the Saint-narcisse Morainic Complex With Youngermentioning

confidence: 99%

The Saint-Narcisse morainic complex and early Younger Dryas events on the southeastern margin of the Laurentide Ice Sheet

Occhietti

2010

gpq

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“…These results show that only small differences exist among the subsets in their portrayal of the major vegetational patterns, but marked differences appear in the record of certain minor patterns. (POTZGER, 1953;POTZGER and COURTEMANCHE, 1954;1956 a,b), and most recently RICHARD (1971 ;1973 a.b.c;1975 a.b.c), MOTT (1976MOTT ( , 1977, TERASMAE andANDERSON (1970), andVINCENT (1973) have described the pollen data from several radiocarbon-dated cores.…”

Section: Découvrir La Revuementioning

confidence: 99%

Mapped patterns in sediment samples of modern pollen from southeastern Canada and northeastern United States

Webb

Yeracaris

Richard

2011

gpq

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Isopoll maps based on 173 modern-pollen samples illustrate the geographical patterns of 12 pollen types within a 600,000 sq. km area centered in southern Québec. The mapped patterns reflect several scales of vegetational pattern that ranges from the major regional change between conifer-hardwood forest and boreal forest down to the minor local differences in vegetation between nearby sites. Picea and other arboreal pollen types are most representative of the regional patterns, whereas Cyperaceae and Ericaceae pollen often vary markedly between adjacent sites. Further analysis of these pollen data explored how much differences in sediment type and variations in analyst practices among the samples can affect the sensitivity of the pollen data to certain of the vegetational patterns. The set of 173 samples was divided into three subsets, two of which differ in sediment types and two of which differ in analyst practices. The distributions of pollen types are then correlated between the contrasting subsets, and their principal components are compared. These results show that only small differences exist among the subsets in their portrayal of the major vegetational patterns, but marked differences appear in the record of certain minor patterns.

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“…Several studies have been conducted to date on the postglacial vegetation history of the regions at the interface of the northeastern United States (Maine, New Hampshire, Vermont, New York) and southern Québec (Canada) using pollen and macrofossil analyses (e.g., Mott 1977;Davis et al 1980;Davis 1983;Davis & Jacobson 1985;Jackson 1989;Whitehead & Jackson 1990;Richard 1994aRichard , 1994bSpear et al 1994;Muller & Richard 2001). Climate has been recognized as the main factor driving long-term regional vegetation development.…”

Section: Introductionmentioning

confidence: 99%

Late Glacial and Holocene vegetation history in the northern foothills of the Adirondack Mountains

Lavoie¹,

Pellerin²,

Larocque³

et al. 2015

Écoscience

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The postglacial history of vegetation at a regional scale is mainly governed by climate. However, the action of other environmental factors can lead to differentiation of the long-term vegetation dynamics in locations that are in proximity. In this context, the vegetation history of Covey Hill, at the northern tip of the Adirondack Mountains, was reconstructed using pollen analysis of a sediment core collected in a bog near the hilltop. This history was then compared with that of other sites in the Adirondacks, in the St. Lawrence Lowlands and in the Appalachian foothills to determine whether differentiations had occurred between sites across the landscape. Regionally, climate seems to have been the main driver of vegetation development. Differences between sites are most pronounced in regard to relative abundance of aspen and alder, and mostly occurred during the Late Glacial and early Holocene. Unlike other sites, fires occurred frequently on Covey Hill for several millennia, and most probably allowed the long-term maintenance of a rare pine barren. Finally, drier conditions are probably partly responsible for the hemlock decline evident around 5100 cal BP. RÉSUMÉL'histoire postglaciaire de la végétation à l'échelle régionale est principalement régie par le climat. Cependant, l'action d'autres facteurs écologiques peut mener à des différentiations dans la dynamique de la végétation pour des sites relativement proches spatialement. Dans ce contexte, l'histoire de la végétation de la colline de Covey, qui constitue l'extrémité septentrionale de la chaîne des Adirondacks, a été reconstituée grâce à l'analyse pollinique d'une carotte sédimentaire prélevée dans une tourbière près du sommet de la colline. Cette histoire a été comparée avec celle d'autres sites dans les Adirondacks, dans les basses-terres du St-Laurent et dans les contreforts des Appalaches afin de voir si des différenciations étaient survenues entre les sites à l'échelle du paysage. Régionalement, le climat semble avoir été le moteur principal de l'amorce des grandes étapes de végétation. Les principales différences entre les sites sont surtout survenues pendant le Tardiglaciaire et l'Holocène inférieur et concernent surtout l'abondance relative du peuplier et de l'aulne crispé. Des feux sont survenus fréquemment sur la colline. Ils ont probablement permis le maintien à long terme d'une rare lande de pins. Enfin, des conditions climatiques plus sèches seraient probablement en partie responsables du déclin de la pruche vers 5100 ans BP. KEYWORDS Adirondack Mountains; Holocene; Late Glacial; pollen analysis; postglacial vegetation history MOTS CLÉS Adirondacks ; analyse pollinique ; histoire postglaciaire de la végétation ; Holocène ; Tardiglaciaire NOMENCLATURE Brouillet et al. (2010+)

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Late-Pleistocene and Holocene palynology in southeastern Québec

Cited by 50 publications

References 18 publications

The Saint-Narcisse morainic complex and early Younger Dryas events on the southeastern margin of the Laurentide Ice Sheet

The Saint-Narcisse morainic complex and early Younger Dryas events on the southeastern margin of the Laurentide Ice Sheet

Mapped patterns in sediment samples of modern pollen from southeastern Canada and northeastern United States

Late Glacial and Holocene vegetation history in the northern foothills of the Adirondack Mountains

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