scholarly journals Formes de corrosion littorale, côte sud du Saint-Laurent

2005 ◽  
Vol 11 (23) ◽  
pp. 379-395 ◽  
Author(s):  
Jean-Claude Dionne
Keyword(s):  
Geographical Distribution ◽  
Rocky Shores ◽  
The South ◽  
Cold Regions ◽  
Lawrence Estuary ◽  
South Shore ◽  
St Lawrence Estuary ◽  
First Time ◽  
Extensive Bibliography

Corrosion features were observed on the South Shore of the Maritime St. Lawrence Estuary, in conglomerate, limestone, sandstone, shale and cristalline boulders, and are here described for the first time. An attempt to classify these minor features characteristic of rocky shores is made and an extensive bibliography is given. An effort should be made to get more information on the geographical distribution of coastal corrosion forms on non calcareous rocks in cold regions.

scholarly journals Drift-Ice Abrasion Marks along Rocky Shores

1985 ◽  
Vol 31 (109) ◽  
pp. 237-241 ◽  
Author(s):  
Jean-Claude Dionne
Keyword(s):  
Hudson Bay ◽  
Rocky Shores ◽  
Tidal Zone ◽  
Cold Regions ◽  
Lawrence Estuary ◽  
Soft Rocks ◽  
Rock Fragments ◽  
Ice Floes ◽  
St Lawrence Estuary ◽  
Fluvial Environments

AbstractDrift-ice abrasion marks are common along present-day rocky shorelines in cold regions. They include polished surfaces, scratches, striations, small grooves, and minor friction cracks. Most are found on relatively soft rocks like shale, sandstone, limestone, dolomite, and basalt, and occasionally on harder rocks like granite and gneiss. They were made by rock fragments frozen at the base of ice cover or by ice floes pushed onshore by wind or dragged along the bottom by waves, tides, and currents. They are found both in the modern and Pleistocene marine, lacustrine, and fluvial environments. Along the Hudson Bay eastern shoreline, these abrasion marks are superimposed on glacially polished and striated surfaces. Along the St. Lawrence Estuary, they are more common on boulders in the tidal zone. Characteristics of drift-ice abrasion marks are described and their significance is pointed out.

scholarly journals La mer de Goldthwait au Québec

2010 ◽  
Vol 31 (1-2) ◽  
pp. 61-80 ◽  
Author(s):  
Jean-Claude Dionne
Keyword(s):  
Quebec City ◽  
The South ◽  
Lawrence Estuary ◽  
Marine Invasion ◽  
North Shore ◽  
The North ◽  
Upper Limit ◽  
South Shore ◽  
Anticosti Island ◽  
St Lawrence Estuary

The Goldthwait Sea is defined as the late- and post-Glacial marine invasion in the St. Lawrence Estuary and Gulf east of Québec City. In Québec, this sea has submerged an area of about 25 000 km2. The largest areas submerged are the north shore of the St. Lawrence between Les Escoumins and Blanc-Sablon, the south shore between Levis and Tourelles, and the Anticosti Island. The upper limit of the Goldthwait Sea varies from place to place. The Goldthwait Sea began 14 000 years ago and land emergence is still in progress, since the pre-Wisconsin marine level has not been recovered yet. For a better chronology, this long interval needs to be subdivided. Three main periods have been recognized: Goldthwaitian I, II and III. However, a geographical subdivision is also needed. Numerous shorelines were observed at various elevations throughout the area formely submerged by the Goldthwait Sea. However, only a few shorelines are well developed and extensive, and correlations between former shorelines are difficult to establish. Only three levels are widespead and common to the Estuary and parts of the Gulf. The isostatic recovery has been rapid during the first three thousand years after déglaciation of the area: about 75%.

scholarly journals Drift-Ice Abrasion Marks along Rocky Shores

1985 ◽  
Vol 31 (109) ◽  
pp. 237-241 ◽  
Author(s):  
Jean-Claude Dionne
Keyword(s):  
Hudson Bay ◽  
Rocky Shores ◽  
Tidal Zone ◽  
Cold Regions ◽  
Lawrence Estuary ◽  
Soft Rocks ◽  
Rock Fragments ◽  
Ice Floes ◽  
St Lawrence Estuary ◽  
Fluvial Environments

AbstractDrift-ice abrasion marks are common along present-day rocky shorelines in cold regions. They include polished surfaces, scratches, striations, small grooves, and minor friction cracks. Most are found on relatively soft rocks like shale, sandstone, limestone, dolomite, and basalt, and occasionally on harder rocks like granite and gneiss. They were made by rock fragments frozen at the base of ice cover or by ice floes pushed onshore by wind or dragged along the bottom by waves, tides, and currents. They are found both in the modern and Pleistocene marine, lacustrine, and fluvial environments. Along the Hudson Bay eastern shoreline, these abrasion marks are superimposed on glacially polished and striated surfaces. Along the St. Lawrence Estuary, they are more common on boulders in the tidal zone. Characteristics of drift-ice abrasion marks are described and their significance is pointed out.

Mud Cracks and Polygons on Ice Push Ridges, in Tidal Flats of the St. Lawrence Estuary

1974 ◽  
Vol 11 (3) ◽  
pp. 489-494 ◽  
Author(s):  
Jean-Claude Dionne
Keyword(s):  
Water Level ◽  
Tidal Flats ◽  
The South ◽  
Lawrence Estuary ◽  
Waves And Currents ◽  
South Shore ◽  
Break Up ◽  
St Lawrence Estuary

Mud cracks and polygons form during summer in tidal flats of the south shore of the St. Lawrence Estuary. They occur near mean low water level at the top surface of ice push mud ridges formed during winter and break-up. They are a source of mud clasts which settle in the surroundings when carried away by waves and currents.

Les parasites de l'éperlan d'amérique (Osmerus mordax) anadrome du Québec et leur utilité comme étiquettes biologiques

1983 ◽  
Vol 61 (3) ◽  
pp. 621-626 ◽  
Author(s):  
A. Fréchet ◽  
J. J. Dodson ◽  
H. Powles
Keyword(s):  
Osmerus Mordax ◽  
The South ◽  
Lawrence Estuary ◽  
Fourth Group ◽  
Saguenay Fjord ◽  
South Shore ◽  
St Lawrence Estuary

Distribution of smelt parasites Glugea hertwigi, Diphyllobothrium sebago, and Echinorhynchus salmonis support previous hypotheses that three groups of anadromous smelt occur in Quebec waters. These groups are associated with three geographical areas: the Saguenay fjord, the south shore of the St. Lawrence estuary, and Chaleur Bay. Furthermore, the presence of two parasites almost exclusive to the smelt sampled in Forestville and Baie Comeau confirms the existence of a fourth group.

Holocene Relative Sea-Level Fluctuations in the St. Lawrence Estuary, Québec, Canada

1988 ◽  
Vol 29 (3) ◽  
pp. 233-244 ◽  
Author(s):  
J.C. Dionne
Keyword(s):  
Sea Level ◽  
The South ◽  
Relative Sea Level ◽  
Lawrence Estuary ◽  
Sea Level Fluctuations ◽  
Emergence Curve ◽  
South Shore ◽  
Slight Rise ◽  
St Lawrence Estuary

Between 7000 and 6000 yr B.P., relative sea level was as much as 5 m lower than today in the St. Lawrence estuary, Québec. A small transgression (Laurentian transgression) occurred between 5800 and 4400 yr B.P., which resulted in the construction of an 8- to 10-m terrace. About 3000 yr B.P., relative sea level was similar to present, and then a stillstand or a slight rise occurred during which a cliff (Micmac cliff) was cut into the emerged terrace. During a subsequent lowering of relative sea level (coastal emergence), a low aggradational terrace (Mitis terrace) was built between 2300 and 1500 yr B.P. at the base of the Micmac cliff. A new emergence curve for the south shore of the St. Lawrence estuary showing a mid-Holocene high stand of relative sea level is therefore proposed.

The genus Rubus in South Africa. I. Chromosome numbers and geographical distribution of species

Bothalia ◽  
1984 ◽  
Vol 15 (3/4) ◽  
pp. 591-596 ◽  
Author(s):  
J. J. Spies ◽  
H. Du Du Plessis
Keyword(s):  
South Africa ◽  
South African ◽  
Geographical Distribution ◽  
Chromosome Numbers ◽  
The Other ◽  
The South ◽  
African Species ◽  
Rubus Species ◽  
First Time

The geographical distribution of 14 of the Rubus species in South Africa is presented. Chromosome numbers of nine of the species were determined: six for the first time, one is confirmed and additional polyploid levels are described for the other two species. It is demonstrated that the South African species of the subgenus Idaeobatus contain less diploid specimens and more polyploid specimens than their extra-African counterparts. This phenomenon could be attributed to hybridization between the subgenera Eubatus and  Idaeobatus.

The St Lawrence Platform and Appalachian deformation front in the St Lawrence Estuary and adjacent areas (Quebec, Canada): structural complexity revealed by magnetic and seismic imaging

2014 ◽  
Vol 151 (6) ◽  
pp. 996-1012 ◽  
Author(s):  
NICOLAS PINET ◽  
DENIS LAVOIE ◽  
PIERRE KEATING ◽  
MATHIEU DUCHESNE
Keyword(s):  
Cross Section ◽  
Seismic Data ◽  
Structural Complexity ◽  
Strike Slip ◽  
Magnetic Data ◽  
Lawrence Estuary ◽  
Structural History ◽  
St Lawrence Estuary ◽  
First Time ◽  
Slip Motion

AbstractNew magnetic and seismic datasets offer a unique opportunity to document the geometry of the Appalachian front in a poorly studied segment of the orogen. Interpretation of high-resolution magnetic data allows, for the first time, the documentation of the contact between the autochthonous St Lawrence Platform and the Appalachians and highlights the regional significance of previously poorly documented ENE faults that experienced post-Ordovician strike-slip motion. Seismic data reveal tectonic slices in the foreland domain underlying the Appalachians and show that the depth of the décollement at the base of the Appalachian tectonic wedge varies significantly. Taken together, geological, magnetic and seismic data suggest that the geometry of the Appalachian front exhibits significant variations in map and cross-section views and recorded a polyphased structural history.

The food and feeding of common eiders in the St. Lawrence estuary in summer

1974 ◽  
Vol 52 (3) ◽  
pp. 319-334 ◽  
Author(s):  
M. Cantin ◽  
J. Bédard ◽  
H. Milne
Keyword(s):  
Intertidal Zone ◽  
Maximum Growth ◽  
Somateria Mollissima ◽  
Lawrence Estuary ◽  
Common Eiders ◽  
Feeding Activities ◽  
Food And Feeding ◽  
South Shore ◽  
Natural Foods ◽  
St Lawrence Estuary

The study was conducted in the St. Lawrence estuary during 1969 and 1970. The food abundance in the intertidal zone was measured in four Sampling stations located on the south shore of the river; the measurements revealed that over 95% of the available food of the common eider (Somateria mollissima) consisted of Littorina spp., Mytilus edulis, and Gammarus oceanicus. Both adult and young birds showed a distinct rhythm of feeding activities associated with tidal level. During the prenesting period, herring eggs and Nereis virens made up most of the food of adult common eiders. When accompanying ducklings, females ate mostly Littorina spp. and amphipods. Littorina spp. made up between 30 and 97% of the diet of the ducklings, the importance of this gastropod growing with age of the bird. Energy requirements during maximum growth were evaluated at about 460 kcal/bird per day on ducklings (age 54 days) fed natural foods, while between week 3 and week 8 it stood at about 520 kcal/bird per day in ducklings fed "turkey starter." These figures were used to assess the importance of the food removed by the eiders from the intertidal zone during the summer. We conclude that between 10 and 30% (according to the area) of the standing-crop biomass of Littorina alone (in July) is removed by the ducklings and the females accompanying them. At various moments through the season, these birds remove between 40 and 100 metric tons of mollusks per day from the intertidal zone.

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