Seaward extension of the Canadian Appalachians

1968 ◽  
Vol 5 (3) ◽  
pp. 337-373 ◽  
Author(s):  
Robert E. Sheridan ◽  
Charles L. Drake
Keyword(s):  
Continental Slope ◽  
Seismic Refraction ◽  
Seismic Velocities ◽  
Crustal Layer ◽  
Cape Breton Island ◽  
Cape Breton ◽  
Acadian Orogeny ◽  
Basement Ridge ◽  
Surrounding Areas ◽  
East West

The subsurface geology of the Gulf of St. Lawrence and of the continental shelf off Nova Scotia and Newfoundland is interpreted primarily from the results of 37 seismic-refraction profiles. The Gulf of St. Lawrence is underlain by more than 7 km of Carboniferous sediments deposited in an east–west-trending trough. Another important Carboniferous section about 5 km thick is observed northeast of Cape Breton Island in the Laurentian Channel. The Carboniferous trough north of Cape Breton Island swings irregularly east and south around a basement ridge and may hook into the deep east–west-trending Carboniferous trough extending out of Chedabucto Bay. The Gulf sedimentary basin is separated from the trough north of Cape Breton Island by a sharp rise in basement across Cabot Strait.Northeast of Newfoundland the pre-Upper Pennsylvanian basement plunges to deeper than 6 km in the area of the continental slope. A northeast–southwest-trending seaward-opening sediment-filled trough more than 5 km deep is revealed by the configuration of this basement northeast of the Avalon Peninsula.Seismic-refraction profiles across the Gulf of St. Lawrence between western Newfoundland and Quebec show no indication of rifting or the rotation of Newfoundland away from Quebec. Refraction profiles across the northeast rim of the Laurentian Channel indicate that the rim is erosional in origin and that the basement horizons pass continuously beneath.The seaward extension of the zone affected by the Acadian orogeny is characterized by highly metamorphosed basement with higher seismic velocities, 6.0–6.6 km/s, than the surrounding areas. Limited data northeast of Newfoundland indicate that these high velocities decrease gradually and suggest that the influence of the Acadian orogeny dies away about half way across the shelf.The seaward extension of the Taconic orogenic zone is characterized by an intermediate crustal layer, 6.6–7.6 km/s, at depths of 3–12 km. This intermediate layer continues intact all the way to the continental slope northeast of Newfoundland. It was not observed on the Labrador shelf, suggesting that the Appalachians continued straight rather than remaining marginal to North America.It is postulated that the Devonian (Acadian) orogenic belt was not continuous with a corresponding European orogen, but that the Ordovician (Taconic) orogeny may have persisted across into Europe. If this is correct, it implies the existence of a major rift at the Newfoundland slope during middle and late Paleozoic times.

Floristic boundaries in the Gulf of St. Lawrence region: a numerical approach based on the moss flora

1989 ◽  
Vol 67 (6) ◽  
pp. 1633-1644 ◽  
Author(s):  
René J. Belland
Keyword(s):  
Environmental Gradients ◽  
Numerical Approach ◽  
Principal Coordinates Analysis ◽  
Cape Breton Island ◽  
Intermediate Composition ◽  
Cape Breton ◽  
Principal Coordinates ◽  
Floristic Change ◽  
East West ◽  
High Diversity

Possible phytogeographic boundaries within the Gulf of St. Lawrence region are examined using the moss floras of 29 smaller geographic units. Principal coordinates analysis (PCoA) shows floristic change in the Gulf to be gradual and to follow two major gradients, a north–south gradient and an east–west gradient. These are positively correlated to the distributions of temperate and arctic species, respectively. PCoA ordinations also show no evidence of distinct boundaries between adjacent units, but indicate that Cape Breton Island and Gaspé Peninsula have floras of intermediate composition to those of the Maritimes and Newfoundland. Randomly generating floras for adjacent units using Monte Carlo simulation supports the results obtained from PCoA. The real Jaccard similarities between adjacent units are found to be greater than those expected from simulation. The lack of distinct boundaries in the Gulf of St. Lawrence region is attributed to the high diversity of species distributions possible in a region with complex environmental gradients.

Geophysical Investigations East of the Magdalen Islands, Southern Gulf of St. Lawrence

1972 ◽  
Vol 9 (11) ◽  
pp. 1504-1528 ◽  
Author(s):  
A. B. Watts
Keyword(s):  
Large Amplitude ◽  
Seismic Refraction ◽  
Low Density ◽  
Eastern Canada ◽  
Cape Breton Island ◽  
Cape Breton ◽  
Basement Rocks ◽  
Gravity And Magnetic ◽  
Geophysical Investigations ◽  
Magdalen Islands

Detailed gravity and magnetic surveys confirm seismic refraction evidence of a deep (8–10 km) Carboniferous infilled sedimentary basin (the Magdalen basin) between the Magdalen Islands and Newfoundland. The basin margins are associated with gravity and magnetic 'highs' indicating shallow depths (1–3 km) to pre-Carboniferous basement rocks east of the Magdalen Islands and between Cape Breton Island and Newfoundland. The central Magdalen basin is associated with a large amplitude gravity 'low' (50–60 mgal). This can be partly explained by a 2–4 km thickness of low density Late Mississippian sediments overlain by 1–2 km of Upper Pennsylvanian or younger sediments. The western Magdalen basin is associated with large amplitude (20–40 mgal) circular and elongate gravity 'lows'. Detailed interpretations suggest they are caused by low density evaporite structures. The circular 'lows' are interpreted as salt diapirs. The elongate 'lows' are interpreted as structures in the crest of Mississippian/Pennsylvanian anticlines similar to occurrences of Windsor Group evaporites in northern Nova Scotia. The western Magdalen basin may represent one of the largest areas of salt accumulation in Eastern Canada.

Culinary tourism on Cape Breton Island

2019 ◽  
Vol 6 (2) ◽  
Author(s):  
Erna MacLeod
Keyword(s):  
Tourism Destination ◽  
Cape Breton Island ◽  
Culinary Tourism ◽  
Economic Significance ◽  
Cape Breton ◽  
Local Stakeholders ◽  
Resilient Communities ◽  
World Class ◽  
Ecological Relations ◽  
Developed World

Cape Breton Island is a well-known North American tourism destination with long-standing attractions such as the Cabot Trail and more recently developed world-class offerings such as the Cabot Links Golf Course. Tourism contributes significantly to Cape Breton’s economy, particularly since the mid-20th century as traditional resource-based industries have declined. In the 21st century, culinary tourism has become increasingly important to expand the island’s tourism offerings and to provide “authentic” tourism experiences. This study examines local-food tourism in Cape Breton to illuminate its cultural and economic significance. I conducted interviews with food producers, restaurateurs, government representatives, and tourism executives. I also consulted websites and policy documents and compared local stakeholders’ experiences and perspectives with official tourism strategies. Promoting culinary tourism raises questions of power, autonomy, inclusion, and accountability. My study accentuates possibilities for aligning economic and ecological goals to create resilient communities, foster equitable social and ecological relations, and establish Cape Breton as a culinary tourism destination.

Cape Breton ruby, a new Canadian gemstone discovery, Cape Breton Island, Nova Scotia

2007 ◽  
Vol 30 (5) ◽  
pp. 279-286 ◽  
Author(s):  
David J. Mossman ◽  
James D. Duivenvoorden ◽  
Fenton M. Isenor
Keyword(s):  
Nova Scotia ◽  
Cape Breton Island ◽  
Cape Breton

A seismic-based cross-section of the Grenville Orogen in southern Ontario and western Quebec

2000 ◽  
Vol 37 (2-3) ◽  
pp. 183-192 ◽  
Author(s):  
D J White ◽  
D A Forsyth ◽  
I Asudeh ◽  
S D Carr ◽  
H Wu ◽  
...  
Keyword(s):  
Cross Section ◽  
Seismic Refraction ◽  
Shear Zones ◽  
Tectonic Zone ◽  
Grenville Province ◽  
Crustal Layer ◽  
Seismic Reflection Data ◽  
Velocity Models ◽  
Laurentian Margin ◽  
Structural Boundary

A schematic crustal cross-section is presented for the southwestern Grenville Province based on reprocessed Lithoprobe near-vertical incidence seismic reflection data and compiled seismic refraction - wide-angle velocity models interpreted with geological constraints. The schematic crustal architecture of the southwest Grenville Province from southeast to northwest comprises allochthonous crustal elements (Frontenac-Adirondack Belt and Composite Arc Belt) that were assembled prior to ca. 1160 Ma, and then deformed and transported northwest over reworked rocks of pre-Grenvillian Laurentia and the Laurentian margin primarily between 1120 and 980 Ma. Reworked pre-Grenvillian Laurentia and Laurentian margin rocks are interpreted to extend at least 350 km southeast of the Grenville Front beneath all of the Composite Arc Belt. Three major structural boundary zones (the Grenville Front and adjacent Grenville Front Tectonic Zone, the Central Metasedimentary Belt boundary thrust zone, and the Elzevir-Frontenac boundary zone) have been identified across the region of the cross-section based on their prominent geophysical signatures comprising broad zones of southeast-dipping reflections and shallowing of mid-crustal velocity contours by 12-15 km. The structural boundary zones accommodated southeast over northwest crustal stacking at successively earlier times during orogeny (ca. 1010-980 Ma, 1080-1060 Ma, and 1170-1160 Ma, respectively). These shear zones root within an interpreted gently southeast-dipping regional décollement at a depth of 25-30 km corresponding to the top of a high-velocity lower crustal layer.

Thermal regime of the lithosphere in the Canadian ShieldThis article is one of a series of papers published in this Special Issue on the theme Lithoprobe — parameters, processes, and the evolution of a continent.

2010 ◽  
Vol 47 (4) ◽  
pp. 389-408 ◽  
Author(s):  
Claire Perry ◽  
Carmen Rosieanu ◽  
Jean-Claude Mareschal ◽  
Claude Jaupart
Keyword(s):  
Heat Flow ◽  
Heat Generation ◽  
Seismic Refraction ◽  
Surface Heat ◽  
Canadian Shield ◽  
P Wave ◽  
Seismic Velocities ◽  
Flow Measurements ◽  
Surface Heat Flow ◽  
Mantle Heat Flow

Geothermal studies were conducted within the framework of Lithoprobe to systematically document variations of heat flow and surface heat production in the major geological provinces of the Canadian Shield. One of the main conclusions is that in the Shield the variations in surface heat flow are dominated by the crustal heat generation. Horizontal variations in mantle heat flow are too small to be resolved by heat flow measurements. Different methods constrain the mantle heat flow to be in the range of 12–18 mW·m–2. Most of the heat flow anomalies (high and low) are due to variations in crustal composition and structure. The vertical distribution of radioelements is characterized by a differentiation index (DI) that measures the ratio of the surface to the average crustal heat generation in a province. Determination of mantle temperatures requires the knowledge of both the surface heat flow and DI. Mantle temperatures increase with an increase in surface heat flow but decrease with an increase in DI. Stabilization of the crust is achieved by crustal differentiation that results in decreasing temperatures in the lower crust. Present mantle temperatures inferred from xenolith studies and variations in mantle seismic P-wave velocity (Pn) from seismic refraction surveys are consistent with geotherms calculated from heat flow. These results emphasize that deep lithospheric temperatures do not always increase with an increase in the surface heat flow. The dense data coverage that has been achieved in the Canadian Shield allows some discrimination between temperature and composition effects on seismic velocities in the lithospheric mantle.

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