The Geologic History of the Passive Margin Off New England and the Canadian Maritime Provinces

UCHUPI, ELAZAR; AUSTIN, JAMES ALBERT

doi:10.1016/b978-0-444-41851-7.50007-8

Cited by 6 publications

(6 citation statements)

References 18 publications

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“…1966cUchupi, , 1968Uchupi and Emery, 1967;Uchupi et al. 1977;Uchupi and Austin, 1979;Valentine, 1981). Figure 6 is based on, and has been derived from, a much larger more detailed chart by Uchupi (1965a), U.S.G.S.…”

Section: Description Of the Region Topographymentioning

confidence: 99%

Quantitative composition and distribution of the macrobenthic invertebrate fauna of the continental shelf ecosystems of the northeastern United States / Roger B. Theroux, Roland L. Wigley.

Theroux¹,

Wigley²

1998

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From the mid-1950s to the mid-1 960's a series of quantitative surveys of the macrobenthic invertebrate fauna were conducted in the offshore New England region (Maine to Long Island, NewYork). The surveys were designed to 1) obtain measures of macrobenthic standing crop expressed in terms of density and biomass; 2) determine the taxonomic composition of the fauna (ca. 567 species): 3) map the general features of macrobenthic distribution; and 4) evaluate the fauna's relationships to water depth, bottom tvpe, temperature range, and sediment organic carbon content. A total of 1,076 samples, ranging from 3 to 3,974 m in depth, were obtained and analyzed. The aggregate macrobenthic fauna consists of 44 major taxonomic groups (phyla, classes, orders). A striking fact is that only five of those groups (belonging to four phyla) account for over 80% of both total biomass and number of individuals of the macrobenthos. The five dominant groups are Bivalvia, Annelida, Amphipoda, Echninoidea, and Holothuroidea. Other salient features pertaining to the macrobenthos of the region are the following: substantial differences in quantity exist among different geographic subareas within the region, but with a general trend that both densitv and biomass increase from northeast to southwest; both densitv and biomass decrease with increasing depth; the composition of the bottom sediments significantlv influences both the kind and quantity of macrobenthic invertebrates, the largest quantities of both measures of abundance occurring in the coarser grained sediments and diminishing with decreasing particle size; areas with marked seasonal changes in water temperature support an abundant and diverse fauna, whereas a uniform temperature regime is associated with a sparse, less diverse fauna; and no detectable trends are evident in the quantitative composition of the macrobenthos in relation to sediment organic carbon content.

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Section: Description Of the Region Topographymentioning

confidence: 99%

Quantitative composition and distribution of the macrobenthic invertebrate fauna of the continental shelf ecosystems of the northeastern United States / Roger B. Theroux, Roland L. Wigley.

Theroux¹,

Wigley²

1998

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“…1) is of particular interest in that it is situated near the intersection of the Scotian margin and the margin south of the Grand Banks. These margins were both formed during the Triassic -Jurassic separation of Africa and North America (Haworth and Keen 1979;Uchupi and Austin 1979) but are of contrasting tectonic styles: the Scotian margin was formed by rifting, whereas the southern Grand ~a n k s margin is a classic example of a transform margin (LePichon and Fox 1971). Therefore, the structure here might provide an indication of how the structure of a rifted margin is affected by the proximity of a transform.…”

Section: Introductionmentioning

confidence: 85%

Crustal structure of the Nova Scotian margin in the Laurentian Channel region

Reid¹

1987

Can. J. Earth Sci.

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A seismic-refraction study on the outer Scotian Shelf of eastern Canada, camed out using large air-gun sources and oceanbottom seismograph receivers, has provided structud information on the entire crustal column. A thick (about 13 km) sedimentary sequence is characterized by significant l a t e d variation in this area, and a marked increase in seismic velocity around 8 km depth may delineate the synrift-postrift transition. Beneath the sediments is highly attenuated continental crust, about 11 krn thick, with some evidence for a lower crustal layer of velocity around 7 kmls, which may be partly due to underplating during rifting. Determination of the complete crustal structure, including the tentative delineation of the rift-drift transition, in a region of large crustal extension provides a useful test for models of continental rifting, and a simple uniform extension-subsidence model is found to produce an adequate fit to the interpreted structure.Une ttude de sismique r6fraction de la plate-forme exteme de Scotian, dans l'est du Canada, r6alisCe au moyen de gros fusils h air comprimt et de gtophones de stismographes localists au fond de l'octan, a apportk des enseignements sur la structure de la colonne crustale ent5re. Une stquence ~Mimentaire tpaisse (environ 13 km) est caractBriste dans cette r6gion par une variation lattrale importante et un accroissement marqut de la vitesse sismique h environ 8 km de profondeur et qui permet de reptrer la zone de transition syn-rift-post-rift. Sous les stdiments se trouve la croiite continentale fortement atttnute, d'une tpaisseur d'environ 11 km, et il existe quelques indices d'une couche crustale inferieure de vitesse autour de 7 kmls laquelle pounait refltter partiellement un sous-placage dtveloppt durant la formation du rift. L'Btablissement de la structure compltte de la croiite, incluant le tract pksumt de la transition rift-dtrive, dans une rtgion de grande extension crustale, foumit un test valable pour les mdeles de formation de rifts continentaux, et un modtle d'extension-subsidence, uniforme et simple, s'harmonise de manikre satisfaisante avec la structure interpktte.[Traduit par la revue]Can.

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“…These upper continental rise deposits consist of carbonate debris from the seaward edge of the Jurassic platform that slumped seaward to form fan-shaped deposits and a thick onlapping wedge of Tertiary and Quaternary clay, claystone, and shale (Schlee et al 1985). Within this sedimentary wedge are a series of smaller, discrete sedimentary packages that are bounded by laterally extensive unconformities (Uchupi et al 1977;Uchupi and Austin 1979;Valentine 1981;Poag 1982;Schlee et al 1985). One of the most prominent of these unconformities is the Paleocene unconformity denoted A u (Tucholke and Mountain 1979), which divides the Cenozoic section along the continental margin into three sedimentary packages: (1) sediment fill below A u but above the top of the Late Cretaceous sediments, (2) chaotic fill above A u , and 3widespread parallel-bedded fill that unconformably overlies the chaotic fill (Danforth and Schwab 1990).…”

Section: Stratigraphy Under the Continental Margin Southeast Of Nantumentioning

confidence: 99%

Ring-shaped morphological features and interpreted small seamounts between southern Quebec (Canada) and the New England seamounts (USA) and their possible association with the New England hotspot track

Marple

Hurd²,

Altamura³

2018

atgeol

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Enhancements of recently available high-resolution multibeam echosounder data from the western Gulf of Maine and Atlantic continental margin and light detection and ranging (LiDAR) and digital elevation model data from southeastern Quebec (Canada) and the northeastern United States have revealed numerous ring-shaped morphological features and interpreted small seamounts between the Monteregian Hills igneous province and the New England seamounts. The morphological features onshore are mainly ring-shaped depressions, several of which surround mapped igneous intrusions in the Monteregian Hills igneous province and White Mountain magma series. Most of the rings offshore are also depressions, although a few rings are curved ridges above the seafloor. The largest ring in the western Gulf of Maine is the 30-km-diameter Tillies ring that lies 20 km east of Cape Ann, MA. Several small (<3 km in diameter) round, flat-topped submerged hills that we interpret to be volcanic necks are also present beneath the western Gulf of Maine. The rings between Cape Cod and the continental slope are more subtle because of thicker sediments and poorer spatial resolution of the sonar data in this area. The southernmost ring-shaped features are located on the continental slope and upper continental rise and coincide with the northwestern end of the New England seamount chain. The concentration of these features between the Monteregian Hills igneous province and the New England seamounts suggests that they are igneous features that may be associated with the New England hotspot track.

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The Geologic History of the Passive Margin Off New England and the Canadian Maritime Provinces

Cited by 6 publications

References 18 publications

Quantitative composition and distribution of the macrobenthic invertebrate fauna of the continental shelf ecosystems of the northeastern United States / Roger B. Theroux, Roland L. Wigley.

Quantitative composition and distribution of the macrobenthic invertebrate fauna of the continental shelf ecosystems of the northeastern United States / Roger B. Theroux, Roland L. Wigley.

Crustal structure of the Nova Scotian margin in the Laurentian Channel region

Ring-shaped morphological features and interpreted small seamounts between southern Quebec (Canada) and the New England seamounts (USA) and their possible association with the New England hotspot track

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