Mid-Tertiary Stratigraphy of the Continental Slope off Nova Scotia

Bartlett, Grant A.

doi:10.4138/1751

Cited by 6 publications

(2 citation statements)

References 15 publications

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“…The seemingly anomalous occurrence of F. fohsi and F. lobata reported by Bartlett (1968) from Nova Scotia may be a reflection of Miocene watermass structure (Cifelli, 1976a).…”

Section: Fohsella Lineagementioning

confidence: 99%

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Stratigraphic Record of the Neogene Globorotalid Radiation (Planktonic Foraminiferida)

Cifelli¹,

Scott²

1986

Smithsonian Contributions to Paleobiology

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Cifelli, Richard, and George Scott. Stratigraphic Record of the Neogene Globorotalid Radiation (Planktonic Foraminiferida). Smithsonian Contribu¬ tions to Paleobiology, number 58, pages 101, 43 figures, 1986.-The histories of lineages forming the Neogene globorotalid radiation in the planktonic foraminifera are reconstructed primarily from stratigraphic distributions. Data on major taxa are synthesized, with particular reference to the devel¬ opment of shell design, and related to biogeograpy and evolutionary strategies. The radiation was established about the base of the lower Miocene by three groups (Fohsella, Globorotalia zealandica lineage, and G. praescitula plexus), which probably arose from separate paragloborotalid lineages. Common trends (size increase, chamber compression, keel development, reduced wall relief) early in the radiation culminated in the evolution of disk¬ like taxa which, since the middle Miocene, have been centered in the tropics. The later phase of the radiation (post middle Miocene) was marked by architectural diversification as spiroconical (e.g., G. margaritae), ventroconical (e.g., G. truncatulinoides), and globose (e.g., G. inflata) taxa arose. Architec¬ tural diversification may be linked with watermass differentiation in the late Neogene. Neogene designs have close counterparts in the earlier, but phyletically isolated, Paleogene and Cretaceous radiations. There are also resemblances in ontogenetic strategies and lineage histories. Common adaptations are suggested, but specific functional explanations have not been established. Periods of major redesign are recognized in most lineages and are not confined to speciation events. Examples of stasis in adult morphology occur particularly in taxa that have evolved compressed, keeled shells. Bifurcations in lineages are indistinctly represented by wide spectra of morphotypes. Within the radiation very rapid speciation events are conspicuously absent, although they possibly occurred at the origin of some lineages. The distinctly sluggish tempo of change may be due to large population sizes and their degree of intercommunication. Good examples of allopatric and parapatric speciation were not found, but the prevalence of polytypic taxa, often distributed in contiguous populations showing clinal variation, would favor the inception of parapatric speciation. Official publication date is handstamped in a limited number of initial copies and is recorded in the Institution's annual report, Smithsonian Year. Series cover design: Thetrilobite Phacops rana Green. Library of Congress Cataloging in Publication Data Cifelli, Richard. Stratigraphic record of the Neogene Globorotalid radiation (Planktonic foraminiferida).

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“…The seemingly anomalous occurrence of F. fohsi and F. lobata reported by Bartlett (1968) from Nova Scotia may be a reflection of Miocene watermass structure (Cifelli, 1976a).…”

Section: Fohsella Lineagementioning

confidence: 99%

“…successful (in population sizes and distribution). (Bartlett, 1968) from 46 °N that proba¬ bly reflect the operation of a Miocene Gulf Stream that introduced tropical planktonic as¬ semblages to a region that now supports subarctic taxa (Cifelli and McCloy, 1983).…”

Section: Analysis Of the Successionmentioning

confidence: 99%

Stratigraphic Record of the Neogene Globorotalid Radiation (Planktonic Foraminiferida)

Cifelli¹,

Scott²

1986

Smithsonian Contributions to Paleobiology

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Cretaceous strata on the Scotian Shelf

King¹,

MacLean²,

Bartlett³

et al. 1970

Can. J. Earth Sci.

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Samples of Cretaceous sediment have been dredged from the Scotian Shelf at a locality 100 km north-northwest of Sable Island.Continuous seismic-reflection profiles across the sample area show the presence of well defined stratification within the bedrock. These beds are truncated by the slopes of submarine valleys which transect the area. Bedrock appears to outcrop along the upper portion of the valley walls or be covered by a layer of unconsolidated material so thin as to be beyond the resolution of the seismic equipment. The dredged material appears to have come from rubble heaps near the base of the valley slopes and is believed to have originated locally.Approximately 450 kg of sedimentary rock were recovered consisting principally of sideritic quartz sandstone and arenaceous sideritic carbonate, both with fossiliferous material. Glauconite is a significant constituent of many samples.The macrofauna include sufficiently diagnostic forms to suggest correlation with the early Upper Cretaceous (Cenomanian) though the possible presence of older or younger forms cannot be wholly excluded. The microflora and microfauna appear to correlate mainly with the Albian-Aptian, and Albian-Cenomanian, respectively.Cretaceous strata immediately underlie much of the central and eastern portions of the Scotian Shelf. Tertiary sediments reported by Marlowe and Bartlett overlie the Cretaceous toward the continental margin and appear to occur as a discontinuous veneer at other localities on the shelf.

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Recent coastal submergence of the Maritime Provinces, Canada

Grant¹

1970

Can. J. Earth Sci.

104

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Hydrographic, archeologic, and geologic evidence indicates that for the last 4000 y the Maritime Provinces have been submerging three to five times faster than the 6 cm/century rate of eustatic rise of sea level. After correcting for the eustatic change, the Bay of Fundy shows an anomalous submergence of 24 cm/century, of which at least 15 cm/century is probably due mainly to rise of high tide, or increase of tidal range, beginning 4000–6000 y ago as eustatic sea-level rise widened and deepened the entrance to the Gulf of Maine. Submergence of the Atlantic coast of Nova Scotia, on the other hand, exceeds the eustatic rate by 9 cm/century, which can be largely explained by new mathematical models as isostatic subsidence of the earth's crust as the sea deepened eustatically over the continental shelf. Only a small part of the residual anomalies of 9 cm and 4 cm/century for the Fundy and Atlantic coasts, respectively, can be attributed to a combination of additional subsidence due to geosynclinal downwarping and relaxation of a possible glacier-margin peripheral bulge, thereby implicating other modes of regional crustal lowering.

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Mid-Tertiary Stratigraphy of the Continental Slope off Nova Scotia

Cited by 6 publications

References 15 publications

Stratigraphic Record of the Neogene Globorotalid Radiation (Planktonic Foraminiferida)

Stratigraphic Record of the Neogene Globorotalid Radiation (Planktonic Foraminiferida)

Cretaceous strata on the Scotian Shelf

Recent coastal submergence of the Maritime Provinces, Canada

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