Episodes of Source‐sediment Deposition (2)the Episodes in Individual Close‐up†

North, F. K.

doi:10.1111/j.1747-5457.1980.tb00709.x

Cited by 12 publications

(3 citation statements)

References 85 publications

(36 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…An alternative hypothesis is that rifting and plate movements, along with widespread transgressions (e.g., Vail et al, 1977), played a critical role in creating an unusually large number of marginal basins (North, 1980), which by Early to middle Cretaceous time were sufficiently deep to induce patterns of sluggish bottom-water circulation. Anoxia eventually developed in these bottom waters, perhaps promoted by instances of high productivity, but such anoxia was relatively local and sporadic.…”

Section: Discussionmentioning

confidence: 99%

“…The distribution of anoxic sediments through time and space suggests that they initially formed in isolated basins as a result of topographic control of circulation patterns. Topography in turn was probably strongly influenced by continental drift after the breakup of Pangea and by rotation of Iberia, which closed the TethysNorth Atlantic passage (North, 1980), as well as by extensive subsea volcanism.…”

Section: Discussionmentioning

confidence: 99%

“…Tectonic movements related to subduction and transform faulting along active margins are important in creating many local basins in which laminated, organicrich sediments can be deposited (e.g., Southern California during Tertiary time [Ingle, 1980]) and were undoubtedly important in the western Tethys Ocean during mid-Cretaceous time (North, 1980). A disproportionately large amount of the world's sediment accumulates in active-margin basins under conditions that foster preservation of organic material (e.g., rapid burial and restricted circulation), and these basins are atypical of pelagic environments in general (Howell and von Huene, 1981).…”

Section: Tethys Oceanmentioning

confidence: 99%

See 2 more Smart Citations

A Reappraisal of Anoxia and Richness of Organic Material, with Emphasis on the Cretaceous North Atlantic

Waples¹

1985

Initial Reports of the Deep Sea Drilling Project

View full text Add to dashboard Cite

Accumulation of anoxic sediments in the North Atlantic from Barremian through Turanian time (Early to middle Cretaceous) was apparently controlled mainly by local conditions, although global climatic and oceanographic factors may have played a supporting role. Evidence does not support the popular hypothesis developed over the past few years of global or ocean-wide anoxia. The data contradicting this hypothesis are based on a reevaluation of criteria for identifying sediments that accumulated in anoxic water, a critical reappraisal of reported world-wide occurrences of anoxic sediments of these ages, and an examination of the spatial and temporal distribution of anoxic sediments in the North Atlantic and elsewhere. A model is proposed in which the earliest anoxic sediments of Cretaceous age in the North Atlantic were deposited in deep restricted basins. By middle Cenomanian time (about 97 m.y. ago), however, sluggish circulation had led to a gradual expansion of the oxygen-minimum layer, permitting deposition of anoxic sediments in nonbasinal settings. The expansion of the oxygen-minimum layer caused the calcite compensation depth to rise, promoting oxidation of organic carbon and causing contraction of the oxygen-minimum layer. The development of anoxia was thus self-damping. Anoxia effectively disappeared by early Senonian time (88 m.y. ago) when improved circulation created oceans more like those of the present. Some evidence indicates that enhanced productivity and upwelling may have played a local role in fostering anoxia, but most data suggest that worldwide marine productivity was generally not high during Early and middle Cretaceous time.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Tethys Oceanmentioning

confidence: 99%

See 1 more Smart Citation