An environmental study of Silurian atrypid communities from southern Norway

Worsley, David; Broadhurst, F. M.

doi:10.1111/j.1502-3931.1975.tb00932.x

Cited by 9 publications

(2 citation statements)

References 16 publications

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“…The small volumes of sediments eroded from continental platforms at these times were channeled into large geographically discrete drainage basins containing many tributaries but with only 1 major outlet to the sea, like the Mississippi, Amazon, and Yangtze Rivers of today (e.g. Tipper 1975, Worsley & Broadhurst 1975, Milliman & Meade 1983. Suspended solids carried by these river systems were deposited in a small number of large estuaries.…”

Section: Geologic Periodsmentioning

confidence: 99%

“…by bottom scour, advection) by ocean turbulence may have become smaller to keep pace with the higher frequencies, shorter durations and smaller area1 sizes of turbulent eddies that characterized intercontinental waterways and shallow inland seas d'uring periods of continental fission and high turbidity (e.g. Worsley & Broadhurst 1975, Marcotte 1980, Jablonski & Flessa 1984. For example, (small) dinoflagellates are adapted to taking up nutrients provided in high frequency fluxes while (large) diatoms are adapted to lower frequency nutrient fluxes (Turpin & Harrison 1979, Turpin et al 1981.…”

Section: Crustaceansmentioning

confidence: 99%

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Turbidity, arthropods and the evolution of perception:toward a new paradigm of marine phanerozoic diversity

Marcotte¹

1999

Mar. Ecol. Prog. Ser.

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Geological, paleo-oceanographic and paleoclimatological studies have independently demonstrated that the volume of preserved marine sediments, eustatic sea level, the depth to which the sea was oxygenated, the concentration of atmospheric oxygen and carbon dioxide and the amount of terrestrial rainfall fluctuated in a 400 million yr cycle over Phanerozoic time. These data are used to develop the hypothesis that the level of oceanic turbidity CO-varied with these changes and that turbidity was the motor, plate tectonics the tempo and perception the mode of evolution in Phanerozoic seas. This hypothesis predicts that during turbidity maxima (Silunan-Devonian, Jurassic-Tertiary), animals with non-visual foraging and predator-avoidance mechamsms and adaptations to marine pelagic. freshwater and terrestrial habits should diversify. During turbidity minima (late-precambrianCambrian, late-Carboniferous-Triassic), animals with vlsual sensory modalities and benthic habitat specializations should diversify. At the boundary of these envlronmental conhtions, alternating mass extinctions of these adaptive characters and the taxa possessing them should occur. Patterns in the evolution of perceptual modalities, foraging strategies, predator avoidance mechanisms, habitat specializations and inferred aspects of behavioral ecology of aquatic arthropods. 1.e. adaptive characters that are less sensitive to instantaneous changes in diversity than are the taxa that carried them, are used to test these predictions. Trilobite diversification and extinction, the adaptive radation of ostracods and eumalacostracan crustaceans; the iterative evolution of small, fast-moving entomostracan crustaceans; and the evolution of terrestrial chelicerates and decapod crustaceans are all consistent m t h these predictions. In short, the hlstory of aquatic evolution m Phanerozoic seas can be told in the evolution of perception. Data as disparate as the diversification and extinction of marine plants, cephalopod mollusks and fish are also consistent with predictions deduced from this hypothesis.

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Section: Geologic Periodsmentioning

confidence: 99%

Section: Crustaceansmentioning

confidence: 99%

Turbidity, arthropods and the evolution of perception:toward a new paradigm of marine phanerozoic diversity

Marcotte¹

1999

Mar. Ecol. Prog. Ser.

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Depositional environments in the Telychian Stage (Silurian) of the central Oslo region, Norway

Baarli

1990

Geological Journal

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The Telychian succession in the central Oslo region was previously interpreted as deposited in a relatively deep, calm environment showing a continuous transgressive development. A new analysis of fossil assemblages shows that sediments in the central districts were deposited at varying water depths in an environment marked by intense infaunal activity in soft substrates. Two small-scale fluctuations in sea level are attributed to eustasy. The maximum deepening events occurred during the Monograptus turriculatus and Monoclimacis crenulata graptolite zones.Previous depositional models include development of a trough to the north of the Oslo region in early Telychian time, which formed due to isostatic loading caused by an advancing thrust front of the Caledonian Orogeny. Bathymetric analysis shows a deepening in the Ringerike district in the latest Aeronian, which here is interpreted as a distal effect of the loading to the north. The local deepening led to reversal of the epicontinental slope between the northern and western districts and the central districts and the development of an east-west elongate positive area further south. The thrust front acted as a source of siliciclastic material; and when the front halted in mid-Telychian time the trough was filled in gradually by a prograding coast or delta. The diachronous Vik Formation is viewed as a distal development of this progradation. When the east-west oriented positive area subsided the Vik Formation was deposited in Skien to the south.

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