Ichnofabrics, ichnocoenoses, and ichnofacies implications of an upper cretaceous tidal‐inlet sequence (Eutaw formation, central Alabama)
| Autor: | Jessica K. Hall, Michael W. Smith, Robert E. Locklair, Charles E. Savrda, Jeffrey D. Warren, Malcolm T. Sadler |
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| Rok vydání: | 1998 |
| Předmět: | |
| Zdroj: | Ichnos. 6:53-74 |
| ISSN: | 1563-5236 1042-0940 |
| DOI: | 10.1080/10420949809386439 |
| Popis: | A siliciclastic tidal‐inlet sequence within the Tombigbee Sand Member of the Upper Cretaceous Eutaw Formation, central Alabama, is composed of two subfacies distinguished primarily on the basis of form, scale, and orientation of cross‐stratification. These subfacies record spatial and temporal variations in net‐sedimentation rate, frequency of reworking, and relative importance of slack‐water stages, most of which were governed by variations in tidal‐current asymmetries and associated hydrodynamic regimes. The dominant ichnocoenosis in both subfacies is characterized by, in general order of decreasing abundance: (1) Macaronichnus, produced by vagile, deep deposit‐feeding polychaetes; (2) Conichnus, produced as temporary dwellings or during equilibrium/ escape movements of anemone‐like animals; (3) a branched form of Skolithos, attributed to deposit‐feeding worms; and (4) Dactyloidites, a subsurface feeding structure made by worms or worm‐like organisms. Relative abundances of these ichnotaxa, and degree o... |
| Databáze: | OpenAIRE |
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