Preservation patterns of calcareous foraminifera on the deep sea floor reflect the state of saturation of the ocean with respect to calcium carbonate, which in turn is a function of overall mixing rate and fertility. Experiments in the field and in the laboratory establish the sequence in which the various species dissolve. The same sequence is evident from seafloor data. The sequence can be used to form dissolution indices. Such indices, as well as other indicators of preservation, e. g. fragmentation, are useful for mapping preservation states and for delineating the preservation stratigraphy in calcareous pelagic sediments. Preservation stratigraphy is an excellent tool for stratigraphic correlation and contains clues to the changing chemistry and fertility of the ocean. Acoustic reflectors in carbonate sequences are closely tied to preservation fluctuations.
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Foraminiferal Ecology and Paleoecology
Perhaps no fossil group is used as much as foraminifera for paleoecologic inference, both in academia and industry. Since the late 1960s, new concepts and much additional data have appeared that make it difficult for the casual worker not immediately concerned with foraminiferal ecology and paleoecology to stay abreast of the latest developments. In these notes, the authors summarize much of that information, or provide reference to more detailed sources. They also attempt to point out problems and other methods of dealing with them. Most paleoecologic work with foraminifera in the past has relied on direct comparison of fossil assemblages with the most similar modern assemblages, and inferring then that the environments were similar also. The method is used widely in scientific studies and in industrial applications. The result is based on the single hypothesis that the fossils are environmentally analogous to their modern counterparts. These notes present a number of alternative working hypotheses, and in some cases, examine the data to attempt of disprove them.