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dc.contributor.authorDaley, Gwen Marieen_US
dc.date.accessioned2014-03-14T21:17:39Z
dc.date.available2014-03-14T21:17:39Z
dc.date.issued1999-08-06en_US
dc.identifier.otheretd-080999-122954en_US
dc.identifier.urihttp://hdl.handle.net/10919/39124
dc.description.abstractThe fossiliferous Yorktown Formation (Pliocene) of Virginia was used as a natural laboratory for testing predictions of ecological and evolutionary theories. Specifically, coordinated stasis and ecological locking models have testable elements that can be analyzed using data from the Yorktown Formation. The ecological locking model requires that species within an ecosystem have strong interactions in order to stabilize morphologies of multiple lineages over millions of years. Species intereactions that are strong enough to do this should also be strong enough to be a major ordering force on the composition of paleocommunities. Single and replicate samples were taken from 30 cm stratigraphic intervals within the Rushmere and Morgart's Beach Members at several localities. A total of 142 samples were collected from 5 localites, which yielded 29,000 specimens belonging to 140 species of bivalves, gastropods, and other taxonomic groups. Principle components analysis, ANOVA, MANOVA, and other analyses were used to test the occurence and recurrence of local paleocommunities, paleocommunities, and paleocommunity types. Three paleocommunity types which occured under specific paleoenvironmental conditions were defined: rubbly bottom, transitional, and muddy bottom. Within a single locality samples from the same paleocommunity type yielded very similar faunal compositions, based on the relative abundance of the contained species. However, samples from the same paleocommunity type but different localities displayed low similarity values. This is consistant with local paleoenvironmental control of paleocommunity composition being more important than strong species interactions. The pattern predicted by the model of ecologic locking is absent from these Yorktown paleocommunities. A guild analysis was performed on the data to test whether the same types of organisms recurred in a predictable fashion under similar paleoenvironmental conditions. While the guild structure of the rubbly bottom paleocommunity type did recur at several localities, the guild structure of the other paleocommunity types varied greatly from place to place.en_US
dc.publisherVirginia Techen_US
dc.relation.haspartetd.pdfen_US
dc.rightsI hereby grant to Virginia Tech or its agents the right to archive and to make available my thesis or dissertation in whole or in part in the University Libraries in all forms of media, now or hereafter known. I retain all proprietary rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part of this thesis or dissertation.en_US
dc.subjectpaleocommunityen_US
dc.subjectmolluscan paleoecologyen_US
dc.subjectYorktown Formationen_US
dc.titlePaleocommunities of the Yorktown Formation (Pliocene) of Virginiaen_US
dc.typeDissertationen_US
dc.contributor.departmentGeological Sciencesen_US
dc.description.degreePh. D.en_US
thesis.degree.namePh. D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineGeological Sciencesen_US
dc.contributor.committeechairBambach, Richard K.en_US
dc.contributor.committeememberMiller, Arnold I.en_US
dc.contributor.committeememberBennington, J. Breten_US
dc.contributor.committeememberWard, Lauck W.en_US
dc.contributor.committeememberKowalewski, Michalen_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-080999-122954/en_US
dc.date.sdate1999-08-09en_US
dc.date.rdate2000-08-11
dc.date.adate1999-08-11en_US


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