{"title":"The structure of the nonmarine fossil record: predictions from a coupled stratigraphic–paleoecological model of a coastal basin","authors":"Steven M. Holland","doi":"10.1017/pab.2022.5","DOIUrl":null,"url":null,"abstract":"Abstract. Presented here is a coupled model of the nonmarine fossil record, based on a geometric model of deposition, a random-branching model of evolution, and an ecological model based on an elevation gradient. This model provides testable predictions about the stratigraphy and fossil occurrences in coastal nonmarine settings under three scenarios of sea-level change. A slow relative rise in sea level causes a declining ratio of channel to floodplain deposits, plus changes in community composition that reflect an upward increase in elevation relative to sea level. A rapid relative rise in sea level drives increasing aggradation rates, decreases the ratio of channel to floodplain deposits, and triggers a shift from higher-elevation (more inland) to lower-elevation (more coastal) communities. A fall in sea level produces an unconformity, manifested by valleys separated by interfluves. The resumption of deposition following the sea-level fall causes an abrupt shift in community composition across the unconformity, reflecting the duration of the hiatus and the increased elevation relative to sea level. This produces a cluster of first and last occurrences at the unconformity, and it is the only sequence-stratigraphic source of such clusters in a nonmarine system, in contrast to the multiple mechanisms for generating these clusters in marine systems. A central prediction of these models is that the nonmarine fossil record preserves systematic changes in community composition that reflect elevation (or equivalently, distance from shore). Diagnosing these gradients in ancient systems is a promising avenue of future research.","PeriodicalId":54646,"journal":{"name":"Paleobiology","volume":"48 1","pages":"372 - 396"},"PeriodicalIF":2.6000,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"2","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Paleobiology","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1017/pab.2022.5","RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"BIODIVERSITY CONSERVATION","Score":null,"Total":0}
引用次数: 2
Abstract
Abstract. Presented here is a coupled model of the nonmarine fossil record, based on a geometric model of deposition, a random-branching model of evolution, and an ecological model based on an elevation gradient. This model provides testable predictions about the stratigraphy and fossil occurrences in coastal nonmarine settings under three scenarios of sea-level change. A slow relative rise in sea level causes a declining ratio of channel to floodplain deposits, plus changes in community composition that reflect an upward increase in elevation relative to sea level. A rapid relative rise in sea level drives increasing aggradation rates, decreases the ratio of channel to floodplain deposits, and triggers a shift from higher-elevation (more inland) to lower-elevation (more coastal) communities. A fall in sea level produces an unconformity, manifested by valleys separated by interfluves. The resumption of deposition following the sea-level fall causes an abrupt shift in community composition across the unconformity, reflecting the duration of the hiatus and the increased elevation relative to sea level. This produces a cluster of first and last occurrences at the unconformity, and it is the only sequence-stratigraphic source of such clusters in a nonmarine system, in contrast to the multiple mechanisms for generating these clusters in marine systems. A central prediction of these models is that the nonmarine fossil record preserves systematic changes in community composition that reflect elevation (or equivalently, distance from shore). Diagnosing these gradients in ancient systems is a promising avenue of future research.
期刊介绍:
Paleobiology publishes original contributions of any length (but normally 10-50 manuscript pages) dealing with any aspect of biological paleontology. Emphasis is placed on biological or paleobiological processes and patterns, including macroevolution, extinction, diversification, speciation, functional morphology, bio-geography, phylogeny, paleoecology, molecular paleontology, taphonomy, natural selection and patterns of variation, abundance, and distribution in space and time, among others. Taxonomic papers are welcome if they have significant and broad applications. Papers concerning research on recent organisms and systems are appropriate if they are of particular interest to paleontologists. Papers should typically interest readers from more than one specialty. Proposals for symposium volumes should be discussed in advance with the editors.