{"title":"Invertebrate trace fossils from Paleogene fluvial strata in Western Washington, USA","authors":"G. Mustoe","doi":"10.1080/10420940.2023.2182295","DOIUrl":null,"url":null,"abstract":"Abstract Fluvial strata in the Paleogene Chuckanut Formation contain a wealth of trace fossils that include both vertebrate and invertebrate ichnofossils. Vertebrate traces have received careful scrutiny, but invertebrate traces have not previously been described. Trace fossils occur in two sediment types. Mudstones deposited in subaqueous environments include highly bioturbated layers that are dominated by horizontal meniscate burrows. Siltstone and fine-grained sandstone beds primarily contain vermiform trails on bedding surfaces, with sparse vertical traces. Some of these sandy beds also contain vertebrate tracks. Chuckanut Formation beds commonly show rapid facies changes in sediments that were deposited along a meandering river during a time of semitropical climate. Transitions from subaqueous to subaerial conditions may have been related to changing water levels caused by variations in seasonal precipitation or episodic flood events. Other possible factors include ponds created by abandonment of channels, overbank sediment s deposited by floods, and breaching of levees to form crevasse splay deposits. Trace fossil assemblages show local variations in the diverse depositional environments of the Chuckanut Formation. Many of the ichnofossil suites clearly represent Scoyenia Ichnofacies, but some occurrences may involve overprinting of Scoyenia and Mermia ichnofacies.","PeriodicalId":51057,"journal":{"name":"Ichnos-An International Journal for Plant and Animal Traces","volume":null,"pages":null},"PeriodicalIF":0.8000,"publicationDate":"2022-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"1","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Ichnos-An International Journal for Plant and Animal Traces","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1080/10420940.2023.2182295","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"PALEONTOLOGY","Score":null,"Total":0}
引用次数: 1
Abstract
Abstract Fluvial strata in the Paleogene Chuckanut Formation contain a wealth of trace fossils that include both vertebrate and invertebrate ichnofossils. Vertebrate traces have received careful scrutiny, but invertebrate traces have not previously been described. Trace fossils occur in two sediment types. Mudstones deposited in subaqueous environments include highly bioturbated layers that are dominated by horizontal meniscate burrows. Siltstone and fine-grained sandstone beds primarily contain vermiform trails on bedding surfaces, with sparse vertical traces. Some of these sandy beds also contain vertebrate tracks. Chuckanut Formation beds commonly show rapid facies changes in sediments that were deposited along a meandering river during a time of semitropical climate. Transitions from subaqueous to subaerial conditions may have been related to changing water levels caused by variations in seasonal precipitation or episodic flood events. Other possible factors include ponds created by abandonment of channels, overbank sediment s deposited by floods, and breaching of levees to form crevasse splay deposits. Trace fossil assemblages show local variations in the diverse depositional environments of the Chuckanut Formation. Many of the ichnofossil suites clearly represent Scoyenia Ichnofacies, but some occurrences may involve overprinting of Scoyenia and Mermia ichnofacies.
期刊介绍:
The foremost aim of Ichnos is to promote excellence in ichnologic research. Primary emphases center upon the ethologic and ecologic significance of tracemaking organisms; organism-substrate interrelationships; and the role of biogenic processes in environmental reconstruction, sediment dynamics, sequence or event stratigraphy, biogeochemistry, and sedimentary diagenesis. Each contribution rests upon a firm taxonomic foundation, although papers dealing solely with systematics and nomenclature may have less priority than those dealing with conceptual and interpretive aspects of ichnology. Contributions from biologists and geologists are equally welcome.
The format for Ichnos is designed to accommodate several types of manuscripts, including Research Articles (comprehensive articles dealing with original, fundamental research in ichnology), and Short Communications (short, succinct papers treating certain aspects of the history of ichnology, book reviews, news and notes, or invited comments dealing with current or contentious issues). The large page size and two-column format lend flexibility to the design of tables and illustrations. Thorough but timely reviews and rapid publication of manuscripts are integral parts of the process.