Taphonomy of fossil plants in the Upper Triassic Chinle Formation.

Persistent Link:
http://hdl.handle.net/10150/187397
Title:
Taphonomy of fossil plants in the Upper Triassic Chinle Formation.
Author:
Demko, Timothy Michael.
Issue Date:
1995
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Fossil plants in the Upper Triassic Chinle Formation are preserved in fluvial channel, overbank, and lacustrine deposits. Plant-bearing units in these deposits are classified into seven types based on these depositional environments or subenvironments. Taphonomic characteristics of these assemblages, and of individual plant fossils within them, indicate that most plant fossils have either not been transported far from their growth sites or are preserved in situ. One particular deposit in the central part of Petrified Forest National Park preserves fossil plants in three associations: (1) allochthonous logs in basal lags in a channel-fill/lateral accretion deposits; (2) autochthonous horsetail trunks and parautochthonous horsetail leaves in a crevasse-splay deposits; and (3) parautochthonous and autochthonous cycadaceous, fern and other types of leaves, and erect and prostrate trunks in a paludal/distal splay deposits. Exposures of contemporaneous high-sinuosity channel and overbank deposits in this area enabled the reconstruction of the local paleogeography, paleohydrology, and paleoecology at a high resolution. Fossil plant assemblages of the Upper Triassic Chinle Formation are concentrated in the lower members of the formation. The lower part of the Chinle Formation was deposited in an incised valley system. Depositional, hydrological, and near-surface geochemical conditions in the incised valley system were conducive to preservation of terrestrial organic material, even though regional conditions were characterized by seasonal/monsoonal precipitation and groundwater conditions. Fossil plant assemblages preserved in these types of fully terrestrial incised valley-fills are taphonomically biased towards riparian wetland environments.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Paleobotany -- Triassic.; Plants, Fossil -- Arizona -- Petrified Forest National Park.; Plants, Fossil -- Colorado Plateau.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Geosciences; Graduate College
Degree Grantor:
University of Arizona
Committee Chair:
Parrish, Judith T.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleTaphonomy of fossil plants in the Upper Triassic Chinle Formation.en_US
dc.creatorDemko, Timothy Michael.en_US
dc.contributor.authorDemko, Timothy Michael.en_US
dc.date.issued1995en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractFossil plants in the Upper Triassic Chinle Formation are preserved in fluvial channel, overbank, and lacustrine deposits. Plant-bearing units in these deposits are classified into seven types based on these depositional environments or subenvironments. Taphonomic characteristics of these assemblages, and of individual plant fossils within them, indicate that most plant fossils have either not been transported far from their growth sites or are preserved in situ. One particular deposit in the central part of Petrified Forest National Park preserves fossil plants in three associations: (1) allochthonous logs in basal lags in a channel-fill/lateral accretion deposits; (2) autochthonous horsetail trunks and parautochthonous horsetail leaves in a crevasse-splay deposits; and (3) parautochthonous and autochthonous cycadaceous, fern and other types of leaves, and erect and prostrate trunks in a paludal/distal splay deposits. Exposures of contemporaneous high-sinuosity channel and overbank deposits in this area enabled the reconstruction of the local paleogeography, paleohydrology, and paleoecology at a high resolution. Fossil plant assemblages of the Upper Triassic Chinle Formation are concentrated in the lower members of the formation. The lower part of the Chinle Formation was deposited in an incised valley system. Depositional, hydrological, and near-surface geochemical conditions in the incised valley system were conducive to preservation of terrestrial organic material, even though regional conditions were characterized by seasonal/monsoonal precipitation and groundwater conditions. Fossil plant assemblages preserved in these types of fully terrestrial incised valley-fills are taphonomically biased towards riparian wetland environments.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectPaleobotany -- Triassic.en_US
dc.subjectPlants, Fossil -- Arizona -- Petrified Forest National Park.en_US
dc.subjectPlants, Fossil -- Colorado Plateau.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGeosciencesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.chairParrish, Judith T.en_US
dc.identifier.proquest9622973en_US
dc.identifier.oclc708248034en_US
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