EARLY PROTEROZOIC TURBIDITE DEPOSITION AND MELANGE DEFORMATION, SOUTHEASTERN ARIZONA

Persistent Link:
http://hdl.handle.net/10150/187544
Title:
EARLY PROTEROZOIC TURBIDITE DEPOSITION AND MELANGE DEFORMATION, SOUTHEASTERN ARIZONA
Author:
Swift, Peter Norton
Issue Date:
1987
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:
Greenschist-facies, Lower Proterozoic metasedimentary rocks of the Johnny Lyon Rills and Little Dragoon Mountains of southeastern Arizona were deposited prior to the intrusion of an approximately 1690 Ma rhyodacite pluton. Well-preserved primary structures indicate deposition by turbidity currents in an intermediate to neardistal setting. Sandstone compositions suggest derivation from either a complex, heterogeneous source or multiple source terranes that provided mature, quartzose sediment as well as lesser quantities of volcaniclastic detritus. Earliest deformation, predating both intrusion of the rhyodacite and metamorphism, produced sections of melange composed primarily of dismembered turbidite beds, but also incorporating large (up to several km long) blocks of deformed basalt. Subsequent deformation, in part post-dating intrusion of the rhyodacite and in part coinciding with metamorphism, affected both melange and coherent strata, and involved isoclinal folding and layerparallel faulting and shearing. It is proposed that turbidite deposition occurred in a trench associated with a north-dipping subduction zone or on ocean floor outboard of such a trench. Melange formed primarily by ductile disruption of unlithified sediments within the subduction zone. Basalt blocks incorporated within the melange represent fragments of oceanic crust or seamounts detached from the lower plate during subduction. Later deformation and intrusion of the rhyodacite occurred within an accretionary prism above the subduction zone. Deformation within the prism ended prior to intrusion of the 1625 ± 10 Ma posttectonic Johnny Lyon Granodiorite.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Geology, Stratigraphic -- Proterozoic.; Turbidites -- Arizona -- Cochise County.; Melanges (Petrology) -- Arizona -- Cochise County.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Geosciences; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Dickinson, William R.
Committee Chair:
Dickinson, William R.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleEARLY PROTEROZOIC TURBIDITE DEPOSITION AND MELANGE DEFORMATION, SOUTHEASTERN ARIZONAen_US
dc.creatorSwift, Peter Nortonen_US
dc.contributor.authorSwift, Peter Nortonen_US
dc.date.issued1987en_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.abstractGreenschist-facies, Lower Proterozoic metasedimentary rocks of the Johnny Lyon Rills and Little Dragoon Mountains of southeastern Arizona were deposited prior to the intrusion of an approximately 1690 Ma rhyodacite pluton. Well-preserved primary structures indicate deposition by turbidity currents in an intermediate to neardistal setting. Sandstone compositions suggest derivation from either a complex, heterogeneous source or multiple source terranes that provided mature, quartzose sediment as well as lesser quantities of volcaniclastic detritus. Earliest deformation, predating both intrusion of the rhyodacite and metamorphism, produced sections of melange composed primarily of dismembered turbidite beds, but also incorporating large (up to several km long) blocks of deformed basalt. Subsequent deformation, in part post-dating intrusion of the rhyodacite and in part coinciding with metamorphism, affected both melange and coherent strata, and involved isoclinal folding and layerparallel faulting and shearing. It is proposed that turbidite deposition occurred in a trench associated with a north-dipping subduction zone or on ocean floor outboard of such a trench. Melange formed primarily by ductile disruption of unlithified sediments within the subduction zone. Basalt blocks incorporated within the melange represent fragments of oceanic crust or seamounts detached from the lower plate during subduction. Later deformation and intrusion of the rhyodacite occurred within an accretionary prism above the subduction zone. Deformation within the prism ended prior to intrusion of the 1625 ± 10 Ma posttectonic Johnny Lyon Granodiorite.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectGeology, Stratigraphic -- Proterozoic.en_US
dc.subjectTurbidites -- Arizona -- Cochise County.en_US
dc.subjectMelanges (Petrology) -- Arizona -- Cochise County.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.advisorDickinson, William R.en_US
dc.contributor.chairDickinson, William R.en_US
dc.contributor.committeememberChase, Clemen_US
dc.contributor.committeememberDamon, Paulen_US
dc.contributor.committeememberGehrels, George E.en_US
dc.contributor.committeememberTitley, Spencer R.en_US
dc.identifier.proquest8715720en_US
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