Stratigraphy and Sedimentology of the Bisbee Group in the Whetstone Mountains, Pima and Cochise Counties, Southeastern Arizona
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Master's Thesis full PDF
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Issue Date
1982Keywords
alluvial fansApache Canyon Formation
Aptian
Arizona
Basin and Range Province
Bisbee Group
Bisbee-Chihuahua Embayment
Carboniferous
Cochise County Arizona
ComancheanCretaceousdeltaic environmentdepositional environmentenvironmentestuarine environmentfluvial environmentGlance ConglomeratelithofaciesLower CretaceousMesozoicNaco GroupNorth AmericaPaleozoicPennsylvanianPermianPima County ArizonaSantoniansedimentary rockssedimentationSenonianShellenberger Canyon Formationsoutheastern ArizonastratigraphyTurney Ranch FormationunconformitiesUnited StatesUpper CretaceousWhetstone MountainsWillow Canyon FormationGeology -- Arizona -- Whetstone Mountains.Geology, Stratigraphic.Sediments (Geology)Geology -- Arizona -- Pima County.Geology -- Arizona -- Cochise County.
Advisor
Dickinson, W. R.Committee Chair
Schreiber, Joseph F., Jr.Metadata
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The University of Arizona.Rights
Copyright © is held by the author. Digital access to this material is made possible by the Antevs Library, Department of Geosciences, and 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 or the department.Collection Information
This item is part of the Geosciences Theses collection. It was digitized from a physical copy provided by the Antevs Library, Department of Geosciences, University of Arizona. For more information about items in this collection, please email the Antevs Library, antevs@geo.arizona.edu.Abstract
The Aptian-Santonian(?) Bisbee Group in the Whetstone Mountains comprises 2375 m of clastic sedimentary rocks and limestones. The basal Glance Conglomerate unconformably overlies the Pennsylvanian-Permian Naco Group. It consists of limestone conglomerates which were deposited in proximal alluvial fan environments. The superadjacent Willow Canyon Formation contains finer grained rocks which were deposited in the distal portions of alluvial fans. The lacustrine limestones in the Apache Canyon Formation interfinger with and overlie these alluvial fan facies. The overlying Shellenberger Canyon Formation is composed mostly of terrigenous rocks derived from westerly terranes. This formation contains thick sequences of fluvio-deltaic facies as well as a thin interval of estuarine deposits which mark a northwestern extension of the marine transgression in the Bisbee -Chihuahua Embayment. The youngest formation (Upper Cretaceous?) in the Bisbee Group, the Turney Ranch Formation, consists of interbedded sandstones and marls which were deposited by fluvial and marine(?) processes.Type
textThesis-Reproduction (electronic)
Degree Name
M.S.Degree Level
mastersDegree Program
Graduate CollegeGeosciences
Degree Grantor
University of ArizonaRelated items
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Environments of Deposition of the Moenkopi Formation in North-Central ArizonaIn north-central Arizona, the Moenkopi Formation of Triassic age consists of generally unfossiliferous red mudstones, siltstones, gypsum, and sandstones that contain abundant sedimentary structures, such as ripple marks, cross-stratification, ripple laminae, salt crystal casts, mud cracks, sole marks, parting lineation, and core-and-shell structures. Three informal members were established for this study: the lower member, the lower massive sandstone, and the upper member. Flaser, wavy, and lenticular bedding, bimodal distribution of ripple laminae dips, parallel ripple marks dominant over cuspate ripple marks, gypsum beds and veins, salt crystal casts, and lack of channel deposits are the suite of sedimentary features that are interpreted to indicate a tidal-flat environment during deposition of the lower member. The very fine grained lower massive sandstone can be divided into four subunits, which were formed by a transgression-regression of the sea. Wavy and ripple laminated beds in subunit one were probably deposited in very shallow water. Medium-scale wedge-planar and trough sets of cross strata with mean dip directions to the southeast make up subunit 2 and indicate megaripples formed by longshore drift. Subunit 3 consists of lenticular, wavy, pod-shaped beds that were created in water shallower than that for subunit 2. Continuous, large-scale, low-angle cross strata of uniform thickness and medium-scale wedge-planar and trough sets of cross strata characterize subunit 4 and are typical of beach deposits. The significant sedimentary features in the upper member are unimodal distribution of ripple laminae dips, cuspate ripple marks dominant over parallel ripple marks, channel deposits with shallow trough cross strata, an increase in the number and thickness of sandstone and siltstone beds compared with the lower member, plus vertebrate bones, tracks, and plant impressions. This suite of features indicates a flood-plain environment. Early in Moenkopi time, north-central Arizona was a tidal flat and sabkha. The sea to the west fluctuated east and west and finally transgressed over the entire area. As the sea regressed, a beach formed, and rivers flowing from the east deposited sediment on a westward-prograding flood plain. In the northern, southern, and central portions of the region, sabkhas existed for a time during regression. At the end of Moenkopi time, the entire area was a flood plain. Considering the association of red beds and evaporites, the absence of fossils in the lower member and the lower massive sandstone, the paleowind directions, and the theory of continental drift, the climate during early and middle Moenkopi time was probably hot and arid. The influx of sandstones, the presence of Calamites (?) impressions, and trackways and bones of amphibians in the upper member suggest that the climate became more humid at the end of Moenkopi time.
