ammonites

Swisshelm Mts. amphibian site: Westphalian A - Westphalian B, Arizona

Where & when
Geology
Taphonomy & methods
Metadata & references
Geography
Country:United States State/province:Arizona County:Cochise
Coordinates: 31.7° North, 109.6° West (view map)
Paleocoordinates:3.8° South, 44.2° West
Basis of coordinate:estimated from map
Altitude:1585 meters
Geographic resolution:small collection
Time
Period:Carboniferous
10 m.y. bin:Carboniferous 4
Key time interval:Westphalian A - Westphalian B
Age range of interval:318.1 - 311.3 m.y. ago
Stratigraphy
Formation:Black Prince Limestone
Stratigraphic resolution:bed
Stratigraphy comments: "The amphibian bed [is] located one meter below the top of the Black Prince [Limestone] [...] The Swisshelm Mountain amphibian bed is dated near the Morrowan-Derryan(= Atokan) boundary, equivalent to the boundary of Westphalian A and B of Europe" (Thayer, 1985).
Lithology and environment
Primary lithology:intraclastic,shelly/skeletal,gray,yellow silty "limestone"
Includes fossils?Y
Lithology description: "light yellow-gray, silty intrabiomicrudit"
Environment:shallow subtidal indet.
Geology comments: "The interpretation best fitting the evidence is a partially protected estuarine environment (for the algal oncolites and marine fauna), close to the outlet of a sluggish coastal river (for transporting the terrestrial and freshwater faunal elements)." (Thayer, 1985).
Taphonomy
Modes of preservation:body
Size of fossils:macrofossils,microfossils
Preservation of anatomical detail:variable
Articulated whole bodies:none
Temporal resolution:time-averaged
Spatial resolution:allochthonous
Taphonomy comments: Some bones show traces of wear through transport, others are completely unworn but may have been transported as a whole carcass into the environment before burial and disarticulation by burrowing organisms. (Thayer, 1985).
Collection methods and comments
Collection excludes:some macrofossils,difficult macrofossils
Collection methods:bulk,acetic
Reason for describing collection:taxonomic analysis
Collection method comments: "Disarticulated faunal elements were obtained by digesting blocks of limestone and silty limestone in a 15 percent solution of acetic acid. The insoluble residue was washed through a 28-mesh screen to remove fine material." (thayer, 1985).
UALP = University of Arizona Laboratory of Paleontology
Metadata
Also known as:UALP 7205
Database number:92271
Authorizer:J. Mueller Enterer:T. Liebrecht
Modifier:T. Liebrecht Research group:micropaleontology,vertebrate
Created:2009-11-04 10:29:34 Last modified:2009-11-04 10:34:23
Access level:the public Released:2009-11-04 10:29:34
Reference information
Primary reference:
31089 D. W. Thayer. 1985. New Pennsylvanian Lepospondyl Amphibians from the Swisshelm Mountains, Arizona. Journal of Paleontology 59(3):684-700 [J. Mueller/T. Liebrecht]