Puerto Blanco, Unit 3, Cerro Rajon, Caborca Region, Mexico - Stewart et. al 1984 (Cambrian to of Mexico)

Where: Mexico (30.4° N, 111.9° W: paleocoordinates 6.1° S, 105.0° W)

When: Unit 3 Member (Puerto Blanco Formation), Montezuman to Montezuman (520.0 - 516.0 Ma)

• All lithology/stratigraphic details are based primarily on exposures of rocks in the Cerro Rajon area. Unit is 117.5m thick. The formation changes facies markedly from one locality to another in the Caborca Region.

• group of beds-level stratigraphic resolution

Environment/lithology: lithified, gray, yellow limestone and lithified, gray, yellow siltstone

• Represents a southern extension of the Cordilleran miogeocline, rocks may be offset 700 to 800km along a left- lateral fault.
• Archaeocyathid-bearing yellow-gray to light-gray indistinctly thin bedded limestone at base and at top of unit. Middle part of unit is yellowish-gray and greenish-gray silststone, yellowish-gray very fine to fine grained quartzite, and minor sandy limestone and siltstone.

Size classes: macrofossils, mesofossils

Preservation: trace

Collection methods: bulk,

Primary reference: J. Stewart, M. A. S. McMenamin, and J. M. Morales-Ramirez. 1984. Upper Proterozoic and Cambrian rocks in the Caborca Region, Sonora, Mexico - physical stratigraphy, biostratigraphy, paleocurrent studies, and regional relations. U. S. Geological Survey Professional Papers (1309)1-33 [M. Patzkowsky/P. Borkow]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 10681: authorized by Mark Patzkowsky, entered by Phil Borkow on 11.06.2001

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
unclassified
  -
Luguella proveedorensis, Linguella sp., Pelgiellidae indet.
Coeloscleritophora
 Chancelloriida - Chancelloriidae
Chancelloria eros
Chancelloria eros Walcott 1920
Archaeocyatha
 Ajacicyathida - Ethmophyllidae
Ethmophyllum americanum, Ethmophyllum whitneyi, Ethmophyllum cooperi
Ethmophyllum americanum Cooper et al. 1952 archaeocyath sponge
Ethmophyllum whitneyi Meek 1868 archaeocyath sponge
Ethmophyllum cooperi Cooper et al. 1952 archaeocyath sponge
 Ajacicyathida - Ajacicyathidae
Ajacicyathus rimouski, Ajacicyathus nevadensis
Ajacicyathus rimouski archaeocyath sponge
Ajacicyathus nevadensis Okulitch 1943 archaeocyath sponge
 Archaeocyathida - Archaeocyathidae
Archaeocyathus yavorskii
Archaeocyathus yavorskii Vologdin 1931 archaeocyath sponge
 Archaeocyathida - Syringocnemidae
? Syringocnema sp.
? Syringocnema sp. archaeocyath sponge
Microdictyon
  -
Microdictyon sp.
Microdictyon sp. Bengston et al. 1981
Trilobita
 Redlichiida -
cf. Nevadia sp., Olenelloidea indet.
cf. Nevadia sp. Walcott 1910 trilobite
Olenelloidea indet. Walcott 1890 trilobite
Hyolitha
 Hyolithida - Hyolithidae
"Hyolithes aff. princeps" = Nevadotheca princeps
"Hyolithes aff. princeps" = Nevadotheca princeps Billings 1872
Obolellata
 Obolellida - Trematobolidae
Alisina mexicana
 Hyolithelminthida - Hyolithellidae
Hyolithellus sp.
Hyolithellus sp. Billings 1872
 Ichnofossils -
Cruziana sp.
Cruziana sp. d'Orbigny 1842
trace fossil