SDA-7: Bioclastic Packstone (Triassic of Mexico)

Where: Sonora, Mexico (30.7° N, 112.6° W: paleocoordinates 11.6° N, 53.9° W)

• coordinate stated in text

• outcrop-level geographic resolution

When: Antimonio Formation, Late/Upper Triassic (237.0 - 201.3 Ma)

• The strata of the Monos and Antimonio Formations at Sierra del Alamo represents a nearly complete succession of marine sedimentary rock that ranges from Late Permian to Early Jurassic age.

• group of beds-level stratigraphic resolution

Environment/lithology: marine; lithified packstone

• This thick-bedded pure to impure limestone lithofacies lies above and below the sandy limestone. This unit is by far the most fossiliferous in the Norian carbonates. The biota consists of upright-growing, encrusting, and binding corals and large upright and encrusting, chambered thalamid sponges, massive, encrusting red algae, spongiomorphs and disjectoporoid sponges. The texture ranges from carbonate mudstone to bioclastic wackestone and packstone. Dissolution cavities and karstic features in the limestone indicate episodes vadose diagenesis. This lithofacies represents the purer carbonate end member in the Norian biostromal interval, indicating that siliciclastic input was minimal

Size class: macrofossils

Primary reference: D. H. Goodwin. 1999. Paleontology, Paleoecology, and Depositional Environments Within the Upper Triassic (Norian) Carbonate Strata of the Antimonio Formation, Northwest Sonora, Mexico. University of Montana [D. Bottjer/N. Bonuso/N. Bonuso]more details

Purpose of describing collection: paleoecologic analysis

PaleoDB collection 41023: authorized by David Bottjer, entered by Nicole Bonuso on 05.07.2004

Creative Commons license: CC BY (attribution)

Taxonomic list

 Nodosariacea - Nodosariidae
cf. Nodosaria sp. Lamarck 1812
 Dasycladales - Triploporellaceae
  - Solenoporaceae
cf. Parachaetetes sp. Deninger 1906
cf. Solenopora sp. Dybowski 1877