SDA-4: Quartz Bioclastic Grainstone (Triassic of Mexico)

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

• coordinate stated in text

• small collection-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, argillaceous grainstone

• The Sandy Limestone lithofacies lies above the lime-cemented sandstone and below and above the bedded pure limestone. This unit varies little in thickness ~ averaging 1m. It consists of limestone with abundant sand to silt-sized quartz grains. Profuse subparallel dissolution residues, stylolites, and geopetal structures are characteristic.

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 41021: authorized by David Bottjer, entered by Nicole Bonuso on 05.07.2004

Creative Commons license: CC BY (attribution)

Taxonomic list

Dasycladophyceae
 Dasycladales - Diploporaceae
Rhodophyceae
  - Solenoporaceae
cf. Solenopora sp. Dybowski 1877