Arroyo Las Paredes, LP 4, San Lucas Formation, Michoacan (Cretaceous of Mexico)

Where: Mexico (18.6° N, 100.8° W: paleocoordinates 16.8° N, 56.2° W)

• coordinate stated in text

• small collection-level geographic resolution

When: Terrero Prieto Member (San Lucas Formation), Early/Lower Barremian (130.0 - 125.5 Ma)

• early Early Barremian; Nicklesia pulchella zone; Arroyo Las Paredes Section is a 11.5 m thick unit

• bed-level stratigraphic resolution

Environment/lithology: submarine fan; lithified sandstone

• a distinct shallow marine shelf within a tectonically active area, oxygen-deficient bottom waters
• well-bedded dark gray to yelloish volcanic sandstones, with scattered siliceous and calcareous bioclasts. Flysch deposit

Size class: macrofossils

Collection methods: quarrying,

Primary reference: R. Barragan, C. Gonzalez-Arreola, and A. B. Villasenor. 2004. Palaeoecological significance of Barremian ammonite assemblages and facies variations from Southwest Mexico. Lethaia 37:223-234 [W. Kiessling/U. Merkel]more details

Purpose of describing collection: paleoecologic analysis

PaleoDB collection 60779: authorized by Wolfgang Kiessling, entered by Uta Merkel on 23.05.2006

Creative Commons license: CC BY (attribution)

Taxonomic list

• proliferation of middle-water depth ammonites
Show authors, comments, and common names
Cephalopoda
 Ammonoidea - Hamulinidae
Hamulina sp.
Hamulina sp. ammonite
 Ammonitida - Oppeliidae
"Eoheteroceras sp." = Oxycerites (Alcidellus)
"Eoheteroceras sp." = Oxycerites (Alcidellus) ammonite
 Ammonitida - Leptoceratoididae
Hamulinites sp., Karsteniceras sp.
Hamulinites sp. Paquier 1900 ammonite
Karsteniceras sp. Royo-Gomez 1945 ammonite
 Ammonitida - Pulchelliidae
Nicklesia sp.
Nicklesia sp. Hyatt 1903 ammonite