La Chilca Creek, El Salto (Triassic of Argentina)

Where: San Juan, Argentina (29.8° S, 68.2° W: paleocoordinates 39.0° S, 31.7° W)

• coordinate estimated from map

• small collection-level geographic resolution

When: Coloradian other zone, Los Colorados Formation (Agua de la Peña Group), Norian (228.0 - 208.5 Ma)

• "basal part" of the formation; formation is considered to be latest Triassic in age

• bed-level stratigraphic resolution

Environment/lithology: fluvial-lacustrine; red siliciclastic sediments

• "The sequence was interpreted as deposited by moderately sinuous fluvial systems, which laterally interfinger with and grade into horizontally bedded flood-plain deposits. To the top of the sequence, thin-bedded sandstones and siltstones dominate and were deposited in ponds and as crevasse splays in overbank settings" (Arcucci et al. 2004)
• "The red beds of Los Colorados Formation are composed by successive thinning-upward cycles characterized by coarse- to medium-grained sandstones and fine-grained sandstones intercalated with siltstones, which progressively dominate to the upper part of the unit (Fig. 2). Coarse-grained sandstone beds are generally tabular in geometry, cross stratified (large-scale trough and tabular cross-bedding) and locally display horizontal lamination. Rounded pebbles and cobbles of chert, quartzite and metamorphic rocks commonly mantle set boundaries. Massive and horizontal laminated siltstones interfinger with rippled lamination fine-grained sandstones forms the uppermost portion of the cycles" (Arcucci et al. 2004)

Size class: macrofossils

Collection methods: quarrying

Primary reference: A. B. Arcucci, C. A. Marsicano, and A. T. Caselli. 2004. Tetrapod association and palaeoenvironment of the Los Colorados Formation (Argentina): a significant sample from western Gondwana at the end of the Triassic. Géobios 37:557-568 [M. Carrano/M. Carrano/J. Alroy]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 105698: authorized by Richard Butler, entered by Richard Butler on 24.02.2011

Creative Commons license: CC BY (attribution)

Taxonomic list

Osteichthyes
 Therapsida - Stahleckeriidae
Jachaleria colorata n. gen. n. sp.
Jachaleria colorata n. gen. n. sp. Bonaparte 1971 dicynodont