Huas. 27-12 (Ordovician of Argentina)

Where: Jujuy, Argentina (23.6° S, 65.3° W: paleocoordinates 44.7° S, 128.8° W)

• coordinate estimated from map

• small collection-level geographic resolution

When: Rupasca Member (Santa Rosita Formation), Tremadocian (485.4 - 477.7 Ma)

Environment/lithology: basinal (); lithified, argillaceous siliciclastic sediments

• Shelf deposits consist of black, thinly parallel laminated shale. Shale units are laterally extensive, displaying sharp bases. Bioturbation is absent. This facies records deposition below storm-wave base in a low-energy environment due to suspension fall-out deposition in the absence of waves and currents (Buatois & Mangano 2003; Buatois et al. 2006). Absence of bioturbation indicates dominantly anoxic conditions at the sediment-water interface. However, oxygenation events leading to the establishment of periods of dysaerobic waters are indicated by the local presence of benthic fauna.

Size classes: macrofossils, mesofossils

Preservation: cast

Collected by N.E. Vaccari

Collection methods: bulk,

Primary reference: D. Balseiro, B. G. Waisfeld, and L. A. Buatois. 2011. Unusual trilobite biofacies from the Lower Ordovician of the Argentine Cordillera Oriental: new insights into olenid palaeoecology. Lethaia 44:58-75 [D. Balseiro/D. Balseiro]more details

Purpose of describing collection: paleoecologic analysis

PaleoDB collection 136948: authorized by Diego Balseiro, entered by Diego Balseiro on 07.12.2012

Creative Commons license: CC BY (attribution)

Taxonomic list

Trilobita
 Agnostida -
Agnostina indet. Salter 1864 trilobite
 Asaphida - Asaphidae
Asaphellus sp. Callaway 1877 trilobite
 Ptychopariida - Olenidae
Leptoplastides sp. Raw 1908 trilobite
Parabolinella sp. Brögger 1882 trilobite
Bienvillia sp. Clark 1924 trilobite