DLA 31 (Arenal) (Ordovician of Argentina)

Also known as Are 20-4.4m

Where: Jujuy, Argentina (23.5° S, 65.3° W: paleocoordinates 44.8° S, 128.8° W)

• coordinate based on unpublished field data

• small collection-level geographic resolution

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

• bed-level stratigraphic resolution

Environment/lithology: offshore; lithified, bioturbated, muddy siliciclastic sediments and lithified, silty, sandy siliciclastic

• Upper-offshore deposits consist of yellowish green, grey and brown parallel-laminated mudstone intercalated with thin light grey, tabular, erosive-based, very fine-grained silty sandstone. Sandstone usually displays parallel lamination, combined-flow ripple cross-lamination, symmetrical to near-symmetrical ripples, micro-hummocky cross-stratification, and hummocky cross-stratification. Load casts, tool marks and wrinkle marks are common. Upper-offshore deposits reflect alternating background suspension fall-out in a low-nergy setting punctuated by distal storm deposition.

Size classes: macrofossils, mesofossils

Preservation: cast, mold/impression

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 136916: authorized by Diego Balseiro, entered by Diego Balseiro on 06.12.2012

Creative Commons license: CC BY (attribution)

Taxonomic list

Trilobita
 Agnostida -
Agnostina indet. Salter 1864 trilobite
 Asaphida - Asaphidae
Asaphellus sp. Callaway 1877 trilobite
 Asaphida - Remopleurididae
Pseudokainella sp. Harrington 1938 trilobite
 Ptychopariida - Olenidae
Leptoplastides sp. Raw 1908 trilobite