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Vargas Pena Shale (Silurian of Paraguay)

Where: Paraguay (25.4° S, 57.3° W: paleocoordinates 44.8° S, 142.4° W)

• coordinate based on political unit

• local area-level geographic resolution

When: Vargas Pena Shale Formation, Llandovery (443.7 - 428.2 Ma)

• Harrington provisionally places this formation as Llandovery. Grahn and Gutierrez (2001, PBDB ref. 7139), on the basis of chitinizoan zonation, conclude that it spans Rhuddanian to Telychian ages.

• formation-level stratigraphic resolution

Environment/lithology: marine; micaceous claystone and argillaceous sandstone

• "The Vargas Pena Shale forms a minor intercalation within the upper part of the Itacurubi Group, conformably interposed between the underlying Ayala Sandstone and the overlying Cariy Sandstone. The beds are clearly of marine origin and were probably deposited under shallow, proximal, neritic environment."
• "[In type locality:] shales altered to white micaceous clay, in places stained yellow, brown, and red...The very poor and scarce outcrops along Rio Piribebuy...consist of very light grayish-white micaceous clay-shale, with thin intercalations of soft, very shaly, fine-grained sandstones."

Collection methods: I have combined lists from type locality (responsible for the great majority of taxa) and from the "poor and scarce outcrops." See PBDB collection 908 for additional taxa.

Primary reference: H. J. Harrington. 1972. Silurian of Paraguay. Geological Society of America Special Paper 133:41-50 [M. Foote/M. Foote/M. Foote] more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 25570: authorized by Michael Foote, entered by Michael Foote on 18.09.2002, edited by Pete Wagner and Austin Hendy

Creative Commons license: CC BY (attribution)