PBDB Collection

Estancia Bajo Grande (Cretaceous of Argentina)

Where: Santa Cruz, Argentina (48.5° S, 69.2° W: paleocoordinates 49.4° S, 35.4° W)

• coordinate stated in text

• outcrop-level geographic resolution

When: Anfiteatro de Ticó Formation (Baqueró Group), Aptian (125.0 - 113.0 Ma)

• formation-level stratigraphic resolution

Environment/lithology: fluvial-lacustrine; lithified conglomerate and lithified, coarse-grained sandstone

• The basal surface of channel deposits is erosive and irregular, forming up to 0,30m deep steeps. The channel basal fill is composed of clast-supported conglomerates with sandy matrix. The most common sedimentary structures are

•planar and trough-crossed bedding with medium scale heterogeneous sets up to 0,60m. The conglomerates show thickening to coarsening grain arangements in cycles composed of associated sandstone and rarely limestone up to 1,5m thick and 40m wide. These channels move laterally and show a tabular geometry. The thick-medium sized sandstones with isolated clasts show trough-cross bedding structures of a maximum of 0,40m divided in normal graded sets. These sandstones are usually associated with conglomerates or they form cosets up to 1.5m thick. Sandstones carry wide branches and trunks 0,20m in diameter.

•

•NOTE: La unidad se compone de litoacies silicoclásticas y volcaniclásticas. Entre las primeras, con tonos castaños, se incluyen ocnglomerados clasto soporte macizos (Gm) y con estructuras cruzadas en artesa (Gt), areniscas gruesas hasta sabulíticas con estructuras cruzadas en artesa (St) y escasas areniscas finas con óndulas asimétricas de corriente (Sr). Asimismo, aparecen arcillitas y imolitas gris oscuro, con estructuras macizas o con discretas estructuras lentiforms arenosas (linsen) (Fm), laminación (Fsc) y mostrando escasas y pequeñas raíces axiales con ramificaciones (Fr). Su composición es caolinítica. (Cladera, 2002)

Size class: macrofossils

Preservation: mold/impression, adpression, original cellulose, replaced with carbon

Collected by M. llorens, G. Cladera in 2002

Collection methods: chemical, hydrochloric, hydroflouric,

• The fossil specimen, microscope slides and samples for SEM and TEM are deposited in the paleobotanical collection of the Museo Argentino de Ciencias Naturales Bernardino Rivadavia.

Primary reference: M. G. Passalia, G. Del Fueyo, and S. Archangelsky. 2010. An Early Cretaceous zamiaceous cycad of South West Gondwana: Restrepophyllum nov. gen. from Patagonia, Argentina. Review of Palaeobotany and Palynology 161:137-150 [C. Jaramillo/J. Moreno]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 150879: authorized by Carlos Jaramillo, entered by Jessica Moreno on 17.09.2013, edited by Elena Stiles

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names

Ginkgoopsida
Ephedrales - Ephedraceae	Ephedra verticillata n. sp.² Ephedra verticillata n. sp.² jointfir
Cycadopsida
Cycadales - Zamiaceae	Restrepophyllum chiguoides n. gen. n. sp. Restrepophyllum chiguoides n. gen. n. sp. Passalia et al. 2010 cycads
Cycadales -	Mesosingeria oblonga n. sp.³ Mesosingeria oblonga n. sp.³ Villar de Seoane 2005 cycads
Cycadales - Beaniaceae	Androstrobus patagonicus¹, Androstrobus munku¹, Androstrobus rayen¹ Androstrobus patagonicus¹ Archangelsky and Villar de Seoane 2004 cycads Androstrobus munku¹ Archangelsky and Villar de Seoane 2004 cycads Androstrobus rayen¹ Archangelsky and Villar de Seoane 2004 cycads
Hepaticae
Marchantiales -	Ricciopsis grandensis n. sp.² Ricciopsis grandensis n. sp.² Cladera et al. 2007 liverwort
Polypodiopsida
Polypodiales - Polypodiidae	Adiantopteris tripinnata n. sp.² Adiantopteris tripinnata n. sp.² Cladera et al. 2007
Schizaeales - Polypodiidae	Schizaeaceae "gen. inc"² Schizaeaceae "gen. inc"² Kaulfuss Family Schizaeaceae, Genus Incertae Sedis

¹Archangelsky and Villar de Seoane 2004; ²Cladera et al. 2007; ³Villar de Seoane 2005