La Matilde Formation is a Jurassic geological formation in the Austral Basin of Santa Cruz Province, Patagonia, Argentina. It is dated to the Middle to Late Jurassic. From the Bathonian age (164.7 to 167.7 million years ago) to the Kimmeridgian age (150.8 to 155.7 million years ago) at the latest.Channing et al., 2007Clarke et al., 2011
The area was once part of the subtropical and temperate regions of the southern supercontinent Gondwana in the Mesozoic era, a more or less continuous landmass consisting of what is now modern South America, Africa, Antarctica, Australia, New Zealand, and New Guinea.Sequiera & Farrell, 2001Iglesias et al., 2011
Description La Matilde consists primarily of sedimentary rocks. It includes claystone, coal beds, conglomerates, siltstones, sandstones, and volcanic tuff. La Matilde overlies but sometimes intersperses with the Middle Jurassic Chon Aike Formation. The two formations are the subunits of the Bahía Laura Group.
Fossil content La Matilde is known for the abundant fossils recovered from it. Notable fossil localities in the formation include the Cerro Cuadrado Petrified Forest, the Cerro Madre e Hija Petrified Forest, and the remains and trace fossils (including trackways) of dinosaurs in the Laguna Manantiales Farm.
Fossil taxa recovered from the La Matilde Formation include:
Flora
Agathoxylon matildense Araucaria mirabilis Araucarites sanctaecrucis Brachyphyllum Equisetum thermale Hermatomycesporites patagonicus Pararaucaria patagonica
Ichnofossils
Ameghinichnus patagonicusLeonardi, 1994, p.27 Casamiquelichnus navesorum Delatorrichnus goyenechei Grallator Notobatrachus degiustoi Sarmientichnus scagliaiLeonardi, 1994, p.26 Wildeichnus navesiLeonardi, 1994, p.25
See also List of stratigraphic units with theropod tracks List of fossil sites
References
Bibliography
Further reading 2009 - Una nueva Equisetaceae fértil de la Formación La Matilde, Jurásico Medio, Argentina