La Matilde Formation | |
---|---|
Stratigraphic range: Bathonian-Kimmeridgian ~ | |
Type | Geological formation |
Underlies | San Julián Formation |
Overlies | Chon Aike Formation |
Lithology | |
Primary | Claystone, sandstone, siltstone |
Other | Coal beds, conglomerate, tuff |
Location | |
Location | Patagonia |
Coordinates | 47°36′S68°06′W / 47.6°S 68.1°W |
Approximate paleocoordinates | 44°12′S27°18′W / 44.2°S 27.3°W |
Region | Santa Cruz Province |
Country | Argentina |
Extent | Austral Basin |
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. [1] [2] [3]
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. [4] [5]
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. [6] The two formations are the subunits of the Bahía Laura Group. [1]
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. [7] [8]
Fossil taxa recovered from the La Matilde Formation include: [9] [10]
The Jurassic is a geologic period and stratigraphic system that spanned from the end of the Triassic Period 201.4 million years ago (Mya) to the beginning of the Cretaceous Period, approximately 145 Mya. The Jurassic constitutes the middle period of the Mesozoic Era and is named after the Jura Mountains, where limestone strata from the period were first identified.
Equisetum is the only living genus in Equisetaceae, a family of vascular plants that reproduce by spores rather than seeds.
A compression fossil is a fossil preserved in sedimentary rock that has undergone physical compression. While it is uncommon to find animals preserved as good compression fossils, it is very common to find plants preserved this way. The reason for this is that physical compression of the rock often leads to distortion of the fossil.
The Patagonian chinchilla mouse is a species of rodent in the family Cricetidae. It was first described by George Robert Waterhouse in 1839. It is found in Tierra del Fuego and neighboring areas of southernmost Argentina and Chile.
The Magallanes Basin or Austral Basin is a major sedimentary basin in southern Patagonia. The basin covers a surface of about 170,000 to 200,000 square kilometres and has a NNW-SSE oriented shape. The basin is bounded to the west by the Andes mountains and is separated from the Malvinas Basin to the east by the Río Chico-Dungeness High. The basin evolved from being an extensional back-arc basin in the Mesozoic to being a compressional foreland basin in the Cenozoic. Rocks within the basin are Jurassic in age and include the Cerro Toro Formation. Three ages of the SALMA classification are defined in the basin; the Early Miocene Santacrucian from the Santa Cruz Formation and Friasian from the Río Frías Formation and the Pleistocene Ensenadan from the La Ensenada Formation.
The Cañadón Asfalto Formation is a geological formation from the Lower Jurassic, with doubtful layers of Late Jurassic age previously referred to it. The Cañadón Asfalto Formation is located in the Cañadón Asfalto Basin, a rift basin in the Chubut Province of northwestern Patagonia, southern Argentina. The basin started forming in the earliest Jurassic.
Paleontology or palaeontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 2011.
Araucaria mirabilis is an extinct species of coniferous tree from Patagonia, Argentina. It belongs to the genus Araucaria.
Araucarites sanctaecrucis is an extinct coniferous tree from Patagonia, Argentina. Its exact affinities are unknown and it is currently assigned to the form genus Araucarites of the family Araucariaceae. A. sanctaecrucis are known from petrified fossils of branches, foliage, and cones from the Cerro Cuadrado Petrified Forest.
Equisetum thermale is an extinct horsetail species in the family Equisetaceae described from a group of whole plant fossils including rhizomes, stems, and leaves. The species is known from Middle to Late Jurassic sediments exposed in the province of Santa Cruz, Argentina. It is one of several extinct species placed in the living genus Equisetum.
Agathoxylon is a form genus of fossil wood, including massive tree trunks. Although identified from the late Palaeozoic to the end of the Mesozoic, Agathoxylon is common from the Carboniferous to Triassic. Agathoxylon represents the wood of multiple conifer groups, including both Araucariaceae and Cheirolepidiaceae, with late Paleozoic and Triassic forms possibly representing other conifers or other seed plant groups like "pteridosperms".
The Botucatu Formation is an Aptian geologic formation of the Paraná and Pelotas Basins in southern Brazil and northern Uruguay. The formation is composed of quartzitic sandstones, deposited in an eolian environment. Fossil theropod tracks have been reported from the formation.
Tobífera Formation is a volcano-sedimentary formation of Middle to Late Jurassic age. The formation is crops out in the Magallanes Region in southern Patagonia and Tierra del Fuego of Chile, the Santa Cruz Province of southern Argentina, and in the subsurface of the Malvinas Basin offshore Argentina and the Falkland Islands.
The Chon Aike Formation is an extensive geological formation, present in the Deseado Massif in north-central Santa Cruz Province, Patagonia, Argentina. It covers an area of approximately 100,000 square kilometres (39,000 sq mi) and consists of rhyolitic volcanic rocks, particularly ignimbrites and lavas, with smaller amounts of agglomerates and tuffs. Within dacitic rocks, plant fossils have been found.
Equisetum dimorphum is an extinct horsetail species of the family Equisetaceae, and one of the oldest records of the genus Equisetum. It was found in rocks from the Lower Jurassic of Chubut, Argentina, among other plants as ferns, conifers and pteridosperms. Their remains consist of stems, leaves, strobili, and pagoda structures, which are preserved as impressions and casts. The combination of fine grained sediment, and the probable silica deposits in the epidermis of the plant, have managed to conserve not only its gross morphology, but also epidermal details not often present in this kind of preservation. This species was described in 2015 in Ameghiniana by a team led by Andres Elgorriaga, that included investigators of the Museum of Paleontology Egidio Feruglio, the Swedish Museum of Natural History, and the Buenos Aires University.
The Cañadón Calcáreo Formation is an Oxfordian to Kimmeridgian-aged geologic formation, from the Cañadón Asfalto Basin in Chubut Province, Argentina, a rift basin that started forming since the earliest Jurassic. It was formerly thought to date into the Cretaceous, but the age has been revised with Uranium–lead dating as likely being solely Late Jurassic in age.
The Cañadón Asfalto Basin is an irregularly shaped sedimentary basin located in north-central Patagonia, Argentina. The basin stretches from and partly covers the North Patagonian Massif in the north, a high forming the boundary of the basin with the Neuquén Basin in the northwest, to the Cotricó High in the south, separating the basin from the Golfo San Jorge Basin. It is located in the southern part of Río Negro Province and northern part of Chubut Province. The eastern boundary of the basin is the North Patagonian Massif separating it from the offshore Valdés Basin and it is bound in the west by the Patagonian Andes, separating it from the small Ñirihuau Basin.
The Gaiman Formation, in older literature also referred to as Patagonian Marine Formation, is a fossiliferous geologic formation of the Peninsula Valdés Basin in the eastern Chubut Province of northwestern Patagonia, eastern Argentina.
Perimys is an extinct genus of neoepiblemid rodent that lived from the Early to Late Miocene in what is now South America. Fossils have been found in the Cerro Bandera, Cerro Boleadoras, Ituzaingó, Santa Cruz, and Sarmiento Formations of Argentina, and the Galera, Santa Cruz and Río Frías Formations of Chile.
Pararaucaria is a genus of conifer cone belonging to the extinct family Cheirolepidiaceae. Fossils are known from the Lower Jurassic to Early Cretaceous of North America, Europe, South America and Asia. It is associated with Brachyphyllum-type foliage.