The Miocene is the first geological epoch of the Neogene Period and extends from about 23.03 to 5.333 million years ago (Ma). The Miocene was named by Scottish author Charles Lyell; its name comes from the Greek words μείων and καινός and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene is preceded by the Oligocene and is followed by the Pliocene.
An inland sea is a shallow sea that covers central areas of continents during periods of high sea level that result in marine transgressions. In modern times, continents stand high, eustatic sea levels are low, and there are few inland seas, the largest being Hudson Bay. Modern examples might also include the recently reflooded Persian Gulf, and the South China Sea that presently covers the Sunda Shelf.
Palaeospheniscus is an extinct genus of penguins belonging to the subfamily Palaeospheniscinae. These penguins are apparently not closely related to the modern genus Spheniscus.
The Patagonian Desert, also known as the Patagonian Steppe is the largest desert in Argentina and is the 8th largest desert in the world by area, occupying 673,000 square kilometers (260,000 mi2). It is located primarily in Argentina and is bounded by the Andes, to its west, and the Atlantic Ocean to its east, in the region of Patagonia, southern Argentina. To the north the desert grades into the Cuyo Region and the Monte. The central parts of the steppe are dominated by shrubby and herbaceous plant species albeit to the west, where precipitation is higher, bushes are replaced by grasses. Topographically the deserts consist of alternating tablelands and massifs dissected by river valleys and canyons. The more western parts of the steppe host lakes of glacial origin and grades into barren mountains or cold temperate forests along valleys.
The North Patagonian Batholith is a series of igneous plutons in the Patagonian Andes of Argentina and Chile.
The Friasian age is a period of geologic time within the Early Miocene epoch of the Neogene, used more specifically within the SALMA classification of South America. It follows the Santacrucian and precedes the Colloncuran age.
Neuquén Basin is a sedimentary basin covering most of Neuquén Province in Argentina. The basin originated in the Jurassic and developed through alternating continental and marine conditions well into the Tertiary. The basin bounds to the west with the Andean Volcanic Belt, to the southeast with the North Patagonian Massif and to the northeast with the San Rafael Block and to the east with the Sierra Pintada System. The basin covers an area of approximately 120,000 square kilometres (46,000 sq mi). One age of the SALMA classification, the Colloncuran, is defined in the basin, based on the Collón Curá Formation, named after the Collón Curá River, a tributary of the Limay River.
The Andean orogeny is an ongoing process of orogeny that began in the Early Jurassic and is responsible for the rise of the Andes mountains. The orogeny is driven by a reactivation of a long-lived subduction system along the western margin of South America. On a continental scale the Cretaceous and Oligocene were periods of re-arrangements in the orogeny. Locally the details of the nature of the orogeny varies depending on the segment and the geological period considered.
Lacui Formation is a marine Miocene sedimentary formation located in Chiloé Island with minor outcrops near Carelmapu on the mainland. Gastropod shells are the most common macrofossils of Lacui Formation. According to Sernageomin (1998) the formation dates to the earliest Serravallian — that is the Middle Miocene.
Abanico Formation is a 3 kilometres (9,800 ft) thick sedimentary formation exposed in the Andes of Central Chile. The formation has been deposited in a timespan from the Eocene to the Miocene. Abanico Formation's contact with the overlying Miocene Farellones Formation has been the subject of differing interpretations since the 1960s. A small part of the formation crops out in the Mendoza Province of western Argentina.
Cura-Mallín Group is a heterogeneous group of volcano-sedimentary formations of Oligocene-Miocene age, Colhuehuapian to Laventan in the SALMA classification, in south-central Chile and nearby parts of Argentina. The sediments belonging to the group were deposited in a lacustrine environment and alongside rivers in an intra-arc basin. Southeast of Laguna del Laja Cura-Mallín Group has a thickness of more than 1,800 metres (5,900 ft). The sediments making up the group deposited in an interval between 22 and 8 million years ago.
Traiguén Formation is a volcano-sedimentary formation of Miocene age, located in the archipelagoes of Aysén Region of western Patagonia.
Patagonia comprises the southernmost region of South America, portions of which lie either side of the Chile–Argentina border. It has traditionally been described as the region south of the Rio Colorado, although the physiographic border has more recently been moved southward to the Huincul fault. The region's geologic border to the north is composed of the Rio de la Plata craton and several accreted terranes comprising the La Pampa province. The underlying basement rocks of the Patagonian region can be subdivided into two large massifs: the North Patagonian Massif and the Deseado Massif. These massifs are surrounded by sedimentary basins formed in the Mesozoic that underwent subsequent deformation during the Andean orogeny. Patagonia is known for their vast earthquakes and the damage.
La Cascada Formation a sedimentary formation near Futaleufú in the western Patagonian Andes of southern Chile. Lithologies vary from sandstone, siltstone and conglomerate. The sediment that now forms the rock deposited during the Oligocene and Early Miocene epoch in shallow marine environment. The formation contain fossils of bivalves and gastropods.
The Cerro Plataforma Formation is a sedimentary formation cropping out at Cerro Plataforma south of Puelo Lake in the Andes of Argentine Patagonia. The formation contains marine fossils of bivalves, gastropods and echinoderms.
The Puduhuapi Formation is a sedimentary formation whose only known outcrops are on Puduhuapi Island of the Chiloé Archipelago, west of Chaitén in western Patagonia, Chile. Lithologies vary from sandstone and siltstone to conglomerate. The sediment that now forms the rock deposited during the Miocene no earlier than 23 million years ago.
The Ayacara Formation is a sedimentary formation made up of interbedded sand and siltstone cropping out around Hornopirén and Ayacara Peninsula in western Los Lagos Region, Chile. Less common rocks are tuff and conglomerate. The formation dates to the Early and Middle Miocene when it deposited during a marine transgression.
Chaicayán Group is a group of poorly defined sedimentary rock strata found in Taitao Peninsula in the west coast of Patagonia. The commones rock types are siltstone and sandstone. Conglomerate occur but is less common.
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 Agua de la Piedra Formation is a Late Oligocene geologic formation of the Malargüe Group that crops out in the southernmost Precordillera and northernmost Neuquén Basin in southern Mendoza Province, Argentina.
