Caleta Herradura Formation (Spanish : Formación Caleta Herradura) is a geologic formation of Late Miocene (Montehermosan) age, cropping out on the Mejillones Peninsula in northern Chile. The erosion at the Coastal Cliff of northern Chile have created particularly good exposures of Caleta Herradura Formation. The formation deposited in a half graben within Mejillones Peninsula. The formation rests nonconformably on the Jorgino Formation. [1]
The following fossils have been found in the formation:
Group | Fossils | Notes |
---|---|---|
Mammals | Balaenopteridae indet., Odontoceti indet., Otariidae indet. | |
Birds | Spheniscus chilensis , Milvago sp. , Phalacrocorax sp. | |
Fish | Carcharodon carcharias , Carcharias sp. , Carcharhinus sp. , Chondrichthyes indet., Myliobatidae indet. | |
Nesodon is a genus of Miocene mammal belonging to the extinct order Notoungulata which inhabited southern South America during the Late Oligocene to Miocene living from 29.0 to 16.3 Ma and existed for approximately 12.7 million years. It had a relatively large size, weighing up to 554 kg (1221 lbs) and reaching 1.5 m in height.
The South American land mammal ages (SALMA) establish a geologic timescale for prehistoric South American fauna beginning 64.5 Ma during the Paleocene and continuing through to the Late Pleistocene. These periods are referred to as ages, stages, or intervals and were established using geographic place names where fossil materials where obtained.
The Colhuehuapian age is a period of geologic time within the Early Miocene epoch of the Neogene, used more specifically within the SALMA classification in South America. It follows the Deseadan and precedes the Santacrucian age.
The Santacrucian age is a period of geologic time within the Early Miocene epoch of the Neogene, used more specifically with SALMA classification in South America. It follows the Colhuehuapian and precedes the Friasian age.
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.
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. The details of the orogeny vary depending on the segment and the geological period considered.
Navidad Formation is a marine Neogene sedimentary formation located in Central Chile. The formation is known for its diverse and abundant fossil record and is considered the reference unit for the marine Neogene in Chile. Originally described by Charles Darwin in 1846 the formation has attracted the attention of numerous prominent geologists and paleontologists since then. As a key formation Navidad has been subject to a series of differing interpretations and scientific disputes over time.
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.
Lauca is a 5,140 metres (16,860 ft) high andesitic stratovolcano in the Central Volcanic Zone of the Andes on the Altiplano in northern Chile. Administratively it is located in Putre, Arica y Parinacota Region. The volcano was active during the Late Miocene from 10.5 million years ago onwards. A major ignimbrite collapsed the volcano in the Late Pliocene.
Coquimbo Formation is a Miocene to Middle Pleistocene sedimentary formation located in Coquimbo Region in Norte Chico, Chile. The lowermost unit belongs to the lower Miocene, with the third-deepest unit dated at 11.9 ± 1.0 Ma. The uppermost unit of the formation is estimated at 1.2 Ma. In the area of Tongoy, the Coquimbo Formation was deposited in an ancient bay that was formed in a graben or half-graben, with a normal fault dipping east. Sea level changes during the Holocene have caused erosion to cut several marine terraces into the formation.
Tectonic erosion or subduction erosion is the loss of crust from an overriding tectonic plate due to subduction. Two types of tectonic erosion exist: frontal erosion at the outer margin of a plate and basal erosion at the base of the plate's crust. Basal erosion causes a thinning of the overriding plate. When frontal tectonic erosion consumes a crustal block at the outer margin it may induce a domino effect on upper crustal tectonics causing the remaining blocks to fault and tilt to fill the “gap” left by the consumed block. Subduction erosion is believed to be enhanced by high convergence rates and low sediment supply to the trench.
The Arauco Basin is a sediment-filled depression –a sedimentary basin– in south-central Chile. In the context of plate tectonics it is classified as a forearc basin. The basin has an approximate area of 8,000 square kilometres (3,100 sq mi) and at its deeper parts the surface of its sedimentary fill reaches 200 metres (660 ft) below sea-level. The basin is interpreted as being part of an uplifted part of the continental shelf. To the west it bounds an active accretionary prism that lies next to the Chile trench and to the east it bounds metamorphic basement representing a fossil Paleozoic accretionary complex that has been intruded by the Coastal Batholith of central Chile.
Mejillones Peninsula protrudes from the coast of northern Chile north of Antofagasta and south of the port of Mejillones.
Way Group is a geologic group of Lower Cretaceous age located in northern Chile. The sediments of the group deposited in Coloso Basin, a small intra-arc basin made up by a half graben. The now inactive Coloso Basin is elongated along a NNW-SSE oriented axis and has its southwestern border made up by faults.
La Portada Formation is a geologic formation of Miocene and Pliocene age located near the Coast Range of northern Chile. The coarse-grained sandstones of the formation contain penguin fossils.
Farellones Formation is a geological formation of Miocene age in the Andes of Central Chile made up almost entirely of volcanic and volcaniclastic rocks. At some location reaches thicknesses in excess of 3,000 metres (9,800 ft). It overlies the Oligo–Miocene Abanico Formation across a diachronous unconformity. The best exposure of the formation is said to be at the ski resort of Farellones east of Santiago.
Parga Formation is a geological formation of sedimentary rock in south-central Chile. The sediments of the formation were deposited during the Late Oligocene and Middle Miocene epochs. The formation's lower sections are made up of conglomerate, sandstone and mudstone some of which is rich in organic material. Additionally there are thin beds of tuff and coal. The formation's composition indicates that sedimentation occurred in an estuarine (paralic) and marine environments. Stratigraphically it overlies the Bahía Mansa Metamorphic Complex and is similar in age and type to Lacui Formation to the south and Cheuquemó and Santo Domingo Formation to the north. It is overlain across an angular unconformity by Pliocene or Quaternary sediments. The formation is intruded by porphyritic trachyte of Oligocene to Miocene age. The outcrops of the formation are restricted to a NW-SE strip near Caleta Parga north of the estuary of Maullín River.
Caleta Chonos Formation is a geological formation of Oligocene age located around Chacao Channel in southern Chile. The formation overlies Bahía Mansa Metamorphic Complex and is overlain by the Ancud Volcanic Complex. It crops out in northwestern Chiloé Island in the isthmus of Lacuy Peninsula.
Caleta Godoy Formation is a geological formation whose main outcrops lie around Chacao Channel in southern Chile. The formation overlies Bahía Mansa Metamorphic Complex and Santo Domingo Formation.
The Mejillones Metamorphic Complex is made up of two separate outcrops of metamorphic rocks in the Mejillones Peninsula of northern Chile. Turbidites of low metamorphic grade make up the northern outcrop at Morro Mejillones. The southern outcrop lies at Morro Jorgiño and is made up of schist, gneiss, amphibolite and quartzite. Rocks at Morro Jorgiño are intruded by garnet-bearing leucogranites.