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Ranquil Formation
The Ranquil Formation () is a Miocene and Pliocene sedimentary geologic formation, formation located in Arauco Province in Zona Sur, south–central Chile, including outcrops in Mocha Island. The formation has its greatest thicknesses in the south-west, where its sediments were largely deposited in marine conditions. It overlies unconformity, unconformably sedimentary formations of the Paleocene-Eocene Lebu Group. The formation is part of the fill of Arauco Basin which is a sedimentary basin that extends south of Concepción, Chile, Concepción. Macrofossils of the formation are similar to those of Navidad Formation, Navidad (34th parallel south, 34° S) and Lacui Formations (43rd parallel south, 43° S), two nearby Miocene marine formations. The base of the Ranquil Formation is the so-called "main unconformity", which is thought to have been formed by erosion during a period of tectonic inversion. The formation was first defined in 1942 by Juan Tavera. Units The formation has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geological Formation
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. A formation must be large enough that it can be mapped at the surface or traced in the subsurface. Formations are otherwise not defined by the thickness (geology), thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of a geologic formation goes back to the beginnings of modern scientific geology. The term was used by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geologic Formation
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. A formation must be large enough that it can be mapped at the surface or traced in the subsurface. Formations are otherwise not defined by the thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of a geologic formation goes back to the beginnings of modern scientific geology. The term was used by Abraham Gottlob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
34th Parallel South
Following are circles of latitude between the 30th parallel south and the 35th parallel south: 31st parallel south The 31st parallel south is a circle of latitude that is 31 degrees south of the Earth's equatorial plane. It crosses the Atlantic Ocean, Africa, the Indian Ocean, Australasia, the Pacific Ocean and South America. At this latitude the sun is visible for 14 hours, 13 minutes during the December solstice and 10 hours, 4 minutes during the June solstice. Around the world Starting at the Prime Meridian and heading eastwards, the parallel 31° south passes through: : 32nd parallel south The 32nd parallel south is a circle of latitude that is 32 degrees south of the Earth's equatorial plane. It crosses the Atlantic Ocean, Africa, the Indian Ocean, Australasia, the Pacific Ocean and South America. At this latitude the sun is visible for 14 hours, 19 minutes during the December solstice and 9 hours, 58 minutes during the June solstice. Around the world Starting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Navidad Formation
Navidad Formation () is a marine Neogene sedimentary geologic formation, 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 paleontology, paleontologists since then. As a key formation Navidad has been subject to a series of differing interpretations and scientific disputes over time. History Charles Darwin saw the formation in September 1834 during the second voyage of HMS Beagle. He became the first to describe it 1846 when he published his book Geological Observations on South America in 1846 and it was named by Darwin after the nearby town of Navidad, Chile, Navidad. In this book Darwin calls the formation "Formation of Navidad" and "Sandstone Formation at Navidad". There are no signs of that Darwin would have attempted to make a for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macrofossil
Macrofossils, also known as megafossils, are the preserved remnants of organic beings and their activities that are large enough to be visible without a microscope. The term ''macrofossil'' stands in opposition to the term microfossil. Microfossils, by contrast, require substantial magnification for evaluation by fossil-hunters or professional paleontologists. As a result, most fossils observed in the field and most specimens are macrofossils. Macrofossils come in many varieties and form in various ways depending on their environment and what is being fossilized including plant, fungi and animal remnants. Historical background Etymology The origins of the term macrofossil dates back to 1937 and was first used by G. D. Hanna, a US paleontologist and malacologist. Scientific thought Macrofossils have been subject to analysis since ancient times. Several Greek philosophers used fossilized shellfish to theorize the land was once covered by oceans. Macrofossils of body parts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concepción, Chile
Concepción (; originally: ''Concepción de la Madre Santísima de la Luz'', "Conception of the Blessed Mother of Light") is a city and Communes of Chile, commune in south-central Chile, and the geographical and demographic core of the Greater Concepción metropolitan area, it is the second largest city in Chile by urban area and one of the three major conurbations in the country. It has a significant impact on domestic trade being part of the most heavily industrialized region in the country. It is the seat of the Concepción Province, Chile, Concepción Province and the capital of the Biobío Region. It sits about 500 km south of the nation's capital, Santiago. The city was first settled in the Bay of Concepción, in the zone that would later become the commune of Penco, now part of the Greater Concepción, Concepción conurbation. The city's demonym, , comes from the place of its original foundation. The city center and historic district is located in the Valle de la Mocha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sedimentary Basin
Sedimentary basins are region-scale depressions of the Earth's crust where subsidence has occurred and a thick sequence of sediments have accumulated to form a large three-dimensional body of sedimentary rock They form when long-term subsidence creates a regional depression that provides Accommodation (geology), accommodation space for accumulation of sediments. Over millions or tens or hundreds of millions of years the deposition of sediment, primarily gravity-driven transportation of water-borne eroded material, acts to fill the depression. As the sediments are buried, they are subject to increasing pressure and begin the processes of compaction (geology), compaction and lithification that transform them into sedimentary rock. Sedimentary basins are created by deformation of Earth's lithosphere in diverse geological settings, usually as a result of plate tectonics, plate tectonic activity. Mechanisms of crustal deformation that lead to subsidence and sedimentary basin formatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arauco Basin
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 and at its deeper parts the surface of its sedimentary fill reaches 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. Traditionally the centre of coal mining in Chile, large-scale coal mining in Arauco Basin ended in the 1990s.Explotacion Reservas CNE ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eocene
The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes from the Ancient Greek (''Ēṓs'', 'Eos, Dawn') and (''kainós'', "new") and refers to the "dawn" of modern ('new') fauna that appeared during the epoch.See: *Letter from William Whewell to Charles Lyell dated 31 January 1831 in: * From p. 55: "The period next antecedent we shall call Eocene, from ήως, aurora, and χαινος, recens, because the extremely small proportion of living species contained in these strata, indicates what may be considered the first commencement, or ''dawn'', of the existing state of the animate creation." The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a brief period in which the concentration of the carbon isoto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleocene
The Paleocene ( ), or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name is a combination of the Ancient Greek ''palaiós'' meaning "old" and the Eocene Epoch (which succeeds the Paleocene), translating to "the old part of the Eocene". The epoch is bracketed by two major events in Earth's history. The K–Pg extinction event, brought on by an asteroid impact (Chicxulub impact) and possibly volcanism (Deccan Traps), marked the beginning of the Paleocene and killed off 75% of species, most famously the non-avian dinosaurs. The end of the epoch was marked by the Paleocene–Eocene Thermal Maximum (PETM), which was a major climatic event wherein about 2,500–4,500 gigatons of carbon were released into the atmosphere and ocean systems, causing a spike in global temperatures and ocean acidification. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unconformity
An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval of time before deposition of the younger layer, but the term is used to describe any break in the sedimentary geologic record. The significance of angular unconformity (see below) was shown by James Hutton, who found examples of Hutton's Unconformity at Jedburgh in 1787 and at Siccar Point in Berwickshire in 1788, both in Scotland. The rocks above an unconformity are younger than the rocks beneath (unless the sequence has been overturned). An unconformity represents time during which no sediments were preserved in a region or were subsequently eroded before the next deposition. The local record for that time interval is missing and geologists must use other clues to discover that part of the geologic history of that area. The interval ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mocha Island
Mocha Island ( ) is a Chilean island located west of the coast of Arauco Province in the Pacific Ocean. The island is the location of numerous historic shipwrecks. In Mapuche mythology, the souls of dead people travel west to visit this island. The waters off the island are a popular place for recreational sea fishing. History The island was historically inhabited by an indigenous coastal population of Mapuches known as the Lafkenches. The first European to document Mocha was Juan Bautista Pastene on September 10, 1544, who named it ''Isla de San Nicolas de Tolentino''. According to Juan Ignacio Molina, the Dutch captain Joris van Spilbergen observed the use of chilihueques (a South American camelid) by native Mapuches of Mocha Island as plough animals in 1614. Mocha Island was regularly visited by pirates and privateers from the Netherlands and England. Francis Drake and Olivier van Noort are known to have used the island as a supply base. When Drake was visiting it dur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
