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Carachipampa
Carachipampa is a Pleistocene volcanic cone in Argentina. Part of a wider, regional volcanic field, it has produced lava flows consisting of andesite. It is surrounded by a lake and a salt flat, the former of which features an ecosystem formed by microbes. Volcano Carachipampa lies in the Catamarca Province of northwestern Argentina. It is a black volcanic cone with its summit on the southeastern crater rim, surrounded by a field of lava flows that were fed from the northwestern side of the cone. Part of the southeastern flank of the cone is collapsed. The occurrence of eroded scoria cones and lava domes has been reported. The lava flows reach thicknesses of and lengths of , and consist of mafic andesite that defines a calc-alkaline suite. Phenocrysts are mostly amphibole, clinopyroxene and olivine. Rock samples from the volcano have been analyzed. The volcano erupted 750,000 years ago and is part of the fourth volcanic stage in the region. There are a number of mafic volcani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerro Blanco (volcano)
Cerro Blanco (, "White Hill") is a caldera in the Andes of the Catamarca Province in Argentina. Part of the Central Volcanic Zone of the Andes, it is a volcano collapse structure located at an altitude of in a depression. The caldera is associated with a less well-defined caldera to the south and several lava domes. The caldera has been active for the last eight million years, and eruptions have created several ignimbrites. An eruption occurred 73,000 years ago and formed the Campo de la Piedra Pómez ignimbrite layer. About 2,300 ± 160 BCE, the largest known volcanic eruption of the Central Andes, with a Volcanic Explosivity Index, VEI-7, occurred at Cerro Blanco, forming the most recent caldera as well as thick ignimbrite layers. About of tephra were erupted then. The volcano has been dormant since then with some Deformation (volcanology), deformation and geothermal activity. A major future eruption would put nearby communities to the south at risk. The volcano is also kno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ignimbrite
Ignimbrite is a type of volcanic rock, consisting of hardened tuff. Ignimbrites form from the deposits of pyroclastic flows, which are a hot suspension of particles and gases flowing rapidly from a volcano, driven by being denser than the surrounding atmosphere. New Zealand geologist Patrick Marshall (1869–1950) coined the term ''ignimbrite'' from the Latin ''igni-'' [fire] and ''imbri-'' [rain]. Ignimbrites are made of a very poorly sorted mixture of volcanic ash (or tuff when Lithification, lithified) and pumice lapilli, commonly with scattered lithic fragments. The ash is composed of glass shards and crystal fragments. Ignimbrites may be loose and unconsolidated, or lithified (solidified) rock called lapilli tuff. Near the volcanic source, ignimbrites often contain thick accumulations of lithic blocks, and distally, many show meter-thick accumulations of rounded cobbles of pumice. Ignimbrites may be white, grey, pink, beige, brown, or black depending on their composition and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neoproterozoic
The Neoproterozoic Era is the last of the three geologic eras of the Proterozoic geologic eon, eon, spanning from 1 billion to 538.8 million years ago, and is the last era of the Precambrian "supereon". It is preceded by the Mesoproterozoic era and succeeded by the Paleozoic era of the Phanerozoic eon, and is further subdivided into three geologic period, periods, the Tonian, Cryogenian and Ediacaran. One of the most severe glaciation events known in the geologic record occurred during the Cryogenian period of the Neoproterozoic, when global ice sheets may have reached the equator and created a "Snowball Earth" lasting about 100 million years. The earliest fossils of complex life are found in the Tonian period in the form of ''Otavia'', a primitive sponge, and the earliest fossil evidence of metazoan evolutionary radiation, radiation are found in the Ediacaran period, which included the namesaked Ediacaran biota as well as the oldest definitive cnidarians and bilaterians in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleogene
The Paleogene Period ( ; also spelled Palaeogene or Palæogene) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period Ma (million years ago) to the beginning of the Neogene Period Ma. It is the first period of the Cenozoic Era, the tenth period of the Phanerozoic and is divided into the Paleocene, Eocene, and Oligocene epochs. The earlier term Tertiary Period was used to define the time now covered by the Paleogene Period and subsequent Neogene Period; despite no longer being recognized as a formal stratigraphic term, "Tertiary" still sometimes remains in informal use. Paleogene is often abbreviated "Pg", although the United States Geological Survey uses the abbreviation "" for the Paleogene on the Survey's geologic maps. Much of the world's modern vertebrate diversity originated in a rapid surge of diversification in the early Paleogene, as survivors of the Cretaceous–Paleogene extinction event took advantage of empty ecolo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Bed
Red beds (or redbeds) are sedimentary rocks, typically consisting of sandstone, siltstone, and shale, that are predominantly red in color due to the presence of ferric oxides. Frequently, these red-colored sedimentary strata locally contain thin beds of conglomerate, marl, limestone, or some combination of these sedimentary rocks. The ferric oxides, which are responsible for the red color of red beds, typically occur as a coating on the grains of sediments comprising red beds. Classic examples of red beds are the Permian and Triassic strata of the western United States and the Devonian Old Red Sandstone facies of Europe. Primary red beds Primary red beds may be formed by the erosion and redeposition of red soils or older red beds, but a fundamental problem with this hypothesis is the relative scarcity of red-colored source sediments of suitable age close to an area of red-bed sediments in Cheshire, England. Primary red beds may also form by in situ (early diagenetic) redde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permian
The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years, from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.902 Mya. It is the sixth and last period of the Paleozoic Era; the following Triassic Period belongs to the Mesozoic Era. The concept of the Permian was introduced in 1841 by geologist Sir Roderick Murchison, who named it after the Perm Governorate, region of Perm in Russia. The Permian witnessed the diversification of the two groups of amniotes, the synapsids and the Sauropsida, sauropsids (reptiles). The world at the time was dominated by the supercontinent Pangaea, which had formed due to the collision of Euramerica and Gondwana during the Carboniferous. Pangaea was surrounded by the superocean Panthalassa. The Carboniferous rainforest collapse left behind vast regions of desert within the continental interior. Amniotes, which could better cope with these ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yardang
A yardang is a streamlined protuberance carved from bedrock or any consolidated or semiconsolidated material by the dual action of wind abrasion by dust and sand and deflation (the removal of loose material by wind turbulence). Yardangs become elongated features typically three or more times longer than wide, and when viewed from above, resemble the hull of a boat. Facing the wind is a steep, blunt face that gradually gets lower and narrower toward the lee end. Yardangs are formed by wind erosion, typically of an originally flat surface formed from areas of harder and softer material. The soft material is eroded and removed by the wind, and the harder material remains. The resulting pattern of yardangs is therefore a combination of the original rock distribution, and the fluid mechanics of the air flow and resulting pattern of erosion. Names The word itself is of Turkic origin, meaning ‘steep bank’, as this type of spectacular landscapes rising are best developed in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Puna De Atacama
The Puna de Atacama or Atacama Plateau article at the ''Encyclopædia Britannica'' website is an arid high plateau, in the Andes of northern Chile (15%) and northwest of Argentina (85%).Historia de la relacciones exteriores de la Argentina Geomorphology, Geomorphologist Walther Penck based his ''Grossfalt'' landform association on Puna de Atacama. Geography The plateau's elevation averages above sea level, and it spans an area of . In Argentina, Puna's territory is extended in the provinces of Salta Province, Salta, Jujuy Province, Jujuy, and western Catamarca Province, Cata ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neotectonic
Neotectonics, a subdiscipline of tectonics, is the study of the motions and deformations of Earth's crust (geological and geomorphological processes) that are current or recent in geologic time. The term may also refer to the motions/deformations in question themselves. Geologists refer to the corresponding time-frame as the neotectonic period, and to the preceding time as the palaeotectonic period. Vladimir Obruchev coined the term ''neotectonics'' in his 1948 article, defining the field as "recent tectonic movements occurred in the upper part of Tertiary (Neogene) and in the Quaternary, which played an essential role in the origin of the contemporary topography". Since then geologists have disagreed as to how far back to date "geologically recent" time, with the common meaning being that neotectonics is the youngest, not yet finished stage in Earth tectonics. Some authors consider neotectonics to be basically synonymous with "active tectonics", while others date the start of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Farallon Negro
Farallon (Farallón meaning cliff in the Spanish Language) may refer to: Places Northern Mariana Islands *Farallon de Medinilla, small island in the Northern Mariana Islands chain *Farallon de Pajaros (Birds Rock), the northernmost island in the Northern Mariana Islands chain *Farallon de Torres, a former name of Zealandia Bank in the Northern Mariana Islands chain California *Farallon Island Light, lighthouse on Southeast Farallon Island, California *Farallon Islands, group of islands and rocks in the Gulf of the Farallones, off the coast of San Francisco, California, USA ** Farallon Steamship Disaster, wooden steamship hit Black Reef in the Farallon Islands in 1910 and sank in Alaska Panama * Farallon (island), Panama Oceans * Farallon Plate, ancient oceanic plate * Farallon Trench, ancient oceanic trench on the west coast of North America during the Late Cretaceous period * Kula-Farallon Ridge, ancient mid-ocean ridge between the Kula and Farallon plates in the P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lineament
''See also Line (geometry)'' A lineament is a linear feature in a landscape which is an expression of an underlying geological structure such as a fault. Typically a lineament will appear as a fault-aligned valley, a series of fault or fold-aligned hills, a straight coastline or indeed a combination of these features. Fracture zones, shear zones and igneous intrusions such as dykes can also be expressed as geomorphic lineaments. Lineaments are often apparent in geological or topographic maps and can appear obvious on aerial or satellite photographs. There are for example, several instances within Great Britain. In Scotland the Great Glen Fault and Highland Boundary Fault give rise to lineaments as does the Malvern Line in western England and the Neath Disturbance in South Wales. The term 'megalineament' has been used to describe such features on a continental scale. The trace of the San Andreas Fault might be considered an example.Whitten & Brooks, The Penguin Dictionary of G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crust (geology)
In geology, the crust is the outermost solid shell of a planet, dwarf planet, or natural satellite. It is usually distinguished from the underlying mantle by its chemical makeup; however, in the case of icy satellites, it may be defined based on its phase (solid crust vs. liquid mantle). The crusts of Earth, Mercury, Venus, Mars, Io, the Moon and other planetary bodies formed via igneous processes and were later modified by erosion, impact cratering, volcanism, and sedimentation. Most terrestrial planets have fairly uniform crusts. Earth, however, has two distinct types: continental crust and oceanic crust. These two types have different chemical compositions and physical properties and were formed by different geological processes. Types of crust Planetary geologists divide crust into three categories based on how and when it formed. Primary crust / primordial crust This is a planet's "original" crust. It forms from solidification of a magma ocean. Toward the end o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
