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Cerro Do Jarau Crater
Cerro do Jarau crater is a diameter circular feature in the Paraná Basin, Rio Grande do Sul in southern Brazil, close to the border with Uruguay. The Russian Academy of Sciences lists the structure as a probable impact crater.Mikheeva, 2017 Description Cerro do Jarau is a prominent, approximately wide, circular landform rising more than above the plains of the pampas in southern Brazil. The name (meaning Jarau hills) comes from the prominent crests of silicified sandstones, which form a semiring of elevated hills in the northern part of the structure. The origin of this structure has been debated for decades, and varied suggestions of its formation include either endogenous tectonic processes or large meteorite impact. However, no conclusive evidence to support either hypothesis has been presented to date. This structure was formed in Mesozoic volcano-sedimentary rocks of the Paraná Basin and consists of the Jurassic to Cretaceous Guará (sandstones), Botucatu (sandstones) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraná Basin
The Paraná Basin ( pt, Bacia do Paraná, es, Cuenca del Paraná) is a large cratonic sedimentary basin situated in the central-eastern part of South America. About 75% of its areal distribution occurs in Brazil, from Mato Grosso to Rio Grande do Sul states. The remainder area is distributed in eastern Paraguay, northeastern Argentina and northern Uruguay. The shape of the depression is roughly elliptical and covers an area of about . The Paraná River, from which the Paraná Basin derived its name, flows along the central axis of the Paraná Basin and drains it. Description The Paraná Basin stretches from the Brazilian state of Mato Grosso in the north to northern Argentina and Uruguay in the south. The southern portion in Uruguay is locally known as Norte Basin.De Santa Ana et al., 2004, p.88Daners et al., 2006, p.148 Pioneer studies The first study on the Brazilian side of the Paraná Basin dates from 1841, when a Brazilian Imperial Government Mission prospected ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basalt
Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90% of all volcanic rock on Earth is basalt. Rapid-cooling, fine-grained basalt is chemically equivalent to slow-cooling, coarse-grained gabbro. The eruption of basalt lava is observed by geologists at about 20 volcanoes per year. Basalt is also an important rock type on other planetary bodies in the Solar System. For example, the bulk of the plains of Venus, which cover ~80% of the surface, are basaltic; the lunar maria are plains of flood-basaltic lava flows; and basalt is a common rock on the surface of Mars. Molten basalt lava has a low viscosity due to its relatively low silica content (between 45% and 52%), resulting in rapidly moving lava flows that can spread over great areas before cooling and solidifying. Flood basalts are thick sequence ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Impact Craters Of Brazil
Impact may refer to: * Impact (mechanics), a high force or shock (mechanics) over a short time period * Impact, Texas, a town in Taylor County, Texas, US Science and technology * Impact crater, a meteor crater caused by an impact event * Impact event, the collision of a meteoroid, asteroid or comet with Earth * Impact factor, a measure of the citations to a science or social science journal Books and magazines * ''Impact'' (novel), a 2010 novel by Douglas Preston *''Impact Press'', a former Orlando, Florida-based magazine * Impact Magazines, a former UK magazine publisher * ''Impact'' (conservative magazine), a British political magazine * ''Impact'' (British magazine), a British action film magazine * ''Impact'', a French action film magazine spun off from ''Mad Movies'' * ''Impact'' (UNESCO magazine), a former UNESCO quarterly titled ''IMPACT of science on society'' * ''Impact'' (student magazine), a student magazine for the University of Nottingham, England * '' Bathim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geological Society Of America
The Geological Society of America (GSA) is a nonprofit organization dedicated to the advancement of the geosciences. History The society was founded in Ithaca, New York, in 1888 by Alexander Winchell, John J. Stevenson, Charles H. Hitchcock, John R. Procter and Edward Orton and has been headquartered at 3300 Penrose Place, Boulder, Colorado, US, since 1967. GSA began with 100 members under its first president, James Hall. In 1889 Mary Emilie Holmes became its first female member. It grew slowly but steadily to 600 members until 1931, when a nearly $4 million endowment from 1930 president R. A. F. Penrose Jr. jumpstarted GSA's growth. As of December 2017, GSA had more than 25,000 members in over 100 countries. The society has six regional sections in North America, three interdisciplinary interest groups, and eighteen specialty divisions. Activities The stated mission of GSA is "to advance geoscience research and discovery, service to society, stewardship of Earth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Praia Grande Crater
Praia Grande crater is a diameter circular feature in the Santos Basin offshore Brazil. It is a possible impact crater that has been identified on 3D seismic by Petrobras in 2004. Further investigation is needed to obtain more information on the structure. The Russian Academy of Sciences lists the structure as a probable impact crater.Mikheeva, 2017 Description The Praia Grande crater is located in the Santos Basin, approximately southeast from the coastline of São Paulo State, Brazil. The identification of this structure is based on the interpretation of three-dimensional seismic data, acquired and processed in 2004 for petroleum exploration in a Petrobras concession block in the Santos Basin. The principal morphological elements, imposed on Upper Cretaceous rocks, are a structural high in the center of the crater, an adjacent ring syncline, and, externally, several concentric circular listric normal faults. The structure is apparently well preserved from erosion, measure ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Impact Craters In South America
This list includes all 11 confirmed impact craters in South America as listed in the Earth Impact Database. These features were caused by the collision of large meteorites or comets with the Earth. For eroded or buried craters, the stated diameter typically refers to an estimate of original rim diameter, and may not correspond to present surface features. Confirmed impact craters Unconfirmed impact craters The following craters are officially considered "unconfirmed" because they are not listed in the Earth Impact Database. Due to stringent requirements regarding evidence and peer-reviewed publication, newly discovered craters or those with difficulty collecting evidence generally are known for some time before becoming listed. However, entries on the unconfirmed list could still have an impact origin disproven. See also * Impact craters * Impact events * Bolides and Meteorites * Earth Impact Database – primary source * Traces of Catastrophe book from Lunar and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Possible Impact Structures On Earth
This is a list of possible impact structures on Earth. More than 130 geophysical features on the surface of the Earth have been proposed as candidate sites for impact events by appearing several times in the literature and/or being endorsed by the Impact Field Studies Group (IFSG) and/or Expert Database on Earth Impact Structures (EDEIS). For the purposes of this list and the List of impact craters on Earth, the terminology of "confirmed" as defined by the Earth Impact Database (EID) is considered authoritative. List of possible impact structures The following tables list geological features on Earth that some individuals have associated with impact events, but for which there is currently no confirming scientific evidence in the peer-reviewed literature. In order for a structure to be confirmed as an impact crater, it must meet a stringent set of well-established criteria. Some proposed impact structures are likely to eventually be confirmed, whereas others are likely to be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aptian
The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous Epoch or Series and encompasses the time from 121.4 ± 1.0 Ma to 113.0 ± 1.0 Ma (million years ago), approximately. The Aptian succeeds the Barremian and precedes the Albian, all part of the Lower/Early Cretaceous. The Aptian partly overlaps the upper part of the Western European Urgonian Stage. The Selli Event, also known as OAE1a, was one of two oceanic anoxic events in the Cretaceous Period, which occurred around 120 Ma and lasted approximately 1 to 1.3 million years. The Aptian extinction was a minor extinction event hypothesized to have occurred around 116 to 117 Ma.Archangelsky, Sergio.The Ticó Flora (Patagonia) and the Aptian Extinction Event" ''Acta Paleobotanica'' 41(2), 2001, pp. 115-22. Stratigraphic definitions The Aptian was named after the small city of Apt in the Provence region of France, which is also known for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vargeão Dome
Vargeão Dome is a meteorite crater in Santa Catarina State, Brazil, straddling the municipalities of Vargeão, Faxinal dos Guedes, and Passos Maia. The crater is an almost perfectly circular depression with steep walls, in diameter and up to deep, relative to its rim. It is of Early Cretaceous age, or about 123 ± 2 Ma. The meteorite impacted on the basaltic rocks of the Serra Geral Formation (Jurassic/Cretaceous). The crater displays several concentric rings and radial faults, and an eroded central bulge. The latter consists of impact breccias and sandstones from the Botucatu/ Pirambóia Formation (Cretaceous/Triassic), which have been displaced about above their mean depth in the surrounding area. At least four post-impact lava flows have been identified between the rim and core. The impact origin of the structure is attested by the presence of shatter cones and shocked quartz grains. Discovery and studies In 1978, Brazilian geologists A. Paiva Filho, C.A.V. Andrad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vista Alegre Crater
The Vista Alegre crater is a meteorite crater in Coronel Vivida, Paraná State, Brazil. On the surface it appears as a circular, relatively flat plain within otherwise hilly terrain. Description It is in diameter and the age is estimated to be less than 65 million years (Paleocene or younger). More recently, a date of about 115 Ma has been givenA. Crósta, M. Vasconcelos (2013)Update On The Current Knowledge Of The Brazilian Impact Craters 44th Lunar and Planetary Science Conference (2013) and closer to the age of Vargeão Dome. Considering the proximity of location, age, and stratigraphic similarities of Vista Alegre and Vargeão, it has been proposed that it was a double impact.A. Crósta, C. Kazzuo-Vieira and A. Schrank (2004)Vista Alegre: A Newly Discovered Impact Crater In Southern Brazil Extract from the 67th Annual Meteoritical Society Meeting" in 2004. See also * Vargeão Dome References {{Portal bar, Geology, Cretaceous Impact craters of Brazil Paleocene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quartz
Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of SiO2. Quartz is the second most abundant mineral in Earth's continental crust, behind feldspar. Quartz exists in two forms, the normal α-quartz and the high-temperature β-quartz, both of which are chiral. The transformation from α-quartz to β-quartz takes place abruptly at . Since the transformation is accompanied by a significant change in volume, it can easily induce microfracturing of ceramics or rocks passing through this temperature threshold. There are many different varieties of quartz, several of which are classified as gemstones. Since antiquity, varieties of quartz have been the most commonly used minerals in the making of jewelry and hardstone carvings, especially in Eurasia. Quartz is the mineral definin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shatter Cone
Shatter cones are rare geological features that are only known to form in the bedrock beneath meteorite impact craters or underground nuclear explosions. They are evidence that the rock has been subjected to a shock with pressures in the range of . Morphology Shatter cones have a distinctively conical shape that radiates from the top (''apex'') of the cones repeating cone-on-cone in large and small scales in the same sample. Sometimes they have more of a spoon shape on the side of a larger cone. In finer-grained rocks such as limestone, they form an easily recognizable "horsetail" pattern with thin grooves ('' striae''). However, the word "striae" should not be used to describe shatter cones, as that is considered misleading. Coarser grained rocks tend to yield less well developed shatter cones, which may be difficult to distinguish from other geological formations such as slickensides. Geologists have various theories of what causes shatter cones to form, including compr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
