Origin of Mesoproterozoic A-type granites in Laurentia
... Granitic rocks are commonly used as a means to study chemical evolution of continental crust. In particular, their isotopic compositions reflect the relative contributions of mantle and crustal sources in their genesis. In Laurentia, a distinctive belt of Mesoproterozoic A-type or “anorogenic” grani ...
... Granitic rocks are commonly used as a means to study chemical evolution of continental crust. In particular, their isotopic compositions reflect the relative contributions of mantle and crustal sources in their genesis. In Laurentia, a distinctive belt of Mesoproterozoic A-type or “anorogenic” grani ...
NORSK GEOLOGISK TIDSSKRIFT 45 DISTRIBUTION PATTERNS
... of increasing enrichment in the lighter REE they are: Basaltic group A. This was first recognized by FREY and HASKIN (1964) under the name 'oceanic basalts', but this is not a good name to designate the group, since it does not include the basalt of Kilauea (Hawaii). Four rocks show this REE distrib ...
... of increasing enrichment in the lighter REE they are: Basaltic group A. This was first recognized by FREY and HASKIN (1964) under the name 'oceanic basalts', but this is not a good name to designate the group, since it does not include the basalt of Kilauea (Hawaii). Four rocks show this REE distrib ...
Resonance locking as the source of rapid tidal migration in the
... location moves outward. If its orbit is perturbed inward (toward resonance) tidal dissipation will increase, and the moon will be pushed back outward toward the fixed point. If the moon’s orbit is perturbed outward (away from resonance) the moon’s outward migration rate will decrease, and the resona ...
... location moves outward. If its orbit is perturbed inward (toward resonance) tidal dissipation will increase, and the moon will be pushed back outward toward the fixed point. If the moon’s orbit is perturbed outward (away from resonance) the moon’s outward migration rate will decrease, and the resona ...
Solar System Exploration - Lunar and Planetary Institute
... Galileo — transformed not only our field of science, but humankind’s perception of the Solar System; Cassini–Huygens is doing so today. Large missions capable of reaching distant locations in the outer Solar System with powerful complements of instruments, enabling serendipitous discovery, and conduc ...
... Galileo — transformed not only our field of science, but humankind’s perception of the Solar System; Cassini–Huygens is doing so today. Large missions capable of reaching distant locations in the outer Solar System with powerful complements of instruments, enabling serendipitous discovery, and conduc ...
Introduction - Beck-Shop
... outcrop evidence of this earliest primitive crust is known to have survived, probably due to the intense meteor bombardment that affected Earth between its formation and c. 4.0 Ga, the age of the oldest known components in outcrops of the Acasta gneisses of northwestern Canada (Bowring & Williams, 1 ...
... outcrop evidence of this earliest primitive crust is known to have survived, probably due to the intense meteor bombardment that affected Earth between its formation and c. 4.0 Ga, the age of the oldest known components in outcrops of the Acasta gneisses of northwestern Canada (Bowring & Williams, 1 ...
Earth`s first two billion years—The era of internally
... Pearce and Cann (1973). When, as often is the case, the Archean analyses cannot be fitted into desired chemotectonic pigeonholes, hypothetical mixtures and derivatives of criteria are devised to postulate hybrid tectonic settings with no modern analogues. That the discriminants for modern rocks lack ...
... Pearce and Cann (1973). When, as often is the case, the Archean analyses cannot be fitted into desired chemotectonic pigeonholes, hypothetical mixtures and derivatives of criteria are devised to postulate hybrid tectonic settings with no modern analogues. That the discriminants for modern rocks lack ...
The origin and evolution of the Earth`s continental crust
... dating the crust because it is least prone to resetting during metamorphism. Fractionation of Sm from Nd takes place at the time of mantle melting. Thus the depleted mantle Nd model age (TOM) of crustal igneous rocks reflects their age of extraction from the mantle. However, processes such as intrac ...
... dating the crust because it is least prone to resetting during metamorphism. Fractionation of Sm from Nd takes place at the time of mantle melting. Thus the depleted mantle Nd model age (TOM) of crustal igneous rocks reflects their age of extraction from the mantle. However, processes such as intrac ...
Uranus Neptune ppt NOTES
... • Miranda appears to have been shattered by an impact, and is still putting itself back together – Long cracks or faults riddle its surface – Rolling hills adjacent to wrinkled terrain ...
... • Miranda appears to have been shattered by an impact, and is still putting itself back together – Long cracks or faults riddle its surface – Rolling hills adjacent to wrinkled terrain ...
Radiometric dating results 5
... transected by several branches of the Karesuando-Arjeplog deformation zone but in domains between these branches the rocks may show only minor signs of deformation, such as at the sample locality. The metadiorite is dark grey, medium-grained and isotropic. In some outcrops it is altered and contains ...
... transected by several branches of the Karesuando-Arjeplog deformation zone but in domains between these branches the rocks may show only minor signs of deformation, such as at the sample locality. The metadiorite is dark grey, medium-grained and isotropic. In some outcrops it is altered and contains ...
Bulletin of the Geological Society of Denmark, Vol. 39/3-4 pp. 179-197
... zircon concordia-intercept U-Pb ages of 30703000 Ma (Baadsgaard & McGregor 1981) and SHRIMP concordant ages of 3040-3000 Ma (H. Baadsgaard, pers. comm.). Large, relatively homogeneous bodies of granodioritic gneiss that intrude the tonalitic gneisses in this area have given bulk zircon concordia-int ...
... zircon concordia-intercept U-Pb ages of 30703000 Ma (Baadsgaard & McGregor 1981) and SHRIMP concordant ages of 3040-3000 Ma (H. Baadsgaard, pers. comm.). Large, relatively homogeneous bodies of granodioritic gneiss that intrude the tonalitic gneisses in this area have given bulk zircon concordia-int ...
523 Resources
... • The outer planets are Jupiter, Saturn, Uranus, Neptune, and Pluto. • Pluto is a small icy planet. The other outer planets are large, gaseous planets. ...
... • The outer planets are Jupiter, Saturn, Uranus, Neptune, and Pluto. • Pluto is a small icy planet. The other outer planets are large, gaseous planets. ...
Geochemistry of Jurassic Oceanic Crust beneath
... and ultramafic massifs (e.g. Zindler & Hart, 1986). Recycling of oceanic crust through subduction zones is generally accepted as one of the major processes, if not the major process, causing heterogeneity within the mantle (e.g. Chase, 1981; Hofmann & White, 1982). Studies of Pb isotopes in OIB and ...
... and ultramafic massifs (e.g. Zindler & Hart, 1986). Recycling of oceanic crust through subduction zones is generally accepted as one of the major processes, if not the major process, causing heterogeneity within the mantle (e.g. Chase, 1981; Hofmann & White, 1982). Studies of Pb isotopes in OIB and ...
McLelland, JM, Selleck, BW, and Bickford, ME, 2010
... ca. 1050 Ma, followed by orogen collapse at ca. 1020 Ma. A final contractional pulse (ca. 1010–980 Ma) ending with extensional collapse gave rise to the Grenville Front thrust. The Allochthonous Monocyclic Belt consists of rocks younger than ca. 1.35 Ga. Details of these belts and the orogenic seque ...
... ca. 1050 Ma, followed by orogen collapse at ca. 1020 Ma. A final contractional pulse (ca. 1010–980 Ma) ending with extensional collapse gave rise to the Grenville Front thrust. The Allochthonous Monocyclic Belt consists of rocks younger than ca. 1.35 Ga. Details of these belts and the orogenic seque ...
19uranusneptune2s
... The Formation of Uranus and Neptune At 20-30 AU the planetesimals were fewer and more widely dispersed than at 5-10 AU ...
... The Formation of Uranus and Neptune At 20-30 AU the planetesimals were fewer and more widely dispersed than at 5-10 AU ...
Insight into landslide kinematics from a broadband seismic network
... A velocity as high as that of the Hsiaolin landslide (approximately 298 km/h) had not been reported anywhere in the world prior to 2009. A high-velocity landslide of that scale is difficult to observe unless it can be predicted. The factors contributing to such a landslide includes a low friction co ...
... A velocity as high as that of the Hsiaolin landslide (approximately 298 km/h) had not been reported anywhere in the world prior to 2009. A high-velocity landslide of that scale is difficult to observe unless it can be predicted. The factors contributing to such a landslide includes a low friction co ...
The Exploration of Neptune and Triton
... instruments on a Flagship mission would follow in the revolutionary footsteps of the Galileo and Cassini missions, but that does not imply a flagship mission is the only worthwhile platform for exploring the system. A smaller subset of those instruments, on a New Frontiers orbiter could address mult ...
... instruments on a Flagship mission would follow in the revolutionary footsteps of the Galileo and Cassini missions, but that does not imply a flagship mission is the only worthwhile platform for exploring the system. A smaller subset of those instruments, on a New Frontiers orbiter could address mult ...
Pluto, Charon & the Plutons
... • Resonant KBOs: are found in resonances with Neptune, mostly at the 3:2 resonance - just like Pluto - and make up about 35% of the KBOs population. They’re often called Plutinos. • Scattered KBOs: are on large highly eccentric and inclined orbits. They’re on very distant orbits - out as a few 100 A ...
... • Resonant KBOs: are found in resonances with Neptune, mostly at the 3:2 resonance - just like Pluto - and make up about 35% of the KBOs population. They’re often called Plutinos. • Scattered KBOs: are on large highly eccentric and inclined orbits. They’re on very distant orbits - out as a few 100 A ...
Preprint - Lunar and Planetary Laboratory
... survival of Neptune Trojans in N -body simulations which had all four giant planets migrating. Gomes included 100 initial Trojan-type test particles and generally migrated the planets using the conventional ∆a values given above. In linear migration models with a 106 year time scale Gomes found 82 p ...
... survival of Neptune Trojans in N -body simulations which had all four giant planets migrating. Gomes included 100 initial Trojan-type test particles and generally migrated the planets using the conventional ∆a values given above. In linear migration models with a 106 year time scale Gomes found 82 p ...
Seeding the Universe with Life
... structures. The laws and constants of physics coincide precisely to allow biological matter to exist. The strong and weak nuclear forces are just right to create the elements. Electromagnetic forces are just right to allow molecular structure. Gravity and the masses of stars, galaxies and the overal ...
... structures. The laws and constants of physics coincide precisely to allow biological matter to exist. The strong and weak nuclear forces are just right to create the elements. Electromagnetic forces are just right to allow molecular structure. Gravity and the masses of stars, galaxies and the overal ...
Generation of new continental crust by sublithospheric silicic
... of the most debated topic in relation to the generation of the rocks forming the continental crust is given in the next section with the aim of offering a reference framework on the problem of continental crust generation. 2. Taylor's andesite model: An overview on the origin of upper and lower cont ...
... of the most debated topic in relation to the generation of the rocks forming the continental crust is given in the next section with the aim of offering a reference framework on the problem of continental crust generation. 2. Taylor's andesite model: An overview on the origin of upper and lower cont ...
Comet Facts, Myths, and Legends
... Earth's path, then at that point, every year for a long time, there will be meteor showers as the long-gone comet's debris strikes our atmosphere. Some of these meteor showers occur every year when the Earth passes the place where the comet had been long ago. ...
... Earth's path, then at that point, every year for a long time, there will be meteor showers as the long-gone comet's debris strikes our atmosphere. Some of these meteor showers occur every year when the Earth passes the place where the comet had been long ago. ...
Late Heavy Bombardment
The Late Heavy Bombardment (abbreviated LHB and also known as the lunar cataclysm) is a hypothetical event thought to have occurred approximately 4.1 to 3.8 billion years (Ga) ago, corresponding to the Neohadean and Eoarchean eras on Earth. During this interval, a disproportionately large number of asteroids apparently collided with the early terrestrial planets in the inner Solar System, including Mercury, Venus, Earth, and Mars. The LHB happened after the Earth and other rocky planets had formed and accreted most of their mass, but still quite early in Earth's history.Evidence for the LHB derives from lunar samples brought back by the Apollo astronauts. Isotopic dating of Moon rocks implies that most impact melts occurred in a rather narrow interval of time. Several hypotheses are now offered to explain the apparent spike in the flux of impactors (i.e. asteroids and comets) in the inner Solar System, but no consensus yet exists. The Nice model is popular among planetary scientists; it postulates that the gas giant planets underwent orbital migration and scattered objects in the asteroid and/or Kuiper belts into eccentric orbits, and thereby into the path of the terrestrial planets. Other researchers argue that the lunar sample data do not require a cataclysmic cratering event near 3.9 Ga, and that the apparent clustering of impact melt ages near this time is an artifact of sampling materials retrieved from a single large impact basin. They also note that the rate of impact cratering could be significantly different between the outer and inner zones of the Solar System.