The Upper Mantle Geoid: Implications for Continental Structure and
... this residual geoid is characterized by two dominant mass anomalies in the deep mantle near the coremantle boundary (Becker and Boschi, 2002). Apart from the geoid highs associated with subduction zones along the western Pacific Rim, there is little correlation between the geoid and surface features ...
... this residual geoid is characterized by two dominant mass anomalies in the deep mantle near the coremantle boundary (Becker and Boschi, 2002). Apart from the geoid highs associated with subduction zones along the western Pacific Rim, there is little correlation between the geoid and surface features ...
Anderson and Natland, 2005
... throwback to the principle of multiple working hypotheses adhered to by several generations of geologists. The idea that volcanoes at the Earth’s surface are fueled by hot, narrow tubes of ascending mantle originating just above the core, 3000 km away, is truly an extraordinary one. Carl Sagan (1934 ...
... throwback to the principle of multiple working hypotheses adhered to by several generations of geologists. The idea that volcanoes at the Earth’s surface are fueled by hot, narrow tubes of ascending mantle originating just above the core, 3000 km away, is truly an extraordinary one. Carl Sagan (1934 ...
Plate Tectonics Jeopardy
... dense so it floats to the top, where it cools and contracts, making it sink. 100 pts. ...
... dense so it floats to the top, where it cools and contracts, making it sink. 100 pts. ...
Earth Science Ch. 4 Practice Test
... Oceanic crust near the mid-ocean ridge is younger than oceanic crust farther away from the ridge. _________________________ ____ 38. If subduction occurs faster than oceanic crust can be created, an ocean will expand. _________________________ ____ 39. Along a spreading boundary, two plates slip pas ...
... Oceanic crust near the mid-ocean ridge is younger than oceanic crust farther away from the ridge. _________________________ ____ 38. If subduction occurs faster than oceanic crust can be created, an ocean will expand. _________________________ ____ 39. Along a spreading boundary, two plates slip pas ...
Propagating rift model for the V‐shaped ridges south of Iceland
... Figure 3. VSR asymmetry shown by (a) compiled multibeam bathymetry data and (b) satellite‐derived gravity [Sandwell and Smith, 2009] combined with new axial mosaic shipboard gravity, illuminated from the southeast. The dots are the ridge jump boundaries (pseudofault wakes) used in our magnetic anoma ...
... Figure 3. VSR asymmetry shown by (a) compiled multibeam bathymetry data and (b) satellite‐derived gravity [Sandwell and Smith, 2009] combined with new axial mosaic shipboard gravity, illuminated from the southeast. The dots are the ridge jump boundaries (pseudofault wakes) used in our magnetic anoma ...
Hotspot Geodynamics Detailed Planning Group
... and the newer model reflects "deeper" flow because of more massive plumes. Hence, the newer results agree less well with observations. Kerguelen is really the only hotspot for which the latest modeling results are substantially different from older ones. Ocean floor age changes across the Ninetyeast ...
... and the newer model reflects "deeper" flow because of more massive plumes. Hence, the newer results agree less well with observations. Kerguelen is really the only hotspot for which the latest modeling results are substantially different from older ones. Ocean floor age changes across the Ninetyeast ...
Palaeocene–Recent plate boundaries in the NE Atlantic and the
... spreading system and proposed that the Jan Mayen microcontinent acted as a microplate during the opening of the Norway Basin. Unternehr (1982) published detailed kinematic analyses of the opening of the Greenland, Norwegian and south of Iceland oceanic basins and recognized that the mismatch of thes ...
... spreading system and proposed that the Jan Mayen microcontinent acted as a microplate during the opening of the Norway Basin. Unternehr (1982) published detailed kinematic analyses of the opening of the Greenland, Norwegian and south of Iceland oceanic basins and recognized that the mismatch of thes ...
essentials-of-oceanography-10th-edition-trujillo-test
... E) plants and animals that live in an area. Answer: B Diff: 2 Skill: comprehension 36) All of the following provide evidence for continental drift except: A) age of selected continental rocks. B) apparent polar wandering. C) location of coral reef fossils. D) seafloor magnetic pattern. E) shape of c ...
... E) plants and animals that live in an area. Answer: B Diff: 2 Skill: comprehension 36) All of the following provide evidence for continental drift except: A) age of selected continental rocks. B) apparent polar wandering. C) location of coral reef fossils. D) seafloor magnetic pattern. E) shape of c ...
Plate Tectonics
... Laboratory Activities: These activities do not require elaborate supplies or extensive pre-lab preparations. These student-oriented labs are designed to explore science through a stimulating yet simple and relaxed approach to each topic. Helpful comments, suggestions, and answers to all questions ar ...
... Laboratory Activities: These activities do not require elaborate supplies or extensive pre-lab preparations. These student-oriented labs are designed to explore science through a stimulating yet simple and relaxed approach to each topic. Helpful comments, suggestions, and answers to all questions ar ...
Grand Challenges in Geodynamics
... Comparative planetology has advanced the idea that the long-term evolution of a terrestrial planet may be dictated, or at least strongly influenced, by events occurring within the first 50-100 Ma of its formation. Relative to the modern Earth, the energy available for heating Earth’s interior was or ...
... Comparative planetology has advanced the idea that the long-term evolution of a terrestrial planet may be dictated, or at least strongly influenced, by events occurring within the first 50-100 Ma of its formation. Relative to the modern Earth, the energy available for heating Earth’s interior was or ...
Hoffman2013_Cordille.. - Department of Earth Sciences
... between the two plates. The inverse problem dawned on him more slowly: using seismic slip vectors as a test of the rigidity of the plates, the central premise of plate tectonics (Wilson 1965). Bob Parker had written a computer program (in Fortran-63) that allowed him to plot vectoral data on a map o ...
... between the two plates. The inverse problem dawned on him more slowly: using seismic slip vectors as a test of the rigidity of the plates, the central premise of plate tectonics (Wilson 1965). Bob Parker had written a computer program (in Fortran-63) that allowed him to plot vectoral data on a map o ...
Pyrenean orogeny and plate kinematics
... our knowledge, nobody tried to identify them. If these lineations are older seafloor spreading magnetic anomalies, then they would allow the calculation of a better constrained model for the motion across the Pyrenees than has been possible so far. We have therefore reexamined the above question of ...
... our knowledge, nobody tried to identify them. If these lineations are older seafloor spreading magnetic anomalies, then they would allow the calculation of a better constrained model for the motion across the Pyrenees than has been possible so far. We have therefore reexamined the above question of ...
A global-scale plate reorganization event at 105−100Ma
... A major plate reorganization is postulated to have occurred at approximately 100 Ma. However, this reorganization has received limited attention, despite being associated with the most prominent suite of fracture zone bends on the planet and many other geological events. We investigate tectonic even ...
... A major plate reorganization is postulated to have occurred at approximately 100 Ma. However, this reorganization has received limited attention, despite being associated with the most prominent suite of fracture zone bends on the planet and many other geological events. We investigate tectonic even ...
Extremely thin crust in the Indian Ocean possibly resulting from
... (Singh et al. 2007) but no other deep subhorizontal reflections are observed that could be interpreted as reflections from the Moho. Fig. 4 shows the seismic image along orthogonal profile WG1 (Singh et al. 2008) with respect to the blow-up of the image along profile WG3 with a 3-D perspective. Alth ...
... (Singh et al. 2007) but no other deep subhorizontal reflections are observed that could be interpreted as reflections from the Moho. Fig. 4 shows the seismic image along orthogonal profile WG1 (Singh et al. 2008) with respect to the blow-up of the image along profile WG3 with a 3-D perspective. Alth ...
View/Open - Earth
... with buoyancy-driven convection within a hot, low viscosity asthenosphere. Each initial axial cell taps a different asthenospheric source and serves as nucleus for axial propagation of oceanic accretion, resulting in linear segments of spreading. ...
... with buoyancy-driven convection within a hot, low viscosity asthenosphere. Each initial axial cell taps a different asthenospheric source and serves as nucleus for axial propagation of oceanic accretion, resulting in linear segments of spreading. ...
Linking Porphyry Deposit Geology to Geophysics via Physical
... This report summarizes the results of a study initiated to investigate physical rock properties of the hosting and mineralized rocks associated with the porphyry deposits targeted for geophysical surveys as part of the QUEST and QUEST-West projects. This research was conducted as part of a Geoscienc ...
... This report summarizes the results of a study initiated to investigate physical rock properties of the hosting and mineralized rocks associated with the porphyry deposits targeted for geophysical surveys as part of the QUEST and QUEST-West projects. This research was conducted as part of a Geoscienc ...
Variations in amount and direction of seafloor spreading along
... responsible for the development of inversion structures in the Vøring Basin and on the Faeroes-Rockall Plateau, rather than in the Møre Basin. [10] On the Faeroe-Rockall Plateau, compressional structures are different from those on the Norwegian Margin and they also vary in size, trend and shape [Tu ...
... responsible for the development of inversion structures in the Vøring Basin and on the Faeroes-Rockall Plateau, rather than in the Møre Basin. [10] On the Faeroe-Rockall Plateau, compressional structures are different from those on the Norwegian Margin and they also vary in size, trend and shape [Tu ...
Newly identi¢ed segments of the Paci¢c^Australia plate boundary
... the North Fiji transform zone (NFTZ), is almost 1500 km long (Fig. 1). It represents one of the major transform boundaries on the Earth's surface [1] and has always been regarded as playing a major role in the recent tectonic development of the Lau and North Fiji basins [2,3]. The NFTZ is characteri ...
... the North Fiji transform zone (NFTZ), is almost 1500 km long (Fig. 1). It represents one of the major transform boundaries on the Earth's surface [1] and has always been regarded as playing a major role in the recent tectonic development of the Lau and North Fiji basins [2,3]. The NFTZ is characteri ...
Earth Planet. Sci. Lett., 139, 1-16, 1996.
... north of the Marquesas FZ) was obtained directly from the digital age database 1371. Magnetic anomaly picks were correlated with a new magnetostratigraphic time scale [33]. The new time scale contains several significant modifications in the ages attributed to isochrons, mostly due to changes in cal ...
... north of the Marquesas FZ) was obtained directly from the digital age database 1371. Magnetic anomaly picks were correlated with a new magnetostratigraphic time scale [33]. The new time scale contains several significant modifications in the ages attributed to isochrons, mostly due to changes in cal ...
TECTONIC ANALYSIS OF NORTHWESTERN SOUTH AMERICA
... from available satellite, airborne and surface gravity and magnetic data integrated with global digital topography, seismic, and GPS plate velocity data. Reliable crustal thickness estimates that help constrain tectonic stress/strain conditions were obtained by inverse modeling of the magnetic anoma ...
... from available satellite, airborne and surface gravity and magnetic data integrated with global digital topography, seismic, and GPS plate velocity data. Reliable crustal thickness estimates that help constrain tectonic stress/strain conditions were obtained by inverse modeling of the magnetic anoma ...
Convergence of tectonic reconstructions and mantle - HAL-Insu
... involving changes in ridge length and global tectonic reorganisations. Although independent, both convection models and kinematic reconstructions suggest that changes in ridge length are at least as significant as spreading rate fluctuations in driving changes in the seafloor area-age distribution t ...
... involving changes in ridge length and global tectonic reorganisations. Although independent, both convection models and kinematic reconstructions suggest that changes in ridge length are at least as significant as spreading rate fluctuations in driving changes in the seafloor area-age distribution t ...
Upper mantle
... Origin of mantle plumes (near mantle core boundary) How does mantle heterogeneity survive convection? Single layer or double layer convection? Upper mantle Low velocity zone (LVZ): 25 to 300 km deep Depth and thickness depends on geothermal gradient Top corresponds to base of lithosphere (“plate”) S ...
... Origin of mantle plumes (near mantle core boundary) How does mantle heterogeneity survive convection? Single layer or double layer convection? Upper mantle Low velocity zone (LVZ): 25 to 300 km deep Depth and thickness depends on geothermal gradient Top corresponds to base of lithosphere (“plate”) S ...
Today`s Quiz -
... got older farther from the ridge (Mid Atlantic Ridge, Guyots) 2) If the Ocean floors are 4.5 Billion years old why is there so little sediment. 3) Why are the oldest fossils found in ocean sediments only 180 Million years old? ...
... got older farther from the ridge (Mid Atlantic Ridge, Guyots) 2) If the Ocean floors are 4.5 Billion years old why is there so little sediment. 3) Why are the oldest fossils found in ocean sediments only 180 Million years old? ...
Plate Tectonics
... Laboratory Activities: These activities do not require elaborate supplies or extensive pre-lab preparations. These student-oriented labs are designed to explore science through a stimulating yet simple and relaxed approach to each topic. Helpful comments, suggestions, and answers to all questions ar ...
... Laboratory Activities: These activities do not require elaborate supplies or extensive pre-lab preparations. These student-oriented labs are designed to explore science through a stimulating yet simple and relaxed approach to each topic. Helpful comments, suggestions, and answers to all questions ar ...
Geodynamics of the South China Sea
... 33 Ma. Chron 12 (32 Ma) is the oldest chron identified in the SCS. The nature of the crust of the northeastern part of the SCS located north of chron C12, where chrons 15 to 17 were previously identified, is not oceanic but thinned continental crust intruded by volcanic elongated features emplaced 17– ...
... 33 Ma. Chron 12 (32 Ma) is the oldest chron identified in the SCS. The nature of the crust of the northeastern part of the SCS located north of chron C12, where chrons 15 to 17 were previously identified, is not oceanic but thinned continental crust intruded by volcanic elongated features emplaced 17– ...
Geomagnetic reversal
A geomagnetic reversal is a change in a planet's magnetic field such that the positions of magnetic north and magnetic south are interchanged. The Earth's field has alternated between periods of normal polarity, in which the direction of the field was the same as the present direction, and reverse polarity, in which the field was the opposite. These periods are called chrons. The time spans of chrons are randomly distributed with most being between 0.1 and 1 million years with an average of 450,000 years. Most reversals are estimated to take between 1,000 and 10,000 years.The latest one, the Brunhes–Matuyama reversal, occurred 780,000 years ago;and may have happened very quickly, within a human lifetime. A brief complete reversal, known as the Laschamp event, occurred only 41,000 years ago during the last glacial period. That reversal lasted only about 440 years with the actual change of polarity lasting around 250 years. During this change the strength of the magnetic field dropped to 5% of its present strength. Brief disruptions that do not result in reversal are called geomagnetic excursions.