Global mass wasting during the Middle Ordovician: Meteoritic trigger
... of almost 10 Ma. Having strong arguments against the impact-related hypothesis, we propose an alternative explanation, which is based on a re-evaluation of the mass wasting sites, considering their plate-tectonic distribution and the global sea level curve. A striking and important feature is the di ...
... of almost 10 Ma. Having strong arguments against the impact-related hypothesis, we propose an alternative explanation, which is based on a re-evaluation of the mass wasting sites, considering their plate-tectonic distribution and the global sea level curve. A striking and important feature is the di ...
Experimental_laboratory_files/2004_The source of Granites
... Archaean crust source for I-type granites receives strong support from field relations and laboratory experiments that will be discussed later on in this paper. The model also accounts for the decoupled behaviour of the Nd isotopic ratios of granite batholiths. If no other source components but rock ...
... Archaean crust source for I-type granites receives strong support from field relations and laboratory experiments that will be discussed later on in this paper. The model also accounts for the decoupled behaviour of the Nd isotopic ratios of granite batholiths. If no other source components but rock ...
Tectonic Assembly of the Northern Andean Block
... units (including terranes, terrane assemblages, physiographic domains, etc.) and their bounding suture and fault systems, which, based on geologic, geophysical, and dynamo-tectonic considerations, define four distinct tectonic realms representing the entire Northern Andean region. These include the ...
... units (including terranes, terrane assemblages, physiographic domains, etc.) and their bounding suture and fault systems, which, based on geologic, geophysical, and dynamo-tectonic considerations, define four distinct tectonic realms representing the entire Northern Andean region. These include the ...
Kistufell: Primitive Melt from the Iceland Mantle
... and a basalt flow capping Kistufell (n = 1) have been analysed in this study. All of the glass analyses were carried out on handpicked fragments or shards without secondary fillings in vesicles, as hydration of basaltic glasses usually leads to considerable leaching of SiO2, Al2O3, CaO, Na2O, K2O, R ...
... and a basalt flow capping Kistufell (n = 1) have been analysed in this study. All of the glass analyses were carried out on handpicked fragments or shards without secondary fillings in vesicles, as hydration of basaltic glasses usually leads to considerable leaching of SiO2, Al2O3, CaO, Na2O, K2O, R ...
PDF
... melt of ∼2.5 Ga crust, demonstrating for the first time that Archean crust or sediments with abundant Archean zircons exists in the SES. In spite of ∼300 million years of Neoproterozoic igneous activity, we see no evidence of systematic compositional evolution in SES igneous rocks from early low-K su ...
... melt of ∼2.5 Ga crust, demonstrating for the first time that Archean crust or sediments with abundant Archean zircons exists in the SES. In spite of ∼300 million years of Neoproterozoic igneous activity, we see no evidence of systematic compositional evolution in SES igneous rocks from early low-K su ...
Lower crustal deformation beneath the central Transverse Ranges
... where there is a left step in the right-lateral transform system (Figure 1a). This restraining bend, in principle, results in approximately north-south compression across the San Andreas fault [e.g., Atwater, 1970; Bird and Rosenstock, 1984], although Weldon and Humphreys [1986] point out that littl ...
... where there is a left step in the right-lateral transform system (Figure 1a). This restraining bend, in principle, results in approximately north-south compression across the San Andreas fault [e.g., Atwater, 1970; Bird and Rosenstock, 1984], although Weldon and Humphreys [1986] point out that littl ...
Tectonic Geomorphology and Paleoseismology
... 1910-1929 no creep, based on offset in two sidewalks constructed in 1910 and 1929, and pipeline laid in 1929 1929 ......- creep commenced, with 8 mm/yr (average) 1961 - 1967, slip rate about 15 mm/yr 1979....2 sites monitored in Hollister with 6.6 mm/yr and 12 mm/yr (2.3km NW) 20.000 earthquakes a y ...
... 1910-1929 no creep, based on offset in two sidewalks constructed in 1910 and 1929, and pipeline laid in 1929 1929 ......- creep commenced, with 8 mm/yr (average) 1961 - 1967, slip rate about 15 mm/yr 1979....2 sites monitored in Hollister with 6.6 mm/yr and 12 mm/yr (2.3km NW) 20.000 earthquakes a y ...
Deep structures and breakup along volcanic rifted margins: insights
... injections within the lower crust at an early stage of the continental breakup. One of the main assumptions of this previous crustal interpretation was to directly assign the crustal doming beneath the outer Vøring Margin to mantle-induced magmatism. Such a chronology and type of crustal deformation ...
... injections within the lower crust at an early stage of the continental breakup. One of the main assumptions of this previous crustal interpretation was to directly assign the crustal doming beneath the outer Vøring Margin to mantle-induced magmatism. Such a chronology and type of crustal deformation ...
Davis, E. E., and Fisher, A. T., Seafloor heat flow
... Pioneering measurements of temperature below the seafloor (e.g., Petterson, 1949; Revelle and Maxwell, 1952; Bullard, 1954) were made to compare the thermal state of the ocean crust with that of continents and thus to improve the knowledge of the present-day heat loss from the Earth. The early data ...
... Pioneering measurements of temperature below the seafloor (e.g., Petterson, 1949; Revelle and Maxwell, 1952; Bullard, 1954) were made to compare the thermal state of the ocean crust with that of continents and thus to improve the knowledge of the present-day heat loss from the Earth. The early data ...
Earth`s heterogeneous mantle: A product of convection
... Ubiquitous heterogeneity in the Earth's mantle has been documented by numerous chemical and isotopic analyses of oceanic basalts. Despite the ever-increasing amount of data, the way in which compositional heterogeneity is manifest in the Earth's mantle, as well as the processes leading to mantle het ...
... Ubiquitous heterogeneity in the Earth's mantle has been documented by numerous chemical and isotopic analyses of oceanic basalts. Despite the ever-increasing amount of data, the way in which compositional heterogeneity is manifest in the Earth's mantle, as well as the processes leading to mantle het ...
Structure of the crust beneath Cameroon, West Africa, from the joint
... least-squares misfit comparable, a normalization of the data set is necessary, and this is done using the number of data points and variance for each of the data sets. An influence factor is used to control the trade-off between fitting the receiver functions and the group velocity curves. During th ...
... least-squares misfit comparable, a normalization of the data set is necessary, and this is done using the number of data points and variance for each of the data sets. An influence factor is used to control the trade-off between fitting the receiver functions and the group velocity curves. During th ...
1 Bathymetry of the Pacific Plate and its Implications for Thermal
... from the HSC model is a key to understanding the dynamics of the mantle. Two proposals have been suggested to explain the deviations: large-scale mantle convective upwellings associated with deep mantle processes and lithospheric reheating (i.e., a plate model) related to shallow mantle processes. F ...
... from the HSC model is a key to understanding the dynamics of the mantle. Two proposals have been suggested to explain the deviations: large-scale mantle convective upwellings associated with deep mantle processes and lithospheric reheating (i.e., a plate model) related to shallow mantle processes. F ...
accepted manuscript
... partial melting should also play a certain role (Yamato et al., 2008), but the impact of UHP transforms on subduction may be of minor importance (Toussaint et al., 2004a), specifically if one remembers that some UHP transforms occur during the exhumation stage only (Peterman et al. , 2009). Preserva ...
... partial melting should also play a certain role (Yamato et al., 2008), but the impact of UHP transforms on subduction may be of minor importance (Toussaint et al., 2004a), specifically if one remembers that some UHP transforms occur during the exhumation stage only (Peterman et al. , 2009). Preserva ...
A2 Course Study Guide
... One of the simplest crystal structures is that of sodium chloride (Na +Cl-). Here, the sodium and chloride ions are situated as if they were at the corners of cubes. Each sodium ion is surrounded by six chlorine ions and each chlorine ion is surrounded by six sodium ions. Minerals containing silico ...
... One of the simplest crystal structures is that of sodium chloride (Na +Cl-). Here, the sodium and chloride ions are situated as if they were at the corners of cubes. Each sodium ion is surrounded by six chlorine ions and each chlorine ion is surrounded by six sodium ions. Minerals containing silico ...
Craton stability and longevity
... While the evidence for the long-term stability of deep cratonic lithosphere is clear, our understanding of all the parameters that contribute to this stability remains relatively poor and conflicting. The longevity and stability of cratons has been attributed to either external factors such as weak ...
... While the evidence for the long-term stability of deep cratonic lithosphere is clear, our understanding of all the parameters that contribute to this stability remains relatively poor and conflicting. The longevity and stability of cratons has been attributed to either external factors such as weak ...
Chapter F4
... take up more space than cooler rocks. • The lithosphere is relatively hot at mid-ocean ridges, but cools as it moves farther from the ridge. • As it cools, the oceanic lithosphere takes up less volume and the ocean floor subsides. ...
... take up more space than cooler rocks. • The lithosphere is relatively hot at mid-ocean ridges, but cools as it moves farther from the ridge. • As it cools, the oceanic lithosphere takes up less volume and the ocean floor subsides. ...
Caribbean Basins - Red Cubana de la Ciencia
... rocks exposed on the island of Hispaniola may represent the continuation of the Grenada and Yucatfin back-arc basins in this area (Fig. 2). Deformation of Caribbean crust and basin formation ...
... rocks exposed on the island of Hispaniola may represent the continuation of the Grenada and Yucatfin back-arc basins in this area (Fig. 2). Deformation of Caribbean crust and basin formation ...
Crustal analysis of maud rise from combined satellite and near-surface
... Hinze, 1998). However, this 6-month mission operated during Austral summer and fall periods when south polar external field activity was maximum. The spatially and temporally dynamic effects of the auroral external fields are at least two orders of magnitude larger than the static lithospheric anoma ...
... Hinze, 1998). However, this 6-month mission operated during Austral summer and fall periods when south polar external field activity was maximum. The spatially and temporally dynamic effects of the auroral external fields are at least two orders of magnitude larger than the static lithospheric anoma ...
SiphonPaper_Supplement_141124
... which an initial siphon can self-sustain under conditions where it would not develop spontaneously from “conductive-hydrostatic.” We also ran subset of the simulations presented in Figs. 3 and 4 beginning from an active siphon that flows in the opposite direction. In all of these cases, the siphon e ...
... which an initial siphon can self-sustain under conditions where it would not develop spontaneously from “conductive-hydrostatic.” We also ran subset of the simulations presented in Figs. 3 and 4 beginning from an active siphon that flows in the opposite direction. In all of these cases, the siphon e ...
Flood basalts, continental breakup and the dispersal of
... 1994a, b), or convective partial melting (Mutter et al., 1988), the mantle plume model has gained widespread acceptance (White and McKenzie, 1989, 1995; Richards et al., 1989; Kent, 1994; Storey and Kyle, 1997; Tackley, 2000). It is likely that large mantle plumes ascending from a thermal layer just ...
... 1994a, b), or convective partial melting (Mutter et al., 1988), the mantle plume model has gained widespread acceptance (White and McKenzie, 1989, 1995; Richards et al., 1989; Kent, 1994; Storey and Kyle, 1997; Tackley, 2000). It is likely that large mantle plumes ascending from a thermal layer just ...
subduction to strike-slip transitions on plate boundaries
... character. The location of the Alpine Fault is well constrained on the Fiordland margin. The southern end of the fault terminates abruptly at the trench deformation front and is aligned with inherited structures on the rifted edge of a continental sliver on the Australian Plate. One possible model i ...
... character. The location of the Alpine Fault is well constrained on the Fiordland margin. The southern end of the fault terminates abruptly at the trench deformation front and is aligned with inherited structures on the rifted edge of a continental sliver on the Australian Plate. One possible model i ...
Plate tectonics
Plate tectonics (from the Late Latin tectonicus, from the Greek: τεκτονικός ""pertaining to building"") is a scientific theory that describes the large-scale motion of Earth's lithosphere. This theoretical model builds on the concept of continental drift which was developed during the first few decades of the 20th century. The geoscientific community accepted the theory after the concepts of seafloor spreading were later developed in the late 1950s and early 1960s.The lithosphere, which is the rigid outermost shell of a planet (on Earth, the crust and upper mantle), is broken up into tectonic plates. On Earth, there are seven or eight major plates (depending on how they are defined) and many minor plates. Where plates meet, their relative motion determines the type of boundary; convergent, divergent, or transform. Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along these plate boundaries. The lateral relative movement of the plates typically varies from zero to 100 mm annually.Tectonic plates are composed of oceanic lithosphere and thicker continental lithosphere, each topped by its own kind of crust. Along convergent boundaries, subduction carries plates into the mantle; the material lost is roughly balanced by the formation of new (oceanic) crust along divergent margins by seafloor spreading. In this way, the total surface of the globe remains the same. This prediction of plate tectonics is also referred to as the conveyor belt principle. Earlier theories (that still have some supporters) propose gradual shrinking (contraction) or gradual expansion of the globe.Tectonic plates are able to move because the Earth's lithosphere has greater strength than the underlying asthenosphere. Lateral density variations in the mantle result in convection. Plate movement is thought to be driven by a combination of the motion of the seafloor away from the spreading ridge (due to variations in topography and density of the crust, which result in differences in gravitational forces) and drag, with downward suction, at the subduction zones. Another explanation lies in the different forces generated by the rotation of the globe and the tidal forces of the Sun and Moon. The relative importance of each of these factors and their relationship to each other is unclear, and still the subject of much debate.