![Ultraslow, slow, or fast spreading ridges](http://s1.studyres.com/store/data/005732856_1-c462c021ad433e535910e121fde57fb0-300x300.png)
Ultraslow, slow, or fast spreading ridges
... temperature anomalies underneath ridges, we note that spreading rates globally correlate with wave speed anomalies at sublithospheric depths, the faster the spreading the slower the shear wave velocity (Figs. 3 and 4b). This result is in accord with Humler et al. (1993) who found a correlation betwe ...
... temperature anomalies underneath ridges, we note that spreading rates globally correlate with wave speed anomalies at sublithospheric depths, the faster the spreading the slower the shear wave velocity (Figs. 3 and 4b). This result is in accord with Humler et al. (1993) who found a correlation betwe ...
The African Plate: A history of oceanic crust accretion and
... of the African continental margin studies). Particularly for the socalled non-volcanic margins, where the presence of exhumed (and serpentinized) continental mantle and isolated blocks of extended continental crust exist for at least tens of kilometers (e.g., Manatschal, 2004), a clear boundary betw ...
... of the African continental margin studies). Particularly for the socalled non-volcanic margins, where the presence of exhumed (and serpentinized) continental mantle and isolated blocks of extended continental crust exist for at least tens of kilometers (e.g., Manatschal, 2004), a clear boundary betw ...
Plate Tectonics - The Web site cannot be found
... Figure 3.3: For the description of the processes involved in the formation of the oceanic lithosphere, we often use a 2D coordinate system perpendicular to the strike of the mid- ocean ridge (MOR). Whereas this view – continually displaced along the transform faults– is suitable to describe the ocea ...
... Figure 3.3: For the description of the processes involved in the formation of the oceanic lithosphere, we often use a 2D coordinate system perpendicular to the strike of the mid- ocean ridge (MOR). Whereas this view – continually displaced along the transform faults– is suitable to describe the ocea ...
782 - Head, J. W., and L. S. Crumpler
... andmorphologiccharacteristicsof cross-strikediscontinuities[high-resolutiondatafrom (23)]. kilometers wide and several hundred meters deep, extensive intrusions and localized extrusive volcanism, and occasional larger volcalinear discontinuities extend for several thousand kilometers across noes on ...
... andmorphologiccharacteristicsof cross-strikediscontinuities[high-resolutiondatafrom (23)]. kilometers wide and several hundred meters deep, extensive intrusions and localized extrusive volcanism, and occasional larger volcalinear discontinuities extend for several thousand kilometers across noes on ...
IDOE Workshop on Tectonic Patterns and Metallogenesis in East
... eastern Asia,from the Sunda Arc to the Japanese islands,and from the stable shelfof the Gulf of Thailand to the stable shelf bordering northern Australia, provide one of the most significant regions of the earth's surface for the study of present-day tectonic processes and of their effects in the re ...
... eastern Asia,from the Sunda Arc to the Japanese islands,and from the stable shelfof the Gulf of Thailand to the stable shelf bordering northern Australia, provide one of the most significant regions of the earth's surface for the study of present-day tectonic processes and of their effects in the re ...
Subduction of young oceanic plates: A numerical study with
... [1] We investigated numerical models of initiation and subsequent evolution of subduction of young (10–30 Myr) oceanic lithosphere. Systematic numerical experiments were carried out by varying the age of the subducting plate (10, 12.5, 15, 17.5, 20, 25 and 30 Myr), the rate of induced convergence (2 ...
... [1] We investigated numerical models of initiation and subsequent evolution of subduction of young (10–30 Myr) oceanic lithosphere. Systematic numerical experiments were carried out by varying the age of the subducting plate (10, 12.5, 15, 17.5, 20, 25 and 30 Myr), the rate of induced convergence (2 ...
Impact origin for the greater Ontong Java Plateau?
... that if one or more OJP plume head(s) had extended underneath these basins, high temperatures induced on preexisting lithosphere arguably could have raised the basalts above the Curie temperature, thus erasing the Mesozoic magnetic anomalies, and suggested that the basin basalts instead originated f ...
... that if one or more OJP plume head(s) had extended underneath these basins, high temperatures induced on preexisting lithosphere arguably could have raised the basalts above the Curie temperature, thus erasing the Mesozoic magnetic anomalies, and suggested that the basin basalts instead originated f ...
DOGAMI Open-File Report O-76-05, Preliminary report on the
... Formation; (2) the Bull of the Woods complex of dikes, plugs and small stocks of porphyritic hornblende, grading into pyroxene andesite, which extends from the Halls Creek pluton at Detroit Lake northeastward through Battle Ax to the promontory of its namesake; (3) non-porphyritic pyroxene andesite ...
... Formation; (2) the Bull of the Woods complex of dikes, plugs and small stocks of porphyritic hornblende, grading into pyroxene andesite, which extends from the Halls Creek pluton at Detroit Lake northeastward through Battle Ax to the promontory of its namesake; (3) non-porphyritic pyroxene andesite ...
Coire Uaigneich
... envelopes to the granites of both the Western Red Hills and the Eastern Red Hills centres may be verified at a number of localities (for example, on the north side of Glamaig, north-east of Mheall a' Mhaoil; on the south and west of Beinn na Caillich, west ofKilchrist). The emplacement of the Skye g ...
... envelopes to the granites of both the Western Red Hills and the Eastern Red Hills centres may be verified at a number of localities (for example, on the north side of Glamaig, north-east of Mheall a' Mhaoil; on the south and west of Beinn na Caillich, west ofKilchrist). The emplacement of the Skye g ...
A relatively reduced Hadean continental crust and - HAL
... makes them widely used in geochemical studies in terms of trace-elements, isotopes, ages and melt/mineral inclusions; in particular, zircons are persistent under most crustal conditions and can survive many secondary processes such as metamorphism, weathering and erosion (Harrison, 2009; Hawkesworth ...
... makes them widely used in geochemical studies in terms of trace-elements, isotopes, ages and melt/mineral inclusions; in particular, zircons are persistent under most crustal conditions and can survive many secondary processes such as metamorphism, weathering and erosion (Harrison, 2009; Hawkesworth ...
Continental arc–island arc fluctuations, growth of crustal carbonates
... concentrations of atmospheric CO2 . Hypotheses for the elevated CO2 concentrations invoke an increase in volcanic CO2 production due to higher oceanic crust production rates, higher frequency of large igneous provinces, or increases in pelagic carbonate deposition, the last leading to enhanced carbo ...
... concentrations of atmospheric CO2 . Hypotheses for the elevated CO2 concentrations invoke an increase in volcanic CO2 production due to higher oceanic crust production rates, higher frequency of large igneous provinces, or increases in pelagic carbonate deposition, the last leading to enhanced carbo ...
Recycled crust in the Galápagos Plume source at 70 Ma
... to correct for instrumental drift. A summary of the primary standards, statistics for the secondary standards, and statistics for the olivine analyses are given in Table S1B in Supplementary Materials. All oxide totals from the olivine analyses were normalized to 100%. Olivine data are also reported ...
... to correct for instrumental drift. A summary of the primary standards, statistics for the secondary standards, and statistics for the olivine analyses are given in Table S1B in Supplementary Materials. All oxide totals from the olivine analyses were normalized to 100%. Olivine data are also reported ...
Large-Scale Thermo-chemical Structure of the Deep Mantle
... Houser et al. 2008). In particular, VΦ is faster than average (by up to about 1 %) throughout the region spanned by LLSVPs. Because the temperature derivatives of VS and VΦ are both negative throughout the Earth’s mantle (e.g., Trampert et al. 2001; Deschamps and Trampert 2003), purely thermal anoma ...
... Houser et al. 2008). In particular, VΦ is faster than average (by up to about 1 %) throughout the region spanned by LLSVPs. Because the temperature derivatives of VS and VΦ are both negative throughout the Earth’s mantle (e.g., Trampert et al. 2001; Deschamps and Trampert 2003), purely thermal anoma ...
Effects of Hydrothermal Cooling and Magma Injection on Mid
... develop in response to the rheology and boundary conditions and are not imposed a priori. Comparing our numerical experiments with observed faulting at the center and ends of several segments along the slow-spreading Mid-Atlantic Ridge, we find that temperatures near the segment end must be warmer t ...
... develop in response to the rheology and boundary conditions and are not imposed a priori. Comparing our numerical experiments with observed faulting at the center and ends of several segments along the slow-spreading Mid-Atlantic Ridge, we find that temperatures near the segment end must be warmer t ...
Linking continental drift, plate tectonics and the thermal state of the
... et al. (2007, 2009) and Phillips and Coltice (2010) proposed a theory in which the evolution of the distribution of continents at the Earth’s surface causes temperature changes of 50–100 K. Geological observations support this hypothesis. For instance, the Central Atlantic Magmatic Province was empl ...
... et al. (2007, 2009) and Phillips and Coltice (2010) proposed a theory in which the evolution of the distribution of continents at the Earth’s surface causes temperature changes of 50–100 K. Geological observations support this hypothesis. For instance, the Central Atlantic Magmatic Province was empl ...
Continent-sized anomalous zones with low
... observed, regions with higher-than-average seismic wave speeds in the deepest mantle. This spatial correlation is consistent with the expectation of descending former lithosphere being cooler and therefore denser than the surrounding mantle. Away from those locations are regions with lower-than-aver ...
... observed, regions with higher-than-average seismic wave speeds in the deepest mantle. This spatial correlation is consistent with the expectation of descending former lithosphere being cooler and therefore denser than the surrounding mantle. Away from those locations are regions with lower-than-aver ...
mid-ocean ridge tectonics, volcanism
... y1) a 1–3 km deep rift valley marks the axis, while for fast spreading rates (490 mm y1) the axis is characterized by an elevation of the seafloor of several hundred meters, called an axial high (Figure 2). The rate of magma supply is a second factor that may influence the morphology of mid-ocean ...
... y1) a 1–3 km deep rift valley marks the axis, while for fast spreading rates (490 mm y1) the axis is characterized by an elevation of the seafloor of several hundred meters, called an axial high (Figure 2). The rate of magma supply is a second factor that may influence the morphology of mid-ocean ...
A new look at the causes and consequences of the Icelandic hot
... has been supported by recent interpretations of the D" layer at the base of the mantle. This probably represents a thermal boundary layer where heat is transferred by thermal conduction from core to mantle. Stacey & Loper (1983) infer a downward increase of about 800 K across this 150 km thick layer ...
... has been supported by recent interpretations of the D" layer at the base of the mantle. This probably represents a thermal boundary layer where heat is transferred by thermal conduction from core to mantle. Stacey & Loper (1983) infer a downward increase of about 800 K across this 150 km thick layer ...
Plate Tectonics Packet with Notes and Questions
... Remember that Wegener used the similarity of the mountains on the west and east sides of the Atlantic as evidence for his continental drift hypothesis. Those mountains rose at the convergent plate boundaries where the continents were smashing together to create Pangaea. As Pangaea came together abou ...
... Remember that Wegener used the similarity of the mountains on the west and east sides of the Atlantic as evidence for his continental drift hypothesis. Those mountains rose at the convergent plate boundaries where the continents were smashing together to create Pangaea. As Pangaea came together abou ...
Geology
![](https://commons.wikimedia.org/wiki/Special:FilePath/Rock_cycle.gif?width=300)
Geology (from the Greek γῆ, gē, i.e. ""earth"" and -λoγία, -logia, i.e. ""study of, discourse"") is an earth science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which they change. Geology can also refer generally to the study of the solid features of any celestial body (such as the geology of the Moon or Mars).Geology gives insight into the history of the Earth by providing the primary evidence for plate tectonics, the evolutionary history of life, and past climates. Geology is important for mineral and hydrocarbon exploration and exploitation, evaluating water resources, understanding of natural hazards, the remediation of environmental problems, and for providing insights into past climate change. Geology also plays a role in geotechnical engineering and is a major academic discipline.