Full text PDF - Geochemical Perspectives
... no mixing is observed between these genera, but all mix with a prevalent mantle component, PREMA, that contributes to many if not all plumes. Although the mantle comprising plumes also show evidence of previous melt extraction events, the more prominent chemical signature is of material anciently re ...
... no mixing is observed between these genera, but all mix with a prevalent mantle component, PREMA, that contributes to many if not all plumes. Although the mantle comprising plumes also show evidence of previous melt extraction events, the more prominent chemical signature is of material anciently re ...
The Rocks Introduction: Igneous Rocks: Occurrence of Igneous Rocks:
... Equigranular Texture. Igneous rocks containing mineral grains of more or less equal size are said to have an "equigranular texture".Equigranular textures are of the following types. (1) PanidiomorphicTexture. Whenmost of the grains areeuhedral, the texture of rock is called "panidiomorphic ". This t ...
... Equigranular Texture. Igneous rocks containing mineral grains of more or less equal size are said to have an "equigranular texture".Equigranular textures are of the following types. (1) PanidiomorphicTexture. Whenmost of the grains areeuhedral, the texture of rock is called "panidiomorphic ". This t ...
The fate of fluids released from subducting slab in
... laboratory-based velocities and Vp/Vs as a function of volume percent serpentinization (antigorite) in the forearc mantle, and percent quartz in the forearc lower crust. From the percent serpentinite, the amount of total water present in a unit column of the forearc mantle was computed and related t ...
... laboratory-based velocities and Vp/Vs as a function of volume percent serpentinization (antigorite) in the forearc mantle, and percent quartz in the forearc lower crust. From the percent serpentinite, the amount of total water present in a unit column of the forearc mantle was computed and related t ...
Whole-mantle convection and plate tectonics
... In the first, the buoyancy forces are distributed fairly uniformly throughout the fluid; this is the type most commonly encountered in other situations, and most often studied. In the second, the buoyancy forces are concentrated in a small part of the fluid; for example, in a cold descending ‘slab’ ...
... In the first, the buoyancy forces are distributed fairly uniformly throughout the fluid; this is the type most commonly encountered in other situations, and most often studied. In the second, the buoyancy forces are concentrated in a small part of the fluid; for example, in a cold descending ‘slab’ ...
Ringwood Phase transformations and their bearing on the
... and petrological studies of the complementary relationships between basaltic magmas and refractory peridotites. The phase transformations which are experienced by pyrolite between depths of 100-800 km are reviewed in some detail, particularly with regard to their capacity to explain the seismic P an ...
... and petrological studies of the complementary relationships between basaltic magmas and refractory peridotites. The phase transformations which are experienced by pyrolite between depths of 100-800 km are reviewed in some detail, particularly with regard to their capacity to explain the seismic P an ...
Impact resistance of Illinois limestones and
... determine impact toughness of rocks by dropping a hammer from continuously increasing heights until the specimen breaks. Impact tests in which a pendulum applies a load sufficient to break the material are described and discussed by Spath (1961). Singh and Hartman (1961) used an impact device consis ...
... determine impact toughness of rocks by dropping a hammer from continuously increasing heights until the specimen breaks. Impact tests in which a pendulum applies a load sufficient to break the material are described and discussed by Spath (1961). Singh and Hartman (1961) used an impact device consis ...
Bounds on the viscosity coefficient of continental lithosphere from
... [10] The nonlinear relationship between deviatoric stress and strain rate that applies to most rock-forming minerals can make lithosphere more stable than it would be if deformation of the lithosphere obeyed Newtonian viscosity [e.g., Conrad and Molnar, 1999; Houseman and Molnar, 2001]. In the case ...
... [10] The nonlinear relationship between deviatoric stress and strain rate that applies to most rock-forming minerals can make lithosphere more stable than it would be if deformation of the lithosphere obeyed Newtonian viscosity [e.g., Conrad and Molnar, 1999; Houseman and Molnar, 2001]. In the case ...
Molnar, P., and C. N. Garzione (2007), Bounds on the viscosity coefficient of continental lithosphere
... [10] The nonlinear relationship between deviatoric stress and strain rate that applies to most rock-forming minerals can make lithosphere more stable than it would be if deformation of the lithosphere obeyed Newtonian viscosity [e.g., Conrad and Molnar, 1999; Houseman and Molnar, 2001]. In the case ...
... [10] The nonlinear relationship between deviatoric stress and strain rate that applies to most rock-forming minerals can make lithosphere more stable than it would be if deformation of the lithosphere obeyed Newtonian viscosity [e.g., Conrad and Molnar, 1999; Houseman and Molnar, 2001]. In the case ...
Mantle convection in the Middle East_ Reconciling Afar upwelling
... geologically-motivated models of lateral viscosity variations as well as several density models to explore the effects of the different components of the AAA convection system. The goal is not so much to find the best model that matches all data at this point, but rather to identify some of the key r ...
... geologically-motivated models of lateral viscosity variations as well as several density models to explore the effects of the different components of the AAA convection system. The goal is not so much to find the best model that matches all data at this point, but rather to identify some of the key r ...
Exploring Earth: Plate Tectonics
... with the standards, key science concepts, and essential features of classroom inquiry (as defined by the National Science Education Standards). In Immersion Units, students learn academic content by working like scientists: making observations, asking questions, doing further investigations to explo ...
... with the standards, key science concepts, and essential features of classroom inquiry (as defined by the National Science Education Standards). In Immersion Units, students learn academic content by working like scientists: making observations, asking questions, doing further investigations to explo ...
A Geology Training Manual for Grand Canyon National
... colorful, picturesque rock layers that make up the walls of the canyon, which have ...
... colorful, picturesque rock layers that make up the walls of the canyon, which have ...
Plate Tectonics
... The movement of plates on Earth causes forces that build up energy in rocks. The release of this energy can produce vibrations in Earth that you know as earthquakes. Earthquakes occur every day. Many of them are too small to be felt by humans, but each event tells scientists something more about the ...
... The movement of plates on Earth causes forces that build up energy in rocks. The release of this energy can produce vibrations in Earth that you know as earthquakes. Earthquakes occur every day. Many of them are too small to be felt by humans, but each event tells scientists something more about the ...
The Río de la Plata Craton: a review of units, boundaries, ages and
... of juvenile Paleoproterozoic crust, but negative Nd isotopic signatures in Tandilia suggest part of the craton was mature continental crust (Cordani et al. 2000; Pankhurst et al. 2003; Peel and Preciozzi 2006; Rapela et al. 2007). Over large areas, Phanerozoic sediments cover the Craton. Rapela et a ...
... of juvenile Paleoproterozoic crust, but negative Nd isotopic signatures in Tandilia suggest part of the craton was mature continental crust (Cordani et al. 2000; Pankhurst et al. 2003; Peel and Preciozzi 2006; Rapela et al. 2007). Over large areas, Phanerozoic sediments cover the Craton. Rapela et a ...
Water transportation from the subducting slab into the mantle
... the structural water at about 2.7 wt.% and the interstitial water is at least 2 wt.%, based on the void volume of the crust (approximately 5 vol.% by Johnson, 1979). The present study uses 5–6 wt.% H2O+ which is stored in hydrous minerals due to ocean-floor hydrothermal metamorphism. Dredged gabbros ...
... the structural water at about 2.7 wt.% and the interstitial water is at least 2 wt.%, based on the void volume of the crust (approximately 5 vol.% by Johnson, 1979). The present study uses 5–6 wt.% H2O+ which is stored in hydrous minerals due to ocean-floor hydrothermal metamorphism. Dredged gabbros ...
Oxygen 18oxygen 16 and DH studies of plutonic granitic and
... wereevidentlyemplacedat shallowdepthsin the crustand are classifiedas mesozonal to epizonal [Gabrielse and Reesor, 1974]. Cenozoicuplift rates are discussedby Parrish [1983]. To the west of the Coast Plutonic Complex, across the 40-km-wide Strait of Georgia, is southern Vancouver Island; this area i ...
... wereevidentlyemplacedat shallowdepthsin the crustand are classifiedas mesozonal to epizonal [Gabrielse and Reesor, 1974]. Cenozoicuplift rates are discussedby Parrish [1983]. To the west of the Coast Plutonic Complex, across the 40-km-wide Strait of Georgia, is southern Vancouver Island; this area i ...
Lab Manual - Canvas @ WWU
... In contrast, plate tectonics is a more recent theory that describes how the continents have moved. The plate tectonics theory is one of the most important and far-reaching theories in geology. It is based on an investigation of the sea floor using technology that was not available until the 1960’s t ...
... In contrast, plate tectonics is a more recent theory that describes how the continents have moved. The plate tectonics theory is one of the most important and far-reaching theories in geology. It is based on an investigation of the sea floor using technology that was not available until the 1960’s t ...
Thermal thickness of the Earth`s lithosphere: a numerical model
... distribution is not accurate, because we do not know exactly the value of radioactive heat generation, coef ficient of thermal conductivity of crustal rocks, thick ness of crustal layers, and surface heat flow; in addi tion, the assumption of the stationarity of the thermal regime can be wrong fo ...
... distribution is not accurate, because we do not know exactly the value of radioactive heat generation, coef ficient of thermal conductivity of crustal rocks, thick ness of crustal layers, and surface heat flow; in addi tion, the assumption of the stationarity of the thermal regime can be wrong fo ...
Chapter 2 The Way the Earth Works: Plate Tectonics
... In September 1930, fifteen explorers led by a German meteorologist, Alfred Wegener, set out across the endless snowfields of Greenland to resupply two weather observers stranded at a remote camp. The observers had been planning to spend the long polar night recording wind speeds and temperatures on ...
... In September 1930, fifteen explorers led by a German meteorologist, Alfred Wegener, set out across the endless snowfields of Greenland to resupply two weather observers stranded at a remote camp. The observers had been planning to spend the long polar night recording wind speeds and temperatures on ...
The SNC meteorites: basaltic igneous processes on Mars
... Hydrous amphiboles have been tentatively identified within melt inclusions (e.g. Floran et al. 1978; Treiman 1985; Johnson et al. 1991). These are calculated, on the basis of the amphibole stability, to have crystallized from melts that contained up to 1.8 wt% H2 O (Johnson et al. 1991; McSween & Ha ...
... Hydrous amphiboles have been tentatively identified within melt inclusions (e.g. Floran et al. 1978; Treiman 1985; Johnson et al. 1991). These are calculated, on the basis of the amphibole stability, to have crystallized from melts that contained up to 1.8 wt% H2 O (Johnson et al. 1991; McSween & Ha ...
The viscosity of Earthв€™s lower mantle inferred from sinking speed
... In the Earth’s mantle, solid-state creep facilitates buoyancy driven material flow on the scale of centimeters per year across the entire mantle. Viscosity characterizes the internal friction of the flow and is one of the key quantities determining the mechanical behavior of the mantle. The latter gov ...
... In the Earth’s mantle, solid-state creep facilitates buoyancy driven material flow on the scale of centimeters per year across the entire mantle. Viscosity characterizes the internal friction of the flow and is one of the key quantities determining the mechanical behavior of the mantle. The latter gov ...
Plumes and Hotspots
... because only the hottest materials in the centre of the plume head ascends to shallow levels, and undergo adiabatic decompression melting to produce picritic lava, which decreases towards the periphery. These picritic flows are often covered by later lava, and are rarely seen in flood basalt provinc ...
... because only the hottest materials in the centre of the plume head ascends to shallow levels, and undergo adiabatic decompression melting to produce picritic lava, which decreases towards the periphery. These picritic flows are often covered by later lava, and are rarely seen in flood basalt provinc ...
full text - NWT Protected Area Strategy
... foliated granite (e.g., Iizuka et al., 2006, 2007). Immediately overlying the AGC to the west and south is a thin, discontinuous package of quartzite, quartz pebble conglomerate, and minor banded iron formation, which is in turn overlain by deformed mafic volcanic rocks. King (1986) and St-Onge et a ...
... foliated granite (e.g., Iizuka et al., 2006, 2007). Immediately overlying the AGC to the west and south is a thin, discontinuous package of quartzite, quartz pebble conglomerate, and minor banded iron formation, which is in turn overlain by deformed mafic volcanic rocks. King (1986) and St-Onge et a ...
o-Emitting mineral inclusions in apatite, their effect on (U–Th
... Besides complicating the a-ejection correction, the inhomogeneous U–Th-distribution inherent to inclusion-bearing apatites also affects the diffusive behavior of the helium. This problem is well studied in the case of concentrically zoned spherical crystals (Meesters and Dunai, 2002b). The ‘‘closure t ...
... Besides complicating the a-ejection correction, the inhomogeneous U–Th-distribution inherent to inclusion-bearing apatites also affects the diffusive behavior of the helium. This problem is well studied in the case of concentrically zoned spherical crystals (Meesters and Dunai, 2002b). The ‘‘closure t ...
Fold Fault Denudation
... Folding, Faulting and Denudation As soon as a rock particle (loosened by one of the two weathering processes) moves, we call it erosion or mass wasting. Mass wasting is simply movement down slope due to gravity. Rock falls, slumps, and debris flows are all examples of mass wasting. We call it erosi ...
... Folding, Faulting and Denudation As soon as a rock particle (loosened by one of the two weathering processes) moves, we call it erosion or mass wasting. Mass wasting is simply movement down slope due to gravity. Rock falls, slumps, and debris flows are all examples of mass wasting. We call it erosi ...
Age of the Earth
The age of the Earth is 4.54 ± 0.05 billion years (4.54 × 109 years ± 1%). This age is based on evidence from radiometric age dating of meteorite material and is consistent with the radiometric ages of the oldest-known terrestrial and lunar samples.Following the development of radiometric age dating in the early 20th century, measurements of lead in uranium-rich minerals showed that some were in excess of a billion years old.The oldest such minerals analyzed to date—small crystals of zircon from the Jack Hills of Western Australia—are at least 4.404 billion years old. Comparing the mass and luminosity of the Sun to those of other stars, it appears that the Solar System cannot be much older than those rocks. Calcium-aluminium-rich inclusions – the oldest known solid constituents within meteorites that are formed within the Solar System – are 4.567 billion years old, giving an age for the solar system and an upper limit for the age of Earth.It is hypothesised that the accretion of Earth began soon after the formation of the calcium-aluminium-rich inclusions and the meteorites. Because the exact amount of time this accretion process took is not yet known, and the predictions from different accretion models range from a few millions up to about 100 million years, the exact age of Earth is difficult to determine. It is also difficult to determine the exact age of the oldest rocks on Earth, exposed at the surface, as they are aggregates of minerals of possibly different ages.