Mountain Building
... – Strike-slip faults • Dominant displacement is horizontal and parallel to the trend, or strike • Transform fault – Large strike-slip fault that cuts through the lithosphere – Often associated with plate boundaries ...
... – Strike-slip faults • Dominant displacement is horizontal and parallel to the trend, or strike • Transform fault – Large strike-slip fault that cuts through the lithosphere – Often associated with plate boundaries ...
Geologic Time
... were dominant Mesozoic land vertebrates that walked with legs positioned directly below their hips. This means that dinosaurs walked upright. In contrast, the legs of a crocodile stick out sideways from its body. As a result, a crocodile appears to drag itself along the ground. Scientists hypothesiz ...
... were dominant Mesozoic land vertebrates that walked with legs positioned directly below their hips. This means that dinosaurs walked upright. In contrast, the legs of a crocodile stick out sideways from its body. As a result, a crocodile appears to drag itself along the ground. Scientists hypothesiz ...
Recycling lower continental crust in the North China craton
... subducted oceanic crust or foundered lower crust with subsequent interaction of the melts with mantle peridotite. Indeed, the observed increase of Mg#, Ni and Cr of the melt (recorded in the orthopyroxene phenocrysts), together with orthopyroxene crystallization, are key features of slab melt-perido ...
... subducted oceanic crust or foundered lower crust with subsequent interaction of the melts with mantle peridotite. Indeed, the observed increase of Mg#, Ni and Cr of the melt (recorded in the orthopyroxene phenocrysts), together with orthopyroxene crystallization, are key features of slab melt-perido ...
Plate Tectonics
... because of heat conducted from the core. 2. Convection: If a material is able to move, even if it moves very slowly, convection currents can form. Convection in the mantle is the same as convection in a pot of water on a stove. Convection currents within Earth’s mantle form as material near the core ...
... because of heat conducted from the core. 2. Convection: If a material is able to move, even if it moves very slowly, convection currents can form. Convection in the mantle is the same as convection in a pot of water on a stove. Convection currents within Earth’s mantle form as material near the core ...
Hot mantle drives elevation, volcanism along mid-ocean
... also the ridges' highest elevation point. Iceland is also where scientists have long debated whether a mantle plume—a vertical jet of hot rock originating from deep in the Earth—intersects the mid-ocean ridge. This study provides strong support for a mantle plume located beneath Iceland. In fact, th ...
... also the ridges' highest elevation point. Iceland is also where scientists have long debated whether a mantle plume—a vertical jet of hot rock originating from deep in the Earth—intersects the mid-ocean ridge. This study provides strong support for a mantle plume located beneath Iceland. In fact, th ...
Lecture 47
... o These granulite terranes have often been subjected to retrograde metamorphism, which compromises their value. o Furthermore, questions have been raised as to how typical they are of lower continental crust. These questions arise because granulite terranes are generally significantly less mafic tha ...
... o These granulite terranes have often been subjected to retrograde metamorphism, which compromises their value. o Furthermore, questions have been raised as to how typical they are of lower continental crust. These questions arise because granulite terranes are generally significantly less mafic tha ...
The Earth`s Crust
... of the crust (the Moho) down to 660 kilometers depth. Many workers distinguish the transition zone between 410 and 660 kilometers, two depths at which major physical changes occur to minerals. The lower mantle extends from 660 down to about 2700 kilometers, a point where seismic waves are affected s ...
... of the crust (the Moho) down to 660 kilometers depth. Many workers distinguish the transition zone between 410 and 660 kilometers, two depths at which major physical changes occur to minerals. The lower mantle extends from 660 down to about 2700 kilometers, a point where seismic waves are affected s ...
HS Plate Tectonics
... because of heat conducted from the core. 2. Convection: If a material is able to move, even if it moves very slowly, convection currents can form. Convection in the mantle is the same as convection in a pot of water on a stove. Convection currents within Earth’s mantle form as material near the core ...
... because of heat conducted from the core. 2. Convection: If a material is able to move, even if it moves very slowly, convection currents can form. Convection in the mantle is the same as convection in a pot of water on a stove. Convection currents within Earth’s mantle form as material near the core ...
Offshore Somalia: crustal structure and implications
... Several regional tectonic events, primarily related to plate reorganisation associated with the closure of the Tethys Ocean and the opening of the Indian Ocean, have shaped the Somalian margin. These superimposed tectonic events are responsible for the present day structural complexity of the East A ...
... Several regional tectonic events, primarily related to plate reorganisation associated with the closure of the Tethys Ocean and the opening of the Indian Ocean, have shaped the Somalian margin. These superimposed tectonic events are responsible for the present day structural complexity of the East A ...
Episodic nature of continental arc activity since 750 Ma - Cin
... We have assumed that felsic magmas, such as granitoids, most likely represent continental arcs for the following reasons. Cawood et al. (2013) suggested that the volumes of subduction-related magmas make up more than 90% of all volcanism, not including mid-ocean ridge related magmatism. In particula ...
... We have assumed that felsic magmas, such as granitoids, most likely represent continental arcs for the following reasons. Cawood et al. (2013) suggested that the volumes of subduction-related magmas make up more than 90% of all volcanism, not including mid-ocean ridge related magmatism. In particula ...
PowerPoint Presentation - Template 02
... continental peatlands suggests these peatlands follow different trajectories historically and may respond to climate change differently (compared to well-studied bogs); • Continental peatlands appear to show sensitive responses to subtle millennial-scale moisture changes during the Holocene; • Fens ...
... continental peatlands suggests these peatlands follow different trajectories historically and may respond to climate change differently (compared to well-studied bogs); • Continental peatlands appear to show sensitive responses to subtle millennial-scale moisture changes during the Holocene; • Fens ...
Worldwide distribution of ages of the continental lithosphere derived
... A relationship between surface heat flow and age at a global scale was proposed by Polyak and Smirnov (1968) and by Pollack and Chapman (1977). Assuming a linear relationship between surface heat flow and radiogenic heat production in the crust, Chapman and Pollack (1977) derived a simple model accord ...
... A relationship between surface heat flow and age at a global scale was proposed by Polyak and Smirnov (1968) and by Pollack and Chapman (1977). Assuming a linear relationship between surface heat flow and radiogenic heat production in the crust, Chapman and Pollack (1977) derived a simple model accord ...
Processes that Shape the Surface of Earth
... found near the surface of Earth's crust; they form the continental landmass. It is this land that humans are most familiar with because we walk and live on it. The remaining 70% of Earth's crust is primarily composed of denser rock that floats over the mantle at lower elevations than continental roc ...
... found near the surface of Earth's crust; they form the continental landmass. It is this land that humans are most familiar with because we walk and live on it. The remaining 70% of Earth's crust is primarily composed of denser rock that floats over the mantle at lower elevations than continental roc ...
tectonic models for the geological evolution of crust, cratons and
... production from the breakdown of radiogenic isotopes were two to three times greater in the Archaean than today (Richter, 1985). Some sixty-five percent of the heat loss from the Earth today is used in oceanic crust creation and cooling (Sclater et al. 1981). Therefore, in the absence of any other e ...
... production from the breakdown of radiogenic isotopes were two to three times greater in the Archaean than today (Richter, 1985). Some sixty-five percent of the heat loss from the Earth today is used in oceanic crust creation and cooling (Sclater et al. 1981). Therefore, in the absence of any other e ...
PlatemarginsL3and4 9.74MB 2017-03-29 12:41:32
... • Have a total length of 60,000km. • In some parts they rise 3,000m above the ocean floor. • Where two plates pull apart there is a weaker zone in the crust and an increase in heat near the surface. The hotter, expanded crust forms a ridge. • Volcanic activity occurs along the ridge. ...
... • Have a total length of 60,000km. • In some parts they rise 3,000m above the ocean floor. • Where two plates pull apart there is a weaker zone in the crust and an increase in heat near the surface. The hotter, expanded crust forms a ridge. • Volcanic activity occurs along the ridge. ...
Geochemical cycle of volatiles during plate
... latter values are approximately three orders of magnitude higher than those for hydroxyl partitioning, fluid flow from subducting slab through the mantle wedge will lead to more efficient sequestration of H2O into the nominally anhydrous minerals. In turn, an aqeuous fluid will experience gradual in ...
... latter values are approximately three orders of magnitude higher than those for hydroxyl partitioning, fluid flow from subducting slab through the mantle wedge will lead to more efficient sequestration of H2O into the nominally anhydrous minerals. In turn, an aqeuous fluid will experience gradual in ...
large igneous provinces and fertile mantle
... bring hot material adiabatically up from depth until it melts; the other is to insert lowmelting point fertile material–delaminated lower arc crust, for example–into the mantle from above and allow the mantle to heat it up. Both mechanisms may be involved in LIP formation. The time-scale for heating ...
... bring hot material adiabatically up from depth until it melts; the other is to insert lowmelting point fertile material–delaminated lower arc crust, for example–into the mantle from above and allow the mantle to heat it up. Both mechanisms may be involved in LIP formation. The time-scale for heating ...
Scotland`s Time Lords
... Hutton also had a keen interest in agriculture and farmed at Slighhouses and Nether Monynut in Berwickshire, farms he had inherited from his father. Hutton wished to apply his scientific understanding to agricultural practice and travelled extensively to gain new ideas, introducing the Suffolk plou ...
... Hutton also had a keen interest in agriculture and farmed at Slighhouses and Nether Monynut in Berwickshire, farms he had inherited from his father. Hutton wished to apply his scientific understanding to agricultural practice and travelled extensively to gain new ideas, introducing the Suffolk plou ...
What They Say in Hong Kong Geography Books and Exam
... places at lower latitudes are subject to a higher linear speed of rotation while the speed of rotation at high latitudes is lower….Places at lower latitudes may have greater lateral force, so the displacement of the fault at low latitudes is greater. What we actually know: The relative plate motion ...
... places at lower latitudes are subject to a higher linear speed of rotation while the speed of rotation at high latitudes is lower….Places at lower latitudes may have greater lateral force, so the displacement of the fault at low latitudes is greater. What we actually know: The relative plate motion ...
Sea-Floor Spreading
... • Sea-floor spreading adds more crust to the ocean floor. At the same time, older strips of rock move outward from either side of the ridge. ...
... • Sea-floor spreading adds more crust to the ocean floor. At the same time, older strips of rock move outward from either side of the ridge. ...
Convergent plate boundaries
... sink? The dense, leading edge of the oceanic plate actually pulls the rest of the plate into the flowing asthenosphere and a subduction zone is born! Where the two plates intersect, a deep trench forms. Geologists aren’t sure how deep the oceanic plate sinks before it completely melts, but we do kno ...
... sink? The dense, leading edge of the oceanic plate actually pulls the rest of the plate into the flowing asthenosphere and a subduction zone is born! Where the two plates intersect, a deep trench forms. Geologists aren’t sure how deep the oceanic plate sinks before it completely melts, but we do kno ...
Supercontinents, mantle dynamics and plate
... destruction of ocean floor, with the oldest oceanic crust on the planet aged more than 200 Ma. Among various distinctions between the two cycles, one important aspect is the time interval, with a shorter time span for the Wilson Cycle as against a much longer time span in which supercontinent cycle o ...
... destruction of ocean floor, with the oldest oceanic crust on the planet aged more than 200 Ma. Among various distinctions between the two cycles, one important aspect is the time interval, with a shorter time span for the Wilson Cycle as against a much longer time span in which supercontinent cycle o ...
Chapter 14 - Mesozoic Geology
... • The movement of continents – affected the global climatic and oceanic regimes – as well as the climates of the individual continents ...
... • The movement of continents – affected the global climatic and oceanic regimes – as well as the climates of the individual continents ...
1 Accretion of terranes and growth of continental crust along the
... Ouachita orogen includes a forearc complex and accretionary prism associated with southward subduction of Laurentia beneath the Sabine continental terrane (affinity unknown) and continental-margin arc. On the corner of the Alabama promontory, the Suwannee-Wiggins suture truncates Laurentian continen ...
... Ouachita orogen includes a forearc complex and accretionary prism associated with southward subduction of Laurentia beneath the Sabine continental terrane (affinity unknown) and continental-margin arc. On the corner of the Alabama promontory, the Suwannee-Wiggins suture truncates Laurentian continen ...
Mechanical and thermal effects of floating continents on the global
... model with implemented continents leads to principally different structures. Several common stages of the continental evolution are revealed. Back-arc basins at the active continental margins are closed at the first stage. In the next stage of the modelled evolution the convection pattern is reorgan ...
... model with implemented continents leads to principally different structures. Several common stages of the continental evolution are revealed. Back-arc basins at the active continental margins are closed at the first stage. In the next stage of the modelled evolution the convection pattern is reorgan ...
Supercontinent
In geology, a supercontinent is the assembly of most or all of the Earth's continental blocks or cratons to form a single large landmass. However, the definition of a supercontinent can be ambiguous. Many tectonicists such as P.F. Hoffman (1999) use the term ""supercontinent"" to mean ""a clustering of nearly all continents"". This definition leaves room for interpretation when labeling a continental body and is easier to apply to Precambrian times. Using the first definition provided here, Gondwana (aka Gondwanaland) is not considered a supercontinent, because the landmasses of Baltica, Laurentia and Siberia also existed at the same time but physically separate from each other. The landmass of Pangaea is the collective name describing all of these continental masses when they were in a close proximity to one another. This would classify Pangaea as a supercontinent. According to the definition by Rogers and Santosh (2004), a supercontinent does not exist today. Supercontinents have assembled and dispersed multiple times in the geologic past (see table). The positions of continents have been accurately determined back to the early Jurassic. However, beyond 200 Ma, continental positions are much less certain.