surface all the way to the asthenosphere‚ at which point the fault disappears due to the plasticity of the rock that exists there. The earth’s plates are moved by convection currents in the mantle caused by localised concentrations of radiation and heat from the earth’s core. The plates are constantly in relative motion to each other‚ but this motion is extremely slow due to the incredible amount of mass being moved‚ friction‚ and the high viscosity of the asthenosphere. Where the different plates
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Study Guide GEOL 1500 test #1 MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) What are the basic differences between the disciplines of physical and historical geology?|1)| A) physical geology is the study of fossils and sequences of rock strata; historical geology is the study of how rocks and minerals were used in the past B) physical geology involves the study of rock strata‚ fossils‚ and deposition in relation
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The outer layer‚ the lithosphere‚ is composed of the crust and uppermost mantle and forms a rigid outer shell down to a depth of approximately 100 km (63 miles). The underlying asthenosphere is composed of partially melted rocks in the upper mantle that acts in a plastic manner on long time scales. The asthenosphere extends from about 100 to 300 km (63-189 miles) depth. The theory of plate tectonics proposes that the lithosphere is divided into a series of plates that fit together like the pieces
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1. Wegner’s hypothesis of continental drift using the observation that the earth’s surfaces are continually changing and other evidence was that the continents had once been joined‚ and over time had drifted apart but he couldn’t explain the mechanism behind it. 2. Evidence gathered by Ewing‚ Tharp and Hess that lead to the theory of plate tectonics was: ⦁ In the early 1950s Ewing‚ with the help of Marie Tharp‚ a cartographer‚ mapped the seafloor using available echo profiles‚ the resulting mapped
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that materials rise from beneath the earths surface. 4 trench The movement of the plates B and C is a convergent plate boundary‚ because the two plates are moved together. What happens at trenches is that the lithosphere is pulled into the asthenosphere. 5 volcanoes and mountains This type of plate collapse is a convergent boundary. When the plates crashes‚ it creates a hot spot in the center‚ which is the cause of the creation of mountains that come out of the oceans‚ which we call volcanoes
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theories (that still have some supporters) proposed gradual shrinking (contraction) or gradual expansion of the globe.[3] Tectonic plates are able to move because the Earth’s lithosphere has a higher strength and lower density 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
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Plate which is an oceanic plate in the west is dragged to move towards the South American Plate which is a continental plate in the east. The force driving the two plates to collide is resulted by converging subcrustal currents of magma in the asthenosphere below the earth crust. Such slow collision of the two plates takes place very slowly over millions of years in earth’s history. Due to the heavier density of the oceanic crust‚ the Nazca Plate is subducted into the mantle at the plate boundary
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-Paleomagnetism *Polar Wandering- (strong evidence that continents move) *Geomagnetic Reversals- (north and south pole switch magnetic forces) -Paleomagnetism *Sea Floor Spreading -Proposed after plate boundaries were recognized and the Asthenosphere was discovered.
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-Continent-continent -Ocean continent Ocean Ocean Convergence -subduction causes a benioff zone -creates a deep broad trench -Accretionary Wedging: marine sediments are scraped off -Partial melting of the asthenosphere(due to flux melting) Magma forms an island arc Continent-Continent -Oceanic crust is first subducted until ocean closes -Neither plate wants to subduct(least buoyant does) -Forms Suture zone plate boundary(in middle) -Crust is greatly thickened
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Review Questions Exam 1 Please provide detailed answers (lists‚ paragraphs‚ diagrams‚ etc). You will earn points as well as have a great study guide for your exam. Chapter 1 Earth science may include the study of: (there are 5) 1. Atmosphere. 2. Biosphere. 3. Hydrosphere. 4. Geosphere. 5. Pedosphere. Geology is the study of what? and can be broken into several sub-disciplines become familiar with at least two sub-disciplines. Geology is the study of the Earth‚ the materials of
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