B. The sea floor spreads apart at divergent boundaries 1. Rift Valley
... • Continents also spread apart at a divergent boundary. •This is when volcanoes form because the rift valley grows wider, the continent begins to split apart. •As the rift valley continues to widen, the thinned valley floor sinks lower and lower until it is below sea level. •Water from a nearby ocea ...
... • Continents also spread apart at a divergent boundary. •This is when volcanoes form because the rift valley grows wider, the continent begins to split apart. •As the rift valley continues to widen, the thinned valley floor sinks lower and lower until it is below sea level. •Water from a nearby ocea ...
Inside the Earth
... • Geologists can’t observe Earth’s interior directly. • Must observe indirectly through seismic waves. • Caused by earthquakes, seismic waves are vibrations of matter (kinetic energy) that travel through the various mediums of earth at different rates. • By measuring recording seismic waves at multi ...
... • Geologists can’t observe Earth’s interior directly. • Must observe indirectly through seismic waves. • Caused by earthquakes, seismic waves are vibrations of matter (kinetic energy) that travel through the various mediums of earth at different rates. • By measuring recording seismic waves at multi ...
Earthquake Vocabulary Part 2
... A secondary earthquake wave; so named because it travels slower than a primary wave and is the second wave to reach the seismograph station after an earthquake. ...
... A secondary earthquake wave; so named because it travels slower than a primary wave and is the second wave to reach the seismograph station after an earthquake. ...
The Solid Earth
... oceanic: Mid-ocean ridges with rift valley continental: eg. East African rift valley convergent: oceanic-oceanic: volcanic island arc, offshore oceanic trench, eg. Aleutian islands oceanic-continental: volcanic mountain belt, orogenic mtns, eg. Andes continental-continental: (collisional) mountain b ...
... oceanic: Mid-ocean ridges with rift valley continental: eg. East African rift valley convergent: oceanic-oceanic: volcanic island arc, offshore oceanic trench, eg. Aleutian islands oceanic-continental: volcanic mountain belt, orogenic mtns, eg. Andes continental-continental: (collisional) mountain b ...
3.3 Plates Move Apart
... Transform faults occur along divergent oceanic and continental plate boundaries Plates slide past each other building up tension until the tension is released during an earthquake ...
... Transform faults occur along divergent oceanic and continental plate boundaries Plates slide past each other building up tension until the tension is released during an earthquake ...
Plate Tectonics Power Point
... (Plates grow denser as they cool.)The plate being subducted melts. Molten rock then rises up and breaks through the surface. As a result, a string of volcanoes erupts on the ocean floor along the trench. Sometimes they may rise above the ocean’s surface as a string of islands, such as Japan and the ...
... (Plates grow denser as they cool.)The plate being subducted melts. Molten rock then rises up and breaks through the surface. As a result, a string of volcanoes erupts on the ocean floor along the trench. Sometimes they may rise above the ocean’s surface as a string of islands, such as Japan and the ...
The Plate Tectonic Model
... A 100 km brittle shell on a 12,756 km Earth means that its thickness is only about 0.78% the diameter of Earth. The average thickness of a chicken eggshell is about 0.3mm, and the average diameter of a large egg is about 40mm (across the smaller circumference). This means that the shell is about 0. ...
... A 100 km brittle shell on a 12,756 km Earth means that its thickness is only about 0.78% the diameter of Earth. The average thickness of a chicken eggshell is about 0.3mm, and the average diameter of a large egg is about 40mm (across the smaller circumference). This means that the shell is about 0. ...
Plate Tectonics Tutoiral Questions
... 3. a rise in sea level after deposition 4. crustal movement occurring after deposition ...
... 3. a rise in sea level after deposition 4. crustal movement occurring after deposition ...
Midterm Study Guide2013
... 24. Describe the two types of measurements scientists use to describe earthquakes. 25. List at least four dangers that are associated with earthquakes. 26. Briefly summarize Alfred Wegener’s hypothesis of continental drift. 27. List four lines of evidence that supported the hypothesis of continenta ...
... 24. Describe the two types of measurements scientists use to describe earthquakes. 25. List at least four dangers that are associated with earthquakes. 26. Briefly summarize Alfred Wegener’s hypothesis of continental drift. 27. List four lines of evidence that supported the hypothesis of continenta ...
EARTH LAYERS REVIEW Name the compositional layers of Earth in
... 3. The hottest layer of Earth is the __INNER CORE_. The layer with the highest pressures is the _____ INNER CORE ____. The layer with the highest density is the _ INNER CORE _. 4. Name the physical layers of Earth in order, starting on the surface and moving to the center. LITHOSPHERE, ASTHENOSPHERE ...
... 3. The hottest layer of Earth is the __INNER CORE_. The layer with the highest pressures is the _____ INNER CORE ____. The layer with the highest density is the _ INNER CORE _. 4. Name the physical layers of Earth in order, starting on the surface and moving to the center. LITHOSPHERE, ASTHENOSPHERE ...
Lecture 7 Plates and Plumes September 27th
... Characteristics of plates Plates can contain BOTH continental and oceanic crust (North American). They may be largely oceanic (Pacific) or mostly continental (Asian). Most plates are bounded by different types of margins (spreading, converging, transform). Plates vary enormously in size (Pa ...
... Characteristics of plates Plates can contain BOTH continental and oceanic crust (North American). They may be largely oceanic (Pacific) or mostly continental (Asian). Most plates are bounded by different types of margins (spreading, converging, transform). Plates vary enormously in size (Pa ...
Layers of the Earth
... radioactive decay) Escape of this inner heat drives geological activity on the planet. It also has heat left over from Earth’s formation. •Inner Core •Under immense pressure •Solid metal mostly iron and nickel •Very high density 13.5 g/ml ...
... radioactive decay) Escape of this inner heat drives geological activity on the planet. It also has heat left over from Earth’s formation. •Inner Core •Under immense pressure •Solid metal mostly iron and nickel •Very high density 13.5 g/ml ...
The Earths Crust Quick Key
... C The C Earth cools and shrinks so the crust cracks into pieces. D The Earth heats and expands causing tectonic plates to rise. 7. What produces the heat to move the crust and upper mantle layer? A Chemical reactions in the mantle B Chemical reactions in the core C radioactive processes in the core ...
... C The C Earth cools and shrinks so the crust cracks into pieces. D The Earth heats and expands causing tectonic plates to rise. 7. What produces the heat to move the crust and upper mantle layer? A Chemical reactions in the mantle B Chemical reactions in the core C radioactive processes in the core ...
Background Information
... minerals (silica, potassium, sodium, aluminum). The average density of continental crust is 2.7 grams/cubic centimeter. b. Oceanic crust is made of mafic rock, composed of denser minerals (magnesium, iron). The average density of oceanic crust is 3.0 ...
... minerals (silica, potassium, sodium, aluminum). The average density of continental crust is 2.7 grams/cubic centimeter. b. Oceanic crust is made of mafic rock, composed of denser minerals (magnesium, iron). The average density of oceanic crust is 3.0 ...
continental drift
... 6. Mid Ocean Ridge transform faults: connect two oceanic ridge segments – and are marked by perpendicular fracture zones causing a discontinuous pattern along the ridge ...
... 6. Mid Ocean Ridge transform faults: connect two oceanic ridge segments – and are marked by perpendicular fracture zones causing a discontinuous pattern along the ridge ...
Plate Tectonics
... continually change shape and size. Their movement is caused by the unequal distribution of heat within the Earth which sets up convection currents in the mantle’s slowly moving material. In some places magma is being pushed up between plates forming new crust, while in other places crust is being ...
... continually change shape and size. Their movement is caused by the unequal distribution of heat within the Earth which sets up convection currents in the mantle’s slowly moving material. In some places magma is being pushed up between plates forming new crust, while in other places crust is being ...
Ocean Floor Characteristics
... forms which are adapted to survival in its cold, high pressure, and dark conditions – Mid-ocean ridges- underwater mountain chains formed where tectonic plates pull apart from one another. • Pulling creates cracks or rift zones. Magma will fill open spaces causing the sides to expand and create ridg ...
... forms which are adapted to survival in its cold, high pressure, and dark conditions – Mid-ocean ridges- underwater mountain chains formed where tectonic plates pull apart from one another. • Pulling creates cracks or rift zones. Magma will fill open spaces causing the sides to expand and create ridg ...
Causes of Plate Motion - Downey Unified School District
... – Mantle Convection Current – ridge push – slab pull ...
... – Mantle Convection Current – ridge push – slab pull ...
How much do we make
... which is made up of rocks that are less dense than those of oceanic crust. Plate boundaries occur where the edges of plates meet. You have learned about the three types of boundaries – convergent, divergent and transform. But different landforms happen if the boundaries are oceanic or continental. L ...
... which is made up of rocks that are less dense than those of oceanic crust. Plate boundaries occur where the edges of plates meet. You have learned about the three types of boundaries – convergent, divergent and transform. But different landforms happen if the boundaries are oceanic or continental. L ...
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.