Science Test (Last one for the year!!!) (the defs. are from the book)

Plate tectonics

(blank) describes large-scale movements of Earth's lithosphere, which is made up o the crust and the rigid, upper part of the mantle. (blank) explains how and why features in Earth's crust form and continents move.

Convergent Boundaries

(blank) form where two plates collide. Three types of collisions can happen at (blank). When two tectonic plates of continental lithosphere collide, they buckle and thicken, which pushes some of the continental crust upward. When a plate of oceanic lithosphere collides with a plate of continental lithosphere, the denser oceanic lithosphere sinks into the asthenosphere. Boundaries where one plate sinks beneath another plate are called subduction zones. When two tectonic plates of oceanic lithosphere collide, one o the plates subducts, or sinks, under the other plate.

Convection

(blank) is the movement of matter that results from differences in density caused by variations in temperature. Scientists can learn about the mantle by observing mantle rock that has risen to Earth's surface. The mantle is denser than the crust. It contains more magnesium and less aluminum and silicon than the crust does.

Transform Boundaries

A boundary at which two plates move past each other horizontally is called a (blank). However, the plate edges do not slide along smoothly. Instead, they scrape against each other in a series of sudden slippages of crustal rock that are felt as earthquakes. Unlike other types of boundaries, transform boundaries generally do not produce magma. The San Andreas Fault in California is a major (blank)between the North American plate and the Pacific plate. Transform motion also occurs at (blank). Short segments of mid-ocean ridges are connected by transform faults called fracture zones.

Craters and Claderas

A volcanic crater is an opening or depression at the top of a volcano caused by eruptions. Inside the volcano, molten rock can form and expanded area of magma called a magma chamber. When the magma chamber below a volcano empties, the roof of the magma chamber may collapse and leave an even larger basin-shaped depression called a caldera. Calderas can form from the sudden drain of a magma chamber during and explosive eruption or from a slowly emptied magma chamber. More than 7,000 years ago, the cone of Mount Mazama in Oregon collapsed to form a caldera. The caldera later filled with water and is now called Crater Lake.

Composite Volcanoes

Alternating layers of hardened lava flows and pyroclastic material crate composite volcanoes. During a mild eruption, lava flows over the sides of the cone. During an explosive eruption, pyroclastic material is deposited around the vent. Composite volcanoes commonly develop into large and steep volcanic mountains.

Mantle Convection

As atoms in Earth's core and mantle undergo radioactive decay, energy is released as heat. Some parts of the mantle becomes hotter than others parts. The hot parts rise as the sinking of cooler, denser material pushes the heated material up. This kind of movement of material due to differences in density is called convection. It was thought that as the mantle convects, or moves, it would drag the overlying tectonic plates along with it. However, this hypothesis has been criticized by many scientists because it does not explain the huge amount of force that would be needed to move plates.

Divergent Boundaries

At a (blank), two plates move away from each other. This separation allows the asthenosphere to rise toward the surface and partially melt. This melting crates magma, which erupts as lava. The lava cools and hardens to form new rock on the ocean floor. As the crust and the upper part of the asthenosphere cool and become rigid, they form new lithosphere. This lithosphere is thin, warm, and light. This warm, light rock sits higher than the surrounding sea floor because it is less dense. It forms mid-ocean ridges. Most (blank) are located on the ocean floor. However, rift valleys may also form where continents are separated by plate movement.

At Convergent Boundaries

At convergent boundaries, two plates move toward each other. In most cases, one plate sinks beneath the other plate. As the sinking plate dives into the mantle, fluids in the sinking plate become super heated and escape. These escaping fluids cause the rock above the sinking plate to melt and form magma. This magma rises to the surface and erupts to form volcanoes. the magma that forms at convergent boundaries has a high concentration of fluids. As the magma rises, decreasing pressure causes the fluid trapped int he mama to form gas bubbles. But, because the magma has a high viscosity, bubbles expand, the magma rises faster. Eventually, the mama can erupt explosively, forming calderas or composite volcanoes. Gas, ash, and large chunks of rock can be blown out of the volcanoes, The cascade Range is a chain of active composite volcanoes in the northwestern United States. In 1980, Mt. St. Helens erupted so violently that the entire top of the mountain was blown away.

At Divergent Boundaries

At divergent boundaries, plates move away from each other. The lithosphere stretches and gets thinner, so the pressure on the mantle rock below decreases. as a result the asthenosphere bulges upward and magma forms. This magma rises through fissures in the lithosphere, out onto the land or the ocean floor. Most divergent boundaries are on the ocean floor. When eruptions occur tin these areas, undersea volcanoes develop. These volcanoes and other processes lead to the formation of a long, underwater mountains range know as the mid-ocean ridge. Two examples of mid-ocean ridges are the East Pacific Rise in the Pacific Ocean and the Mid-Atlantic Ridge in the Atlantic Ocean. The youngest rocks in the ocean are located at mid-ocean ridges. Shield volcanoes and cinder cones are common in Iceland, where the Mid-Atlantic Ridge runs though the country. As the plates move away from each other, new crust forms. When a divergent boundary is located in the middle of the continent, the crust stretches until a rift valley is formed.

Slab Pull

At subduction zones, a denser tectonic plate sinks, or subducts, beneath another, less dense plate. The leading edge of the subducting plate is colder and denser than the mantle. As it sinks, the leading edge of the plate pulls the rest of the plate with it. This process is called (blank). In general, subducting plates move faster than other plates do. This evidence leads many scientist to think that slab pull may be the most important mechanism driving tectonic plate motion.

List the compositional layers in order of most dense to least dense.

Core, Mantle, Crust

What are Earth's compositional layers?

Earth can be divided into three layers based on chemical composition. These layers are called the crust, the mantle, and the core. Each compositional layer is made up of a different mixture of chemicals.

Fault-Block Mountians

Fault-block mountains form when tension makes the lithosphere break into many normal faults. Along the faults, pieces of the lithosphere drop down compared with other pieces. The pieces left standing from fault-block mountains. The Teton Mountains and the Sierra Nevadas are fault-block mountains.

Fissures and Lava Plateaus

Fissure eruptions happen when lava flows from giant cracks, or fissures, in Earth's surface. The fissures are found on land and on the ocean floor. A fissure eruption has no central opening. Lava flows out of the entire length of the fissure, which can be many kilometers long. As a result, a thick and mostly flattened layer of called lava, called a lava plateau, can form. One example of a lava plateau is the Columbia Plateau Province in Washington, Oregon, and Idaho.

Folded Mountains

Folded mountains form when rock layers are squeezed together and pushed upward. They usually form at convergent boundaries, where plates collide. For example, The Appalachian Mountains formed form folding and faulting when the North American plate collided with the Eurasian and African plates millions of years ago. In Europe, the Pyrenees are another range of folded mountains. They are folded over and older, pre-existing mountain range. Today, the highest peaks are over 3,000 m tall.

What are two kinds of folds?

Folded rock layers appear bent or buckled. Folding occurs when rock layers bend under stress. the bends are called folds. Scientists assume that all rock layers start out as horizontal layers deposited on top of each other over time. Sometimes, different layers of rocks can sill be seen even after the rocks have been folded. When scientists see a fold, they knew that deformation has happened. Two common types of folds are synclines and anticlines.

Synclines and Anticlines

Folds are classified based on the age of the rock layers. In a syncline, the youngest layers of rock are found at the core of a fold. The oldest layers are found on the outside of the fold. Synclines usually look like rock layers that are arched upward, like a bowl. In an anticline, the oldest layers of rock are found at the core of the fold. The youngest layers are found on the outside of the fold. Anticlines often look like rock layers that are arched downwards and high in the middle. Often, both types of folds will be visible in the same rock layers.

Strike-Slip Faults

In a Strike-Slip fault, the fault blocks move past each other horizontally. Strike-Slip faults form when rock is under shear stress. Shear stress is stress that pushed rocks in parallel but opposite directions. As rocks are deformed deep in Earth's crust, energy builds. The release of this energy can cause earthquakes as the rocks slide past each other. Strike-Slip faults are common along transform boundaries, where tectonic plates move past each other. The San Andreas fault system in California is an example of a strike-slip fault.

Normal Faults

In the normal fault, the hanging way loves down relative to the footwall. The faults are called normal because the blocks move in a way that you would normally expect as a result of gravity. Normal faults form when the rock is under tension. Tension is stress that stretches or pulls rock apart. Therefore, normal faults are common along divergent boundaries. Earth's crust can also stretch in the middle of a tectonic plate. The Basin and Range area of the southwestern United States is an example of a location with many normal fault structures.

Revers Faults

In the reverse fault, the hanging wall moves up relative to the footwall. The faults are called reverse because the hanging blocks move up, which is the reverse of what you would expect as a result of gravity. Reverse faults form when rocks undergo compression. Compression is stress that squeezes or pushed rock together. Reverse faults are common along convergent boundaries, where two plates collide. The San Gabriel Mountains in the United States are caused by reverse faults.

Volcanic Mountains

Materials ejected from a volcano may build up around a vent to create volcanic mountains. Viscosity is the resistance of a liquid material, such as lava, to flow. The viscosity of lava determines the explosiveness of an eruption and the shape of the resulting volcanic mountain. Low-viscosity lava flows easily, forms low slopes, and erupts without large explosions. High-viscosity lava does not flow easily, forms steep lopes, and can erupt explosively. Pyroclastic materials, or hot ash and bits of rock, may also be ejected into the atmosphere.

Ridge Push

Newly formed rock at mid-ocean ridge is war and less dense than older, adjacent rock. Because of its lower density the new rock rests at a higher elevation than the older rock. The older rock slopes downward away from the ridge. As the newer, warmer rock cools, it also becomes more dense. These cooling and increasingly dense rocks respond to gravity by moving down the slope of the asthenosphere, away form the ridge. This force, called (blank), pushes the rest of the plate away form the mid-ocean ridge.

What are the three types of faults?

Rock can be under so much stress that it cannot bend and may break. The crack that forms when large blocks of rock break and move past each other is called a fault. the blocks of rock on either side of the fault are called fault blocks. The sudden movement of fault blocks can cause earthquakes. Any time there is a fault in Earth's crust, rocks tend to move in predictable ways. Earth has three main kinds of faults: Strike-Slip faults, normal faults, and reverse faults. Scientists classify faults based on the way fault blocks move relative to each other. The location where two fault blocks meet is called the fault plane. A fault plane can be oriented horizontally, vertically, or at any angle in between. For any fault except a perfectly vertical fault, the block above the fault plane is called the hanging wall. the block below the fault plane is the footwall. The movement of faults can create mountains and other types of landforms. At any tectonic plate boundary, the amount of stress on rock is complex. Therefore, any of the three types of faults can occur at almost all plate boundaries.

What causes tectonic plates to move?

Scientists have proposed three mechanisms to explain how tectonic plates move over Earth's surface. mantle convection drags plates along as mantle material moves beneath tectonic plates. Ridge push moves plates away from mid-ocean ridges as rock cools and becomes more dense. Slab pull tugs plates along as the dense edge of a plate sinks beneath earth's surface.

Pangaea

Scientists think that about 245 million years ago, the continents were joined in a single large landmass they called Pangaea. As the continents collided to form Pangaea, mountains formed. A single, large ocean called Panthalassa surrounded Pangaea.

Cinder Cones

Sometimes, ash and pieces of lava harden in the air and can fall to the ground around a small vent. The hardened pieces of lava are called cinders. The cinders of ash build up around the vent and form a steep volcano called a (blank). A (blank) can also form at a side vent on other volcanic mountains, such as on shield or composite volcanoes.

Core

The (blank) extends from below the mantle to the center of Earth. Scientists think that the core is made mostly of iron and some nickel. Scientists also think that it contains much less oxygen, silicon, aluminum, and magnesium than the mantle does. The core is the densest layer. It makes up about one-third of Earth's mass.

Asthenosphere

The (blank) is a layer of weak or soft mantle that is made of rock that flows slowly. Tectonic plates move on top of this layer.

Mantle

The (blank) is located between the core and the crust. It is a region of hot, slow-flowing, solid rock. When convection takes place in the mantle, cooler rock sinks and warmer rock rises.

Outer Core

The (blank) is the liquid layer of Earth's core. It lies beneath the mantle and surrounds the inner core.

Inner Core

The (blank) is the solid, dense center of our planet that extends form the bottom of the outer core to the center of Earth, which is about 6,380 km beneath the surface.

What are the tree kinds of mountains?

The movement of energy as heat and material in Earth's interior contribute to tectonic plate motions that result in mountain building. Mountains can form through folding, volcanism, and faulting. Uplift, a process that can cause land to rise can also contribute to mountain building. Because tectonic plates are always in motion, some mountains are constantly being uplifted.

Tectonic plates

The lithosphere is divided into pieces called (blank). These plates move around on top of the asthenosphere. The plates are moving in different directions at different speeds. Each tectonic plate fits together with the plates that surround it. The continents are located on tectonic plates and move around with them. The major tectonic plates include the Pacific, North American, Nazca, South American, African, Australian, Eurasian, Indian, and Antarctic plates. Not all tectonic plates are the same. The South American plate has an entire continent on it and has oceanic crust. The Nazca plate has only oceanic crust.

What are the kinds of volcanic landforms?

The location of a volcano and the composition of magma determine the type of volcanic landforms created. Shield volcanoes, cinder cones, composite volcanoes, lave plateaus, craters, and calderas are all types of volcanic landforms.

How ca tectonic plate motion cause deformation?

The movement of tectonic plates place stress of rocks. A tectonic plate is a block of lithosphere that consists of crust and the ridged outermost part of the mantle. Stress is the amount of force per unit area that is placed on an object. Rocks can bend or break under stress. In addition, low temperatures make materials more brittle, or easily broken. High temperatures can allow rock to bend. When a rock is placed under stress, it deforms, or changes shape. Deformation is the process by which rocks change shape when under stress. Rock can bend if it is placed under high temperature and pressure for long periods of time. If the stress becomes too great, or is applies quickly, rock can break. When rocks bend, folds, forms. When rocks break, faults form.

Crust

The outermost solid layer of earth is the crust. There are two types of crust-continental and oceanic. Both types are made mainly of the elements oxygen, silicon, and aluminum. However, the denser oceanic crust has almost twice as much iron, calcium, and magnesium. These elements form minerals that are denser than those in the continental crust.

Lithosphere

The outermost, rigid layer of Earth is the (blank). The (blank) is made of two parts-the crust and the rigid, upper part of the mantle. The lithosphere is divided into pieces called tectonic plates

Mesosphere

The strong, lower part of the mantle is called the (blank). Rock in the (blank) flows more slowly than rock in the asthenosphere does.

Sea-Floor Spreading

To explain the age and magnetic patterns of sea-floor rocks, scientists proposed a process called (blank). IN this process, molten rock from inside Earth rises though the cracks in the ridges, cools, and forms new oceanic crust. The old crust breaks along the mid-point of the ridge and the two pieces of crust move away in opposite directions form each other. In this way, the sea floor slowly spreads apart. As the sea floor moves, so do the continents on the same piece of crust

Volcanic Mountains

Volcanic mountains form when melted rock erupts onto Earth's surface. many major volcanic mountains are located at convergent boundaries. Volcanic mountains can form on land or on the ocean floor. Volcanoes on the ocean floor can grow so tall that they rise above the surface of the ocean, forming islands. Most of Earth's active volcanoes are concentrated around the edge of the Pacific Ocean. This area is know as the Ring of Fire. Many volcanoes, including Mt. Griggs, are located on the Northern rim of the Pacific plate in Alaska.

Where do volcanoes form?

Volcanoes can form at plate boundaries or within the middle of a plate. Recall that tectonic plates are giant sections of lithosphere on where two plates are moving away from each other. Most fissure eruptions occur at divergent boundaries. Shield volcanoes, fissure eruptions, and cinder cones can also occur away form plate boundaries within a plate at hot spots. The type of lava normally associated with these volcanoes has a relatively low viscosity, few trapped gases, and is usually not explosive. Composite volcanoes are most common along convergent boundaries where oceanic plates subduct. In order for the rock to melt, it must be hot and the pressure on it mus drop, or water and other fluids must be added to it. Extra fluids from ocean water form magma of higher viscosity with more trapped gases. Thus, composite volcanoes produce the most violent eruptions. The Ring of ire is a name used to describe the numerous explosive volcanoes that form on convergent plate boundaries surrounding the Pacific Ocean.

At Hot Spots

Volcanoes can form within a plate, away form the plate boundaries. A Hot Spot is a location where a column of extremely hot mantle rock, called a mantle plume, rises through the asthenosphere. As Eruptions at a hot spot commonly form shield volcanoes. As tectonic plates move over a mantle plume, chains of volcanic mountains can form. The youngest Hawaiian island, the Big Island, is home to Kilauea. The Kilauea volcano is an active shield volcano located over a mantle plume. To the north and west of Kilauea is a chain of progressively-older shield volcanoes. These volcanoes were once located over the same mantle plume. Hot spots can also occur on land. Yellowstone National Park, for example, contains a huge volcanic caldera that was formed by the same mantle plume that crated the Columbia Plateau.

Shield Volcanoes

Volcanoes with a broad base and gently sloping sides are (blank). (blank) cover a wide area and generally form from mild eruptions. Layers of lava flow out from the vent, harden, and slowly build up to form the cone. The Hawaiian Islands are shield volcanoes.

What is a Volcano?

What do volcanoes look Like? Most people think of a steep mounting with smoke coming out of the top. In fact, a volcano is any place where gas, ash, or melted rock come out of the ground. A volcano can be a tall mountain, or a small crack in the ground. Volcanoes occur on land and underwater. There are even volcanoes on other planets. Not all volcanoes actively erupt. Many are dormant, meaning an eruption has not occurred in a long period of time. Volcanoes form as rock below the surface of Earth melts. the melted rock, or magma, is less dense than solid rock, so it rises toward the surface. lava is magma that has reached Earth's surface. Lava and clouds of ash can erupt form a vent, or opening of a volcano.

Continent-Ocean Collisions

When a plate of oceanic lithosphere collides with a plate of continental lithosphere, the oceanic lithosphere subducts because it is denser.

Continent-Continent Collisions

When two plates of continental lithosphere collide, they buckle and thicken. This causes mountains to form.

Ocean-Ocean Collisions

When two plates of oceanic lithosphere collide, the older, denser plate subducts under the other plate.