Plate Tectonics Science Test

A divergent boundary is the correct answer because it refers to the boundary between two tectonic plates that are moving away from each other. This movement causes the plates to separate and creates a gap where new crust is formed through volcanic activity. Divergent boundaries are typically found along mid-ocean ridges and can also occur on land, such as the East African Rift.

Pangea is the correct answer because it is the supercontinent that formed around 300 million years ago and started to break up around 250 million years ago. Pangea was a massive landmass that included all of Earth's current continents, and its breakup eventually led to the formation of the continents we have today.

Convection is the correct answer because it refers to the movement of matter due to differences in density caused by temperature variations. This movement can result in the transfer of heat.

A convergent boundary occurs when two tectonic plates collide. This collision can result in the formation of mountains, volcanic activity, and earthquakes. The plates can either be oceanic or continental, and the type of convergent boundary depends on the types of plates involved. In this case, the correct answer is "Convergent Boundary" because it describes the boundary between two tectonic plates that are colliding.

A mountain range refers to a series of mountains that are closely related in terms of their orientation, age, and mode of formation. This means that the mountains in a mountain range are typically aligned in a similar direction, formed during the same geological period, and have similar processes of formation, such as tectonic activity or volcanic eruptions. Therefore, the correct answer for this question is Mountain Range.

A transform boundary occurs when two tectonic plates slide past each other horizontally. This type of boundary is characterized by the absence of crustal deformation or the creation of new crust. Instead, the plates are locked together and build up stress until they suddenly slip, causing earthquakes. This type of boundary is commonly found along the San Andreas Fault in California.

Oceanic crust is denser than continental crust because it is composed mainly of basalt, which is a dense and heavy rock. Continental crust, on the other hand, is made up of lighter rocks such as granite. The denser nature of oceanic crust is also due to its higher iron and magnesium content. This density difference causes oceanic crust to sink beneath continental crust in a process called subduction.

Seafloor spreading is the correct answer because it accurately describes the process by which new oceanic lithosphere (seafloor) is formed. It involves the rising of magma to Earth's surface at a mid-ocean ridge and its subsequent solidification, leading to the creation of new seafloor. This process is a key component of plate tectonics and contributes to the continuous movement and reshaping of Earth's crust.

Plate tectonics is the correct answer because it is the theory that explains the movement and changing shape of large pieces of the lithosphere, known as plates. This theory states that the Earth's lithosphere is divided into several plates that float on the semi-fluid asthenosphere. These plates interact at their boundaries, causing various geological phenomena such as earthquakes, volcanic activity, and the formation of mountain ranges. Plate tectonics provides a comprehensive understanding of the dynamic nature of the Earth's crust and the processes that shape its surface.

Continental crust refers to the outermost layer of the Earth's surface that makes up the continents. It is characterized by a low density and is primarily composed of rocks that are rich in silica. This type of crust is thicker and less dense compared to oceanic crust. It is also less dense than the underlying mantle, which allows it to "float" on top. The presence of silica-rich rocks in continental crust contributes to its lower density and different physical properties compared to oceanic crust.

The continental crust is not made of rock that is rich in iron and magnesium. Instead, it is primarily composed of granite, which is rich in aluminum and silicon. The oceanic crust, on the other hand, is made of basalt, which does contain higher levels of iron and magnesium. Therefore, the statement that the continental crust is rich in iron and magnesium is false.

Stress refers to the amount of force per unit area that acts on a rock. It is a measure of the internal resistance of a material to deformation. When a force is applied to a rock, the stress it generates can cause the rock to deform or break. Stress is an important concept in geology and engineering, as it helps to understand the behavior of rocks and structures under different loading conditions.

Deformation refers to the bending, tilting, and breaking of Earth's crust, which occurs due to the change in shape of rock in response to stress. It is the process by which rocks undergo changes in their shape, volume, and orientation. This can happen through various mechanisms such as folding, faulting, and fracturing. Deformation is a fundamental process in geology and is responsible for the creation of mountain ranges, valleys, and other geological features.

A mid-ocean ridge is a long, undersea mountain chain that forms as magma rises from the asthenosphere and creates new oceanic lithosphere (sea floor) as tectonic plates move apart. It is characterized by a steep, narrow valley at its center. This process is known as sea floor spreading, where new crust is formed and pushes the existing crust apart. The mid-ocean ridge is an important feature of plate tectonics and is responsible for the creation of new oceanic crust.

Continental Drift is the correct answer because it refers to the hypothesis that suggests the continents were once joined together in a supercontinent called Pangea, which later broke apart and drifted to their current positions. This theory was proposed by Alfred Wegener in the early 20th century and has since been supported by various lines of evidence, including matching coastlines, similar rock formations, and fossil distribution. Isostasy, on the other hand, refers to the equilibrium of the Earth's crust, while Pangea is the name given to the supercontinent itself.

Strain refers to any change in a rock's shape or volume caused by stress. When stress is applied to a rock, it causes the rock to deform, resulting in a change in its shape or volume. This change is known as strain. Therefore, strain is the correct answer to the given question.

A fold is a form of ductile strain in which rock layers bend. This bending usually occurs as a result of compression, where the rock layers are pushed together. This can happen due to tectonic forces or other geological processes. Folds can take various shapes, such as anticlines (upward arching) and synclines (downward folding). They are common features in areas with intense tectonic activity and can be seen in mountain ranges and other regions where rock deformation has occurred.

Oceanic crust is the correct answer because it is the crust that is dense and made of rock that is rich in iron and magnesium. Unlike continental crust, which is less dense and made of rock that is rich in silicon and aluminum, oceanic crust is primarily composed of basaltic rock. This type of crust is found beneath the Earth's oceans and is thinner and younger than continental crust. Terrane refers to a distinct geological region or fragment that has been added to a larger landmass, and it is not directly related to the composition or characteristics of crust.

Isostasy refers to the balance or equilibrium between the Earth's lithosphere (the rigid outer layer) and asthenosphere (the partially molten layer below). This equilibrium is achieved when the buoyant force exerted by the asthenosphere is equal to the gravitational force exerted on the lithosphere. Isostasy plays a crucial role in plate tectonics as it helps explain the vertical movement of the Earth's crust, such as the rising and sinking of continents and the formation of mountains. Therefore, isostasy is the most suitable answer among the given options.

A fault is a break in a body of rock along which one block slides relative to another. It is a form of brittle strain where the rocks on either side of the fault move past each other. This movement can occur horizontally, vertically, or at an angle. Faults are commonly associated with earthquakes as the release of accumulated stress along the fault line causes the rocks to slip and generate seismic waves.

Rifting is the process in which Earth's crust breaks apart, and it can occur within both oceanic and continental crust. This process leads to the formation of rift valleys and the separation of land masses. It is a key geological phenomenon that contributes to the creation of new ocean basins and the formation of new continents over millions of years.

A terrane is a piece of lithosphere that has a unique geologic history and may be part of a larger piece of lithosphere, such as a continent. It is a distinct geological unit that has been transported and attached to another lithospheric plate. Terranes can have different rock types, ages, and tectonic histories compared to the surrounding lithosphere. This concept helps explain the formation and movement of continents over time, such as the assembly and breakup of the supercontinent Pangea. The correct answer is "Terrane".

The supercontinent cycle refers to the process by which supercontinents form and break apart over millions of years. This cycle involves the movement of tectonic plates, which can cause continents to collide and merge into a supercontinent, and then later separate and disperse into individual continents. This process is driven by convection in the Earth's mantle and is known as continental drift.