Plate Tectonics Assessment Mcfadden Period 2 2015

The correct answer is "At the mid-ocean ridges". This is because the process of seafloor spreading occurs at the mid-ocean ridges, where new oceanic crust is formed. As the molten material from the Earth's mantle rises and cools, it solidifies to form new rocks. Therefore, the youngest rocks on the ocean floor can be found at these mid-ocean ridges.

The crust and upper mantle make up Earth's lithosphere. The lithosphere is the rigid outer layer of the Earth, consisting of the crust and a portion of the upper mantle. It is divided into several large and small tectonic plates that float on the semi-fluid asthenosphere below. The lithosphere plays a crucial role in plate tectonics and is where most geological activity, such as earthquakes and volcanic eruptions, occurs.

Scientists have observed that the plates move at rates ranging from 2 cm to 12 cm per year. This suggests that the movement of tectonic plates is a slow process that occurs over long periods of time. The yearly movement of the plates is significant enough to cause earthquakes, volcanic activity, and the formation of mountains. This observation highlights the dynamic nature of the Earth's crust and the continuous reshaping of the planet's surface.

The plates of the lithosphere float on the asthenosphere. The asthenosphere is a semi-fluid layer of the mantle beneath the lithosphere. It is made up of hot, partially melted rock that allows the plates to move and float on top of it. This movement of the plates, known as plate tectonics, is responsible for creating earthquakes, volcanic activity, and the formation of mountain ranges. The asthenosphere acts as a lubricating layer that allows the plates to slide past each other, collide, or diverge, shaping the Earth's surface over time.

The Himalaya mountains were formed when the Indian tectonic plate collided with the Eurasian plate. This collision caused the Indian plate to be pushed upward, resulting in the formation of the Himalayas. The Himalayas are located in Asia and are known as the highest mountain range in the world, with Mount Everest being the highest peak.

The presence of the same fossils and rock structures on several continents supports the hypothesis of continental drift. This is because the movement of continents over time would explain how these identical fossils and rock structures ended up in different locations. If the continents were once connected and then drifted apart, it would make sense for them to share similar geological features and fossil records. Therefore, the presence of both fossils and rock structures on multiple continents provides strong evidence for the theory of continental drift.

At divergent boundaries, plates move apart from each other. This movement occurs due to the upwelling of magma from the mantle, which creates new crust and pushes the plates away. This process is known as seafloor spreading and is responsible for the formation of mid-ocean ridges. Divergent boundaries are characterized by volcanic activity, earthquakes, and the creation of new crust.

The alignment of the magnetite in the seafloor reflects the fact that Earth's magnetic field has reversed itself several times in the past. This is because magnetite is a magnetic mineral that can align itself with the Earth's magnetic field at the time of its formation. The reversals of the Earth's magnetic field have been recorded in the magnetite crystals found in the seafloor, providing evidence of the changing nature of the Earth's magnetic field over time.

The correct answer is Pangaea. The lack of explanation for continental drift prevented many scientists from accepting that a single supercontinent called Pangaea once existed. Continental drift refers to the movement of Earth's continents over time, and the concept of Pangaea was proposed by Alfred Wegener in the early 20th century. However, without a satisfactory explanation for how and why the continents moved, many scientists were skeptical of this idea. It was not until the discovery of seafloor spreading and the development of plate tectonics theory in the 1960s that the concept of Pangaea became widely accepted.

The Glomar Challenger provided support for the theory of plate tectonics by collecting samples of rock from the seafloor. These rock samples allowed scientists to study the composition and age of the seafloor, which provided evidence for the movement and interaction of tectonic plates. By analyzing these samples, scientists were able to confirm the existence of mid-ocean ridges, where new seafloor is formed, and the process of seafloor spreading. This supported the theory of plate tectonics, which states that the Earth's lithosphere is divided into several large plates that move and interact with each other.

Transform boundaries occur when two plates slide past one another horizontally, without creating or destroying crust. This movement can result in earthquakes as the plates grind against each other. Transform boundaries are commonly found along mid-ocean ridges, where they connect segments of divergent boundaries, and also on land, such as the San Andreas Fault in California.

A convergent boundary is the correct answer because it refers to the boundary between two tectonic plates that are colliding together. At this type of boundary, the two plates are moving towards each other, resulting in the formation of mountains, earthquakes, and volcanic activity. This collision can occur between two continental plates, two oceanic plates, or between a continental and an oceanic plate.

Seafloor spreading occurs because molten material beneath Earth's crust rises to the surface at the mid-ocean ridge. This process is known as volcanic activity, where magma from the mantle rises and creates new oceanic crust at the mid-ocean ridge. As the magma cools and solidifies, it forms new seafloor, pushing the existing crust away from the ridge. This continuous process of magma rising and solidifying creates seafloor spreading, leading to the expansion of the oceanic crust.

Continental drift is a theory that explains the movement of continents over time. It suggests that continents have shifted slowly from their original positions to their current locations. This movement occurs due to the gradual movement of tectonic plates on the Earth's surface. The theory of continental drift was proposed by Alfred Wegener in the early 20th century and has since been supported by various pieces of evidence, such as the matching shapes of coastlines and the distribution of fossils and rock formations across different continents.

Wegner believed that the continents originally broke apart about 200 million years ago. This is based on his theory of continental drift, which suggests that the Earth's continents were once joined together in a single landmass called Pangaea. Over time, the continents gradually moved apart due to the movement of tectonic plates. The evidence supporting this theory includes the matching shapes of coastlines on different continents, similar rock formations, and the presence of identical fossils on separate landmasses.

Glossopteris is a fossil plant that helps support the theory of continental drift because its fossils have been found in multiple continents that are now widely separated. This indicates that these continents were once connected and later drifted apart. The distribution of Glossopteris fossils provides evidence for the existence of the supercontinent Pangaea and supports the theory of continental drift.

Rock structures on different continents are evidence for continental drift because they provide clues about the geological history and formation of the continents. Similar rock formations found on different continents suggest that these landmasses were once connected and have since drifted apart. This supports the theory of continental drift, which proposes that the continents were once part of a single supercontinent called Pangaea and have gradually moved over millions of years. The presence of matching rock structures on different continents provides strong evidence for this process of continental drift.

Bands of rock on the seafloor showing alternating magnetic orientation indicate that Earth's magnetic field has reversed itself in the past. This means that the magnetic north and south poles have switched places at some point in history. The alternating bands of rock are formed when molten lava solidifies and records the orientation of the magnetic field at that time. By studying these bands, scientists can determine the history of Earth's magnetic field and its changes over time.

A magnetometer is a sensitive device used to detect magnetic fields on the seafloor. It is commonly used in marine exploration to study the Earth's magnetic field and identify underwater geological features such as ridges, faults, and volcanic activity. By measuring the intensity and direction of magnetic fields, magnetometers provide valuable information about the seafloor's composition and structure.

The correct answer is density. Scientists believe that differences in density cause hot, plasticlike rock in the asthenosphere to rise toward Earth's surface. Density refers to the mass of an object divided by its volume, and it determines how buoyant an object is in a fluid. In the case of the asthenosphere, regions with lower density rise due to their buoyancy, while regions with higher density sink. This movement of hot rock is responsible for various geological phenomena such as volcanic activity and plate tectonics.

In order to complete a convection current, the rising material must eventually cool and sink. This is because convection currents occur due to differences in temperature. When a material is heated, it becomes less dense and rises. As it rises, it cools down and eventually reaches a point where it becomes denser than the surrounding material. At this point, it starts to sink back down, completing the convection current. So, cooling and sinking is necessary for the cycle of rising and sinking to continue and maintain the convection current.

The Great Rift Valley in Africa is a divergent boundary. Divergent boundaries occur when two tectonic plates move away from each other, creating a gap. In the case of the Great Rift Valley, the African Plate and the Arabian Plate are moving apart, causing the Earth's crust to crack and form a rift. This rift has created a long valley with steep walls, known as the Great Rift Valley. The movement of the plates also results in volcanic activity and the formation of new crust.

The Andes mountain range of South America was formed at a convergent boundary. Convergent boundaries occur when two tectonic plates collide, causing one plate to be forced beneath the other in a process called subduction. In the case of the Andes, the Nazca Plate is subducting beneath the South American Plate, leading to the formation of the mountain range. This subduction process results in the uplift and deformation of the Earth's crust, leading to the creation of large mountain ranges like the Andes.

Active volcanoes are most likely to form at convergent oceanic-continental boundaries. This is because at these boundaries, oceanic crust is forced beneath continental crust in a process called subduction. As the oceanic crust sinks into the mantle, it melts and forms magma. This magma, being less dense than the surrounding rock, rises and eventually erupts at the surface, creating volcanoes. This is a common occurrence along the Pacific Ring of Fire, where many active volcanoes are located.

When two continental plates collide, the immense pressure and force cause the crust to buckle and fold, resulting in the formation of mountain ranges. The collision forces the rocks to compress and uplift, creating large-scale geological structures. The collision also leads to the formation of faults, which can contribute to the creation of mountain ranges. Therefore, mountain ranges are formed as a result of the collision between continental plates.

The San Andreas Fault is an example of a transform boundary. Transform boundaries occur when two tectonic plates slide past each other horizontally. The San Andreas Fault is located in California and is where the Pacific Plate and the North American Plate meet. The movement along this fault line has resulted in numerous earthquakes in the region. This type of boundary does not involve the creation or destruction of crust, but rather the movement of existing crust.

A subduction zone forms where two oceanic plates collide. In this type of plate boundary, one of the plates is forced beneath the other and into the mantle, creating a deep trench. This process is called subduction. Subduction zones are known for their intense geological activity, including volcanic eruptions and earthquakes.

Based on the given diagram, the North American Plate and the Eurasian Plate are moving away from each other. This indicates a divergent boundary, where two plates are moving apart. At divergent boundaries, new crust is formed as magma rises to fill the gap created by the separating plates. This process is commonly observed at mid-ocean ridges, where new oceanic crust is continuously being formed. Therefore, the correct answer is Divergent Boundary.

The diagram provided shows two plates, the Nazca Plate and the South American Plate, converging. The Nazca Plate is an oceanic plate, while the South American Plate is a continental plate. In a convergent oceanic-continental plate boundary, the denser oceanic plate is subducted beneath the less dense continental plate. This results in the formation of a subduction zone, where volcanic activity and earthquakes occur. Therefore, the correct answer is convergent oceanic-continental plate boundary.

Alfred Wegener believed that the continents were once joined. This theory, known as continental drift, proposed that the continents were once part of a supercontinent called Pangaea, which gradually broke apart and drifted to their current positions. Wegener supported his theory with evidence such as matching coastlines, similar rock formations, and the distribution of fossils across continents. His ideas were initially met with skepticism but eventually led to the development of the theory of plate tectonics, which explains the movement of the Earth's lithosphere, including the continents, over time.

Pangaea is the correct answer because the name Pangaea is derived from two Greek words, "pan" meaning "all" and "gaea" meaning "land". This name was given to the supercontinent that existed millions of years ago, when all the continents were joined together as one large landmass.

The asthenosphere is the correct answer because it is described as Earth's thick, plasticlike layer. This layer is located beneath the lithosphere and is composed of partially molten rock that is capable of flowing slowly. It plays a crucial role in plate tectonics and is responsible for the movement of the Earth's tectonic plates.

In a subduction zone, one tectonic plate is forced beneath another plate. This occurs when two plates collide, and the denser plate sinks into the Earth's mantle. Subduction zones are typically associated with convergent boundaries, where two plates are moving towards each other. This process is responsible for creating deep ocean trenches, volcanic activity, and the formation of mountain ranges.

A mid-ocean ridge is an underwater mountain chain formed by tectonic plates spreading apart. As the plates move apart, magma rises from the asthenosphere and solidifies, creating new crust. This process results in the formation of a long, elevated ridge on the ocean floor. The mid-ocean ridge is characterized by volcanic activity, earthquakes, and the presence of hydrothermal vents. It is an important feature in plate tectonics and plays a significant role in the formation of new oceanic crust.

The correct answer is Continental Drift. The main points of evidence for Continental Drift are fossils, rocks, and climate. Fossils provide evidence of past life forms that were once connected but are now separated by oceans. Rocks show similar formations and structures on different continents, indicating that they were once joined together. Climate evidence includes the presence of glacial deposits in areas that are now too warm for glaciers, suggesting that these areas were once located near the poles.

The statement mentions that new seafloor rock is continually being formed at mid-ocean ridges and old seafloor is continually removed at ocean trenches. This implies that the seafloor is constantly being recycled, which means that the oldest rocks on the seafloor would be relatively young. On the other hand, the rock on the continents is continually formed but not removed, which means that the oldest rocks on the continents would be much older than the oldest rocks on the seafloor. Therefore, the answer is "Continent is OLDER than the seafloor."

The diagram represents the concept of magnetic north alternating between the geographic north and south poles. This means that over time, the magnetic north pole has shifted between the two geographic poles. This can be seen in the diagram, which likely shows the movement of the magnetic north pole in relation to the geographic poles.

The oldest rock on the seafloor is located at the trench. Trenches are formed where one tectonic plate is being forced beneath another, in a process called subduction. As the older plate is subducted, it sinks into the mantle and eventually melts. This means that the rock at the trench is the oldest, as it has been present on the seafloor for the longest period of time. In contrast, the mid-ocean ridge is where new oceanic crust is formed, so the rock there is much younger. The area halfway between the mid-ocean ridge and a trench would also have younger rocks compared to the trench.

The picture below shows a normal fault. A normal fault occurs when the hanging wall moves downward relative to the footwall due to tensional forces pulling the rocks apart. This results in the footwall being uplifted and the hanging wall being lowered. The angle of the fault plane is typically less than 60 degrees.

The picture below shows a reverse fault. This is indicated by the displacement of the rock layers, where the hanging wall moves upward relative to the footwall. Reverse faults occur when compressional forces cause the crust to shorten and the rocks to be pushed together, resulting in a steeply inclined fault plane.

The picture shows a strike-slip fault because it displays a clear horizontal displacement of the rock layers on either side of the fault line. In a strike-slip fault, the rocks move past each other horizontally, without any significant vertical displacement. This can be observed in the picture where the rock layers on either side of the fault line appear to have moved horizontally in opposite directions.

The correct answer is convergent. In convergent plate boundaries, two tectonic plates are moving towards each other. This movement causes the plates to collide, resulting in the formation of mountains, volcanoes, and trenches. In the given pictures, there might be evidence of mountain building, volcanic activity, or subduction zones, which are all characteristics of convergent plate boundaries.

At the boundary between two oceanic plates, a trench is created. Trenches are long, narrow depressions on the ocean floor that are formed when one oceanic plate is forced beneath another in a process called subduction. This occurs at convergent plate boundaries where two plates are moving towards each other. As the denser oceanic plate sinks into the mantle, it forms a deep trench. Trenches are some of the deepest parts of the Earth's oceans and are often associated with volcanic activity and earthquakes.

Subduction is the correct answer because it refers to the process in which one tectonic plate is forced beneath another plate, causing the crust to be pulled down into the mantle. This process occurs at convergent plate boundaries, where two plates collide. As the denser plate sinks into the mantle, it undergoes melting and recycling, leading to the formation of volcanic activity and the recycling of crustal material.

Convection currents inside Earth are currently the best explanation for tectonic plate motion. Convection refers to the transfer of heat through the movement of a fluid, in this case, the molten rock in Earth's mantle. As the hot rock near the core rises, it cools and sinks back down, creating a circular motion known as convection currents. These currents are believed to be responsible for the movement of tectonic plates, as they drag the plates along with them. Vertical and horizontal currents alone cannot account for the observed plate motion, making convection the most plausible explanation.