Sea-floor Spreading And Plate Tectonics Quiz

Explanation
A divergent boundary is the correct answer because it is the boundary where two plates move away from each other. At these boundaries, new crust is formed as magma rises to fill the gap created by the separating plates. This process leads to the formation of features such as mid-ocean ridges and rift valleys.

Explanation
Magma, or molten material, cools and hardens. When magma is exposed to lower temperatures, it loses heat and begins to cool down. This cooling process causes the magma to solidify and harden, forming igneous rocks. As the magma cools, it transitions from a liquid state to a solid state, resulting in the formation of solid rock structures. Therefore, the correct answer is "Cools."

Explanation
The mid-ocean ridge is a continuous underwater mountain range that runs through the center of the ocean basins. It is formed by the upwelling of magma from the Earth's mantle, which creates new oceanic crust. As the magma rises and solidifies, it pushes the older crust aside on both sides of the ridge. This process, known as seafloor spreading, is responsible for the continuous growth of the oceanic crust and the widening of the ocean basins.

Explanation
Subduction is the correct answer because it refers to the process of the ocean floor sinking back into the mantle beneath a deep-ocean trench. This occurs when one tectonic plate moves beneath another plate, causing the oceanic crust to be pushed down into the Earth's mantle. This process is responsible for the formation of deep-ocean trenches and is a key mechanism in plate tectonics. Continental drift, sea-floor spreading, and material addition to the ocean floor are not the appropriate terms to describe this specific process.

Explanation
Convergent ocean-ocean plate collision occurs when two oceanic plates collide. This collision results in the subduction of one plate beneath the other, leading to the formation of a deep oceanic trench. As the subducted plate melts, it generates magma that rises to the surface, creating a chain of volcanic islands known as an island arc. Therefore, the correct answer is Island Arc/Volcanic Islands.

Explanation
Continental crust is mainly made up of granite. Granite is a type of igneous rock that is formed from the slow cooling and solidification of magma deep within the Earth's crust. It is composed primarily of quartz, feldspar, and mica minerals. Granite is known for its durability and strength, making it a common rock found in the Earth's continental crust. It is often used as a building material and is also found in many mountain ranges around the world.

Explanation
Fossil evidence is not the evidence of sea-floor spreading because fossils are typically found in sedimentary rocks, which are formed on land or in bodies of water such as lakes or rivers. Sea-floor spreading occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity. The process does not involve the deposition of sedimentary rocks or the preservation of fossils. Therefore, the presence or absence of fossils cannot provide direct evidence of sea-floor spreading.

Explanation
The Earth plates meet at boundaries, where they interact with each other. These boundaries can be classified into three types: convergent boundaries, where plates collide; divergent boundaries, where plates move apart; and transform boundaries, where plates slide past each other. At these boundaries, various geological phenomena occur, such as earthquakes, volcanic eruptions, and the formation of mountain ranges.

Explanation
The broken sections of Earth's lithosphere are called plates. These plates are large pieces of the Earth's crust that fit together like a jigsaw puzzle and float on the semi-fluid asthenosphere below. The movement and interaction of these plates at their boundaries result in various geological phenomena such as earthquakes, volcanic activity, and the formation of mountain ranges.

Explanation
Plate Tectonics is the correct answer because it is a scientific theory that explains the movement and interaction of Earth's lithospheric plates. This theory states that the Earth's outer shell is divided into several large plates that float on the semi-fluid asthenosphere beneath them. These plates move slowly over time, causing various geological phenomena such as earthquakes, volcanic activity, and the formation of mountain ranges. Plate Tectonics also explains the distribution of continents, the formation of oceanic trenches, and the occurrence of seafloor spreading. This theory has been widely accepted by the scientific community and has greatly contributed to our understanding of Earth's geology.