1.
Who proposed the seafloor spreading hypothesis?
Correct Answer
B. Harry Hess
Explanation
Harry Hess proposed the seafloor spreading hypothesis. This theory suggests that new oceanic crust is formed at mid-ocean ridges and then spreads outwards, pushing older crust away from the ridge. Hess's hypothesis was a significant contribution to the understanding of plate tectonics and provided a mechanism for how continents move and interact with each other.
2.
What instrument was used in mapping the variations in the Earth's magnetic field in oceanic rocks?
Correct Answer
C. Magnetometer
Explanation
A magnetometer is used to map the variations in the Earth's magnetic field in oceanic rocks. Magnetometers are sensitive instruments that can measure the strength and direction of magnetic fields. By using a magnetometer, scientists can detect and map the magnetic anomalies in the oceanic rocks, which can provide valuable information about the Earth's magnetic field and its variations.
3.
What is seafloor spreading?
Correct Answer
B. A process that occurs at mid-ocean ridges.
Explanation
Seafloor spreading is a process that occurs at mid-ocean ridges. This process involves the creation of new oceanic crust as tectonic plates move apart. Magma rises from the mantle and fills the gap, solidifying to form new crust. As the new crust is created, older crust is pushed away from the ridge, leading to the spreading of the seafloor. This process plays a crucial role in plate tectonics and the formation of ocean basins.
4.
Mid-Ocean ridges form long chains of what that rise up from the ocean floor.
Correct Answer
C. Mountains
Explanation
Mid-Ocean ridges are underwater mountain ranges that form as tectonic plates move apart. The movement of the plates causes magma to rise and create new crust, which results in the formation of these mountainous ridges. These ridges can stretch for thousands of kilometers and are characterized by volcanic activity, earthquakes, and the presence of hydrothermal vents. Therefore, the correct answer is "mountains".
5.
In which year the seafloor spreading theory was proposed?
Correct Answer
A. 1960
Explanation
The seafloor spreading theory was proposed in 1960. This theory suggests that new oceanic crust is formed at mid-ocean ridges and spreads outwards, pushing the older crust aside. It was proposed by Harry Hess, a geologist and naval officer, who observed evidence such as magnetic anomalies and age differences in the oceanic crust that supported this idea. This theory revolutionized our understanding of plate tectonics and provided a key mechanism for how the Earth's crust is constantly changing and renewing itself.
6.
What does seafloor spreading explain?
Correct Answer
A. A continental drift
Explanation
Seafloor spreading explains the phenomenon of continental drift. It is the process by which new oceanic crust is formed at mid-ocean ridges and spreads outwards, pushing the existing crust apart. This movement of the oceanic crust causes the continents to move and drift over time. The theory of seafloor spreading provides a mechanism for explaining how the continents have moved and changed their positions on the Earth's surface throughout history.
7.
The process by which magma rises forming new oceanic lithosphere layer is called
Correct Answer
A. Sea floor spreading
Explanation
Sea floor spreading is the correct answer because it refers to the process where magma rises from the Earth's mantle, creating new oceanic lithosphere. As the magma cools and solidifies, it forms a new layer of crust on the ocean floor. This process occurs at mid-ocean ridges, where tectonic plates are moving apart, allowing for the upwelling of magma. Sea floor spreading plays a crucial role in the theory of plate tectonics and is responsible for the continuous expansion of the ocean basins.
8.
Molten rock inside the earth is called
Correct Answer
A. Magma
Explanation
Molten rock inside the earth is called magma. Magma is formed when rocks in the earth's mantle melt due to high temperatures and pressure. It is a mixture of molten minerals, gases, and solids. Magma can be found beneath the earth's surface in magma chambers and can eventually erupt onto the surface as lava during volcanic eruptions. It is an important component in the formation of igneous rocks and plays a crucial role in shaping the earth's geology and landscapes.
9.
Which one of the following is not an evidence of seafloor spreading?
Correct Answer
D. Fossil fuels
Explanation
Fossil fuels are not evidence of seafloor spreading because they are formed from the remains of ancient plants and animals that lived on land or in bodies of water such as lakes and swamps. Seafloor spreading, on the other hand, refers to the process where new oceanic crust is formed at mid-ocean ridges and spreads outwards. The molten material, magnetic stripes, and seafloor drilling are all pieces of evidence that support the theory of seafloor spreading.
10.
Seafloor spreading theory is also known as
Correct Answer
C. The mid-ocean ridge system
Explanation
The correct answer is "the mid-ocean ridge system." This is because seafloor spreading theory explains how new oceanic crust is formed at the mid-ocean ridges, where tectonic plates are moving apart. As the plates separate, magma rises from the mantle and solidifies to form new crust, pushing the existing crust away from the ridge. This process of crust formation and movement is known as seafloor spreading, and it occurs primarily at the mid-ocean ridge system. Therefore, the theory of seafloor spreading is closely associated with the mid-ocean ridge system.