1 Why is the area around the divergent boundary also known as the sea floor spreading 2 Features can be found around the sea floor spreading zone that indicates the plates are moving apart 3 Why do most seafloor spreading zones usually occur under water 4 Which part of the convection current in the mantle is causing this to happen
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1. The area around the divergent boundary is known as the sea floor spreading zone because it is where two tectonic plates are moving away from each other, creating a gap. This gap is filled with magma from the Earth's mantle that rises to the surface, solidifies, and forms new oceanic crust. As the new crust is continuously produced, the older crust is pushed away from the spreading zone, giving the impression of the sea floor spreading apart.
2. There are several features that indicate plates are moving apart at the sea floor spreading zone. These include:
- Mid-ocean ridges: These underwater mountain ranges form at the divergent boundaries where the plates are separating. They are characterized by volcanic activity and the formation of new oceanic crust.
- Rift valleys: These are deep, elongated depressions that form along the crest of the mid-ocean ridges. They are created as magma rises to the surface and pushes the plates apart.
- Transform faults: These are fractures in the oceanic crust that occur perpendicular to the spreading zone. They connect different segments of the mid-ocean ridge and accommodate horizontal motion as the plates move apart.
3. Most sea floor spreading zones occur under water because the majority of divergent boundaries are found along the oceanic ridges. This is where the Earth's tectonic plates are moving apart in the oceanic crust, leading to the formation of new crust. As the magma rises and solidifies, it creates new oceanic crust, which continuously pushes the older crust away from the spreading zone. This process primarily occurs in the deep ocean, hence most sea floor spreading zones are underwater.
4. The part of the convection current in the mantle that causes sea floor spreading is known as the upward flow. In the mantle, there is a constant circulation of heat through convection currents. These currents are driven by the heat imbalance between the Earth's interior and its surface. As the mantle material near the core heats up, it becomes less dense and rises towards the surface, carrying heat with it. This upward flow of hot mantle material beneath the oceans causes the sea floor spreading by providing the necessary influx of magma to create new oceanic crust at the divergent boundaries.
1. The area around the divergent boundary is known as the sea floor spreading because it is where two tectonic plates are moving away from each other. As they move apart, magma from the Earth's mantle rises up and fills the gap between the plates, creating new crust on the ocean floor. This process of creating new crust is called sea floor spreading.
To understand why this happens, you can imagine the Earth's crust as consisting of multiple puzzle pieces. At divergent boundaries, these puzzle pieces (plates) are continuously moving away from each other, creating gaps. The mantle beneath the crust is under immense heat and pressure, causing it to become less dense than the overlying crust. As a result, the molten rock (magma) in the mantle is able to rise up and fill these gaps, forming new crust as it cools and solidifies.
2. Several features can be found around the sea floor spreading zone that indicate the plates are moving apart. One such feature is a mid-ocean ridge, which is a long chain of mountains that runs along the center of many ocean basins. These underwater mountain ranges are formed when the new crust is created through sea floor spreading. Another feature is a rift valley, which is a deep trench-like depression that forms when the plates separate. Rift valleys occur where the sea floor is spreading and pulling apart.
Additionally, scientists have found evidence of alternating magnetic stripes on the ocean floor, known as magnetic anomalies. These stripes are created by the Earth's magnetic field, which periodically reverses its polarity. As new crust forms through sea floor spreading, it preserves the magnetic field orientation of the time when it was created. By studying these magnetic anomalies, scientists have been able to confirm the process of sea floor spreading and the movement of tectonic plates.
3. Most seafloor spreading zones occur under water because the majority of the Earth's divergent boundaries are located in the oceanic crust. This is primarily due to the fact that oceanic crust is younger and thinner compared to continental crust. Since oceanic crust is continuously being created at divergent boundaries, it tends to be more susceptible to sea floor spreading processes.
On the other hand, continental crust is generally thicker and older, making it less likely to undergo significant sea floor spreading. However, there are exceptions to this, such as the East African Rift Zone, where a divergent boundary is causing continental crust to split apart. In such cases, sea floor spreading can also occur on land, though it is still lesser in extent compared to the oceanic environments.
4. The movement of tectonic plates and the occurrence of sea floor spreading are primarily driven by convection currents in the Earth's mantle. Convection currents are caused by the transfer of heat from the Earth's core towards the surface. As the mantle heats up, it becomes less dense and rises towards the surface, while the cooler, denser mantle sinks back down.
Within the mantle, there are several convection cells or currents that circulate the molten rock. These currents distribute heat throughout the mantle, creating a dynamic environment. It is the upward movement of the less dense, heated mantle material that causes the plates to move apart at divergent boundary locations. This upwelling of mantle material leads to the formation of magma chambers, which then supply the molten rock required for sea floor spreading.