1. Convection Currents: Deep within the Earth's mantle, heat from the core creates convection currents. Hotter, less dense material rises, while cooler, denser material sinks.
2. Plate Movement: The Earth's outer layer (the lithosphere) is broken into large plates that ride on top of these convection currents. The movement of these currents drags the plates along with them.
3. Divergent Boundaries: At divergent boundaries, plates move apart. This happens primarily at mid-ocean ridges, where magma rises from the mantle, cools, and solidifies to form new oceanic crust. This process pushes the plates apart, expanding the ocean basin.
4. Evidence:
* Seafloor Spreading: The magnetic stripes on the ocean floor, symmetrical on either side of the mid-ocean ridges, provide strong evidence for seafloor spreading. These stripes reflect changes in Earth's magnetic field over time.
* Matching Coastlines: The shapes of continents on opposite sides of the Atlantic Ocean fit together like puzzle pieces, suggesting they were once connected.
* Fossil Distribution: Identical fossils of extinct organisms have been found on continents now separated by vast oceans, indicating they were once connected.
* Rock Formations: Similar rock formations, including mountain ranges, can be found on continents now separated by oceans, suggesting they were once part of the same landmass.
In summary: Geological evidence helps us understand the process of plate tectonics, which is the driving force behind continental drift. The evidence shows that continents are indeed moving apart, and it helps us understand how and why this happens.
