大陆漂移：地球板块的舞蹈
Continental drift is the theory that the Earth's continents have moved over time. The idea was first proposed by Alfred Wegener in the early 20th century, but it wasn't until the 1960s that scientists had enough evidence to support it. Today, continental drift is a well-accepted theory in geology.
The movement of the Earth's tectonic plates is what causes continental drift. Tectonic plates are large pieces of the Earth's crust that move around on the mantle, the layer of rock beneath the crust. The mantle is made up of hot, molten rock that moves in convection currents. These currents are what drive the movement of the tectonic plates.
Continental drift has had a profound effect on the Earth's geography. For example, it has created the continents and oceans as we know them today. It has also caused mountain ranges to form as tectonic plates collide. Continental drift has even been linked to changes in climate.
There is a lot of evidence to support the theory of continental drift. Some of the most convincing evidence includes:
-- Fossil Record: Fossils of the same plants and animals have been found on different continents, even though they are now separated by oceans. This suggests that these continents were once connected.
-- Rock Formations: Similar rock formations have been found on different continents, even though they are now separated by oceans. This suggests that these continents were once part of the same landmass.
-- Magnetic Stripes: The Earth's magnetic field has changed over time, and this has left a record in the rocks. These magnetic stripes can be used to track the movement of the continents over time.
Continental drift is still happening today, although it is happening very slowly. The continents are currently moving apart at a rate of about 2 centimeters per year. This might not seem like much, but it adds up over time. In a few million years, the continents will look very different than they do today.