Question

Why are continents considered to be adrift?

a. Convection currents in the asthenosphere and upper mantle provide upwelling and downwelling that push and pull portions of the lithosphere

b. Gravitational forces from the moon and the sun continuously exert pressure on the Earth's surface, causing the continents to shift gradually over time.

c. Tectonic plates move due to the influence of magnetic forces from the Earth's core, leading to the drifting of continents.

d. Continental drift occurs as a result of erosion and weathering, which slowly but steadily move the landmasses over millions of years.

Answer 1

a. Convection currents in the asthenosphere and upper mantle provide upwelling and downwelling that push and pull portions of the lithosphere.

Step-by-step explanation:

You know how the Earth's surface is divided into these big puzzle pieces called tectonic plates, right? Well, underneath these plates, there are these super hot and flowy layers called the asthenosphere and upper mantle. These currents push and pull on the tectonic plates, causing them to move. And since the continents are part of these plates, they also move and drift around.

Answer 2

Continents are considered to be adrift due to plate tectonics, driven by convection currents in the Earth's mantle, which cause the lithosphere to move. This process is responsible for the slow and gradual shifting of the continents, as well as the formation of mountains and other geologic features.

Step-by-step explanation:

Continents are considered to be adrift primarily due to the actions of plate tectonics. The mechanism behind this drifting is the convection currents in the asthenosphere and upper mantle. These currents facilitate an upwelling and downwelling motion which acts upon the lithosphere, the rigid outer layer of the Earth which includes the crust and the upper mantle.

Earth's crust and upper mantle are divided into tectonic plates that are moved by these slow convection currents. This results in the gradual movement of continents, the formation of mountains, and other large-scale geological changes. For instance, the African plate bumping into the Eurasian plate led to the formation of the Alps.

To understand plate tectonics better, it's essential to know that these tectonic plates are composed of oceanic and continental lithosphere. The movement of these plates leads to the dynamic nature of the Earth's surface, creating and modifying landforms and giving rise to various geological phenomena, from earthquakes to the creation of mountain ranges.