What is a key difference between oceanic tectonic plates and continental plates?

Oceanic plates are indeed denser than continental plates, which is a fundamental aspect of tectonic plate theory. This density difference is primarily due to their composition. Oceanic plates are mainly formed from basalt, which is a denser, mafic rock. In contrast, continental plates are primarily made of granite, which is a lighter, felsic rock.

This difference in density has significant geological implications, particularly when it comes to plate interactions. For example, when an oceanic plate converges with a continental plate, the denser oceanic plate tends to subduct, or sink, beneath the lighter continental plate. This process leads to various geological features and phenomena, such as the formation of mountain ranges and volcanic activity. Understanding the density differences helps explain many of the dynamics involved in tectonic plate movement and earth science as a whole.