プレートテクトニクス
Plate tectonics (from the , from the ) is a scientific theory describing the large-scale motion of the plates making up the Earth's lithosphere since tectonic processes began on Earth between 3.3 and 3.5 billion years ago. The model builds on the concept of continental drift, an idea developed during the first decades of the 20th century. The geoscientific community accepted plate-tectonic theory after seafloor spreading was validated in the late 1950s and early 1960s.