a branch of the Indo-European family of languages, including especially Irish, Scottish Gaelic, Welsh, and Breton, which survive now in Ireland, the Scottish Highlands, Wales, and Brittany. adjective. 2. of the Celts or their languages.
Movement of tectonic plates-higher. Volcanoes, mountains and earthquakes occur at the edges of tectonic plates-their creation depends on the direction the plates are moving.
Quick Answer. Plate tectonics is primarily caused by Earth's cooling mechanism, which generates convection currents in the planet's mantle that trigger slow but constant tectonic plate movement. This phenomena occurs on the boundaries of adjacent plates, which are classified as divergent, convergent and transform boundaries. Continue Reading