Animated Maps: Tectonic Plate Movement

The continents and ocean basins are in constant motion due to plate tectonics. This animation shows the plate tectonic evolution of the Earth during the last 540 million years. Modern countries are shown in shads of brown and tan. The age of the ocean floor is show in colors that range from blue (oldest) to red (youngest). The age in millions of years is shown in the upper left-hand corner of the screen. The geologic period is shown in the lower left-hand corner of the screen. Text and animation

VOLCANO FORMATION (Volcanology) INTRODUCTION Volcanology is the scientific study of volcanoes, lava, magma, and related geological phenomena. A volcano is an opening in the Earth’s crust through which molten rock (magma), gases, and ash escape from beneath the surface. FORMATION OF VOLCANOES 1. HEAT AND PRESSURE IN THE MANTLE: Deep within the Earth, high temperatures and pressures cause rocks to melt, forming magma in the mantle. 2. MAGMA MOVEMENT: Because magma is less dense than the surroundin