Plate tectonics explains Earth's surface features and movement since 1950s. Earth's outer shell consists of plates that glide over mantle. Lithosphere is 60-140 kilometers thick, asthenosphere below
Earth's lithosphere consists of moving tectonic plates that interact to create geological features. Plate tectonics theory developed from Ortelius's 1596 continental drift concept. Plates move 2-10 cm yearly in response to mantle convection. Asthenosphere lubricates plates' movement
Geology studies Earth's interior, surface, rocks, and processes over billions of years. Earth is approximately 4.57 billion years old. Geological time is measured in eons, eras, periods, and epochs. Uniformitarianism states that present processes are same as past ones
Alfred Wegener proposed continental drift theory in 1912. He suggested all continents were once connected in Pangaea. Wegener's theory was rejected due to lack of explanation
Continental shelves are broad, shallow submarine terraces forming continental landmass edges. Make up about 8% of ocean area, extending to depths of 100-200 metres. Average width is about 65 km, with steep slope of 0.1°. Covered with sand, silts, and silty muds with ridges and valleys
Continental Drift proposed by Alfred Wegener in early 20th century. Various scientists noticed continents fitting across Atlantic Ocean. Theory became accepted after plate tectonics discovery in 1960s