Presentation on theme: "PLATE TECHTONICS TEXT CH. 3..PG. 80. How do geologists study inside earth? Look at rock samples – Can determine conditions deep in the earth by looking."— Presentation transcript:
How do geologists study inside earth? Look at rock samples – Can determine conditions deep in the earth by looking at rocks formed there – Get rocks by drilling and blasting Seismic waves: Waves produced by earthquakes – Speed & Path of the waves are used to look at structure
Earth’s Interior 3 layers: Crust, Mantle, Core Vary in size, composition, temperature, and pressure Temperature increases as you go deeper Pressure (force pushing on an area) increases as you go deeper Why do you think these things increase?
Crust Outermost layer of the earth Solid rock, dry land, ocean floor Very thin…5-40 km thick Thickest crust is under mountains (up to 70 km)…. Thinnest under ocean floor (oceanic crust) Oceanic Crust made of basalt Continental crust mainly granite
Mantle Approximately 40 km beneath the surface of earth Solid, hot layer of rock Divided into 3 layers: – Lithosphere – Astenosphere – Lower Mantle
Lithosphere Uppermost Mantle & lower part of the crust Rigid layer Approximately 100 km thick
Asthenosphere Hotter and more pressure Less rigid—more soft like plastic or plahdoh Bendable Thickest part of the mantle “Asthenes” means “Weak” in Latin
Core Made mostly of iron and nickle 2 parts: Liquid outer & Solid Inner 3,486 km thick Tons of pressure here…inner core has so much pressure, it has to stay solid Creates magnetic field of the earth---Acts as a bar magnet