Our Amazing Planet

Planet Earth Earth’s Layers

Crust Earth’s thin outermost layer. Continental Crust (land) - thick low density rock (granite). Oceanic Crust (sea floor)- thin dense rock (basalt)‏

Mantle Earth’s thickest layer made of dense iron-rich super heated soft rock. Where convection currents occur.

Core Earth’s innermost layer made of hot, dense iron and nickel. Outer core - Liquid Inner core - Solid

Lithosphere Earth’s outermost layer Includes the crust and solid upper part of the mantle. Divided into huge pieces called “Tectonic Plates”. Move around on top of the asthenosphere - very hot, soft layer of the mantel.

Earth’s Tectonic Plates

Continental Drift Theory that the Earth’s continents move over time Proposed by Alfred Wegener in the early 1900’s Evidence of Continental Drift: Continents fit together Similar fossils records Similar rocks and minerals Similar rock formations and striations Similar climatic conditions – Glaciations

Evidence of Pangaea

Continents Fit Together

South America and Africa

Similar Fossil Records

Similar Mountain Ranges

Similar Rocks Rock Striations Match

Other Evidence - Glaciations

Sea Floor Spreading Occurs where tectonic plates spread apart at Mid Ocean Ridges Magma rises from inside the Earth creating new sea floor. New sea floor pushes the existing sea floor out explaining why continents move. Evidence that supports the theory of Continental Drift.

Sea Floor Spreading New crust is formed at mid-ocean ridges spreading the sea floor

Mid-Atlantic Ridge

Convection Currents in the Mantle Causes Sea Floor Spreading The main cause of plate tectonics Convection Currents Hot magma rises and cooler magma sinks in the Earth’s Mantel

Tectonic Plate Boundaries

Convergent Boundaries Tectonic plates collide - Forms trenches, mountains, and subduction zones CTMS – Convergent – trenches – mountains - subduction

Convergent Boundaries Subduction Zones Creates trenches in the ocean and mountains and volcanoes on land

Divergent Boundaries Tectonic plates move apart Forms Mid Ocean Ridges in oceans and Rift Valleys on land East African Rift Mid-Atlantic Ridge

Mid-Ocean Ridges Chain of volcanoes at the middle of the ocean floor. Causes Sea Floor Spreading Magma comes up from inside the Earth, cools and hardens and creates new sea floor. The rock at the mid-ocean ridge is the youngest and gets older as it moves farther away from the ridges.

Mid-Atlantic Ridge

Transform Boundaries Tectonic plates slide past each Forms Fault lines San Andreas Fault in California

Volcanoes and Earthquakes Most Occur at Tectonic Plate Boundaries

Ring Of Fire

Ring of Fire Volcanoes around the Pacific Ocean caused by tectonic plates colliding into each other creating subduction zones at CONVERGENT boundaries.

Hot Spots Areas in the middle of tectonic plates where magma inside the Earth rises through the crust and forms volcanoes. Like the Hawaiian Islands

Hawaii Islands

Super Volcano Yellowstone National park Underground volcano caused by another Hot Spot 3 overlapping calderas underground is believed to have formed from a hot spot creating Yellowstone’s “Super Volcano”

Yellowstone