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Geology of Earth. Plate Tectonics. Layers of the Earth. The Earth's interior is composed of three primary layers: Core Mantle Crust. The Core. The Earth ’ s core is made of mainly iron and nickel These heavy elements were pulled by gravity to the center of the Earth 2 layers:
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Geology of Earth Plate Tectonics
Layers of the Earth The Earth's interior is composed of three primary layers: Core Mantle Crust
The Core The Earth’s core is made of mainly iron and nickel These heavy elements were pulled by gravity to the center of the Earth 2 layers: Inner core is solid metal Outer core is liquid metal Extremely high temperature and pressure
Mantle: River of Rock Hot, soft rock. Like Silly Putty!! So hot it’s soft, but not liquid Hot rock rises up from the depths and cooler rock descends This creates very slow-moving, circular currents called CONVECTION CURRENTS
The Crust Outermost layer of the Earth. Where we live! Rocks, soil, and seabed. 5 miles thick beneath the oceans 25 miles thick beneath the continents.
Igneous Rocks Extremely common in the Earth's crust, igneous rocks are volcanic and form from cooled, hardened magma or lava.
Sedimentary Rocks “Sediments” are formed by erosion of larger rocks. They are laid down in layers over time. These small particles undergo compaction to form rock Fossils are most frequently found in sedimentary rock, which appears in layers, called strata.
Metamorphic Rocks Metamorphic rocks were sedimentary or igneous rocks that have been transformed by heat and pressure. The heat may come from nearby magma or hot, ion-rich water intruding into existing rock. It can also come from subduction, when tectonic forces draw rocks deep beneath the Earth's surface. High pressure causes rock deformation during mountain building when continental plates collide.
Plates The plates make up Earth's outer shell Churning convection currents in the soft mantle below propel them along like a conveyor belt. The movement of the plates creates three types of tectonic boundaries.
Types of Boundaries Plates move from a fraction of an inch to about 5 inches a year. A plate moving at 2 inches a year will travel about 30 miles in a million years. Convergent plates toward one another. Collide!! Divergent plates move apart. Depart from each other Transform plates move sideways in relation to each other. Sliding!!
Convergent Plates 3 Types of Convergent Plates: Continental-Continental Oceanic-Continental Oceanic-Oceanic
Convergent Plates:Continental--Continental Where continental plates collide, the crust crumples and buckles into mountain ranges (Himalayas)
Ocean plate dives under the continental plate in a process called subduction. Overlying plate lifts up to form mountain ranges. The subducting plate melts creating active volcanoes. A deep trench runs right along the boundary Convergent Plates:Continental--Oceanic
Subduction Uplift (Islands form in a volcanic arc) Trench forms at boundary Convergent Plates:Oceanic--Oceanic
Divergent Plates Divergent boundaries occur when plates move away from each other (Depart!) “Seafloor spreading” in the oceans creates new rock: Under water mountain ranges form as magma rises when a crack forms Rift Valleys are formed with oceanic ridges on either side. On land, giant troughs may form where plates are tugged apart.
A cloud of hydrothermal fluids streams from a black smoker, or mineral chimney, along the Mid-Ocean Ridge off the west coast of Mexico. Black smokers are common to spreading zones in plate boundaries
Transform Boundary Plates slide past each other. Pressure builds up and is released when the plates move. This causes a lot of shallow earthquakes! California’s San Andreas Fault
Not at plate boundaries: HOT SPOTS: Area of the earth where a plate moves over a magma chamber/hot spot Hawaii:
Review • Layers of the Earth • Types of Rock and the Rock Cycle • Plate Tectonic Boundaries: • Convergent • Divergent • Transform
