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 Earths 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 its 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
CONVECTION CURRENTS IN THE MANTLE!!! What are these convection
currents causing at the surface? 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. The Rock Cycle:
Igneous, Sedimentary and Metamorphic 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. Metamorphic
Rocks The Rock Cycle Plate Tectonics 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 Collide!!
Depart from each other
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) Himalaya Mountain Range Convergent
Plates: Continental--Oceanic
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:
Oceanic--Oceanic
Subduction Uplift (Islands form in a volcanic arc) Trench forms at
boundary 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! Californias San Andreas Fault
Transform Plates Where will Los Angeles be in the future? Not at
plate boundaries:
HOT SPOTS:Area of the earth where a plate moves over a magma
chamber/hot spot Hawaii: Yellowstone National Park Review Layers of
the Earth Types of Rock and the Rock Cycle
Plate Tectonic Boundaries: Convergent Divergent Transform