Plate Tectonics1 The Earths’ Interior

Plate Tectonics2 Earth Facts

Plate Tectonics3 Happy the man whose lot it is to know the secrets of the earth. He hastens not to work his fellows' hurt by unjust deeds, but with rapt admiration contemplate immortal Nature's ageless harmony, and how and when her order came to be. Such spirits have no place for thoughts of shame. - Euripides ( B.C.) Don’t copy this slide

Plate Tectonics4 Inside the Earth

Plate Tectonics5 Crust The exterior portion of the earth Lies above the Moho discontinuity

Plate Tectonics6 Crust 3 types of solid rock – igneous, sedimentary, & metamorphic Oxygen & silicon Oceanic crust 8 km thick: basalt Continental crust 32km thick: granite & basalt

Plate Tectonics7 Elements in the Crust Oxygen 46.6% Silicon 27.72% Aluminum 8.13% Iron 5.00% Calcium 3.63% Sodium 2.83% Potassium 2.59% Magnesium 2.09% Titanium 0.40% Hydrogen 0.14% Don’t Copy

Plate Tectonics8 Mantle Layer between the crust and the core Silicon, oxygen, iron & magnesium 870°-2200°c 2900 km thick

Plate Tectonics9 Lithosphere Thin outer shell of the earth Consisting of the crust and the rigid upper mantle

Plate Tectonics10 Lithosphere Rigid layer Broken up into 7 major lithospheric plates

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Plate Tectonics12 Asthenosphere Zone of the mantle beneath the lithosphere Consists of slowly flowing solid rock Plasticity: when solid rock flows

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Plate Tectonics14 Moho The Mohorovicic discontinuity Croatian scientist found increased speed of seismic waves Boundary between the mantle and the earth’s crust Reveals increase in density

Plate Tectonics15 Seismic Waves

Plate Tectonics16 Shadow Zones Location on the earth’s surface where no seismic waves or only P waves can be detected.

Plate Tectonics17 Core Central portion of earth Below the mantle Depth of about 2,900 kilometers (1,800 miles) Consisting of iron and nickel Liquid outer core and a solid inner core

Plate Tectonics18 Magnetosphere

Plate Tectonics19 Magnetosphere Region of space that is affected by the Earth’s magnetic field

Plate Tectonics20 The Dynamic Earth Plate Tectonics

Plate Tectonics21 Theory of Continental Drift 1900’s Alfred Wegener proposed that the earth used to be one giant landmass that split to form today’s continents

Plate Tectonics22 Continental Drift Pangaea –“all lands” –a single landmass –origin of all the continents Panthalassa –“all seas” –giant ocean that must have surrounded Pangaea.

Plate Tectonics23 Wegener's Evidence for Continental Drift The shape of continents suggests they once fit together –Noticed first in 1858 as soon as good maps were being made

Plate Tectonics24 Wegener's Evidence for Continental Drift Fossils – The glossopterus flora and fauna are now found in widely separated continents in the southern Hemisphere.

Plate Tectonics25 Fossil Evidence Fossils support Wegener’s theory Glossopteris Mesosaurus Lystrosaurus Cynognathus

Plate Tectonics26 Wegener's Evidence for Continental Drift Paleoclimate evidence Distribution of Paleozoic –Coral reefs –Coal beds –Deserts million years ago

Plate Tectonics27 Wegener's Evidence for Continental Drift Rock types and mountain ranges can be traced across now widely separated continents.

Plate Tectonics28 Rock Evidence Glacial deposits Folded mountains Coal deposits

Plate Tectonics29 Wegener's Evidence for Continental Drift Evidence of ancient glaciers in all of the southern continents Do you think all of this satisfied the critics?

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Plate Tectonics31 Where is the Force? What makes the plates move? The answer is on the ocean floor

Plate Tectonics32 Mid-ocean Ridge System of undersea mountain ranges Wind around the earth 65,000 km Ocean rocks much younger than continental rocks

Plate Tectonics33 Mid-Atlantic Ridge Undersea mountain range Steep, narrow valley down the center

Plate Tectonics34 Seafloor Spreading Movement of the ocean floor away from either side of a mid-ocean ridge Caused by convection currents

Plate Tectonics35 Seafloor Spreading

Plate Tectonics36 Convection Cells

Plate Tectonics37 Uneven heating causes movement in fluids

Plate Tectonics38 Paleomagnetism of the Ocean Floor Magnetic fossil record of the alternating magnetic field of the ocean floor.

Plate Tectonics39 Plate Tectonics Theory that the lithosphere is made up of plates that float on the asthenosphere Plates possibly moved by convection currents

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Plate Tectonics42 Types of Crust Oceanic crust –Material that makes up the ocean floor Continental crust –Material that makes up landmasses

Plate Tectonics43 Divergent Boundary Formed by two lithospheric plates that are moving apart

Plate Tectonics44 Rift Valley Steep, narrow valley Formed as lithospheric plates separate

Plate Tectonics45 Convergent Boundary Border formed by the collision of two lithospheric plates

Plate Tectonics46 Continental vs. Continental

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Plate Tectonics50 Oceanic vs Continental

Plate Tectonics51 Subduction Zone Region where one lithospheric plate moves under another.

Plate Tectonics52 Ocean Trench Formed when one oceanic crust is subducted under another oceanic crust

Plate Tectonics53 Oceanic vs Oceanic

Plate Tectonics54 Island arc Chain of volcanic islands Formed by subduction at ocean trenches

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Plate Tectonics56 Transform Fault Boundary Formed by two lithospheric plates that slide past each other

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Plate Tectonics58 Theory of Suspect Terrains – theory that continents are a patchwork of pieces of land that have individual geologic histories

Plate Tectonics59 The earth was made so various, that the mind of solitary man, studious of change and pleased with novelty, might be indulged. - Cowper, English poet

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Plate Tectonics61 Crust Asthenosphere –Lithosphere

Plate Tectonics62 Continental Drift Hypothesis stating that the continents once formed a single landmass Broke up and drifted to their present location

Plate Tectonics63 The Earths’ Interior