Chapter 1 SAMPLE_Monroe

8/4/2019 Chapter 1 SAMPLE_Monroe

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PowerLecturePowerLectureA Microsoft PowerPoint Link Tool

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academic.cengage.com/earthsci

Changing EarthChanging EarthExploring Geology

and EvolutionExploring Geologyand Evolution

55thth EditionEdition

James S. MonroeJames S. Monroe || Reed WicanderReed Wicander


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Chapter 1

UnderstandingEarth

A Dynamic andEvolving Planet


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Introduction

Geology

Geology is a complex, integratedsystem of related

parts, components, or sub-systems that interactin an organized fashion, affecting one another in

various ways.


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Introduction

The principal subsystemsof theearth are the:

Atmosphere

BiosphereHydrosphere

Lithosphere

Mantle

Core


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The interaction of these subsystems has resulted in a

dynamically changing planet in which matter andenergy are continuously recycled into different forms.

Introduction


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Geology is the study of the Earth.

Physical geology is concerned with the

materials and processes which compose andoperate on the surface of, and within, Earth.

Historical geology is concerned with the

origin andevolution of Earth's continents,oceans, atmosphere, and life.

What is geology?


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What is geology?

Geologists areemployed indiverse occupations.

Principle occupationsinclude:

Mineral and

energy resource

exploration

Solvingenvironmental

problems

Predicting

natural disasters


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Geology and theFormulation of Theories

What is a theory?

It is arrived at through thescientific method, which

involvesgathering and analyzing facts

formulating hypotheses to explain the phenomenon

testing the hypotheses

and finally proposing a theory.

Thehypotheses is a tentative explanation.

Ascientific theory is a testable explanation for some

natural phenomenon, that is supported by a large body

ofevidence.


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How Does Geology Relateto theHuman Experience?

Geology pervades oureveryday lives

and is a part of many aspects of

human experience, including the artsand literature.

The range ofenvironmental problems

and issues of concern to society

require a basic understanding ofgeology.


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How does geology affectour daily lives?

Natural Events

Economics andPoliticsOur Role as Decision

makers

Consumers andCitizens

Sustainable Development


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Global Geologic and EnvironmentalIssues Facing Humankind

Most scientists would argue

that overpopulation is thegreatest problem facing the

world today.

Increasingly large numbers of

people must be fed, housed,

and clothed, with a minimal

impact on theenvironment.


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Global Geologic and EnvironmentalIssues Facing Humankind

The greenhouseeffect is the retention of heat in the

atmosphere, which results in an increase in thetemperature of Earths surface and atmosphere, thus

producing global warming.


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Origin ofthe Universe

Did it begin with a Big Bang?

In theBig Bang theory, the

universe began approximately15 billion years ago.

An extremely dense, hot body

of matterexpanded and

cooled


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Origin ofthe Universe

How do we know? Evidence for theBig Bang:

the universe is expanding

from a central point.Theentire universe has a

pervasive and constant

background radiation,

thought to be the faintafterglow of theBig Bang.


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Our Solar System

Its Origin and Evolution

The Solar System formed from a rotating cloud ofinterstellar matter about 4.6 billion years ago.

This cloud, upon condensing, collapsed under theinfluence of gravity and flattened into a rotating disk.

The sun, planets, and moons formed within this disk.


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Earth

Its Place in Our Solar System

Earth formed from a swirling eddy of nebular

material 4.6 billion years ago, accreting as a solid

body and soon thereafterdifferentiated into a

layered planet during a period of internal heating.


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Why Earth is a Dynamic

and Evolving Planet

Earthhas continuously changed during its 4.6

billion year existenceas aresultof

interactions between its various subsystems

and cycles.


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Earth is composed of 3 concentric layers.

Core

Mantle

Crust.

Why Earth is a Dynamicand Evolving Planet


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The core consists of

a small, solid innerregion

a larger,liquid, outerportion

Composed ofiron and a small amount ofnickel.

TheCore



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The mantle surrounds the core and

is divided into: a solid lower mantle

an asthenosphere that behavesplastically and flows slowly

a solid upper mantle.

Composed primarily ofperidotite, an igneous rockmade of olivine.

TheMantle


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The outermost layer, the crust,

is divided into:

thick continental crust

thin oceanic crust

TheCrust


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TheAsthenosphere

Surrounds the lower mantle

Behaves plastically and slowlyflows

Partial melting in the

asthenospheregenerates magma

(molten rock) that rises to theearths surface.


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TheLithosphere

The crust and upper mantle make

up the lithosphere which forms thesolid outer layers of the Earth.


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PlateTectonic Theory

The lithosphere is composed of rigid plates that

diverge, converge, or slide sideways past oneanother as they move over the asthenosphere


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Volcanoes andearthquakes occur at the

boundaries between the plates.


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Plate tectonic theory isa unifying explanation

for many geologicfeatures andevents,helping us understandthe composition andinternal processes of

Earth on a global scale.


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The Rock Cycle

Arock is a solid aggregate of one or more minerals, as

well as non-crystalline matter such as natural glass ororganic material like coal.

There are three major groups of rocks

Igneous

Sedimentary

Metamorphic


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The Rock CycleIgneous Rocks form from the crystallization

of magma as it cools or the consolidation ofvolcanic ejecta.

Intrusive igneous rock

crystallizes beneath theearths surface.

Extrusive igneous rock

crystallizes and cools at the

earths surface. At times it

cools so fast that it forms a

glass or ash.

GraniteGranite

Intrusive Igneous RockIntrusive Igneous Rock

BasaltBasalt

Extrusive Igneous RockExtrusive Igneous Rock


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The Rock Cycle

Sedimentary Rocks are typically depositedin layers formed from:

rock/mineral fragments

precipitation of minerals from solution

the compaction of plant and animal remains.

LimestoneLimestone

Precipitation from seawaterPrecipitation from seawater

ConglomerateConglomerate

Forms from river gravelsForms from river gravels


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The Rock Cycle

Metamorphic Rocks form from alteration of

other rocks, usually by:

Heat

PressureChemically active fluids

QuartziteQuartziteGneissGneiss


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The Rock Cycle

The rock cycle illustrates the interactions between

Earths internal andexternal processes and how thethree rock groups are interrelated.


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The Rock Cycle

How are the rock cycle and plate tectonics

related?

Plate movement is the

driving mechanism of therock cycle. Plate inter-

action determines, to

someextent, which of the

three rock groups will form.


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Organic Evolution andtheHistory of Life

The theory oforganic evolution states:

that all living things are related and

havedescended with modification from organismsliving in the past.

Charles Darwin proposed that the mechanism of

natural selection results in survival reproductive age

of those organisms best suited to theirenvironment.

Fossils, the remains of once-living organisms provide

theevidence forevolution and a history of life before

humans.


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Organic Evolution

and Plate Tectonics

Together the theories of platetectonics and organic evolution

have changed the way we view

our planet.


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Geologic Time

An appreciation of the immensity of geologic time is

central to understanding theevolution of the Earthand its life.

Geologic timediffers from the humanperspective of time

Earth goes through cycles of muchlongerduration than the humanperspective of time

The immense span of timeencompassed by the Earth's

existence and geological processessets geology apart

Thegeologic time scale is thecalendar that geologists use to datepast events in Earths history.

G l i Ti d


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Geologic TimeandUniformitarianism

Uniformitarianism forms a cornerstone of geology. It is

a fundamental tenet of geology.

This principle states that the laws of nature have

remained unchanged through time and thus, thatthe processes observed today have also operated in

the past, though possibly at different rates.

Therefore, to understand and interpret geologic

events from evidence preserved in rocks,geologists

must first understand present-day processes in

rocks.


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How does the study of geology

benefitus?

Understanding how the Earths subsystems

work will help ensure the survival of thehuman species.

It will help us to understand how our

actions affect thedelicate balance betweenthese systems.


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