Introduction to Earth Science

42:160

Dr. Simon A.J. PattisonDepartment of Geology

Topic 1A - Introduction

OutlineCourse Logistics

Course Objectives

What is Geology?

Geology: Practical Applications

Being a Geologist

Physical vs. Historical Geology

Course LogisticsCourse Outline/Lab Schedule

Instructor: Dr. Simon A.J. Pattison

Brodie Bldg 2-7

727-7468 (voice mail available)

Policy on Office Hours: Open Door (8:00 am to 5:00 pm, M to F)

 

 

Lecture notes available on the s:drive.

Students on ‘Weber/Vol15’ (S:)

Geology, Pattison, 160 Introduction to Earth Science

 

- files are read-only

- download notes and save as separate file names to your memory stick

- switch-out of read-only and reformat/revise/annotate

Excellent textbook Second hand copies should be available.Students are responsible for reading the assigned chapters Course structure closely follows the textbook structureHowever, lots of additional material will be presented in class, therefore, please attend Different textbook used for Historical Geology (42:161)Second term geology course (Slot 5), for those interestedAlso has a lab component (Wednesday Afternoon) Two other courses offered in 1st year geologyOur Dynamic Earth (42:162): Slot 5, Term 1, Theater BThis Old Earth: A Trip Through Time (42:163): Slot 5, Term 2, Theater BBoth of these courses do not have labsDesigned mostly for non-science students

Teacher Expectations:Hard Work Read Textbook Ask Questions- lots of terminology in geology- I may use terms in the lecture that you have not heard before- please stop me and ask me to define and clarify Turn Off Cell Phones/No TextingLap Tops: Lecture Notes Only No Talking- respect fellow students- hard to listen or concentrate with background talking- if you need to talk, please leave my class (door is unlocked)

Course Objectives(a) Provide an introduction to earth science, especially physical geology.

(b) Review and describe Earth materials: minerals and rocks.

- strong emphasis in the lab

(c) Understand the processes which make our Earth dynamic.

- earthquakes, volcanoes, weathering/transport (e.g. rivers, ocean waves)

(d) Learn the significance of plate tectonic theory to modern geology.

- unifying theory that explains many geological features (e.g. mountains)

- theory developed in the 1960’s

(e) Emphasize examples and practical applications where appropriate.

- geology is very applied and practical

What is Geology? Geology is defined as the study of the Earth. Geology:geo- (Greek roots, meaning “of the Earth”)

-logia or -logos (Greek roots, meaning study or science) Scientists who study the Earth are called geologists. Some questions that geologists could ask:

What causes earthquakes? Why do earthquakes occur in some regions and not in others? Similar questions for volcanoes.

What processes lead to mountain building? What rate?What controls mountain growth? Why are mountains present on the West Coast of Canada and not in Central Canada?

Does sea level rise and fall? What controls sea level change?

Earth is always changing.Small/slow vs. large/rapid changes.

 Small slow changes.

e.g. mountain building, cm per 100 years.Continuous.Gradualism.

e.g. Rocky Mountains (slow upward movement). 

vs. 

Rapid changes.e.g. hurricane ripping up a beach/coastline.

e.g. volcanic eruption.Catastrophic.

Geology is a unique science because the geological laboratory is the world in which we live.Very difficult for geologists to carry out controlled experiments.Problems with space and time. Geologists must study the Earth as it exists today.From their assembled observations they can draw conclusions about the processes that are shaping the Earth today and events that have shaped the Earth over the past 4.5 billion years.Increasingly geologists are called upon to use their understanding of the Earth machine to make predictions on future change.e.g. global warming. “Present is the key to the past”.Fundamental principle in geology.

Grand Canyon - Arizona

Six key aspects to the science of geology:

A. Solid Earth/Earth Materials

B. History of Life

C. History of the Earth

D. Study of Earth Resources

E. Earth Hazards (egs. earthquakes, volcanoes,

landslides, subsidence, coastal erosion)

F. Solid Bodies in the Solar System

Geology: Practical Applications Geologists work in every corner of the Earth. Government, academia and industry. e.g. hydro-geologist: ground water movement, environmental impact assessment (EIA), pollutants (location, mobility, mitigation).e.g. predict location of new oil fields.e.g. predict best location for a water well.e.g. location of rich ore deposits.  Geology discipline is very broad. Many specialties. Also geologists are interdisciplinary in nature. i.e. work with many other disciplines. Interaction with physics, chemistry, biology and engineering.e.g. petroleum geologist (oil and gas).e.g. paleontologist (fossils).e.g. hydro-geologist- geology, chemistry, 3D modelling(simulation). “Earth scientist”: e.g. shark’s tooth discovered in the desert of Utah?How did it get there? How old? What does this imply for environmental change?Rate? Magnitude of change?

BU Geologists:85 % of our graduates from the 4-year Honours program continue in a geology-related career.Get any geological-related experience possible.Co-op work experience program in conjunction with BU alumni, petroleum and mining industries and appropriate government departments.Students gain project-oriented employment skills.Ensures a steady stream of graduates with both industry and applied research experience. Practical training. Graduates have travelled and worked in Africa, Middle East, SE Asia, Chile, Holland, Scotland, USA and throughout Canada.Petroleum industry.Mineral exploration and mining industry.Environmental careers (government, industry, academia).Graduate school (M.Sc. and Ph.D.).

Majors in GeologyWhat do they do? Where do they go? PetroleumMiningEnvironmentalGovernmentAcademia/Education With the appropriate geology degree and additional work experience, one can obtain designation as a professional geoscientist (P. Geo.) in Manitoba.  Minors in GeologyWhat do they do? Where do they go? Business (resources)Education (teaching)Other Sciences (biology, chemistry, physics, engineering, geography)Environmental

Being a Geologist:

Outside!

Where do we start?

Field work…

Equipment…

Transport…

Camp…

Tourist field work…

Field work in remote area

Nice things about field work…

Nice things about field work…

Surprises…

Earth Scientists...

• Exploration Geologist• Mapping Geologist• Geological surveys

– Provincial / Territorial– Federal (GSC)

• Mining Geologist• Petroleum Geologist• Hydrogeologist• Environmental Geologist• Geological Engineer

Example of an Earth Scientist: Hydrogeologist

Environmental Geologist

• Degree needed: – B.Sc., +/- M.Sc., +/- Ph.D.– Geology, Hydrology, Hydrogeology, Chemistry, Math,

Sedimentology, Computer Modelling...

• Type of work:– 9:00 am – 5:00 pm– Office work / computer / field work...

• Salary (see handout).

Let’s find water...

Let’s pump it...

Dug well

Contaminant Propagation

Contaminant monitoring...trench

Remediation and/or Risk Assessment

• Remediation – removal

• Risk assesment– Contaminant– Pathway– Receptors

Physical vs. Historical Geology Geology has traditionally been divided into two broad topic areas: physical geology, and historical geology. physical geology – concerned with understanding the processes that operate at or beneath the surface of the Earth and the materials on which these processes operate. Physical geology is the main focus of this course (42:160).Also the main focus of Our Dynamic Earth (42:162): Slot 5, no labs! Questions to ponder: What causes a volcano to erupt? How can we predict earthquake activity? How do we minimize the risk of loss of life and property damage from floods and landslides? Problems in geology: time and scale.Dealing with complexity of natural systems.

historical geology – concerned with the chronology of physical and biological events that occurred in the past. Recommend the following course for those of you that are interested:Historical Geology (42:161): Slot 5, Wed labs, next term.This Old Earth: A Trip Through Time (42:163): Slot 5, no labs, next term. Questions to ponder:When were the oceans formed? When did oxygen first occur in the atmosphere? How did plants evolve? Why did dinosaurs become extinct? What was the Earth’s climate in the geological past: Hotter? Colder? Very practical reason for studying the Earth.Understand the environment in which we live and make predictions about changes that might occur in the future.In order to fully understand how we humans may be affecting the Earth, we need to examine both the Earth’s materials and processes.

Topic 1B - IntroductionOutline

Origin: Universe and Solar SystemEarth a Dynamic Planet

ConvectionPlate Tectonics

Plate BoundariesRock TypesRock Cycle

Plate Tectonics and Rock CycleGeologic Time

Principle of Uniformitarianism

Origin of the Universe and Solar System

• Universe formation (BIG BANG)

– 13.7 billion years ago

• Solar system formation– 4.6 billion years ago

Nebula

RotationContraction

Sun (fusion - core)

Planets(dust...)

Our solar system…

Earth formation… 4.6 billion years ago

The CoreSolid inner. Liquid outer. Density of 9-13 g/cm³.

The MantleSurrounds the core. Density of 3.3-5.7g/cm³. Three distinct zones.

The CrustOceanic - 3 g/cm³. Continental - 2.7 g/cm³.

Plate Tectonic Theory explains the interactions of these zones. Earth’s internal heat causes volcanoes and earthquakes, and mountains to rise and continents to move.

Geothermal gradient: Rate of temperature increase with depth. Varies from 15-75 °C/km. Average: 25 °C/km.

Earth a Dynamic Planet

Convection

Process by which hot, less-dense materials rise upward and are replaced by cold, downward and sideways flowing material.

Operates in the Earth’s interior. Moves tectonic plates.

Plate Tectonics

Has provided a framework for interpreting the composition, structure and internal processes of the Earth on a global scale.

Plate tectonic theory is a unifying theory that explains the following earth patterns:

A. Occurrence and distribution of earthquakes and volcanoes (i.e. mostly in linear zones).

B. Volcanoes and earthquakes occur together.

C. Large earthquakes occur in zones where there are long narrow deep sea trenches.

D. Why the ocean contains deep trenches and high ridges.

E. Jigsaw fit of the continents.

F. Why mountain building occurs.

G. Distribution of ore and petroleum deposits.

Theory of plate tectonics:

Outer surface of the Earth is relatively cool and rigid: LITHOSPHERE. Middle part of Earth is hotter and somewhat viscous: ASTHESNOSPHERE. Lithosphere floats on the asthenosphere: ISOSTASY.

The lithosphere is divided up into a number of PLATES.

CONVECTION occurs in the asthenosphere, and this is one of the main reasons the plates move.

Deformation, volcanoes, and earthquakes mostly occur at the edges of the plates, not in their interiors. Therefore most of the geological action occurs at the PLATE BOUNDARIES.

Plate Tectonics is a global model for the Earth as a DYNAMIC SYSTEM.

Convection and Tectonics

Plate Boundaries:3 types:

• Divergent• Convergent• Transform

Divergent Plate Boundary

• Plates move apart.• Magma rises to the surface.• New oceanic crust is generated.

Convergent Plate Boundary

• Plates move together and collide.• One plate sinks beneath the other plate… subduction zone.• Associated with major mountain belts.

Transform Plate Boundary

• Plates slide sideways past one another.• e.g. San Andreas fault in California.

Rock Types

There are THREE different types of rocks:

IgneousMetamorphicSedimentary

Each group contains a variety of individual rock types that differ from one another on the basis of composition (mineralogy/chemistry) or

texture (size, shape and arrangement of mineral grains)

Igneous RockGranite

Igneous RockBasalt

Sedimentary RockConglomerate

Sedimentary RockLimestone

Metamorphic RockGneiss

Metamorphic RockQuartzite

Rock CycleRelates the 3 rock groups to one another.

Igneous: from melted rock material (lava or magma solidifies).

Sedimentary: broken up rock material (weathered) or chemical/biochemical precipitation (evaporites – salts, carbonate particles – reefs).

Metamorphic: new rocks formed from old rocks as a result of pressure and temperature (no melting).

 

Interrelationships between the Earth’s internal and external processes.

Surface processes: weathering, transportation and deposition.

Internal processes: magma generation and metamorphism.

Plate Tectonics and the Rock Cycle

Plate movements drives the rock cycle.

Recycling rock materials (subduction).

 

Plate interactions determine to some degree which rock type will form.

e.g. igneous and metamorphic rocks are generated along convergent margins due to the melting of previously deposited sedimentary rocks or igneous rocks (oceanic crust).

Sedimentary rocks are buckled and thrusted upwards to form mountain chains.

Eventually these mountains are eroded and the sediments are transported back into the ocean basin to renew the cycle.

Geologic Time

Not in years, months, days, minutes, seconds…

But in hundreds of thousands, millions, and billions years!

• First fossils (algae)– 3.5 billion years agoFirst fossils (animals-invertebrates)- 545 million years ago

Earth

algae• Age of the Earth– 4.55 billion years ago (4,550,000,000 yrs)

• Dinosaurs extinction– 65 million years ago

• Abundant reptiles– 230 million years ago

• Earliest hominids– 3 million years ago

Geologic Time

Principle of Uniformitarianism

• Laws of nature have been constant through time.

• Present day processes have operated throughout Earth’s history.

• Therefore we can better understand past events by studying modern processes.

• “The present is the key to the past.”