Unit 1 Geology Notes Name_. Overview of Earth Science 1.1 What Is Earth Science? Encompasses all sciences that seek to understand ____

Unit 1 Geology Notes

Name_______________

Overview of Earth Science

1.1 What Is Earth Science?

Encompasses all sciences that seek to understand

• __________________

• Earth's neighbors in ____________________

Overview of Earth Science

Earth science includes

4. astronomy, the study of the ___________________

3. _________________________, the study of the atmosphere and the processes that produce weather

1. geology, the study of _____________

2. oceanography, the study of the _______________

1.1 What Is Earth Science?

Earth's Major Spheres

1.2 A View of Earth

1. __________________• _________ is the most prominent feature of the hydrosphere.

- Is nearly ____ __of Earth's surface

- Holds about 97% of Earth's water

• Also includes _______ ___________found in streams, lakes, and glaciers, as well as that found underground


1.2 A View of Earth

2. Atmosphere • Thin, tenuous blanket of _____________

• One half lies below 5.6 kilometers (3.5 miles)

3. Biosphere • Includes all ____________

• Concentrated near the surface in a zone that extends from the ocean floor upward for several kilometers into the atmosphere


1.2 A View of Earth

4. __________________ • Consists of the crust, mantle, and core.

- Crust—the thin, rocky ___________ layer of Earth.

- Mantle—the 2890-kilometer-thick layer of Earth located __________ _______ _______________.

- Core—the ____________________ layer of Earth, located beneath the mantle.

Earth’s Layered Structure

Determining Location

1.3 Representing Earth’s Surface

Latitude and longitude are lines on the globe that are used to determine location.• Latitude is distance ____________ or ________________of

the equator, measured in degrees.

• Longitude is distance ____________ or ______________of the _____________ ________________, measured in degrees.

Satellites and Information Technology

• Key idea: Today’s technology gives us the ability to more precisely analyze Earth’s physical properties

• Remote sensing: collecting data about the Earth from a _________. – Weather—watch temp of air and sea, clouds, storms– Navigation—assist ships and subs exact location– Landsat—photos of land and seacoasts– VLBI—used to measure the earth

• GPS: find precise _________________ on earth used by:– Military– Geologists– Farmers– Drivers– Sports enthusiasts

What Is a System?

1.4 Earth System Science

Closed systems are self contained (e.g., an automobile cooling system).

_________________ systems allow both energy and matter to flow in and out of the system (e.g., a river system).

A _______________ is any size group of interacting parts that form a complex whole.

Earth as a System


Earth is a dynamic body with many separate but highly ____________ parts or spheres.

Earth system science studies Earth as a system that is composed of numerous parts, or ________________.

Earth as a System


Sources of Energy• ________—drives external processes such as weather,

ocean circulation and erosional processes

• Earth’s _____________—drives internal processes including volcanoes, earthquakes and mountain building

Earth as a System


_______________ are part of the Earth system.

Consists of a nearly endless array of subsystems (e.g., hydrologic cycle)

The carbon cycle

Rocks

3.1 The Rock Cycle

Rocks are any solid mass of mineral or mineral-like matter occurring naturally as part of our planet.

Types of Rocks 1. ________________ rock is formed by the crystallization of

molten magma.

Rocks

3.1 The Rock Cycle

Types of Rocks2. _____________________ rock is formed from the weathered

products of preexisting rocks that have been transported, deposited, compacted, and cemented.

3. _____________________ rock is formed by the alteration of pre-existing rock deep within Earth (but still in the solid state) by heat, pressure, and/or chemically active fluids.

The Rock Cycle

3.1 The Rock Cycle

Shows the _____________________ among

the three rock types (igneous, sedimentary, and metamorphic)

____________ is molten material that forms deep beneath the Earth’s surface.

________ is magma that reaches the surface. ___________ is a process in which rocks are broken down by water, air, and living things.

____________ is weathered pieces of Earth elements.

The Rock Cycle

Energy That Drives the Rock Cycle

3.1 The Rock Cycle

Processes driven by heat from the Earth’s ___________ are responsible for forming both ___________ and _____________ rock.

External processes produce sedimentary rocks.

________________ and the movement of weathered materials are external processes powered by energy from the ___________.

Formation of Igneous Rocks

3.2 Igneous Rocks

1. ____________ igneous rocks are formed when magma hardens beneath Earth’s surface.

2. _____________ igneous rocks are formed when lava hardens.

Classification of Igneous Rocks

3.2 Igneous Rocks

1. Texture

Igneous rocks can be classified based on their composition and texture.

• ________________-grained texture is caused by ________ cooling resulting in ____________ crystals.

• Fine-grained texture is caused by rapid cooling resulting in smaller, interconnected mineral grains.

Course-Grained Igneous Texture

Fine-Grained Igneous Texture


3.2 Igneous Rocks

1. Texture (continued)• ______________ texture is caused by very rapid cooling.

• Porphyritic texture is caused by different rates of cooling resulting in varied sized minerals.

2. Composition• Granitic composition rocks are made mostly

of light-colored quartz and feldspar.

Obsidian Exhibits a Glassy Texture.

Porphyritic Igneous Texture


3.2 Igneous Rocks

2. Composition (continued)• Basaltic composition rocks are made mostly of dark-colored

silicate minerals and plagioclase feldspar.

• Andesitic composition rocks are between granitic light-color minerals and basaltic composition dark-colored minerals.

• Ultramafic composition rocks are made mostly from iron and magnesium-rich minerals.

Basalt


Formation of Sedimentary Rocks

3.3 Sedimentary Rocks

• _______________ involves the weathering and the removal of rock.

• ___________________ occurs when an agent of erosion—water, wind, ice, or gravity—loses energy and drops sediments.

Weathering, Erosion, and Deposition

Formation of Sedimentary Rocks


• ______________________ is a process that squeezes, or compacts, sediments.

• _____________________ takes place when dissolved minerals are deposited in the tiny spaces among the sediments.

Compaction and Cementation

Classification of Sedimentary Rocks


1. Clastic_____________________of weathered bits of __________ and minerals.

• Classified by particle size

Two Main Groups

- Shale (most abundant)

• Common rocks include

- Conglomerate

- Sandstone

Shale with Plant Fossils

Conglomerate



Two Main Groups2. ________________ sedimentary rocks form when dissolved

substances precipitate, or separate, from water.

• Common rocks include

-______________—most abundant chemical rock

- microcrystalline quartz known as chert, flint, jasper, or agate

- evaporites such as rock salt or gypsum - coal

Fossiliferous Limestone


Features of Some Sedimentary Rocks


Features of sedimentary rocks are clues to how and where the rocks are formed

Formation of Metamorphic Rocks

3.4 Metamorphic Rocks

Metamorphism means “___ _________ _______________

Conditions for formation are found a few _____________ below the Earth’s surface and extend into the _________ ___________

Most metamorphic changes occur at elevated ____________ and _________



________________ metamorphism occurs when magma moves into rock.

• Changes are driven by a rise in temperature.

• Occurs near a body of _______________



Regional metamorphism results in large-scale deformation and high-grade metamorphism. • Directed pressures and high temperatures occur during

______________________ _____________________.

• Produces the __________________metamorphic rock

Agents of Metamorphism


____________

_____________

• Provides the energy needed to drive chemical reactions

• Causes a more compact rock with greater density

Origin of Pressure in Metamorphism

Agents of Metamorphism


• Hot water-based solutions escaping from the mass of magma

• Promote recrystallization by dissolving original minerals and then depositing new ones

Hydrothermal Solutions

Classification of Metamorphic Rocks


1. ___________________ Metamorphic Rock

2. ______________ Metamorphic Rock

Two main categories

• Has a banded or layered appearance

• Does not have a banded texture

Classification of Metamorphic Rocks

Gneiss Typically Displays a Banded Appearance

Marble—A Nonfoliated Metamorphic Rock

An Idea Before Its Time

9.1 Continental Drift

Wegener’s ____________ ___________hypothesis stated that the continents had once been joined to form a single supercontinent.• Wegener proposed that the supercontinent, Pangaea, began to

break apart _______ __ __ __and form the present landmasses.

Breakup of Pangaea

An Idea Before Its Time


Evidence• The Continental ____________

• Matching Fossils

- Fossil evidence for continental drift includes several __________

organisms found on ______________ ____________________

Matching Mountain Ranges

Glacier Evidence

Rejecting the Hypothesis


A New Theory Emerges• Wegener could not provide an explanation of exactly ________

____________the continents move. News technology lead to findings which then lead to a new theory called plate tectonics.

Earth’s Major Roles

9.2 Plate Tectonics

According to the plate tectonics theory, the uppermost mantle, along with the overlying crust, behaves as a strong, ________ layer. This layer is known as the ________________________.

• A plate is one of numerous rigid ____________ of the lithosphere that move as a unit over the material of the asthenosphere.

Types of Plate Boundaries

9.2 Plate Tectonics

Divergent boundaries (also called ____________ ______________) are the place where two plates move apart.

Convergent boundaries form where two plates move ________________.

Transform fault boundaries are margins where two plates _________ _________ each other without the production or destruction of the lithosphere.

Three Types of Plate Boundaries

Divergent Boundaries

9.3 Actions at Plate Boundaries

Oceanic Ridges and Seafloor Spreading• Oceanic ridges are continuous elevated zones on the floor of all

major ocean basins. The __________ at the crest of ridges

represent divergent plate boundaries.

• ____________ _______________are deep faulted structures found along the axes of divergent plate boundaries. They can develop on the seafloor or on land.

• Seafloor spreading produces ________ oceanic _______________.

Spreading Center

Divergent Boundaries


Continental Rifts• When spreading centers develop within a continent, the landmass

may split into two or more smaller segments, forming a ________________.

East African Rift Valley

Convergent Boundaries


A _____________________ zone occurs when one oceanic plate is forced _______ into the mantle _________ a second plate.

• __________ oceanic slab sinks into the asthenosphere. Oceanic-Continental

• Pockets of magma develop and rise.

• Continental volcanic arcs form in part by volcanic activity caused by the ________________ of oceanic lithosphere beneath a continent.

• Examples include the Andes, ______________, and the Sierra Nevadas.

Oceanic-Continental Convergent Boundary



• Two oceanic slabs converge and one descends beneath the other.

Oceanic-Oceanic

• This kind of boundary often forms volcanoes on the ocean floor.

• _______________ ______________ _________form as volcanoes emerge from the sea.

• Examples include the Aleutian, Mariana, and Tonga islands.

Volcanic island arc—Aleutian islands

Oceanic-Oceanic Convergent Boundary



• When subducting plates contain continental material, two continents collide.

Continental-Continental

• This kind of boundary can produce new _____________ _______________, such as the ___________________.

Continental-Continental Convergent Boundary

Collision of India and Asia

Transform Fault Boundaries


At a _________________ fault boundary, plates grind past each other without destroying the lithosphere.

Transform faults • Most join two segments of a mid-ocean ridge.

• At the time of formation, they roughly parallel the direction of plate movement.

• They aid the movement of oceanic crustal material.

Transform Fault Boundary

Evidence for Plate Tectonics

9.4 Testing Plate Tectonics

Paleomagnetism is the ________ remnant __________ in rock bodies; this permanent magnetization acquired by rock can be used to determine the location of the magnetic poles at the time the rock became magnetized.• __________________ polarity—when rocks show the same

magnetism as the present magnetism field

• __________________ polarity—when rocks show the opposite magnetism as the present magnetism field

Paleomagnetism Preserved in Lava Flows



The discovery of strips of __________ ______________, which lie as mirror images across the ocean ridges, is among the strongest evidence of seafloor spreading.

Polarity of the Ocean Crust



Earthquake Patterns• Scientists found a close link between deep-focus

• ___________________ and ocean trenches.

• The _______________ of deep-focus earthquakes along the oceanic ridge system was shown to be consistent with the new theory.



Ocean Drilling• The data on the _____________ of seafloor sediment confirmed

• what the seafloor spreading hypothesis predicted.

• The youngest oceanic crust is at the ridge ___________, and the oldest oceanic crust is at the continental __________________.



Hot Spots• A hot spot is a concentration of heat in the mantle capable of

producing magma, which rises to Earth’s surface; The Pacific plate moves over a hot spot, producing the Hawaiian Islands.

• Hot spot __________ _______________that the plates move over the Earth’s surface.

Hot Spot

Causes of Plate Motion

9.5 Mechanisms of Plate Motion

Scientists generally agree that __________ occurring in the mantle is the basic driving force for plate movement.• Convective flow is the motion of matter resulting from changes

in temperature.



Slab-Pull and Ridge-Push

• Ridge-push causes oceanic lithosphere to slide down the sides of the oceanic ridge under the pull of gravity. It may contribute to plate motion.

• Slab-pull is a mechanism that contributes to plate motion in which cool, dense oceanic crust sinks into the mantle and “pulls” the trailing lithosphere along. It is thought to be the primary downward arm of convective flow in the mantle.



Mantle Convection

• The ______________________l distribution of heat within Earth causes the thermal ____________________ in the mantle that ultimately drives plate motion.

• Mantle plumes are masses of hotter-than-normal mantle material that ascend toward the surface, where they may lead to igneous activity.

Mantle Convection Models

Rocks Record Earth History

12.1 Discovering Earth’s History

Rocks record __________ __________and changing l______ _______of the past.

We have learned that Earth is much older than anyone had previously imagined and that its surface and interior have been changed by the same geological processes that continue today.

A Brief History of Geology


______________________ means that the forces and processes that we observe today have been at work for a ________ _______ ___________.

Relative Dating—Key Principles


Relative dating tells us the _____________ in which events occurred, ______ how long ago they occurred.

Law of Superposition• The law of superposition states that in an undeformed sequence

of sedimentary rocks, each bed is _____________ than the one

above it and ________________ than the one below it.

Ordering the Grand Canyon’s History



Principle of Original Horizontality• The principle of original horizontality means that

_______________ of sediment are generally deposited in a ______________________ position.

Disturbed Rock Layers



Principle of Cross-Cutting Relationships• The principle of cross-cutting relationships states that when a

fault cuts through rock layers, or when magma intrudes other rocks and crystallizes, we can assume that the fault or intrusion is __________________ than the rocks affected.

Inclusions• Inclusions are __________ __________________within other

rocks.

• Rocks containing inclusions are ______________________ than the inclusions they contain.

Applying Cross-Cutting Relationships

Formation of Inclusions



Unconformities• An unconformity represents a long period during which

______________ ________________, erosion _____________ previously formed rocks, and then deposition _______________.

• An angular unconformity indicates that during the pause in

deposition, a period of deformation (_____________ or

______________) and erosion occurred.

Formation of an Angular Conformity



types of unconformities• A ___________________________ is when the erosional surface

separates older metamorphic or intrusive igneous rocks from younger sedimentary rocks.

• A ___________________ is when two sedimentary rock layers are separated by an erosional surface.

A Record of Uplift, Erosion, and Deposition

Correlation of Rock Layers


Correlation is establishing the ___________________ of rocks of similar age in ______________ _____________.

Correlation of Strata at Three Locations

Fossil Formation

12.2 Fossils: Evidence of Past Life

Fossils are the remains or traces of prehistoric life. They are important components of sediment and sedimentary rocks.

• Some remains of organisms—such as teeth, bones, and shells—may not have been altered, or may have changed hardly at all over time.

The type of fossil that is formed is _____________ _________the conditions under which an organism died and how it was buried.

_____________ Remains

Fossil Formation


Altered Remains• The remains of an organism are likely to be changed over time.

• Fossils often become _____________ or turned to __________.

• _____________ and __________are another common type of fossil.

• ________________ is particularly effective in preserving leaves and delicate animals. It occurs when an organism is buried under fine sediment.

Fossil Formation


Indirect Evidence• _____________ fossils are indirect evidence of prehistoric life.

Tracksburrowscoprolites—fossilized fecesgastroliths—stomach stones for help digesting

Conditions Favoring Preservation

• Two conditions are important for preservation: __________

__________and the possession of ____________ parts.

Types of Fossilization

Fossils and Correlation


Principle of _______ _____________states that fossil organisms succeed one another in a definite and determinable order. Therefore, any time period can be recognized by its fossil content.

Index fossils are _________ geographically, are limited to a _______ span of geologic time, and occur in _______ numbers.

Fossil Formation


Interpreting Environments• Fossils can also be used to interpret and ____________ ancient

___________________.For example, if you find ______________ fossils on top of a

mountain, that is a clue that the before it was a mountain the rock was once under an ____________.

Overlapping Ranges of Fossils

Basic Atomic Structures

12.3 Dating with Radioactivity

Orbiting the nucleus are _____________, which are negative electrical charges.

_________ ______________is the number of protons in the atom’s nucleus.

_________ ______________is the number of protons plus the number of neutrons in an atom’s nucleus.

Radioactivity


____________________ is the spontaneous decay of certain unstable atomic nuclei.

Common Types of Radioactive Decay

Half-Life


A __________-___________is the amount of time necessary for one-half of the nuclei in a sample to _____________ to a stable isotope.

The Half-Life Decay Curve

Radiometric Dating


Each radioactive isotope has been _______________ at a constant rate since the formation of the rocks in which it occurs.

Radiometric dating is the procedure of ______________ ______ _____________ _______ of rocks and minerals that contain radioactive isotopes.

Radiometric Dating _____ a radioactive isotope ___________,

atoms of the ___________ ______________are formed and accumulate.


An _______________ radiometric date can be obtained only if the mineral remained in a ________________ system during the entire period since its formation.

Radioactive Isotopes Frequently Used in Radiometric Dating

Dating with Carbon-14 Radiocarbon dating is the method for

determining age by comparing the amount of carbon-14 to the amount of carbon-12 in a sample.


When an organism dies, the amount of carbon-14 it contains gradually decreases as it decays. By comparing the ___________ of carbon-14 to carbon-12 in a sample, radiocarbon dates can be determined. The half-life of C-14 is ______________ years.

Importance of Radiometric Dating Radiometric dating has supported the ideas

of James Hutton, Charles Darwin, and others who inferred that geologic time must be _________________.


Structure of the Time Scale

12.4 The Geologic Time Scale

Based on their interpretations of the rock record, geologists have divided Earth’s 4.56-billion-year history into ________ that represent specific amounts of time. Taken together, these ________ _____________make up the geologic time scale.



______________ represent the greatest expanses of time. Eons are divided into ____________. Each era is subdivided into periods. Finally, periods are divided into smaller units called epochs.

There are three eras within the _______________ eon: the Paleozoic, which means “ancient life,” the Mesozoic, which means “middle life,” and the Cenozoic, which means “recent life.”



Each ___________ within an era is characterized by somewhat less profound changes in _______ forms as compared with the changes that occur during an era.

The periods of the ___________ era are divided into still smaller units called __________, during which even less profound changes in life forms occur.

Precambrian Time


During _________________ time, there were fewer life forms. These life forms are more difficult to identify and the rocks have been disturbed often.

The Geologic Time Scale

____________ With the Geologic Time Scale


A sedimentary rock may contain particles that contain radioactive isotopes, but these particles are ______ the _____ ______ as the rock in which they occur.

The _______ of a particular mineral in a metamorphic rock does ______ necessarily represent the ______ when the rock was first formed. Instead, the date may indicate when the rock was metamorphosed.

Using Radiometric Methods to Help Date Sedimentary Rocks

Precambrian History

13.1 Precambrian Time: Vast and Puzzling

The Precambrian encompasses immense geological time, from Earth’s distant beginnings ____ _______ ________ago until the start of the Cambrian period, over 4 billion years later.

Precambrian Rocks• ______________ are large, relatively flat expanses of ancient

metamorphic rock within the stable continental interior.

• Much of what we know about Precambrian rocks comes from _____________ mined from shields.

Geologic Time Scale

Remnants of Precambrian Rocks

Precambrian History


Earth’s Atmosphere Evolves• Earth’s original atmosphere was made up of gases similar to those

released in ______________ ________________today—water vapor, carbon dioxide, nitrogen, and several trace gases, but no oxygen.

• Later, primary plants evolved that used photosynthesis and

_______________________ ____________________.

• Oxygen began to accumulate in the atmosphere about _____ billion years ago.

Precambrian History


Precambrian Fossils• The most common Precambrian fossils are _______________

• Stromatolites are distinctively ____________ ______________ or columns of calcium carbonate. They are not the remains of actual organisms but are the ______________ ____________ ________ _______________.

• Many of these ancient fossils are preserved in chert—a hard dense chemical sedimentary rock.

Stromatolites then and now

• Then

Now

Early Paleozoic

13.2 Paleozoic Era: Life Explodes

Following the long Precambrian, the most recent _______ ____________ _______ of Earth’s history are divided into three eras: Paleozoic, Mesozoic, and Cenozoic.

Early ______________


Early Paleozoic History• During the Cambrian, Ordovician, and Silurian periods, the vast

southern continent of _____________________ encompassed five continents (South America, Africa, Australia, Antarctica, and part of Asia).

Gondwana and the Continental Landmasses

Early Paleozoic


Early Paleozoic Life• Life in early Paleozoic time was restricted to the _________.

There was no life on land yet.

Life in the Ordovician Period

Late Paleozoic


Late Paleozoic History• ____________________ is the continental mass that formed the

_________________ portion of Pangaea, consisting of present-day North America and Eurasia.

• By the ________ of the Paleozoic, all the continents had fused into the supercontinent of ________________________.

Late Paleozoic Plate Movements

Late Paleozoic


Late Paleozoic _____________• Some _________ __ __ __, plants that had adapted to survive

at the water’s edge began to move inland, becoming ___________ plants.

• The ____________________ rapidly diversified because they had minimal competition from other land dwellers.(Amphibians include frogs, toads, and salamanders)

Armor-Plated Fish

Model of a Pennsylvanian Coal Swamp

The Great Paleozoic Extinction


The world’s __________ became very ______________, probably causing the dramatic _____________ of many species.

The late Paleozoic extinction was the greatest of at least _____ ______ _____________ to occur over the past 500 million years.

Mesozoic Era

13.3 Mesozoic Era: Age of Reptiles

____________________ were land-dwelling reptiles that thrived during the Mesozoic era. Mesozoic History • A major event of the Mesozoic era was the ______________ ____

_______________.

Mesozoic Era Mesozoic Life


• ______________________ are seed-bearing plants that do not depend on free-standing water for fertilization. Gymnosperms are plants that have cones.

• The gymnosperms quickly became the dominant plants of the Mesozoic era.

Gymnosperms

Canadian Rockies Were Formed Throughout the Cretaceous Period

Mesozoic Era The Shelled Egg


• Unlike amphibians, reptiles have __________-covered eggs that can be laid on the ____________.

• The elimination of a water-dwelling stage (like the _____________ stage in frogs) was an important evolutionary step.

Mesozoic Era Reptiles Dominate


• With the perfection of the shelled egg, reptiles quickly became the

__________________ ______________ ________________.

• At the end of the Mesozoic era, many reptile groups became

___________________.

The Flying Reptile Pteranodon

Cenozoic North America The Cenozoic era is divided into ________

periods of very unequal duration, the Tertiary period and the Quaternary period.

13.4 Cenozoic Era: Age of Mammals

Plate interactions during the Cenozoic era caused many events of _______________ building, volcanism, and earthquakes in the West.

Cenozoic Life Mammals—animals that ______ _______

___________ and maintain a steady body temperature— _____________ reptiles as the dominant land animals in the Cenozoic era.


Angiosperms—______________ plants with covered seeds—___________ gymnosperms as the dominant land plants.

Cenozoic Life Mammals Replace Reptiles


• Adaptations like being warm blooded, developing insulating body hair, and having more efficient heart and lungs allow mammals to lead more active lives than reptiles.

Fossils from La Brea Tar Pits

Cenozoic Life Large Mammals and Extinction


• In North America, the ___________ and ____________, both huge relatives of the elephant, became extinct. In addition, saber-toothed cats, giant beavers, large ground sloths, horses, camels, giant bison, and others died out on the North American continent.

• The reason for this recent wave of extinctions puzzles scientists. 3 probable causes are: ____________ killed them off, ______________ change (end of ice age) and

______________________—humans and domesticated animals contained germs that jumped to the wild species.

Wooly mammoths

Mastodons

Documents

Unit 1 Geology Notes Name_______________. Overview of Earth Science 1.1 What Is Earth Science? Encompasses all sciences that seek to understand __________________

Unit 1 Geology Notes Name_. Overview of Earth Science 1.1 What Is Earth Science? Encompasses all sciences that seek to understand ____