What is Geology?

1. What is Geology?What is Geology?What is Geology?What is Geology?

2. The Science of GeologyThe Science of GeologyThe Science of GeologyThe Science of Geology
---- Physical geologyPhysical geologyPhysical geologyPhysical geology examines the materials composingexamines the materials composingexamines the materials composingexamines the materials composing
Earth and seeks to understand the many processesEarth and seeks to understand the many processesEarth and seeks to understand the many processesEarth and seeks to understand the many processes
that operate beneath and upon its surface.that operate beneath and upon its surface.that operate beneath and upon its surface.that operate beneath and upon its surface.
GeologyGeologyGeologyGeology is the science that pursues and understanding ofis the science that pursues and understanding ofis the science that pursues and understanding ofis the science that pursues and understanding of
planet Earth. It is normally separated into two types:planet Earth. It is normally separated into two types:planet Earth. It is normally separated into two types:planet Earth. It is normally separated into two types:
---- Historical geologyHistorical geologyHistorical geologyHistorical geology seeks to understand the originseeks to understand the originseeks to understand the originseeks to understand the origin
of Earth and its development through timeof Earth and its development through timeof Earth and its development through timeof Earth and its development through time
(including establishing a chronological timeframe of(including establishing a chronological timeframe of(including establishing a chronological timeframe of(including establishing a chronological timeframe of
physical and biological changes that have occurred inphysical and biological changes that have occurred inphysical and biological changes that have occurred inphysical and biological changes that have occurred in
the geological past).the geological past).the geological past).the geological past).

3. The Science of GeologyThe Science of GeologyThe Science of GeologyThe Science of Geology
This semester, our study of planetThis semester, our study of planetThis semester, our study of planetThis semester, our study of planet
Earth will cover a lot of territory:Earth will cover a lot of territory:Earth will cover a lot of territory:Earth will cover a lot of territory:
---- Biosphere (Life)Biosphere (Life)Biosphere (Life)Biosphere (Life)
---- Atmosphere (Air)Atmosphere (Air)Atmosphere (Air)Atmosphere (Air)
---- Hydrosphere (Water)Hydrosphere (Water)Hydrosphere (Water)Hydrosphere (Water)
---- Geosphere/LithosphereGeosphere/LithosphereGeosphere/LithosphereGeosphere/Lithosphere
(Earth Materials)(Earth Materials)(Earth Materials)(Earth Materials)

4. Earth as a SystemEarth as a SystemEarth as a SystemEarth as a System
Earth is a dynamic planet with many interacting parts orEarth is a dynamic planet with many interacting parts orEarth is a dynamic planet with many interacting parts orEarth is a dynamic planet with many interacting parts or
spheres. These spheres are constantly linked.spheres. These spheres are constantly linked.spheres. These spheres are constantly linked.spheres. These spheres are constantly linked.
For example, aFor example, aFor example, aFor example, a
weather systemweather systemweather systemweather system
(atmosphere)(atmosphere)(atmosphere)(atmosphere)
provides precipitationprovides precipitationprovides precipitationprovides precipitation
to land (geosphere)to land (geosphere)to land (geosphere)to land (geosphere)
that eventually filtersthat eventually filtersthat eventually filtersthat eventually filters
into the oceaninto the oceaninto the oceaninto the ocean
(hydrosphere). That(hydrosphere). That(hydrosphere). That(hydrosphere). That
same precipitationsame precipitationsame precipitationsame precipitation
helps plants growhelps plants growhelps plants growhelps plants grow
(biosphere).(biosphere).(biosphere).(biosphere).

5. Earth as a SystemEarth as a SystemEarth as a SystemEarth as a System
The Earth is powered by two main sources; one externalThe Earth is powered by two main sources; one externalThe Earth is powered by two main sources; one externalThe Earth is powered by two main sources; one external
and one internal.and one internal.and one internal.and one internal.
---- Above the ground (external), Earth is powered byAbove the ground (external), Earth is powered byAbove the ground (external), Earth is powered byAbove the ground (external), Earth is powered by
the sun.the sun.the sun.the sun. Weather, climate, ocean circulation, rivers,Weather, climate, ocean circulation, rivers,Weather, climate, ocean circulation, rivers,Weather, climate, ocean circulation, rivers,
glaciers, wind, and waves are all driven by energyglaciers, wind, and waves are all driven by energyglaciers, wind, and waves are all driven by energyglaciers, wind, and waves are all driven by energy
from the sun.from the sun.from the sun.from the sun.
---- Under the ground (internal), Earth is powered byUnder the ground (internal), Earth is powered byUnder the ground (internal), Earth is powered byUnder the ground (internal), Earth is powered by
radioactive decay.radioactive decay.radioactive decay.radioactive decay. This is heat remaining from whenThis is heat remaining from whenThis is heat remaining from whenThis is heat remaining from when
our planet formed. This power helps produceour planet formed. This power helps produceour planet formed. This power helps produceour planet formed. This power helps produce
volcanoes, earthquakes, and mountains.volcanoes, earthquakes, and mountains.volcanoes, earthquakes, and mountains.volcanoes, earthquakes, and mountains.

6. How Do We Know?How Do We Know?How Do We Know?How Do We Know?
---- Geologic writings date back to the Greeks, more thanGeologic writings date back to the Greeks, more thanGeologic writings date back to the Greeks, more thanGeologic writings date back to the Greeks, more than
2,300 years ago. Unfortunately, these writings weren’t2,300 years ago. Unfortunately, these writings weren’t2,300 years ago. Unfortunately, these writings weren’t2,300 years ago. Unfortunately, these writings weren’t
very scientific. (Aristotle thought fish fossils were justvery scientific. (Aristotle thought fish fossils were justvery scientific. (Aristotle thought fish fossils were justvery scientific. (Aristotle thought fish fossils were just
REALLYREALLYREALLYREALLY still live fish, living in the dirt.)still live fish, living in the dirt.)still live fish, living in the dirt.)still live fish, living in the dirt.)
---- In the midIn the midIn the midIn the mid----1600s James1600s James1600s James1600s James UssherUssherUssherUssher, a biblical scholar,, a biblical scholar,, a biblical scholar,, a biblical scholar,
declared Earth to be a few thousand years old. People ofdeclared Earth to be a few thousand years old. People ofdeclared Earth to be a few thousand years old. People ofdeclared Earth to be a few thousand years old. People of
the time believed inthe time believed inthe time believed inthe time believed in catastrophismcatastrophismcatastrophismcatastrophism –––– the idea that allthe idea that allthe idea that allthe idea that all
Earth’s landscapes were created in sudden catastrophes.Earth’s landscapes were created in sudden catastrophes.Earth’s landscapes were created in sudden catastrophes.Earth’s landscapes were created in sudden catastrophes.
---- In the late 1700s, Scottish physician JamesIn the late 1700s, Scottish physician JamesIn the late 1700s, Scottish physician JamesIn the late 1700s, Scottish physician James HuttonHuttonHuttonHutton
introduced the idea ofintroduced the idea ofintroduced the idea ofintroduced the idea of uniformitarianismuniformitarianismuniformitarianismuniformitarianism –––– thethethethe
foundation of today’s geology. It states that allfoundation of today’s geology. It states that allfoundation of today’s geology. It states that allfoundation of today’s geology. It states that all
processes that operate today, also operated in the past.processes that operate today, also operated in the past.processes that operate today, also operated in the past.processes that operate today, also operated in the past.

7. Why Is This Important?Why Is This Important?Why Is This Important?Why Is This Important?
---- Just because humans weren’t around for certainJust because humans weren’t around for certainJust because humans weren’t around for certainJust because humans weren’t around for certain
geological events, doesn’t mean they didn’t happen.geological events, doesn’t mean they didn’t happen.geological events, doesn’t mean they didn’t happen.geological events, doesn’t mean they didn’t happen.
Geological eventsGeological eventsGeological eventsGeological events –––– mountain building, plate movements,mountain building, plate movements,mountain building, plate movements,mountain building, plate movements,
erosion, etc.erosion, etc.erosion, etc.erosion, etc. –––– happen on a different time scale than ahappen on a different time scale than ahappen on a different time scale than ahappen on a different time scale than a
human lifespan.human lifespan.human lifespan.human lifespan.
For example, the NorthFor example, the NorthFor example, the NorthFor example, the North
American continent isAmerican continent isAmerican continent isAmerican continent is
eroding away at a rate oferoding away at a rate oferoding away at a rate oferoding away at a rate of
3cm every 1,000 years.3cm every 1,000 years.3cm every 1,000 years.3cm every 1,000 years.
This means in about 100This means in about 100This means in about 100This means in about 100
million years, erosionmillion years, erosionmillion years, erosionmillion years, erosion
can make a 10,000can make a 10,000can make a 10,000can make a 10,000----footfootfootfoot
mountain disappear!mountain disappear!mountain disappear!mountain disappear!

8. Geologic TimeGeologic TimeGeologic TimeGeologic Time
---- In 1896, radioactivity was discovered. This allowed forIn 1896, radioactivity was discovered. This allowed forIn 1896, radioactivity was discovered. This allowed forIn 1896, radioactivity was discovered. This allowed for
absolute datingabsolute datingabsolute datingabsolute dating, which provided an exact means of dating, which provided an exact means of dating, which provided an exact means of dating, which provided an exact means of dating
geologic events (like knowing your birth date tells megeologic events (like knowing your birth date tells megeologic events (like knowing your birth date tells megeologic events (like knowing your birth date tells me
your age). By 1905, scientists began to assign fairlyyour age). By 1905, scientists began to assign fairlyyour age). By 1905, scientists began to assign fairlyyour age). By 1905, scientists began to assign fairly
accurate dates to events in Earth history. For example, weaccurate dates to events in Earth history. For example, weaccurate dates to events in Earth history. For example, weaccurate dates to events in Earth history. For example, we
now know dinosaurs died out about 65 million years ago,now know dinosaurs died out about 65 million years ago,now know dinosaurs died out about 65 million years ago,now know dinosaurs died out about 65 million years ago,
and the age of the Earth is 4.6 billion years.and the age of the Earth is 4.6 billion years.and the age of the Earth is 4.6 billion years.and the age of the Earth is 4.6 billion years.
---- In Hutton’s time, there wasn’t any way to calculateIn Hutton’s time, there wasn’t any way to calculateIn Hutton’s time, there wasn’t any way to calculateIn Hutton’s time, there wasn’t any way to calculate
accurate dates for geologic events. Instead, they usedaccurate dates for geologic events. Instead, they usedaccurate dates for geologic events. Instead, they usedaccurate dates for geologic events. Instead, they used
relative datingrelative datingrelative datingrelative dating, which placed events in a sequence based on, which placed events in a sequence based on, which placed events in a sequence based on, which placed events in a sequence based on
logical assumptions and observations (like knowing thatlogical assumptions and observations (like knowing thatlogical assumptions and observations (like knowing thatlogical assumptions and observations (like knowing that
your mom is older than you without knowing her age).your mom is older than you without knowing her age).your mom is older than you without knowing her age).your mom is older than you without knowing her age).

9. Geologic TimeGeologic TimeGeologic TimeGeologic Time
---- When viewed in context of Earth’s 4.6When viewed in context of Earth’s 4.6When viewed in context of Earth’s 4.6When viewed in context of Earth’s 4.6----billionbillionbillionbillion----yearyearyearyear
history, a geologic event that occurred 100 million yearshistory, a geologic event that occurred 100 million yearshistory, a geologic event that occurred 100 million yearshistory, a geologic event that occurred 100 million years
ago may be called “recent” by a geologist, and a rockago may be called “recent” by a geologist, and a rockago may be called “recent” by a geologist, and a rockago may be called “recent” by a geologist, and a rock
sample dated at 10 million years may be called “young.”sample dated at 10 million years may be called “young.”sample dated at 10 million years may be called “young.”sample dated at 10 million years may be called “young.”
---- Humans tend to think of 100 years asHumans tend to think of 100 years asHumans tend to think of 100 years asHumans tend to think of 100 years as oldoldoldold, and 1,000, and 1,000, and 1,000, and 1,000
years asyears asyears asyears as ancientancientancientancient. Geologists work on a MUCH larger scale,. Geologists work on a MUCH larger scale,. Geologists work on a MUCH larger scale,. Geologists work on a MUCH larger scale,
which can be hard to grasp.which can be hard to grasp.which can be hard to grasp.which can be hard to grasp.
---- Next week we will spend time specifically talking aboutNext week we will spend time specifically talking aboutNext week we will spend time specifically talking aboutNext week we will spend time specifically talking about
both relative and absolute time; however, this week I’dboth relative and absolute time; however, this week I’dboth relative and absolute time; however, this week I’dboth relative and absolute time; however, this week I’d
like you to get used to the geologic time scale andlike you to get used to the geologic time scale andlike you to get used to the geologic time scale andlike you to get used to the geologic time scale and
thinking about large units of time.thinking about large units of time.thinking about large units of time.thinking about large units of time.

10. Geologic TimeGeologic TimeGeologic TimeGeologic Time
---- The time scale divides the vastThe time scale divides the vastThe time scale divides the vastThe time scale divides the vast
history of Earth into eons, eras,history of Earth into eons, eras,history of Earth into eons, eras,history of Earth into eons, eras,
periods, and epochs.periods, and epochs.periods, and epochs.periods, and epochs.
---- We are living in the HoloceneWe are living in the HoloceneWe are living in the HoloceneWe are living in the Holocene
epoch of the Quaternary period.epoch of the Quaternary period.epoch of the Quaternary period.epoch of the Quaternary period.
This period is part of theThis period is part of theThis period is part of theThis period is part of the
Cenozoic era, which is the latestCenozoic era, which is the latestCenozoic era, which is the latestCenozoic era, which is the latest
era of the Phanerozoic eon.era of the Phanerozoic eon.era of the Phanerozoic eon.era of the Phanerozoic eon.
---- Numbers on the scale representNumbers on the scale representNumbers on the scale representNumbers on the scale represent
time in millions of years beforetime in millions of years beforetime in millions of years beforetime in millions of years before
the present.the present.the present.the present.

11. Who Needs Geology?Who Needs Geology?Who Needs Geology?Who Needs Geology?
Stone: 12,965 lbsStone: 12,965 lbsStone: 12,965 lbsStone: 12,965 lbs Sand/gravel: 8,945 lbsSand/gravel: 8,945 lbsSand/gravel: 8,945 lbsSand/gravel: 8,945 lbs Cement: 895 lbsCement: 895 lbsCement: 895 lbsCement: 895 lbs
Salt/Phosphate: 756 lbsSalt/Phosphate: 756 lbsSalt/Phosphate: 756 lbsSalt/Phosphate: 756 lbs Nonmetals: 974 lbsNonmetals: 974 lbsNonmetals: 974 lbsNonmetals: 974 lbs Metals: 709 lbsMetals: 709 lbsMetals: 709 lbsMetals: 709 lbs
WeWeWeWe ALLALLALLALL do!do!do!do!

12. Geology CareersGeology CareersGeology CareersGeology Careers