Geology 142

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Geology 142 Deciphering Earth History Dr. Bruce
F. Rueger bfrueger_at_colby.edu Phone
859.5806 Office Mudd 214 Lab Mudd 219
Office Hours Monday, Wednesday 930 -
1030 Tuesday, Thursday 930 - 1100
Text The Earth Through Time (8th edition)
Author Harold L. Levin Lab Manual
Deciphering Earth History (4th ed.) Author
Gastaldo, Savrda, and Lewis
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Course Format (What You Need to Know To Do Well)
1. Come to class (all the time). 2. Buy the
textbook and the lab manual. 3. READ the
textbook and the lab manual. (Preferably before
you come to class) 4. Do the assignments in
lecture and lab. 5. Go to lab. (the lab guy is
really tough about this) 6. Study for the exams.
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Lecture Part of the Course
Consists of Three meetings each week. Three
written experiences (exams). Exams will be worth
600 points Written exercises and projects are
worth 150 points. There will be some
unannounced exercises. Lecture portion of the
course is worth 750 points. Lecture is worth 75
of your course grade. I strongly recommend that
you buy the book.
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The Geology 142 Web Site
http//www.colby.edu/personal/b/bfrueger/
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Laboratory Part of the Course
Consists of One laboratory session each
week. Lab exercises are worth 150 points. Lab
final is worth 100 points. Lab portion of the
course is worth 250 points. Lab is worth 25 of
your course grade. You DO need the laboratory
manual. It would be beneficial to read the lab
before lab Lab starts this week.
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Field Trip to Acadia National Park Date to be
determined
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Things You Might Find Useful to Bring
1. Some colored pencils or pens These will be
useful for diagrams. 2. 5x7 index cards These
will be used for questions or impromptu written
exercises. 3. An interest in learning about
the Earth.
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IMPORTANT STUFF YOU SHOULD KNOW (at least to
start with today)
You should be able to do simple conversion from
English measurements to Metric using the
following
1 inch 2.54 centimeters 3.3 feet 1
meter 0.62 miles 1 kilometer 1.1 quarts 1
liter 1 pound 0.45 kilograms ?C (Celsius)
(5/9)(?F-32) ?F (Fahrenheit) ?C (9/5)32
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GEOLOGY Study of planet Earth Includes materi
als (131/141) physical chemical
processes (131/141) history of Earth and life
on it (142) Based on physics, chemistry,
biology, astronomy and mathematics
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TIME
Age of the Earth?
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Time is a critical ingredient to most geologic
processes. Geologic time has an immense
vastness. We have 4.6 BILLION years to work
with. (info comes from the moon and
meteorites) To us a decade is a long time! Lots
of events happen in this interval of time. How
big is a billion? Consider 1,000,000,000
seconds. 1,000,000,000 seconds equals 31.71 YEARS!
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GEOLOGIC TIME in PERSPECTIVE
Appearance of first Hominids 3-4,000,000
yBP Demise of the Dinosaurs 65,000,000 yBP First
Land Plants 483,000,000 yBP First
Fish 505,000,000 yBP First Shelled
Invertebrates 570,000,000 yBP First Appearance
of Life 3,770,000,000 yBP Oldest Known Earth
Rocks 3,960,000,000 yBP Age of the
Earth 4,600,000,000 yBP
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GEOLOGIC TIME in PERSPECTIVE
Appearance of first Hominids 4 mm Demise of the
Dinosaurs 65 mm First Land Plants 483
mm First Fish 505 mm First Shelled
Invertebrates 570 mm First Appearance of
Life 3,770 mm Oldest Known Earth Rocks 3,960
mm Age of the Earth 4,600 mm
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Founders of Historical Geology
Can be traced back to classical Greece
Nicolaus Steno (Neils Stensen) 1638-1687 Origina
lly a Danish physician An expert in
anatomy (Public Dissections) Developed the
fundamental principles of historical geology
Physician to the de Medici family in Florence
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Founders of Historical Geology
Nicolaus Steno (Neils Stensen) 1638-1687 In
1669, Steno wrote De solido intra solidum
naturaliter contento dissertationis
prodromus Prodromus to a dissertation on
Solids Naturally Enclosed in Solids only 78
pages long
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Founders of Historical Geology
Superposition - The scientific law stating that
in any unaltered sequence of rock strata, each
stratum is younger than the one beneath it and
older than the one above it, so that the youngest
stratum will be at the top of the sequence and
the oldest at the bottom.
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Founders of Historical Geology
With tilted beds, we need to consider
other sedimentary structures, like ripple
marks, mudcracks, graded bedding, geopetal
structures or cross-bedding to help
determine up direction. Can also use vesicles
in lava flows.
Superposition, cont.
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Founders of Historical Geology
Principle of Original Horizontality - The
scientific law stating that sediments settling
out of a fluid (air and water) are deposited
horizontally or nearly horizontally in layers
that lie parallel or nearly parallel to the
Earths surface.
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Founders of Historical Geology
Principle of Lateral Continuity - The scientific
law stating that as originally deposited, strata
extend in all directions until they terminate by
thinning at the margins of the basin,
end abruptly against some former barrier to
deposition, or grade laterally into a different
kind of sediment.
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Founders of Historical Geology
John Strachey 1671-1743 Used superposition and
original lateral continuity Determined the
stratigraphic succession of coals in
England Recognized what would later be termed
unconformities Performed local-scale
observations.
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Founders of Historical Geology
Giovanni Arduino 1714-1795 Had a broader global
view of sedimentary layers Developed the first
classification of rocks and relative
ages Primary Mountains crystalline
rocks oldest rocks on Earth later became
igneous/metamorph. Secondary
Mountains layered fossiliferous
rocks later sedimentary rocks Terti
ary unconsolidated sediments lava flows
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Founders of Historical Geology
Johann Lehmann 1719-1767 Georg Füchsel 1722-1776
Came up with classification similar to that of
Arduino Developed stratigraphic successions of
rocks in Thuringia, and the Hartz and Ertz
Mountains. Began to understand the events that
lead to mountain building
Lehmann
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Founders of Historical Geology
Peter Simon Pallas 1741-1811 Improved geologic
history of the mountains of Europe Developed the
general geologic history of the Urals Observed
changes in rock assemblages going from margins
to the core of mountains.
Reise durch verschiedene Provinzen des
Russischen Reiches 1771-1776 Journey
Through Several Provinces of the Russian Empire