Download Geologic Time - MSU Billings

Geologic Time
and
Stratigraphic
Relationships
Geologic Time vs Human Time
Lifespan of a human
~ 100 years
Human civilization
~10,000 years
Modern humans
~100,000 years
Stone tools
~1,000,000 years
Age of oceanic crust
~100,000,000 years
Precambrian Explosion
~540,000,000 years
Oldest Rocks
~3.8 Billion years
Age of the Earth
~4.56 Billion years
Age of the Solar System
~4.6 Billion years
Age of the Universe
~14 Billion years
Absolute
vs
Relative Dating
Absolute Dating
How old is a rock?
Relative Dating
Is one rock older than
another?
But first
How old is the Earth?
How old is the Earth?
Originally Based on Mythology
Buddhist Tradition:
Infinite Age (Cyclic)
How old is the Earth?
Originally Based on Mythology
Buddhist Tradition:
Infinite Age (Cyclic)
Han Chinese Tradition:
23 Million Year Cycle
Counting the generations in the Bible
Archbishop James Usher (1654)
Counting the generations in the Bible
4004 BC
October 23
Archbishop James Usher (1654)
Counting the generations in the Bible
4004 BC
October 23
9:00 AM
Archbishop James Usher (1654)
The ‘father' of modern Geology
James Hutton
“The present is the key to the
past”
Uniformitarianism
vs
Catastrophism
“The present
is the key to
the past”
The unconformity at Siccar Point
Scientific approaches to determine the
absolute age of the Earth
Scientific approaches to determine the
absolute age of the Earth
Scientific approaches to determine the
absolute age of the Earth
Requires:
1. Natural Process
2. Occurs at a Constant Rate
3. Leaves a Geologic Record
Scientific approaches to determine the
absolute age of the Earth
Requires:
1. Natural Process
2. Occurs at a Constant Rate
3. Leaves a Geologic Record
Age (Time) = Amount of Change
Rate of Change
Lord Kelvin
(1824-1907)
20-400 Million yrs old
Cooling of Molten Ball
Magma Solidified into Early Crust
Other methods
Saltiness of the Ocean (John Joly)
Accumulation of sediments (John Philips)
Evolution of the Earth/Moon System (George Darwin)
The Discovery of Radioactivity (1896)
Antoine Henri Becquerel
Marie and Pierre Curie
Becquerel’s
Mistake
http://en.wikipedia.org/wiki/Henri_Becquerel
Bertram Boltwood
First to use radioactive elements to
date rocks:
250 million to 1.3 billion years
Authur Holmes
Found old rocks:
Earth 4 billion years old!
Daughter Isotope
Atomic Number = -2
Atomic Weight = -4
Alpha Decay
Uranium-238 --> Thorium-234 + Alpha Particle + Energy
Beta Decay
Daughter Isotope
Atomic Number = +1
Atomic Weight = +0
Carbon-14 --> Nitrogen-14 + Beta Particle + Energy
Fig. 8.9. Chart of Isotopes
Decay of Uranium-238 to Lead 206
Alpha Decay
Beta Decay
Half Life
Time it takes for half of the parent isotope to decay into
daughter isotope
Daughter Isotopes
Parent Isotopes
Radioactive Decay
N = N0
-kt
e
Where N is the amount of the radioactive element in the rock now; N0 is the amount
originally in the rock, e ~ 2.718 (natural logarithm); k is the decay constant of the
radioactive element, and t is time.
What do you need to know to
radiometricly date a rock?
What do you need to know to
radiometricly date a rock?
• Initial Parent Isotope Content (N0)
What do you need to know to
radiometricly date a rock?
• Initial Parent Isotope Content (N0)
• Current Parent Isotope Concentration (Nt)
What do you need to know to
radiometricly date a rock?
• Initial Parent Isotope Content (N0)
• Current Parent Isotope Concentration (Nt)
• Half Life of Isotope or the decay constant (k)
What do you need to know to
radiometricly date a rock?
• Initial Parent Isotope Content
• Current Parent Isotope Concentration
• Half Life of Isotope or the decay constant
• Closed System
Radioactive Decay
N = N0
-kt
e
Where N is the amount of the radioactive element in the rock now; N0 is the amount
originally in the rock, e ~ 2.718 (natural logarithm); k is the decay constant of the
radioactive element, and t is time.
How do you measure isotope
concentrations?
How do you measure isotope
concentrations?
Mass Spectrometer
Dating & Radioactive Decay
Back to the Age of the Earth
Oldest Rocks on Earth
(Acasta Gneiss, Northern Canada)
- about 3.96 Billion Years
Oldest Mineral Crystals on Earth
(Zircon, Jack Hills Conglomerate,
Western Australia)
- about 4.4 Billion Years
Age of the Earth ~ 4.56 Billion Years
How old are Meteorites?
Carbonaceous Chondrite
(Allende Meteorite)
Iron Meteorite
Meteorite Ages
Type
Number Method Age (Gyr))
Chondrites (CM, CV, H, L, LL, E)
13
Sm-Nd 4.21 +/- 0.76
Carbonaceous chondrites
4
Rb-Sr
4.37 +/- 0.34
Chondrites (undisturbed H, LL, E)
38
Rb-Sr
4.50 +/- 0.02
Chondrites (H, L, LL, E)
50
Rb-Sr
4.43 +/- 0.04
H Chondrites (undisturbed)
17
Rb-Sr
4.52 +/- 0.04
H Chondrites
15
Rb-Sr
4.59 +/- 0.06
L Chondrites (relatively undisturbed) 6
Rb-Sr
4.44 +/- 0.12
L Chondrites
5
Rb-Sr
4.38 +/- 0.12
LL Chondrites (undisturbed)
13
Rb-Sr
4.49 +/- 0.02
LL Chondrites
10
Rb-Sr
4.46 +/- 0.06
E Chondrites (undisturbed)
8
Rb-Sr
4.51 +/- 0.04
E Chondrites
8
Rb-Sr
4.44 +/- 0.13
Eucrites (polymict)
23
Rb-Sr
4.53 +/- 0.19
Eucrites
11
Rb-Sr
4.44 +/- 0.30
Eucrites
13
Lu-Hf
4.57 +/- 0.19
Diogenites
5
Rb-Sr
4.45 +/- 0.18
Iron (plus iron from St. Severin)
8
Re-Os 4.57 +/- 0.21
-----------------------------------------------------------------------After Dalrymple (1991, p. 291); duplicate studies on identical meteorite types omitted.
Other Forms of Absolute Dating
Dedrochronology
Counting tree rings
Fission Tracks
Annual snow layers
Other Forms of quasi Absolute Dating
Oxygen isotope stages
Magnetic
polarity
Core A
Core B
Magnetic Reversals
Relative Dating
Relative Dating
When is a rock older than
another rock?
Principles (Laws) of Stratigraphy
Principles (Laws) of Stratigraphy
• Law of Original Horizontality
Principles (Laws) of Stratigraphy
• Law of Original Horizontality
• Law of Superposition
Principles (Laws) of Stratigraphy
• Law of Original Horizontality
• Law of Superposition
• Law of Lateral continuity
Principles (Laws) of Stratigraphy
•
•
•
•
Law of Original Horizontality
Law of Superposition
Law of Lateral continuity
Law of Cross cutting relationships
Principles (Laws) of Stratigraphy
•
•
•
•
•
Law of Original Horizontality
Law of Superposition
Law of Lateral continuity
Law of Cross cutting relationships
Law of Inclusions
Principles (Laws) of Stratigraphy
•
•
•
•
•
•
Law of Original Horizontality
Law of Superposition
Law of Lateral continuity
Law of Cross cutting relationships
Law of Inclusions
Law of Faunal succession
1. Principle of Original Horizontality
2. Principle of Superposition
Youngest Strata
Oldest Strata
3. Principle of Lateral Continuity
Lateral Continuity
4. Principle of Cross Cutting
Relationships
5. Principle of Inclusions
6. Principle of Faunal Succession
Sketch by Baron Cuvier (1769-1832)
William “Strata”
Smith
6. Principle of Faunal Succession
" . . . each stratum contained organized fossils peculiar to
itself, and might, in cases otherwise doubtful, be recognized
and discriminated from others like it, but in a different
part of the series, by examination of them."
Biostratigraphy
Superzone - Biozones - Subzones
Defined by first and last
appearance of index
fossils and/or fossil
assemblages
William Smith: father of stratigraphy
Relative Dating of Rocks Using
Stratigraphic Principles
Example 2 of Relative Time
Boundaries:
Conformable Bed Contacts
Gradational
Sharp
Boundaries:
Unconformities
Gaps in Rock = Gaps in Time
Types of Unconformities: Nonconformity
Using Inclusions to Recognize a
Nonconformity
Types of Unconformities:
Angular Unconformity
Formation of an Angular Unconformity
Angular Unconformity in the Grand
Canyon
The Angular
Unconformity
at Siccar Point,
Scotland
Source: Edward A. Hay, De Anza College, Cupertino, CA
Types of Unconformities: Disconformity
Formation of a Disconformity
Geologic Time Scale
Eon
Era
Period
Quaternary
C
e
n
o
z
o
i
c
Geologic
Time
Scale
recreating this
figure is your next
homework
assignment
P
h
a
n
e
r
o
z
o
i
c
0.01
1.8
Neogene
5.3
23.8
Tertiary
33.6
Paleocene
54.8
65
M
e
s
o
z
o
i
c
Cretaceous
144
Jurassic
Triassic
Permian
P
a
l
e
o
z
o
i
c
Pennsylvanian
Mississippian
Devonian
Silurian
Ordivician
Cambrian
P
r
e
c
a
m
b
r
i
a
n
Age (Myrs)
206
248
290
323
354
417
443
490
543
Proterozoic
2500
Archean
3800
Hadean
Age of the Earth 4600 Myrs (4.6 Byrs)
Source: Geological Society of America (1999)
Epoch
Holocene
Pleistocene
Pliocene
Miocene
Oligocene
Eocene
Paleocene
The Magnitude of Geologic Time
• Earth History condensed to 1 year
– Jan 1, 12:00:01 - Earth is formed
– March 15 - Oldest remaining rocks
– May - One celled organisms, algae first
appear in the oceans
– November (Thanksgiving) - First land plants
and animals appear
The Magnitude of Geologic Time
• December 6-9 - Widespread swamps form
coal deposits during the Pennsylvanian Period
(320 to 286 million years ago)
• Dec 12-26 - Dinosaurs dominate (Mesozoic)
• Dec 31, ~5:00pm - first man-like creatures
• Dec 31, 11:58:45 - ice sheets retreat from the
Great Lakes area
The Magnitude of Geologic Time
– Dec 31, 11:59:45 to 11:59:50 - Roman
Empire
– Dec 31, 11:59:57 - Columbus discovers
America
– Dec 31, 11:59:58.5 - Declaration of
Independence is signed
Hadean Earth
2004 - Fred Sulahria
Heavy Bombardment Period
Life on Earth - Timing
First Photosynthesis & Stromatolites
4.6 Byrs
Today
No Life
Single Celled Life Only
Multi-Celled
First Eukaryotes
Oxygen Revolution
Aerobic Respiration
First Sex
Major Steps in the Precambrian
Evolution of Life
1.
2.
3.
4.
5.
6.
7.
Origin of Life (4.0 - 3.8 Gyrs)
Photosynthesis (3.8 - 3.5 Gyrs)
Aerobic (Oxygen-based) Respiration (3-2 Gyrs)
Eukaryotes / Endosymbiosis (2.1-1.6 Gyrs)
Sex / Death (1.2 - 1 Gyrs)
Multicellular Life (1,000 - 800 Myrs)
Skeletons & Shells (600 Myrs)
* All dates are approximate
Apex
Chert Fossils
(3.5 Gyr)
Formed Colonies called
Stromatolites
4. Eukaryotes & Endosymbiosis
Chuaria circularis
Tawuia dalensis
800 Myrs
Fossil Acritarch
First Appear 1.6 Gyrs
Oldest Eukaryote
Grypania spiralis
2.1 Gyrs
1.3 Gyrs
Ediacara Hills, Australia
Dickinsonia
Ediacara Fauna
Spriggina floundersi
Skeletons and Shells
Small Shelly Fossils
(SSF’s)
Tommotian Fauna: first skeletons,
then vanished
Mass Extinctions:
Death and Destruction
Paleozoic Life
Ocean Planet….
and migration to land
a modern coral reef
Many figures from Stanley, 2005
Geologic Time Scale
Eon
Era
Period
Quaternary
Late
C
e
n
o
z
o
i
c
Middle
P
h
a
n
e
r
o
z
o
i
c
Paleozoic
Early
0.01
1.8
Neogene
5.3
23.8
Tertiary
33.6
Paleocene
54.8
65
M
e
s
o
z
o
i
c
Cretaceous
144
Jurassic
Triassic
Permian
P
a
l
e
o
z
o
i
c
543-248 Myr
Pennsylvanian
Mississippian
Devonian
Silurian
Ordivician
Cambrian
P
r
e
c
a
m
b
r
i
a
n
Age (Myrs)
206
248
290
323
354
417
443
490
543
Proterozoic
2500
Archean
3800
Hadean
Age of the Earth 4600 Myrs (4.6 Byrs)
Source: Geological Society of America (1999)
Epoch
Holocene
Pleistocene
Pliocene
Miocene
Oligocene
Eocene
Paleocene
Cambrian Explosion
Trilobites
(Arthropods)
Fossil
Paleozoic
Sponge
Cnideria (Corals &
Jellyfish)
Graptolites
Brachiopods (Lamp Shells)
Phylum Chordata
Including Subphylum Vertebrata
1. Notochord
2. Nerve cord
3. Pharyngeal
gill slits
Vertebrates
Vertebral column
replaces notochord
& skull encloses
brain
Osteichthyes: Lobe Finned
Subclass: Sarcopterygii
Amphibians
Anapsids & Diapsids
(True Reptiles)
First Colonists: Bryophytes
No “Plumbing System” - small low to the ground
Horsetails
(Calamites)
Annularia
stellata
Miss/Penn Forests
(Ferns, Horsetails & Clubmoss)
Illustration by Mary Parrish
The Mesozoic
“The Age of Dinosaurs”
Geologic Time Scale
Eon
Era
Period
Quaternary
Mesozoic
C
e
n
o
z
o
i
c
248-65 Myr
P
h
a
n
e
r
o
z
o
i
c
0.01
1.8
Neogene
5.3
23.8
Tertiary
33.6
Paleocene
54.8
65
M
e
s
o
z
o
i
c
Cretaceous
144
Jurassic
Triassic
Permian
P
a
l
e
o
z
o
i
c
Pennsylvanian
Mississippian
Devonian
Silurian
Ordivician
Cambrian
P
r
e
c
a
m
b
r
i
a
n
Age (Myrs)
206
248
290
323
354
417
443
490
543
Proterozoic
2500
Archean
3800
Hadean
Age of the Earth 4600 Myrs (4.6 Byrs)
Source: Geological Society of America (1999)
Epoch
Holocene
Pleistocene
Pliocene
Miocene
Oligocene
Eocene
Paleocene
Major Marine Predators
Ammanoids
Marine Reptiles
Mosasaurus
Largest150 ft long!
Ichthyosaurus
Sauropods
Barapasaurus
Theropods
Hadrosaurs - “Duck-billed Dinosaurs”
Ouranosaurus
Ceratopsids
Triceratops
Pterosaurs – Winged Reptiles
Pterosaurs
Criorhynchus
Cynodonts
mammal like reptiles
Small Insectivores
First mammals
First Flowers
Cretaceous Flower
Magnolia
The Cenozoic
Age of Flowers & Mammals
Herbs
& Weeds
Sharks Diversify:
Megalodon
Titanis & Hipparian
Basilasaurus
Mammal Evolution
Marsupials
Eutheria
(Placentals)
Cretaceous
Multituberculates
Cretaceous
Placenta
Monotremes
Late Jurassic
Early Mammals
Live Birth
Rodents
Artiodactyls (Even-toes Ungulates)
Cows - Camels - Deer - Hippos - Pigs - Giraffe
Eocene Primate- Notharctus
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