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Stratigraphy

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Title: Stratigraphy


1
Stratigraphy
  • The study of the origin, relationship and extent
    of rock layers (Strata).

2
LithostratigraphyEach layer is a different rock
type.
ChronostratigraphyEach layer is a different age.
BiostratigraphyEach layer contains a different
fossil assemblage.
3
Lithostratigraphic Units
Supergroup Group A Formation A Member A
Supergroup Group A Formation A Member B
Supergroup Group A Formation A Member C
Supergroup Group A Formation B Member D
Supergroup Group A Formation B Member E
Supergroup Group A Formation B Member F
Supergroup Group A Formation C Member G
Supergroup Group A Formation C Member H
Supergroup Group B Formation D Member I
Supergroup Group B Formation D Member J
Supergroup Group B Formation D Member K
Supergroup Group B Formation D Member L
Supergroup Group B Formation D Member M
Supergroup Group B Formation E Member N
Supergroup Group B Formation E Member O
Supergroup Group B Formation E Member P
Supergroup Group B Formation E Member Q
Supergroup Group B Formation F Member R
Supergroup Group B Formation F Member S
Supergroup Group B Formation F Member T
Supergroup Group Formation Member Bed
4
Lithostratigraphic ExampleGrand Canyon
5
How do we Illustrate Stratigraphy?
  • Stratigraphic Columns
  • Cross Sections
  • Geologic Maps

6
Stratigraphic ColumnJohn Day Fossil Beds NM
7
Geologic MapsSnoqualmie Pass
8
Chronostratigraphic Map of Washington
9
Cross Sections
10
Principles (Laws) of Stratigraphy
  • Principle of
  • Original Horizontality
  • Superposition
  • Lateral Continuity
  • Cross Cutting Relationships
  • Inclusions
  • Faunal Succession
  • Walthers Law

11
Nicholas Steno
12
1. Principle of Original Horizontality
13
2. Principle of Superposition
14
3. Principle of Lateral Continuity
15
Lateral Continuity
16
Charles Lyell
17
4. Principle of Cross Cutting Relationships
18
5. Principle of Inclusions
19
6. Principle of Faunal Succession
Sketch by Baron Cuvier (1769-1832)
20
William Strata Smith
21
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."
22
Biostratigraphy
Superzone - Biozones - Subzones
Defined by first and last appearance of index
fossils and/or fossil assemblages
23
Diatoms
24
BoundariesConformable Bed Contacts
Gradational
Sharp
25
BoundariesUnconformitiesGaps in Rock Gaps in
Time
26
Types of Unconformities Nonconformity
27
Nonconformity - Grand Canyon
28
Using Inclusions to Recognize a Nonconformity
29
Types of Unconformities Angular Unconformity
30
Formation of an Angular Unconformity
31
Angular Unconformity in the Grand Canyon
32
The Angular Unconformity at Siccar Point,
Scotland
Source Edward A. Hay, De Anza College,
Cupertino, CA
33
Types of Unconformities Disconformity
34
Formation of a Disconformity
35
Walthers Law
Johannes Walther(1860-1937)
36
Concept ofSedimentary Facies
Depositional Environments
Facies
Sedimentary Facies refers to all of the
characteristics of a particular rock unit. The
characteristics of the rock unit come from the
depositional environment.
37
Facies Example
Facies Change
A Sandstone facies (beach environment) B
Shale facies (offshore marine environment) C
Limestone facies (far from sources of terrigenous
input)
38
Marine Transgression Sea Level RiseMarine
Regression Sea Level Fall
39
Walthers Law
Sedimentary environments that started out
side-by-side will end up overlapping one another
over time due to transgressions and regressions.
Facies
Limestone
Shale
Siltstone
Sandstone
Lagoon
Beach
Reef
Near Shore
Environment
40
Marine Trangression
Walthers Law
41
Marine Regression
42
The sea goes in, the sea goes out.
43
Blue No deposition
44
Vail Curve of Sea Level History
Transgression Regression
45
Correlation
46
A
B
C
47
Example of Correlation
48
Colorado Plateau Correlation
49
Colorado Plateau Correlation
50
Chronostratigraphic Units
  • Chronostratigraphic (Time-Rock) Unit
  • Eonothem
  • Erathem
  • System
  • Series
  • Stage

51
Chronostratigraphy and the Development of the
Geologic Time Scale
52
Chronostratigraphic Time Units
  • Time Unit
  • Eon
  • Era
  • Period
  • Epoch
  • Age
  • Time-Rock Unit
  • Eonothem
  • Erathem
  • System
  • Series
  • Stage

53
GeologicTimeScale
54
(No Transcript)
55
Relative Dating of Rocks Using Stratigraphic
Principles
56
Example 2 of Relative Time
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