Siliciclastic Sedimentary Rocks

1
Siliciclastic Sedimentary Rocks
Distribution Classification
2
Three Major Types of Siliclastic Sedimentary Rocks
Conglomerates
Mudrocks
Sandstones
3
Conglomerates Breccias
Sandstones
Mudstones
4
Conglomerates
5
Generally repesents only a short transport
distance
Cgl 1
Cgl 2
Cgl 1
6
Breccias Angular clasts
Mud-supported
Cement-supported
7
Breccias
Clast-supported, point-to-point contact
Mega-Breccia, Death Valley, CA
8
Generally repesents only a short transport
distance
Cgl 1
Cgl 2
Cgl 1
9
Intraformational Conglomerate
10
Distribution of sediments across the floodplains
11
(No Transcript)
12
(No Transcript)
13
Classification of Conglomerates An example
14
Sandstones
15
Sandstones consist of Grains, Matrix, Cement,
and Porosity
16
Three Primary sorts of Grains
Quartz
Feldspars
Lithic Fragments
17
Sandstone Maturity
Texturally and compositionally immature . Mainly
unstable grains, poor sorting, angular grains.
Texturally and compositionally mature. Mainly
quartz grains, well sorted, rounded grains
18
Goldich Reaction Series
19
Sandstone mineralogy related to time, climate
and transport distance
IMMATURE
Lithics, Feldspars Quartz
SUBMATURE
Feldspars Quartz
Quartz Feldspars
Quartz Feldspars
SUBMATURE
MATURE
SUPER MATURE
Quartz
Quartz
20
(No Transcript)
21
Sandstone Classification Systems The Pettijohn
(1975) System
22
Lithic Arenite
Quartz Arenite
Mature/Distant/Old
Immature/Proximal/ Young
23
Arkose
Submature/ Proximal-Distal/ Moderately old
24
(No Transcript)
25
(No Transcript)
26
(No Transcript)
27
(No Transcript)
28
Sandstone Classification Systems The Pettijohn
(1975) System
29
Graywackes
Q
Quartz wacke
5
Arkosic wacke
Lithic wacke
F
50
R
30
Graywackes
31
Sandstone Classification Systems The Pettijohn
(1975) System
32
Mudstones/Shales

• Consists of silt and clay-size minerals
• Quartz
• Phyllosilicates
• (a) Kaolinite
• 11 mineral
• (b) Smectite
• 21 mineral
• (c) Illite
• 21 mineral

Very fine particle size and cohesiveness of
sediments results in a sheet-like appearance.
33
(No Transcript)
34
(No Transcript)
35
(No Transcript)
36
(No Transcript)
37
Diagrammatic Representation of Illite
4Si
6O
Various Cations, Commonly K
6O
3Si1Al
4O, 2(OH)
6Al
4O, 2(OH)
4Si
6O
38
(No Transcript)
39
(No Transcript)
40
(No Transcript)
41
(No Transcript)
42
(No Transcript)
43
(No Transcript)
44
(No Transcript)
45
Distribution of Siliciclastics
Conglomerates Arenites
SUBMATURE
Arenites
Arenites Graywackes
Graywackes Mudstones
46
Provenance
47
Burial
Lithification 1. Cementation 2. Compaction 3.
Loss of Perm- iability 4. Loss of Poros-
ity 5. Mineralogical Alteration
48
(No Transcript)
49
(No Transcript)
50
Pressure solution/cementation
51
Siliceous cements
52
(No Transcript)
53
(No Transcript)
54
(No Transcript)