P1254325981YzbAU

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SEDIMENTARY ROCKS
Texture, structure and composition
Form sheet for clastic sedimentary rocks
I Color II Texture gr. Size, sorting,
roundness III Structure IV Allogenic
constituents A. Grains B. Matrix V
Authigenic constituents A. Cement B.
Secondary minerals VI Name
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SEDIMENTARY ROCKS
Texture, structure and composition
Form sheet for clastic sedimentary rocks
I Color
colorless (white or tan) red, brown or yellow
gray, black
fe oxides hydroxides
organic matter
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SEDIMENTARY ROCKS
Texture, structure and composition
Form sheet for clastic sedimentary rocks
I Color II Texture gr. size, sorting,
roundness III Allogenic constituents A.
Grains B. Matrix IV Authigenic
constituents A. cement B. secondary
minerals V Name
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SEDIMENTARY ROCKS
Textures
Form sheet for clastic sedimentary rocks
II Texture
stream competence relief, gradient distance from
source
gr. size
textural maturity kinetic energy
characteristics of environment time and amount
sorting
textural maturity, also composition and
environment turbidites - angular qtz streams -
subangular qtz beach rounded qtz
roundness
depositional medium
sphericity
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SEDIMENTARY ROCKS
Textures
Sorting
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SEDIMENTARY ROCKS
Textures
Roundness
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SEDIMENTARY ROCKS
Sphericity
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SEDIMENTARY ROCKS
Texture, structure and composition
Form sheet for clastic sedimentary rocks
I Color II Texture gr. Size, sorting,
roundness III Structure IV Allogenic
constituents A. Grains B. Matrix V
Authigenic constituents A. Cement B.
Secondary minerals VI Name
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SEDIMENTARY ROCKS
Structures

• III Structure
• Bedding (internal fabrics)
• bedding thickness
• cross-bedding
• graded bedding
• imbricate structures
• soft-sediment deformation, bioturbation
• B. Bedding plane
• ripple marks
• current structures
• load structures
• trace fossils

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SEDIMENTARY ROCKS
Structures
Bedding structures
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SEDIMENTARY ROCKS
Structures
Graded bedding
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SEDIMENTARY ROCKS
Structures
Graded bed in scour fill
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SEDIMENTARY ROCKS
Structures
X-bedding
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SEDIMENTARY ROCKS
Structures
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SEDIMENTARY ROCKS
Structures
asymmetrical
symmetrical
Which type can be used to determine tops of beds?
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SEDIMENTARY ROCKS
Structures
Ripples
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SEDIMENTARY ROCKS
Structures
Ripple marks Alameda Road cut
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SEDIMENTARY ROCKS
Structures
Bioturbated zone in ss
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SEDIMENTARY ROCKS
Structures
flute casts
flute casts
current groove casts
current lineations
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SEDIMENTARY ROCKS
Structures
Current marks
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SEDIMENTARY ROCKS
Structures
Trace fossils
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SEDIMENTARY ROCKS
Structures
Mud cracks w/ raindrop imprints
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SEDIMENTARY ROCKS
Texture, structure and composition
Form sheet for clastic sedimentary rocks
I Color II Texture gr. Size, sorting,
roundness III Structure IV Allogenic
constituents A. Grains B. Matrix V
Authigenic constituents A. Cement B.
Secondary minerals VI Name
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SEDIMENTARY ROCKS
Composition
IV Allogenic constituents A. Grains B.
Matrix
reveals 1. provenence 2. diagenetic
events 3. length of transport (indirectly)
Quartz 2/3 of average ss Why? H
7 isotropic chemically inert
Feldspar 10-15 of average ss (60 average ig.
rock)
Lithic fragments average 15
Heavy minerals
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SEDIMENTARY ROCKS
Texture, structure and composition
Form sheet for clastic sedimentary rocks
I Color II Texture gr. Size, sorting,
roundness III Structure IV Allogenic
constituents A. Grains B. Matrix V
Authigenic constituents A. Cement B.
Secondary minerals VI Name
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SEDIMENTARY ROCKS
Composition
V Authigenic constituents A. Cement usually
silica, calcite also siderite, clays B.
Secondary minerals Fe oxides
hydroxides manganese hydroxides sulfides cla
ys from feldspar