沉积构造(Sedimentary_structures)_英文课件
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Contents
• Introduction
• Stratigraphic principles
• Unconsolidated clastic sediments • Sequence stratigraphy
• Sedimentary rocks
• Sedimentary basins
• Diagenesis
EaES 350-6
19
EaES 350-6
20
Sedimentary structures
Planar stratification
• Planar lamination (or planar bedding) is formed under both lower-stage and upper-stage flow conditions
• Planar stratification can easily be confused with planar cross stratification, depending on the orientation of a section (strike sections!)
7
Animation
EaES 350-6
8
Sedimentary structures
Cross stratification
• Cross lamination (small-scale cross stratification) is produced by ripples
• Cross bedding (large-scale cross stratification) is produced by dunes
10
EaES 350-6
11
EaES 350-6
12
EaES 350-6
13
EaES 350-6
14
EaES 350-6
15
EaES 350-6
16
EaES 350-6
17
EaES 350-6
18
Sedimentary structures
Cross stratification
• The angle of climb of cross-stratified deposits increases with deposition rate, resulting in ‘climbing ripple cross lamination’
• Straight-crested bedforms lead to planar cross stratification; sinuous or linguoid bedforms produce trough cross stratification
EaES 350-6
9
EaES 350-6
• Microforms (e.g., ripples) • Mesoforms (e.g., dunes) • Macroforms (e.g., bars)
EaES 350-6Fra bibliotek2EaES 350-6
3
EaES 350-6
4
Sedimentary structures
• Laminae and beds are the basic sedimentary units that produce stratification; the transition between the two is arbitrarily set at 10 mm
• Models in sedimentary geology
• Sediment transport and deposition • Applied sedimentary geology
• Sedimentary structures
• Reflection
• Facies and depositional environments
• Cross-stratified deposits can only be preserved when a bedform is not entirely eroded by the subsequent bedform (i.e., sediment input > sediment output)
• Antidunes form cross strata that dip upstream, but these are not commonly preserved
• A single unit of cross-stratified material is known as a set; a succession of sets forms a co-set
• Glacial/eolian/lacustrine environments
• Fluvial/deltaic/coastal environments
• Shallow/deep marine environments
EaES 350-6
1
Sedimentary structures
• Sedimentary structures occur at very different scales, from less than a mm (thin section) to 100s–1000s of meters (large outcrops); most attention is traditionally focused on the bedform-scale
• Fining-upward successions and coarsening-upward successions are the products of vertically stacked individual beds
EaES 350-6
5
EaES 350-6
6
Animation
EaES 350-6
• Normal grading is an upward decreasing grain size within a single lamina or bed (associated with a decrease in flow velocity), as opposed to reverse grading
• Introduction
• Stratigraphic principles
• Unconsolidated clastic sediments • Sequence stratigraphy
• Sedimentary rocks
• Sedimentary basins
• Diagenesis
EaES 350-6
19
EaES 350-6
20
Sedimentary structures
Planar stratification
• Planar lamination (or planar bedding) is formed under both lower-stage and upper-stage flow conditions
• Planar stratification can easily be confused with planar cross stratification, depending on the orientation of a section (strike sections!)
7
Animation
EaES 350-6
8
Sedimentary structures
Cross stratification
• Cross lamination (small-scale cross stratification) is produced by ripples
• Cross bedding (large-scale cross stratification) is produced by dunes
10
EaES 350-6
11
EaES 350-6
12
EaES 350-6
13
EaES 350-6
14
EaES 350-6
15
EaES 350-6
16
EaES 350-6
17
EaES 350-6
18
Sedimentary structures
Cross stratification
• The angle of climb of cross-stratified deposits increases with deposition rate, resulting in ‘climbing ripple cross lamination’
• Straight-crested bedforms lead to planar cross stratification; sinuous or linguoid bedforms produce trough cross stratification
EaES 350-6
9
EaES 350-6
• Microforms (e.g., ripples) • Mesoforms (e.g., dunes) • Macroforms (e.g., bars)
EaES 350-6Fra bibliotek2EaES 350-6
3
EaES 350-6
4
Sedimentary structures
• Laminae and beds are the basic sedimentary units that produce stratification; the transition between the two is arbitrarily set at 10 mm
• Models in sedimentary geology
• Sediment transport and deposition • Applied sedimentary geology
• Sedimentary structures
• Reflection
• Facies and depositional environments
• Cross-stratified deposits can only be preserved when a bedform is not entirely eroded by the subsequent bedform (i.e., sediment input > sediment output)
• Antidunes form cross strata that dip upstream, but these are not commonly preserved
• A single unit of cross-stratified material is known as a set; a succession of sets forms a co-set
• Glacial/eolian/lacustrine environments
• Fluvial/deltaic/coastal environments
• Shallow/deep marine environments
EaES 350-6
1
Sedimentary structures
• Sedimentary structures occur at very different scales, from less than a mm (thin section) to 100s–1000s of meters (large outcrops); most attention is traditionally focused on the bedform-scale
• Fining-upward successions and coarsening-upward successions are the products of vertically stacked individual beds
EaES 350-6
5
EaES 350-6
6
Animation
EaES 350-6
• Normal grading is an upward decreasing grain size within a single lamina or bed (associated with a decrease in flow velocity), as opposed to reverse grading