Sediments and Sedimentary Rocks Chapter 5 Concepts you
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Sediments and Sedimentary Rocks Chapter 5
• • • Concepts you will need to know for the exams Weathering Erosion Transportation Sorting Angularity Sedimentary environments, Cross-bedding (sedimentary structures) Bioturbation, bedding sequences, diagenesis Classes of sediments and sedimentary rock: -based on grain size -based on chemical composition, e. g. , carbonate rocks ("carbonates") and evaporitic rocks ("evaporites")
Lecture Outline 1. Sedimentary rocks 2. Your sedimentary environment and Burial Diagenesis 3. Interpretation of clastic texture 4. Sedimentary structures 5. Sedimentary Rock classification
1. Sedimentary Rocks • Cover most of the land surface and seafloor • Your physical geography determines the dominant process at work in the sedimentary rock cycle • e. g. (1) Mountains => weathering and/or erosion • e. g. , (2) Southern Louisiana => • e. g. , (3) offshore Louisiana =>
1. Sedimentary Rocks • Cover most of the land surface and seafloor • Your physical geography determines the dominant process at work in the sedimentary rock cycle • e. g. (1) Mountains => weathering and/or erosion • e. g. , (2) Southern Louisiana => transportation or deposition or erosion • e. g. , (3) offshore Louisiana =>
1. Sedimentary Rocks • Cover most of the land surface and seafloor • Your physical geography determines the dominant process at work in the sedimentary rock cycle • e. g. (1) Mountains => weathering and/or erosion • e. g. , (2) Southern Louisiana => transportation or deposition or erosion • e. g. , (3) offshore Louisiana => erosion or sedimentation
erosion weathering transportation Erosion includes BOTH weathering and transportation
Sedimentary rocks are typically layered, (although layering is not diagnostic of only sedimentary rocks)
Lecture Outline 1. Sedimentary rocks; surface processes 2. Your sedimentary environment and Burial and diagenesis 3. Interpretation of clastic texture 4. Sedimentary structures 5. Sedimentary Rock classification
A sedimentary environment is a geographic location that has a peculiar combination of geological processes
Walther’s Rule (1894) “The different (sedimentary) rocks (types) were formed beside each other in space, but in a crustal profile we see them lying on top of each other…. ”
Bedding sequences--are successions of rock ( in a vertical profile) that help geologists work out the past environment
Lateral associations Vertical stacking http: //www. mines. unr. edu/geology/faculty/jthomepage/GEOL _202_files/10%20 depmodel%20%2712. pdf
Mount Sharp, Mars– What type of sedimentary environment created these layer geometries?
Where do you live? • What dominant sedimentary process is at work where you live? http: //sedimentlog. blogspot. com/
If deposition is the dominant process, e. g. , offshore Lousiana then rocks are in the process of being formed: Diagnesis includes (1) compaction = volume loss (mechanical squeezing) and is accompanied by dewatering (= water loss) (by chemical or physical means) (2) changes in mineral composition (chemical process with heat and or fluids) (3) cementation (physical) If a sediment eventually becomes a rock we say it is lithified
DIAGENESIS compaction
DIAGENESIS compaction dewatering
DIAGENESIS compaction dewatering Cementation & mineral changes
Lecture Outline 1. Sedimentary rocks; surface processes 2. Your sedimentary environment and Burial and diagenesis 3. Interpretation of clastic texture 4. Sedimentary structures 5. Chemical and biological classification
Geological FUZZY rules for determining degree of weathering and transport a rock or sediment has experienced respectively
(1) Product composition
(2) Degree of sorting
• Sorting is a measure of how similar grain sizes are within a sediment or rock and tells us about the relative strength of the current before it dropped (deposited) it cargo. • In a current of water or air, the larger and denser grains fall faster than the smaller grains. That is, for the same density, size determines settling velocity
(3) Angularity or roundness (antonym) is a measure of the distance of transportation
Which of the following sediment characteristics is best used to determine former current speed? 1. sorting 2. angularity or roundness 3. diagenesis
Lecture Outline 1. Sedimentary rocks; surface processes 2. Your sedimentary environment and Burial and diagenesis 3. Interpretation of clastic texture 4. Sedimentary structures 5. Chemical and biological classification
Cross-bedding: sets of bedded material within rock layers that are inclined at angles as large as 35 degrees from the horizontal. These latter indicate windblown conditions in either a desert or a beach.
2 directions of fluid movement
Fossil example of the past activity of organisms mixing sediment --- an example of fossil BIOTURBATION
Lecture Outline 1. Sedimentary rocks; surface processes 2. Your sedimentary environment and Burial and diagenesis 3. Interpretation of clastic texture 4. Sedimentary structures 5. Sedimentary Rock classification
Three types of sedimentary Rocks • Clastic • Biochemical • Chemical
Major Classes of sediments and sedimentary rocks For clastic sedimentary rocks there is a classification scheme based on the SIZE of their clasts, (or rock fragments) that comprise them.
Clst size indicates ancient relative current velocity weak moderate >=1. 8 km/hr (strong currents)
MOBILE SEISMIC LABORATORY Radio antenna 240 -channel Sercel 388 radiotelemetric seismic acquisition system Electricalmechanically detonated surface seismic shear
17 th St Canal Breach W E ~6 m sand N S ~16 m sand ~6 -9. 00 a. m. , Aug. 29, 2005 (Adapted from Rogers et al. , 2008;
What type of sediment is peat? 1. chemical 2. clastic 3. biological
The End of Chapter 5
- Igneous metamorphic sedimentary
- Igneous rock to metamorphic rock
- Chapter 6 sedimentary and metamorphic rocks answer key
- Concept map of different types of rocks
- Clastic chemical and biochemical sedimentary rocks
- Sedimentary rocks
- Sedimentary rocks record past geological events and ____.
- Sedimentary weathering
- Esrt sedimentary rocks
- Sedimentary rocks examples
- Concept map of rocks
- Biochemical sedimentary rocks
- Clastic
- Sedimentary
- Characteristics of sedimentary rocks
- What are sedimentary rocks
- In sedimentary rocks lithification includes
- How do sedimentary rocks form
- Cementation sedimentary rocks
- How is chert formed
- Sedimentary rocks examples
- Soest hawaii
- Fun facts about sedimentary rocks
- Metamorphic rocks properties
- Characteristics of sedimentary rocks
- Classify sedimentary rocks
- Formation of sedimentary rocks leaving cert
- Esrt sedimentary rocks
- Features of sedimentary rocks
- Matrix supported conglomerate
- Attritiom
- Facts on sedimentary rocks
- Classification of rocks
- Shale rock classification
- Non banded grains
- Types of sedimentary rocks
- Sedimentary igneous rocks
- Transportation sedimentary rocks
- Clastic sedimentary rocks
- Luster streak
- Sedimentary rocks in texas
- Orthochemical and allochemical
- Chemical sedimentary rocks formed
- Sedimentary rock description
- Sedimentary rocks
- How are sedimentary rocks formed
- Explain the rock cycle
- Chemical sedimentary rocks formed
- How are sedimentary rocks formed
- How are sedimentary rocks made
- Classifying rocks
- Sedimentary rocks physical properties
- Sedimentology
- Sedimentary rocks turn into metamorphic
- Sedimentary rocks
- Importance of sedimentary rocks
- Sedimentary rock
- Marine regression
- How do chemical sedimentary rocks form
- Characteristics of sedimentary rocks
- Process of formation of sedimentary rocks
- Sedimentary rocks
- Fossils in sedimentary rocks
- Schist rock
- Angular sedimentary rocks
- Sedimentary rocks
- How is intrusive igneous rock formed
- Rhyolite
- Classification of marine sediments
- A low hill is composed of unsorted sediments
- A process that squeezes or compacts sediments
- A process that squeezes, or compacts, sediments
- The process that presses sediments together
- Biogenous sediments definition
- Chapter 4 section 1 the rock cycle answer key