Sediments and Sedimentary Rocks Chapter • • • • • • • • • • • • 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 Sedimentary rocks Your sedimentary environment and Burial and diagenesis Interpretation of clastic texture Sedimentary structures Sedimentary Rock classification 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 => 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 => 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 Sedimentary rocks; surface processes Your sedimentary environment and Burial and diagenesis Interpretation of clastic texture Sedimentary structures Sedimentary Rock classification A sedimentary environment is a geographic location that has a peculiar combination of geological processes The End of Chapter [...]... 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... determines settling velocity velocity (3) Angularity or roundness (antonym) is a measure of the distance of transportation 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 Cross-bedding: sets of bedded material within rock layers...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 Where do you live? •What dominant sedimentary process is at work where you live? If deposition... that help geologists work out the past environment Where do you live? •What dominant sedimentary process is at work where you live? 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