GEOL 1425 1st Edition Lecture 10 Outline of Last Lecture I. About sedimentationII. Processes forming sedimentary rockIII. Some sedimentary environments Outline of Current Lecture I. Sedimentary basinsII. Sedimentary environments III. Sedimentary structuresIV. Burial and digenesisCurrent Lecture—Sedimentary Rock III. Sedimentary basinsA. With plate separation—plates move apart, crust gets thinner, and plates become colder and denser and eventually the crusts are dragged underneath the continent.B. Rift basins (or thermal sag basins) are deep, narrow, and long with thick successions of sedimentary rocks and extrusive and intrusive igneous rocks. EX—East Africa, Rio Grande, Jordan Valley in Middle East, rifting of Iceland. C. Continental plates tend to be lighter such as granite and basalt, and most saggingand deposition near the coast. D. Sedimentary basins started to form when Pangaea started to split, and when American and European plates began to split. E. CONCEPT 1—sedimentary basins- depressions are formed by subsidence, in which a broad area of crust sinks. They are regions of at least 10000 km^2 wherethe combination of deposition and subsidence.II. Sedimentary environmentsA. Consist of continental, shoreline, and marine.B. Siliclastic sediments= the stuff that’s eroded from continentsIII. Sedimentary structuresA. All kinds of features in sediments formed at the time of deposition. EX: bedding (stratification), cross-bedding, These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.B. Cross-beds form when grains are deposited of the steeper, down current (lee) slopes of sand dunes con land or of sandbars in rivers and under the sea. Beds deposited on the leeward side. The can be complex because of change in wind directions, which can cause them to be in large crossbed sequences. C. Grading is generally size-based rather than density-based!D. Bedding sequences—usually formed by rivers. In some points of its movement has more movement than others. Deposits material on inside of curve, and erodes materials along outside curve. IV. Burial and digenesis-A. Preservation of sediments within a sedimentary basinB. The major physical and digenetic change is compaction. It squeezes the water out of rocks and makes rocks much
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