GEOL 1425 1st Edition Lecture 11 Outline of Last Lecture I. Sedimentary basinsII. Sedimentary environments III. Sedimentary structuresIV. Burial and digenesisOutline of Current Lecture I. MetamorphismII. Metamorphism and the earth systemIII. Causes of metamorphismIV. Types of metamorphismV. What you should know about Sedimentary Rocks (left out in last lecture, so posted here!)Current Lecture—Metamorphic Rocks II. About metamorphismA. Occurs when Rock is subject to new temperatures and pressures, dependent on temperature, pressure, and time. The minerology and texture of the rocks change until in equilibrium with the new temperatures and pressuresB. EX- a limestone filled with fossils may be changed to a white marble with no trace of fossils. (Unless there is water involved, in which other things will seep into the rock. C. Shale is so fine-grained that it is difficult to recognize the individual crystals. It may be come micacious schist, where the crystals are seen. D. CONCEPT 1: Chemically similar but visually very different!II. Metamorphism and the earth systemA. Driven by the Earth’s internal heat which power the parts of the earth system that govern metamorphic and igneous processes.B. Things at the surface will become pushed down into the earth, heating and pressurizing it (metamorphism!)i. Three primary factors that drive metamorphism: 1. Pressure (stress) – increases with depth about the same rate everywhere; 2. Temperature – 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.increases with depth; 3. Fluids- introducing or removing chemical components that dissolve in water. III. Causes of metamorphism A. 3 grades:i. Low grade- low pressure, high temperature- to 400C.ii. Intermediate grade- iii. High grade- high temperature and pressures of deeper rocks, temp over 500C- 100C, pressure can be minimal to extremely highB. Role of pressurei. Confining pressure- things around the rock, pressure from all around and not in a particular directionii. Directed pressure- directional pressure, exerted in a particular direction. (likea rock being compressed on both sides, deformation of the rocks near the plate boundary)C. Role of fluidsi. Metasomatism—change in a rocks bulk composition by fluid transport of chemical substances into or out of the rock without changing the rock’s texture.IV. Types of metamorphism:A. Shock metamorphism- pressure and heat changeB. Contact metamorphism- not a pressure thing, it’s about the heat. Limited to thinzones, due to quickly cooling lavaC. Regional metamorphism- most widespread type. Directly pressure over a long spatial difference, a regional effect. Convergent plate tectonic settings. D. Regional high pressure metamorphism- regional metamorphism that occurs under very high pressures and temperatures takes place at deeper levels of the crust along boundaries—deep down. E. High-pressure and ultra-high-pressure metamorphismF. Burial metamorphism- buried during subsidence and thermal sag. Digenesis alters minerology and texture of sedimentary rock. Pressure causes huge sequences of metamorphic rockG. Seafloor metamorphism (or metasomatism)V. What you need to know about sedimentary rocks for Test 2 (answers will be posted in the review)… 1. Sediment sorting2. Sedimentary basins3. Formation of clastic biogenic and chemical sediments4. The variety of sediment depositional environments5. Transport agents for sediments6. Sedimentary structures caused by particle motion then deposition7. Grading of sediment8. Clastic sedimentary rock classification9. Clastic sedimentary rock classification10. Rocks formed from calcium carbonate11. Marine organisms that form sediments12. Different environments where marine organisms live that form sediments13. Evaporite mineral