EAR 110 1st Edition Lecture 14Outline of Last Lecture:I. Rocks formed by chemical reactionsII. Rocks by organismsIII. OtherIV. Sedimentary rock characteristicsV. Common sedimentary rocksVI. Indicators of environmentVII. Resources in sedimentary rocksOutline of Current Lecture:I. Force and stressII. Strength of rockIII. How rocks respond to force and stressIV. Types of fracturesV. Stresses that form jointsVI. Describing faultsVII. FoldsCurrent LectureChapter 8: Metamorphic RocksI. Force and stressa. Push or pull, expressed as acceleration experienced by a massb. Kinds of stressi. Confining pressure – same amount of stress from all directionsii. Differential stress – different amounts of stresses from different directionsII. Strength of rocka. Strength of continental crust increases with depth, then weakensb. Too much stress = failureIII. How rocks respond to force and stressa. Displacementb. Rotationc. Straind. Or remained unchanged if stress is small enoughe. Types of stress: compression (pushing), tension (pulling), shear (ripping)i. Shallow levels – rocks fracture1. Break along faults (compression), brittle strike slip faults (shear)ii. Deeper levels – rocks flow1. Fold (compression), ductile shear zone (shear)IV. Types of fracturesa. Joint = crack where rock pulled apartb. Fault = rocks have slipped past one anotherThese 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.V. Stresses that form jointsa. Burial and tectonic forcesb. Cooling and contraction i. i.e. columnar joints in basalt flowsc. unloadingVI. describing faultsa. direction i. strike direction – line on map where fault existsii. dip direction – what direction water would flow; measured angle from horizontalb. parts of faultsi. hanging wall – where you hang your lanternii. footwall – where your feet would standc. sense of movementi. normal fault – hanging wall moves down relative to footwallii. reverse fault/thrust fault – hanging wall moves up relative to footwalliii. strike slip 1. left lateral – block on opposite side moves to the left2. right lateral – block on opposite side moves to the rightVII. Foldsa. Usually in pairs or repeatedb. Anticline – fold goes upc. Syncline – fold bends downd. Monocline – only has one limb of folde. Geometry of foldsi. Hinge – in center where fold bends sharplyii. Limbs – two sides of fold coming off of