EES 1030 Lecture 10 Outline of Last Lecture I. Structure of an AtomII. Atoms and IsotopesIII. Radioactive DecayIV. Requirements for Isotopic DatingV. Carbon-14 or radiocarbon datingVI. Radiometric Dating MethodsVII. Earth’s oldest rocksVIII. Sedimentary rocks: not easy!IX. Volcanic Ash LayersOutline of Current Lecture X. Structural GeologyXI. Mapping Geological StructuresXII. Investigation of the shallow EarthXIII. Style of Rock DeformationXIV.Brittle DeformationXV. FaultsXVI. Dip-Slip FaultsXVII. Strike-Slip FaultsXVIII. Ductile Deformation: FoldsXIX. MonoclinesThese 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.XX. Domes and BasinsCurrent Lecture- Structural Geologyo Study type of rocks and their geometry: deformation? Folds, faults, jointso Important to society Examples: Stability of ground or building, groundwater flow, tracing surface coal & ore deposits, gas & oil traps, construction siteso Defomation: general term for all changes in the original form or size of a rock unit Most common forms of deformation are: folding and faultingo Stress force applied to a given areao Strain: changes in the shape or size of a rock unit caused by stresso Elastic deformation: the rock returns to nearly its original size and shape when the stressis removedo One elastic limit (strength) of rock is exceeded, it either: Flows (ductile or plastic deformation) or fractures (brittle deformation)- Mapping Geological Structureso Critical to know structure & type of rock unitso Strike (trend): Compass direction of line produced by intersection of an inclined rock layer or fault with horizontal planeo Dip (inclination): Angle of inclination of the surface of a rock unit or fault measured froma horizontal plane- Investigation of the shallow eartho Drilling: expensive, information from one spoto Seismic reflection: sound waves into ground get reflected from boundaries of different rock types- Style of Rock Deformationo What controls brittle vs. ductile deformationo Factors that influence the strength of a rock and how it will deform, include: Temperature Confining pressure Rock minerals Timeo Rapid deformation = brittleo Slow deformation = ductile- Brittle Deformationo Two type of rock fracture: Joints: no appreciable movement across crack- Very common rock structures- Concentrates effects of chemical weathering Faults: relative movement of rocks on either side of fracture- Faultso Sudden movement along fault  Earthquake- Dip-Slip Faultso Hanging Wall: rock surface above the faulto Footwall: rock surface below the faulto Dip-Slip Faults: Normal Normal faults accommodate lengthening or extension of crusto Dip-Slip Faults: Reverse & Thrust Reverse faults have dips greater than 45 degrees Thrust faults have dups less than 45 degrees- Strike-Slip Faultso Dominant displacement is horizontal and parallel to the strike of the fault Example: San Andreas fault- Ductile Deformation: Foldso During crustal deformation rocks are often bent into a series of wave-like undulations called folds as compressional stresses shorten and thicken the crust Anticline: upfolded into arch Syncline: downfolded into trough- Monoclineso Large, step-like folds in otherwise horizontal sedimentary strata, often the result of a buried fault- Domes and Basinso Broad gentle warping of sedimentary stratao Dome: anticlinal structure: oldest rocks in centero Basin: synclinal structure: youngest rocks in