460:429—Tectonics & Regional Structural Geology Fall 2017 || Thursdays, 2:00-5:00 pm, WL-260 Martha Oliver Withjack & Roy W. Schlische Goal: Students will study the diversity of structural styles and tectonic settings worldwide using seismic-reflection, outcrop, and well data as well as the results of geometric and experimental modeling; students will become proficient in interpreting seismic data, avoiding seismic pitfalls (e.g., velocity pull-ups and push-downs), and unraveling the geologic history expressed on seismic profiles. Who can take this course? Students who have successfully completed an undergraduate-level course in structural geology (e.g., 01:460:407) may take 515. Other students may take the course with the permission of the instructors. Who should take this course? • Students interested in gaining experience in seismic interpretation • Students who wish to learn more about the structural geology or tectonics of rift systems, passive margins, fold-and-thrust belts, salt provinces, etc. • Geology students interested in interning or working for resource companies Grading: • Weekly projects*: ~50% • Class participation: ~25% • Exam (open book) (Monday, 12/18/2017, 12-3 pm): ~25% • A: 90-100; B+: 85-90; B: 80-85; C+: 75-80; C: 70-75; D: 60-70; F: <60 *Weekly projects typically involve interpreting a seismic-reflection profile and preparing of a short, written report that addresses questions related to the profile. Tentative Schedule:
Goal: Students will study the diversity of structural styles and tectonic settings worldwide using seismic-reflection, outcrop, and well data as well as the results of geometric and experimental modeling; students will become proficient in interpreting seismic data, avoiding seismic pitfalls (e.g., velocity pull-ups and push-downs), and unraveling the geologic history expressed on seismic profiles.
Who can take this course?Students who have successfully completed an undergraduate-level course in structural geology (e.g., 01:460:407) may take 515. Other students may take the course with the permission of the instructors.
Who should take this course?• Students interested in gaining experience in seismic interpretation• Students who wish to learn more about the structural geology or tectonics of rift systems, passive
margins, fold-and-thrust belts, salt provinces, etc.• Geology students interested in interning or working for resource companies
*Weekly projects typically involve interpreting a seismic-reflection profile and preparing of a short, written report that addresses questions related to the profile.
Tentative Schedule:09/07 Week 1 – Introduction to Structural Styles and Experimental Modeling: review of types of
faults and folds; strain-state associated with simple and reactivated faults; brittle vs. ductile behavior; scaling of experimental models; boundary conditions and edge effects; modeling materials (dry sand, wet clay, putty); types of structural styles
09/14 Week 2 – Tectonostratigraphic Packaging: mechanical stratigraphy; recognition of tectonostratigraphic packages by identifying faults and folds, highly ductile units (salt, shale), growth beds (syndeformational deposits), unconformities, and prograding wedges; examples include the Gulf of Mexico, North Sea, and Northwest Shelf (Australia)
09/21 Week 3 – Interpretation of Seismic-Reflection Data: wavefronts and raypaths, basics of exploration seismology, normal-incident raypaths, stacked vs. time-migrated seismic sections; water-bottom and peg-leg multiples; examples include the Gulf of Mexico and passive margin of Maritime Canada
09/28 Week 4 – Seismic-Interpretation Pitfalls: diffractions, seismic velocities, depth conversion, vertical exaggeration, pull-ups, push-downs; examples include the North Sea rift system, Northwest Shelf (Australia), and the Nankai trough (Japan)
10/05 Week 5 – Extensional Tectonics: divergent plate boundaries, continental rift systems, extensional collapse; geometry and scaling of normal-fault systems; fault-displacement folds; causes of continental rifting; pure vs. simple shear; examples include the Basin and Range, East African, eastern North American, and Suez (Egypt) rift systems
10/12 Week 6 – Basement-Involved Extensional Tectonics: rift basins and rift systems, transfer zones and accommodation zones; pre-rift and post-rift unconformities; types of rift basins; sedimentary systems in rift basins; fault-propagation folds; examples include Fundy, Newark and Jeanne d’Arc rift basins of eastern North America, Basin and Range, Suez, Rhine, Vøring / Viking (North Sea), and Dampier (Australia) rift basins
10/19 Week 7 – Passive Margins / Igneous Intrusions: relationship among rift basins, passive margins, spreading centers, transform faults, and fracture zones; magma-rich vs. magma-poor passive margins; seaward-dipping reflectors and large-igneous provinces; geometries of dikes, sills and sheets; examples include the Galicia and Norwegian continental margins, offshore Canada (Nova Scotia & Newfoundland), Baltimore Canyon and Carolina troughs, offshore France, Exmouth Plateau & Northwest Shelf (Australia)
10/26 Week 8 – Basement-Involved Compressional Tectonics: subduction and collision zones, fault-bend folds; examples include the Bighorn basin, Wind River basin, and Caspar Arch of the Rocky Mountains foreland; Ngalia basin (Australia)
11/02 Week 9 – Inversion Tectonics: positive and negative inversion; fault reactivation; null points; buttress folds; examples include the eastern North American rift system, North Sea rift system, Norwegian continental margin, Sunda arc (Indonesia), Cuyo basin (Argentina)
11/09 Week 10– Strike-Slip and Oblique-Slip Tectonics: transform, tear, transfer, and transcurrent faults; transtension and transpression; examples include the San Andreas (California) and Alpine faults (New Zealand); Ardmore basin (Oklahoma), and SE Asia (Thailand, Vietnam, etc.)
11/16 Week 11 – Restorations and Detached Extension: translation & rotation, bed-length balance; vertical and inclined simple shear; causes of detached extensional systems; recognition of detachment level; extensional fault-bend folds; examples include the Basin and Range, offshore France, Gulf of Mexico, and the Scotian margin (Canada)
11/21 (Tu) Week 12 – Detached Compressional Tectonics: evidence for the presence of highly-ductile units; linked extensional and compressional systems; accretionary prisms and fold-thrust belts; compressional fault-bend, fault-propagation, and detachment folds; examples include the Gulf of Mexico, Brazilian continental margin, southern Appalachians, Jura Mountains (Switzerland), and Nankai trough (Japan)
11/30 Week 13 – Salt and Shale Tectonics 1: properties of salt and shale; location of major salt provinces; salt structures (turtles, pillows, walls, diapers); allochthonous vs. autochthonous salt; examples include Gulf of Mexico, Brazalian continental margin, Zagros Mountains (Iran)
12/07 Week 14 – Salt and Shale Tectonics 2: factors that promote the flow of salt and influence the shape of salt structures; downbuilding; salt structures and extension; salt structures and
shortening; examples include the Gulf of Mexico, offshore France, and offshore Brazil.
Final open-book exam: Monday, December 18, 2017, 12:00 – 3:00 pm
