Across
- 1. smooth, striated surface caused by friction along fault
- 5. tilted fold • hinge line not horizontal • sloped downwards (“plunges” into ground) • make “V” pattern on surface
- 7. type of Deformation • temporary and reversible • rock returns to original shape after stress is removed • environment: all plate boundaries, at shallow depths • only up to elastic limit • beyond: progresses to ductile or brittle deformation • results: storing of stress (elastic energy) • not usually visible in rock structures • measured with GPS over time
- 9. • step-like fold with only one limb • result from vertical displacement beneath sedimentary strata
- 11. type of fault • low angle (<30°) reverse fault • older material set atop younger material • mostly regional – 100s of km in length
- 14. rock block above fault plane
- 16. cluster of parallel faults
- 20. type of Deformation • irreversible • bending, stretching, flowing • chemical bonds break, new ones quickly form • environment: primarily convergent plate boundaries • results: folds (and metamorphism)
- 22. imaginary axis around which a layer is bent and traces maximum curvature
- 23. • fractures in rock structures *without* displacement • not directly related to plate boundaries • often parallel groups • weathering enlarges cracks • types: columnar jointing, exfoliation, expansion
- 26. stress is applied equally in all directions, aka pressure, environment: burial – weight of overlying material, source: lithostatic pressure, deformation: reduces volume and increases rock density (pore spaces reduced)
- 28. upthrown block
- 30. angle that a rock surface makes with a horizontal plane (e.g., water)
- 31. elongated, vertical offset • produced by rapid slip at surface • looks like a single step!
- 32. v-shaped down-dropped block
- 33. type of Fault • displacement is along dip direction • vertical movement up or down • pronounced scarp • types: normal and reverse
- 36. type of Fault • movement: hanging wall up, footwall down • older/deeper layers pushed up relative to younger layers • compressional stress • shortens crust • convergent settings
- 38. parallel mountain ranges formed by large normal faults
- 39. force applied to an object (σ=F/A), units: Pascals (Pa) = N/m2, causes deformation, main types of stress: confining and differential
- 40. stress is *not* applied equally in all directions, 3 types – compression, tension, shear
- 42. • rock is stretched/pulled apart • environment: divergent plate boundaries • results: crustal thinning • widened in direction of stress, thinned perpendicular to it • deformation: fractures
- 43. • forces are parallel but moving in opposite directions • Rocks slip along planes of weakness • environment: transform plate boundaries • results: one part of rock moves past another • deformation: fractures
- 45. Jointing • tension: expansion of intrusive igneous rock due to reduced pressure after formation • usually granite • form curved exfoliation sheets (layers) • “onion skin weathering”
- 46. • block opposite of observer moves left
- 47. type of Fault • movement: hanging wall down, footwall up • tensional stress • extends crust • divergent settings
- 48. • circular downfolded structure • youngest rock in middle • causes: crustal subsidence or meteorite impacts
- 49. • rock fractures caused by brittle deformation • earthquake if sudden and significant • fault creep if slow and continuous • displacement occurs along fault plane • breakage and movement! • environments: • all plate boundaries • generally shallower depths (low T and P) • types: dip-slip and strike-slip
- 50. type of Fault • displacement is along both strike and dip directions • normal or reverse + strike slip • stress: multiple types • multiple settings • types: it’s complicated
Down
- 2. type of Fault • displacement is along strike direction • blocks move horizontally past each other • ~vertical fault plane • visible surface offsets • lack: scarp, hanging wall, footwall • shear stress • transform settings • types: right-lateral and left-lateral
- 3. • rock structures formed by ductile deformation • compression • curved shape in rock layer(s) • environments: • convergent plate boundaries • great depths (high T and P)
- 4. changes to volume, shape, or position of crustal rock due to tectonic stresses and burial, types: mountain building bending (folding) breaking (fracturing or jointing)
- 6. pressure increases with depth beneath the surface, expressed as megapascals (MPa) or gigapascals (GPa)
- 7. Joints • tension: removal of overburden (material on top) • erosion or uplift • stretching over a rising anticline • vertical or angular cracks
- 8. rock block below fault plane
- 10. • rock is squeezed together • environment: convergent plate boundaries • results: crustal thickening • shortened in direction of stress, thickened perpendicular to it • deformation: folds or fractures
- 12. flat plane that represents the fracture surface of a fault
- 13. place where fault can be seen at surface
- 15. • circular upfolded structure • oldest rock is in the middle • causes: usually igneous intrusion
- 17. • seams of minerals that form when dissolved substances carried by water solutions precipitate in cracks • commonly: quartz, calcite, feldspar • less common: pyrite, galena, magnetite, gold, silver
- 18. • form by collision and compression • associated with folds • Alps, Himalayas, Appalachians
- 19. • change in size, shape, or position of a material under stress • 3 types: elastic, ductile, brittle
- 21. 3D orientation of a rock layer • mapped and described by strike and dip
- 24. arch-shaped fold • convex upwards • limbs dip away from hinge • oldest rock is in middle
- 25. – measure of deformation
- 26. Jointing • ~hexagonal columns formed by contracting lava • mostly basalt
- 27. rocks formed by sudden brittle deformation and lithification
- 29. direction of a horizontal line in an inclined plane
- 34. Deformation • irreversible • cracking, breaking, fracturing • chemical bonds break, no longer connected • environment: all plate boundaries, variety • results: faults, joints, veins
- 35. • break in rock caused by brittle deformation • tension, compression, shear • expansion, contraction • environments: • all plate boundaries and plate interiors • generally shallower depths (lower T and P) or surface • types: faults, joints
- 37. • block opposite of observer moves right
- 41. trough-shaped fold • concave upwards • limbs dip towards hinge • youngest rock in middle
- 44. imaginary surface that connects all hinge lines of folded strata
- 46. “halves” of fold separated by axial plane