Remote sensinggeology[1]

• 1. Remote Sensing, Rocks and Soils

2. Prospecting and Exploration What were looking for is subtle Most rocks, even the most favorable, donot have extractable resources 1% of mineral occurrences are worthdetailed study 1% of those are worth drilling 1% of those are worth mining 3. Geologic Map ofWisconsin 4. Gravity Map ofWisconsin 5. Gravity Mean value about 9.8 m/sec2 = 1 g About 0.5% smaller at equator than poles Map unit = gal (for Galileo) = 1 cm/sec2 Mean gravity = 980 gal Maps contour in mgal = 10-6 g Modern gravimeters can detect .001 mgalvariations (= 1 ppb) A gravimeter is essentially a spring balance. 6. Gravimeter 7. Gravity Maps Gravity varies by latitude due to earthsequatorial bulge and centrifugal force Need altitude correction = 0.3 mgal/m = 3 x 10-7g/m Altitude only correction = Free-Air Anomaly Map Correct for mass between you and sea level =Bouguer Anomaly Map Correct for variations in thickness of crust =Isostatic Anomaly Map 8. Colorado Bouguer Map 9. Colorado Isostatic Map 10. ChicxulubImpact BasinGravity Map 11. Gravity Mapping Simple corrections for Gravimeters arelatitude and altitudebasically sensitive Density = Lithologyspring balances Can sense deep into Fragilecrust Prone to drift Discrete data points Labor intensive, low detail 12. Magnetic Map ofWisconsin 13. Geomagnetism Magnetic field of Earth = 40 microtesla =40,000 nt Varies from 25 to 70 mt Non-axial Not centered on the earth Varies over a human lifetime 14. Overall Magnetic Field of Earth 15. MAGSAT Map of Earth 16. Magnetic Mapping Corrections are Magnetism iscomplex and timeelectromagneticvariablephenomenon No simple correlation Instruments can bewith lithologypurely electronic Cant sense deep into Can recordcrust because heatcontinuouslydestroys magnetism Can be extremelydetailed 17. Gravity and Magnetic Mapping Greater sensing depth Complex corrections Greater detail possible 18. Gravity and Magnetic MappingGravity mapsMagnetic MapsMechanical Instrument Instruments are purely electronicDiscrete readings Continuous readingsLess detail Great detailCan sense to great depths Can sense only a few kilometersdeepSimple corrections for latitude and Complex corrections in time andelevation spaceDensity correlates with rock type No simple correlation with rocktype 19. SatelliteImage ofWisconsin 20. GrandCanyon 21. Lake Vostok,Antarctica 22. CopperMines, Iran 23. Saline Valley,California 24. The Moon 25. Mercury 26. MarsFalseColorView 27. Remote and NotSo Remote Sensing 28. Telling Minerals Apart 29. Martian Minerals? 30. AbsorptionBands 31. RadarInterferometry: LAquila, Italy,2009 32. Haiti,2010 33. Haiti, 2010 34. Damage, Port au prince 35. Chile, 2010 36. Chile 2010 37. Chile, 2010, GPS 38. Ice Flow, Antarctica 39. Kilauea,Hawaii 40. Venus 41. Topography of Venus 42. RadarMap ofVenus 43. RadarMap ofVenus 44. Venus Gravity Maps 45. Gravity Map of Mars 46. Titan 47. Radar Image, Titan 48. Lakes onTitan 49. Sun Glint 50. Laser Rangefinder 51. Laser Reflector 52. LAGEOS 53. HerstmonceauxCastle (London) Latitude increasing(moving N) Longitude increasing(Moving E) 54. Lamont EarthObservatory(Near New York) Latitude increasing(moving N) Longitude decreasing (Moving W) 55. Trans-Atlantic Plate Motion New York moving west at 15.4 mm/yr London moving east at 16.6 mm/yr Relative motion = 32 mm/yr 56. Churchill, Manitoba Latitude decreasing(moving S) Longitude decreasing (Moving W) Rising rapidly 57. Real-Time Plate Motions 58. Sturgeon Bay,Wisconsin