100 likes | 291 Views
GRACE. See movie. Free air gravity anomalies derived from radar altimetric determinations of geoid height. milligals. Bathymetry determined from satellite radar derived gravity plus shipboard measurements. Major types of isostatic compensation
E N D
Free air gravity anomalies derived from radar altimetric determinations of geoid height milligals
Bathymetry determined from satellite radar derived gravity plus shipboard measurements
Major types of isostatic compensation • 1. Airy: crustal root compensates elevated topography • Ocean-continent crustal thicknesses • Majority of variations in elevations on continental mountain belts • Oceanic plateaus • 2. Thermal: elevated topography a result of thermal expansion • Ocean ridge system • Basin and Range • 3. Flexural isostasy • Bending of the lithosphere: oceanic trenches • Regional isostasy
Airy isostasy crust crustal thickening mantle
Airy isostasy topographic “load” crust compensating root mantle Simple Airy isostasy is dealt with in more detail in grav_anom.ppt
1300 C Thermal isostasy Temperature, degrees C uplift from thermal expansion 1300 0 crust A 50 A mantle lithosphere B B Lithospheric thinning 100 150 mantle athenosphere 200 Thermal thinning and uplift are dealt with in more detail in thermal.pdf
Outstanding continental examples of thermal or Airy isostasy thermal Airy Airy