Unformatted text preview: Earth Structure & the Geologic Cycle TODAY'S DISCUSSION ____________________________ Earth structure The geologic cycle Earth Structure ____________________________ Three Earth structural regions Isostacy Three Earth stuctural regions ____________________________ Core Mantle Crust Earth in cross section Figure 11.2, page 325 Earth in cross section: Earth's interior Figure 11.2, page 325 Earth in cross section: Inner core to crust Figure 11.2, page 325 Structural units of Earth's interior
ZONE Lithosphere Athenosphere Upper mantle Lower mantle Outer core Inner core THICKNESS (mi) 43 112 260 1385 1400 760 MATERIAL Granite,basalt,olivine Olivine Olivine Olivine Liquid iron Solid iron Earth in cross section: detail from upper mantle to crust Figure 11.2, page 325 Structure of the lithosphere & asthenosphere
ZONE SUBZONE THICKNESS (mi) MATERIAL DENSITY LITHOSPHERE Continental crust Oceanic crust Uppermost mantle ASTHENOSPHERE 43 1937 3 Rigid granite Rigid basalt Rigid olivine Low Middle Dense Dense 112 Plastic olivine Isostacy ____________________________
Definition: The buoyant adjustment that takes place as weight is loaded on & unloaded off portions of Earth's crust Greater weight depresses asthenosphere Lesser weight allows asthenoshere to rise Resulting uplift is called isostatic rebound Isostatic adjustment of crust: maximum mass, maximum sinking (displacement) Figure 11.4a, page 328 Isostatic adjustment of crust: loss of mass results in isostatic rebound Figure 11.4b, page 328 Isostatic adjustment of crust: gain of mass by oceanic crust means sinking there Figure 11.4c, page 328 The geologic cycle ____________________________ Three components Hydrologic cycle Rock cycle Tectonic cycle The geologic cycle Figure 11.5a, page 330 The geologic cycle Figure 11.5b, page 330 The hydrologic cycle ____________________________ Simplified model of the transformations & paths of water as it flows through the Earth system Powered by the Sun and gravity Involves tremendous flows of mass & energy The hydrologic cycle Figure 9.1, page 247 The rock cycle Figure 11.6, page 332 ...
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- Spring '08
- Structure of the Earth, crust Oceanic crust, Geologic Cycle, Athenosphere Upper mantle Lower mantle