{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

4_isostasy_geodynamo-1 - Isostasy(wrapup andearthsgeodynamo...

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon
Isostasy (wrap-up), and earth’s geodynamo GS222 Lecture 4
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Overview - this lecture Review of the isostasy homework – what did we learn? Why is the earth’s geodynamo important (to the climate  system, plate tectonics, and organisms)? How did the moon form and why should we care?
Background image of page 2
Hypsographic curve Contrast in height  largely driven by  crustal thickness ~50% of earth’s  surface is deeper  than 4000 m Change in sea level  of 10 m swamps  huge area (millions of  km 2)
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Isostatic rebound Ice sheets were up to 3000 m thick over N. America... Last Ice Age (~20,000 yr BP; 20 kyr BP) Deglaciation (20 kyr to 8 kyr BP)
Background image of page 4
Key points (Isostasy) Earth’s structure is composed of dense Fe-rich core,  and progressively less dense layers including mantle  and crust Density dictated primarily by chemical composition  (oxygen and silicon key) Rigid lithospheric plates float on asthenosphere    (a  ductile solid) Floating crustal blocks will reach level dictated by their  thickness and density relative to asthenosphere, known  as  isostatic equilbrium
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
The geodynamo system Magnetic field produced  in the fluid outer core of  the earth  Analogous to bar magnet,  inclined ~10 °  from  rotation axis
Background image of page 6
Image of page 7
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}