1. Extreme climates of the past
Snowball Earth

4. Closer to now and closer to home
the last great ice sheets

7. Glacial evidence from Marine Sediment Cores

12. Ice Rafted Detritus
Glaciers produce completely unsorted sediments (sorting is the process of removing or enriching specific grain sizes based on the capacity of water or wind to carry them)
Included are very coarse grains (>0.063 mm or 63 microns)
In deep ocean away from margin slopes, coarse grains must have been “rafted” or floated to that site by ice

13. Changes in ice volume (d18O) over the last 150 Kyr
Holocene
LGM (MIS2)
MIS3
MIS5e

14. Flux of Terrigenous Clastic Sediment coarser than 63 microns
(mg/cm2/ky) Ka
(MIS5e)
Ruddiman, 1977

15. Changes in ice volume (d18O) over the last 150 Kyr
Holocene
LGM (MIS2)
MIS3
MIS5e

16. Flux of Terrigenous Clastic Sediment coarser than 63 microns
(mg/cm2/ky)
40-25 Ka
(MIS3)
Ruddiman, 1977

17. Changes in ice volume (d18O) over the last 150 Kyr
Holocene
LGM (MIS2)
MIS3
MIS5e

18. Flux of Terrigenous Clastic Sediment coarser than 63 microns
(mg/cm2/ky)
25-13 Ka
(MIS2)
Ruddiman, 1977

19. Ka
(MIS5e)
Ruddiman, 1977

20. 40-25 Ka
(MIS3)
Ruddiman, 1977

21. 25-13 Ka
(MIS2)
Ruddiman, 1977

22. Northern Hemisphere Glaciation
Developed ~3 million years ago
Waxing and waning of the Northern Hemisphere glaciers follows summer insolation at 60°N (Milankovich)
During the past 800 thousand years, the dominant cycle period is 100 thousand years
Ice rafted detritus concentrations increase with increasing ice volume

23. Climatic Importance of Glaciers
Albedo
Topography (Jet stream)
Fresh water in surface ocean