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EthanWM
Dec10-09, 11:36 AM
Hey guys,

I have an assignment to do on Glaciation for university but i'm a bit lost with an aspect of the question and was wondering could anyone help.

The aspect is how the Thermohaline Circulation is linked to the Quaternary Glaciation. I can't find any published articles about it from researchers or anything. Could anyone help by pointing me in the right direction?

Thanking you,

Ethan

Xnn
Dec10-09, 12:15 PM
http://geology.rutgers.edu/~jdwright/MarGeol/Old%20Marine%20Geol%20folder/Driscoll.pdf

The cause of Northern Hemisphere glaciation about 3 million years ago remains
uncertain. Closing the Panamanian Isthmus increased thermohaline circulation
and enhanced moisture supply to high latitudes, but the accompanying heat
would have inhibited ice growth. One possible solution is that enhanced moisture
transported to Eurasia also enhanced freshwater delivery to the Arctic via
Siberian rivers. Freshwater input to the Arctic would facilitate sea ice formation,
increase the albedo, and isolate the high heat capacity of the ocean from the
atmosphere. It would also act as a negative feedback on the effciency of the
"conveyor belt" heat pump.

http://www.nature.com/nature/journal/v415/n6874/full/415863a.html

Data and models both suggest that abrupt climate change during the last glaciation originated through changes in the Atlantic thermohaline circulation in response to small changes in the hydrological cycle.

http://wapedia.mobi/en/Quaternary_glaciation

No completely satisfactory theory has been proposed to account for Earth's history of glaciation. The cause of glaciation may be related to several simultaneously occurring factors, such as astronomical cycles, atmospheric composition, plate tectonics, and ocean currents. [2]

Andre
Dec10-09, 12:33 PM
Maybe google with AMO Atlantic Meridional Overturning

To get for instance:

http://www.sciencemag.org/cgi/content/abstract/316/5821/66

But although the question is simple, the answer is worth several PhD level studies and then it's probably still different.

There is a whole more to that.

Xnn
Dec10-09, 02:51 PM
Probably worth mentioning that CO2 levels were a factor in the Antarctic glaciation. It not as if they were all that high at the time compared to the glacial free Eoecen and Oligocene. See the following:

http://earth.geology.yale.edu/~mp364/index.cgi?page-selection=2

The fall in pCO2 likely allowed for a critical expansion of ice sheets on Antarctica, and promoted conditions that forced the onset of terrestrial C4 photosynthesis.

mspelto
Dec10-09, 05:22 PM
The key is that ocean currents are density driven and cold temps and added salinity increase the density of water. Changes in meltwater inputs and temperature can then alter the formation and movement of deep water. Wallace Broecker came up with the original conveyor belt idea. I had a meeting with him and George Denton back in the mid- 1980's when he was putting this together.
http://www.tos.org/oceanography/issues/issue_archive/issue_pdfs/4_2/4.2_broecker.pdf There are plenty of articles the first link is for a general look at how it is realted to present. The second in on the glaciation link in the past.
http://www.whoi.edu/page.do?pid=12455&tid=282&cid=10149
http://www.essc.psu.edu/~bjhaupt/papers/guest97.sh/guest-sh.html