Re: Origins: rapid flooding
David Campbell (bivalve@isis.unc.edu)
Mon, 9 Sep 1996 11:58:53 -0500>David Campbell wrote:
>
>>The "madhouse" climate model (versus icehouse or greenhouse) was based on
>>some geologic evidence of very rapid change in sea level-less than a
>>century. It's not necessary to melt the glaciers all at once, though-if
>>they started to float, that would displace a lot of sea water very fast
>>(and not show up in 18O records).
>
>Beg to differ here. It most assuredly WOULD show up in the O-18 records. The
>O18 record comes from the shells of planktonic foraminifera and other
>photosynthetic organisms which die and fall to the ocean bottom. Since
>glacial ice is fresh water it will float on top of the salty sea water,
>creating a less saline, O-18 deficient layer on the ocean surface. The
>plankton will be forced to live in an environment in which there is less O-18
>to incorporate into their shells. When they fall to the sea floor, there will
>be an unmistakable signature in the sedimentary record of this event.
>
I don't seem too have been quite clear-floating the glaciers would not have
produced an 18O record. Melting certainly would.