All Questions
Tagged with paleoclimatology oceanography
12 questions
5
votes
0
answers
87
views
Ocean oscillations with long time periods
I heard that some ocean oscillations act on a time scale of a millennium. Is this true, or at least argued by some oceanographers? If so, what are they and what causes them? If not, what are the ...
- 615
7
votes
1
answer
98
views
Why aren't diatoms' shells used as a temperature proxy, but foraminifera shells are?
Changes in oceanic oxygen isotope ratios (18O to 16O) are reflected in the shells of ancient foraminifera.
However, I have not read of diatom shells being used, despite the fact that they were (and ...
- 857
8
votes
1
answer
865
views
how old are the gulf stream and the NAC?
After reading about the NAC (North Atlantic Current) weakening in the news, we got to wondering about its history and that of the gulf stream. Specifically, how and when did they start? Were there ...
- 183
5
votes
1
answer
388
views
Why the $\delta \, ^{18}\text{O}$ in foraminifera shells decrease with temperature even if the oceanic $\delta \, ^{18}\text{O}$ stay constant?
I understand why foram shells contain more $^{18}\text{O}$ when there are ice sheets present, since $^{16}\text{O}$ evaporates more readily and gets trapped in the ice, increasing the relative ...
- 17.7k
11
votes
2
answers
284
views
Would a volcanic winter trigger an oceanic "spring"?
There is large amounts of observations supporting the effects of volcanic eruptions on climate: A long term subtle warming effect due to $\small\mathsf{CO_2}$ and a short term, but more intense ...
- 17.7k
4
votes
2
answers
427
views
Is this scientific explanation of The Bible flood accurate?
I googled "the flood and freshwater fish" and came up with this question Christianity StackExchange: How did Noah preserve fresh water fish?.
The writer makes a lot of claims like how the salinity of ...
- 149
5
votes
2
answers
177
views
Why is the ocean paleotemperature trend downwards?
In The Encyclopedia of Paleoclimatology and Ancient Environments by Vivien Gornitz (2008, Springer) it is found that 50 My ago the sea temperature was about 13ºC above the present value.
.
AFAIK the ...
- 283
19
votes
3
answers
2k
views
Why deep ocean didn't freeze during snowball Earth?
I know that at least twice in its history Earth was totally frozen. I also know that the last time it happened there were already life on Earth, and it survived. In deep water, under the ice, which ...
- 525
19
votes
2
answers
1k
views
Current consensus on the Messinian Salinity Crisis
In 1973, Hsü et al. explained the findings of a large evaporite deposit during the Messinian (Latest Miocene stage, ca. 6Ma) in the Mediterranean by a basin-wide desiccation event. It has been ...
- 5,348
8
votes
1
answer
546
views
How global was the Bonarelli Oceanic Anoxic Event?
The Bonarelli Event (a.k.a. OAE2) is a well-studied episode of "worldwide" oceanic anoxic event at the Cenomanian-Turonian boundary (ca. 94 Ma). It is characterized by the presence of organic-rich ...
- 5,348
8
votes
1
answer
140
views
How has river to ocean flux changed over the last 500 million years?
Do we have any rough indices of how this flux has changed? I'm particularly interested in knowing whether the flux was higher or lower during the time of Pangaea, or during the time of the unusually ...
- 7,827
20
votes
1
answer
2k
views
What was the ocean circulation like during the time of Pangaea?
So Enderton and Marshall (2009) wrote an interesting paper on the ocean circulation of various aquaplanets covered with certain terrain: e.g. an aquaplanet with a small ridge of land that ranged from ...
- 7,827