Salinity Paradox

[Hasanuddin]

I found this article and am perplexed as to the merit of the scientific logistics inherent in the data described: http://www.nature.com/nature/journal/v503/n7475/full/nature12714.html

 

Can anyone describe a mechanism how the oceans would have been much more salty 100M years ago, as this study claims, even though the planet was warmer (i.e., and the ice caps would've been more melted) and 100M year of salt leaching from the land had yet to happen???

 

Popular wisdom would suggest that the ancient oceans were less salty, not more, than they are today. Assuming that popular wisdom holds true, these same findings could be the result of some water got trapped underground because of the meteor blast (assuming that part of their hypothesis is correct); but that "underground" does not equate with being hermetic sealed. Rather the meteor blast would have shattered the ground, thereby facilitating the of direct leaching of salts.

[sman]

The salinity of the global oceans through time, it seems, results from some very complicated interplay among many diverse processes. High salinity fluids, for instance, dissolve further mineral solutes at a much slower rate. Also, recession of coastlines due to glaciation is surely accompanied by trapped, and then evaporated, seawater and therefore desalinization - at what rate I don’t know.

 

 

I found this article and am perplexed as to the merit of the scientific logistics inherent in the data described: http://www.nature.com/nature/journal/v503/n7475/full/nature12714.html

 

Nature is not a magazine in the habit of publishing anyone’s crackpot speculations, but a peer-reviewed scientific journal of the very highest caliber. Articles are published in here because it’s one of the best ways for one’s work to be scrutinized in detail by highly trained skeptics from diverse specialties. So some merit is granted with the platform.

 

If you are subscribed - and can thereby read further than the abstract - then this article (also from Nature) looks like it may detail some of the dynamics of global ocean salinity through geological time, but I can’t tell if it contains anything relevant on the timeframe you’re interested in. (100 million years ago?)

[Hasanuddin]

Dear Sman,

 

I hope you realize that your reply did not contain any mechanism that would account for a higher salinity level 100M years ago, given that that was a time which was substantially warmer than it is today, hence less water would be trapped in glaciers than is today; therefore one should expect lower salinity.

 

Thank you for the article, but I already acknowledged that salinity levels are both complex and connected to glaciation, therein lays the paradox. One hundred million years ago, scientific consensus of multiple studies puts it about 4C higher than today. http://www.google.com/imgres?imgurl=http://ossfoundation.us/projects/environment/global-warming/natural-cycle/images/542M_palaeotemps_2385x1067.png/image_large&imgrefurl=http://ossfoundation.us/projects/environment/global-warming/natural-cycle&h=343&w=768&sz=117&tbnid=ZKTxCLmOp8WK5M:&tbnh=90&tbnw=202&zoom=1&usg=__kBW_7m4O8-mZ2qgE8HNFmXcvKEI=&docid=gpRVAhfzHSDcRM&sa=X&ei=KLSZUuiQKc_roAS44IK4Dw&ved=0CGMQ9QEwCQ Which is significant if one also believes even a slight majority of studies coming out theorizing various climate change models. If the ideals of climate change are correct, and if past work correctly marks the temperature of the Earth 100M years ago at 4C higher than today, then significantly more polar/glacier ice would have been melted leading one to predict that the seas would have been much less salty that they are today.

 

As far as peer review and merit are concerned, isn’t wise to take that in a case-by-case basis? To assume that anyone source is pure and without error is to become dogmatic and blind.

 

In this case:

-I believe some scientists to core samples from Maryland and Virginia

-I believe they found an interesting formation

-I agree with their hypothesis that it could have been formed from a meteor

-I agree that their tests conclusively showed the presence of salts

 

Now, as to the origins of those salts I cannot agree that the suspected origin of this high salinity was necessarily from ancient oceans.

 

In order to believe that conclusion, one must hold two pretty high assumptions:

1. That the formation of trapped water was significantly trapped from “the outside.”

2. That there are no other naturally occurring sources of salt

 

I believe that this study is shortsighted on both of these accounts.

 

The authors of this article make the case pretty well how these pockets are isolated from any contact with the current ocean itself… that’s all well and good. But in terms of proximity to the described formation of trapped water, there is a lot more neighboring it than just the greater modern ocean… “outside” includes also a lot of rock, layer upon layer of rock. Common within the earth’s crust are various other formations within the rock, many of those involve layering or doming of salts.

 

Now, when a meteor hits it shatters the rock… that’s how we can identify impact craters. If you went to Delmarva, you won’t see any visible signs of impact… but the ground is shattered. Mapping that shattering shows us our impact area.

 

When meteors hit, they flip huge chunks of out and over backwards… thereby creating the potential for trapping ancient seawater.

 

My point is that by simultaneously shattering the ground and flipped the land over to create this trapped area of water… the meteor could have also linked the newly trapped seawater with a common salt formation thereby allowing salinity levels within that pocket to rise, therefore it does not reflect the actual salinity of ancient oceans.

[Essay]

Can anyone describe a mechanism how the oceans would have been much more salty 100M years ago, as this study claims, even though the planet was warmer (i.e., and the ice caps would've been more melted) and 100M year of salt leaching from the land had yet to happen???

Part of your 'solution' may be found here:

 

"Late Miocene salt deposits in the western Mediterranean indicate that the Mediterranean completely desiccated... ...about 40 times in the latest Miocene, withdrawing about 6% of the salt from the world's oceans (Ryan 1973). The net reduction in average ocean salinity by about 2.0% may have had a significant effect on ocean circulation." -p.201

 

Oxford Monographs on Geology and Geophysics no.16; Paleoclimatology; Crowley & North; 1991.

 

Note:

"If the Straights of Gibralter were closed today, the Mediterranean would dry up in about 1000 years...." -p.201

"Since the Mediterranean deposits are 2-3 km thick, and only 70 m of salt would be produced by isolation if it happened just once, the cycle of evaporation must have been repeated about 40 times...." -p.201

 

~ :)