#Sea Levels?
Hi, Chris–
Welcome to the forum section!
While the evidence may hint at disappearing oceans, it hints at oceans gone for
a longer time than human prehistory and at an earlier age, if at all.
1. The anhydrites from the Mediterranean, as Michael noted in his excellent
answer, are from 6 million years ago. I have read that the Mediterranean and
Black Seas lose more water than they receive from sources other than the
Atlantic. When the Straits of Gibraltar were closed 6 mya they dried up. I
wish I could have seen the waterfall when the Straits were reopened!!
Dates from the evidence are likely to show all the items are disconnected,
disproving any notion that we have evidence for disappearing oceans, as the
date of the Mediterranean evaporites removes them.
How thick are the Gulf of Mexico anhydrites and what date?
2. Seeming "beach sand" on the Mid-Atlantic ridge may be the only evidence that
survives inspection as far as I know, and someone else may be able to demolish
that (I am no professional in these matters).
3. I doubt limestone (as reported from the Marianas basin) is going to be
built up in any short time. To become limestone (as opposed to un-lithified
deposits of seashells and whatnot), I believe there must be some buildup of
sediments to allow lithification. Perhaps someone can tell us what the minimum
time would be; I am guessing it turns out to be comparable to the entire human
residence on earth.
4. If continental shelf canyons require missing oceans to be generated, surely
this will take a lot of time, millions of years, especially noting they seem
deeper than anything rivers have cut on land.
5. Sunken flat topped seamounts, if they are caused by low sea-levels, require
a slow decline of levels to allow time for the flattening of their tops. As
you already noted, Cretaceous fossils date some of them out of human prehistory
anyway, and separate them from Mediterranean anhydrites, to illustrate the
point that datings will be critical in dealing with the hypothesis.
5. Australia need not hinder the hypothesis or help it; as a plateau it would
still be semi-isolated.
6. If admissible as evidence at all, flood legends seem to me evidence for
non-disappearing oceans. If someone remembers floods, would they not also have
noticed the poor fishing, unemployment of sailors, and rotten weather (even
they vanish without becoming ice, the oceans moderate temperatures) before
those floods?
7. Language spreading patterns seem easier to explain without such disruptions;
see the Scientific Americans of 3/90 and 10/89 with articles about the
Indo-European languages; one of them at least (I am away from my collection) as
best I recall offers accounts of such dispersals worldwide that is at least as
easy without confusion by missing waters.
While it is fair enough to consider the evidence without requiring mechanisms,
some consequences follow no matter what the mechanism. Either (1) the water
vanished but not the salt (the water became ice on the continents, water of
hydration in rocks, or whatever), or (2) the salt vanished also (this seems to
require a wormhole or extraterrestrials to remove the water).
If the salt remained, any remnant of the oceans are horribly salty, and marine
life must have undergone an extinction that would make the demise of the
dinosaurs and their friends insignificant and likely would leave land life
gasping for oxygen (consider the rotting algae). This _must_ show up in the
fossil record, so these events must have been pre-Cambrian. If the salt
vanished also (well, at least there is no troublesome ice on the continents to
explain!), the same mechanism is going to have to leave some of the salt water
(else we have the marine extinctions again) and most of the plankton, and put
the salt water back later (Occam's razor says no fair demanding two
off-the-wall mechanisms) because volcanic water emissions and leaching of salts
are not going to do the job without ripping up the landscape quite detectably.
Even so, we have some of the air filling the vacated spaces, thinner air up on
the continents, and very interesting Oxygen-18 readings from the people trying
to measure ice age temperatures.
–Doug