|Map From David Pratt Compounded from Russian Authorities|
There are several articles on the formation of the Azores islands which speak of it: the Atlantis books by Otto Muck and Zhirov both record some of the subsidences, many of which are marked by corals which need to grow near the surface now found at depths of 2-3 kilometers down or more. ALL of these subsidences must date to a process beginning at the end of the Ice Age because in some cases the volcanic rock would degrade over a longer length of time. We also have the remnants of the lava from this last event strewn over the entire North Atlantic floor and the layer is directly datable to the end of the Ice Age, and the sediment covering the stratum is of Holocene (Postglacial) age.
The really major part of the evidence is that it was initially assumed that all of the midocean ridges of the world were generating seafloor spreading by means of active magma chambers down the middle. Further investigations turned up the odd fact that while the East Pacific rise has a proper domed-up cross setional profile the Mid-Atlantic ridge does NOT: it has a caved-in profile with once again a subsidence of 2-3 kilometers indicated. And most recently of all came the big shock: The Mid-Atlantic ridge has blown out nearly its entire magma reserve and the magma chamber under it is nearly empty and nearly completely inactive. The magma chambers on the mid-ocean ridghes are typically located about 3 kms down as determined by soundings: blowing out the chamber would logically lower the ridge 3 kms as well.
One source you can give is:
About halfway down there is a section which includes these statements:
Not every ophiolite has all these components complete, and it is not always for tectonic reasons. Often the gabbro is missing, or the sheeted dykes, and in some cases the dykes may intrude the harzburgite. Of course sheeted dykes can only be formed if there is a continuously extending magma chamber (try doing it without!). So if sheeted dykes are missing it may mean that there has not been such a magma chamber. In fact there is a lot of debate on this issue. Some geophysical studies indicate a possible continuous magma chamber beneath the East Pacific Rise. However, the EPR is a smooth fast-spreading ridge, and maybe there is enough thermal input to keep a continuous magma chamber going. On the other hand in the slow-spreading Atlantic with its central rift valley and irregular topography, there is no direct evidence for a continuous magma chamber. Some workers, including those at Leicester, suggest that with slow-spreading ridges, each eruption may be a distinct event, and that any magma chamber is only short-lived. Some sections of the Atlantic ridge, like the FAMOUS area (south of the Azores) have numerous small volcanic cones, and this is now being recognised all over the Atlantic.
A consequence is that that there may be a variety of magma chamber profiles, with those from fast-spreading ridges having fat "onion" shapes, those from rather slower-spreading ridges having "leek" shapes. Very slow spreading ridges (e.g. SW Indian Ridge) may just have dykes feeding lavas which directly overly peridotite. There are ophiolites with this profile, where the dykes cut harzburgite tectonite and gabbro is only locally developed. Even with the type Troodos ophiolite, which has a moderatley thick gabbro section, geochemical studies have shown that the gabbros are in fact a compound of a number of small bodies.
[The shapes are evidently successive stages of the full magma chambers bleeding dry over time. As noted, the Mid-Atlantic Ridge seems to currently be continuing without any large magma chamber left-DD]
Transform Fault Effects
It has long been known that the ocean crust is much thinner in the vicinity of oceanic transform faults. Also that a greater variety of rock types can be drilled or dredged in the vicinity of transforms, and that there is usually a significant topographic difference between the two sides of a transform fault (esp. the larger ones).
The latter effect arises because the ocean crust sinks as much as 3 km over the first 30 m.y. of its existence.[ie, after the new sheets of rock are extruded at the central rift area-DD] So the greater the age difference of adjacent bits of ocean crust across a transform, then the greater the height of the transform wall. Obviously if the wall is 1 km high, then a large amount of rubble will fall down onto the lower plate, and deeper parts will become exposed. Moreover as the transform fault moves, the movement can deform the basalts into hornblende schists.
[Emphasis Added: the statement should be made that the sinking occurs "Within" the stated millions of years and not "Over". We do not have direct evidence for the actual timing of the sinking, we can only verify the fact of the sinking-DD]
BTW, confusing the fact of Atlantis' sinking at the end of the Ice Age is the clear evidence we have there WAS a catastrophe of considerable proportions at the end of the Bronze age also, and we DO have evidences for the tsunami it generated on both sides of the Atlantic. There is the general problem with the dates involved and several authors have also called into question the entire framework of accepted chronology at the time (Not only in Velikovsky's Ages in Chaos but also now more mainstream objections which tend to confirm parts of his reconstructed chronology)
The real objection to that part is thart Plato ALSO clearly mentioned that catastrophe and made a distinction between the two catastrophes, making it clear tht he counted a lapse of many thousands of years between the two. He even counted the two as different types of catastrophe, the Atlantis catastrophe being a deluge and the Bronze Age one being a catastrophe of "Fire from the sky". The way he explained the theory left no doubt as to the fact that there were two types of catastrophe and that they were several thousand years apart, he gave an exact date in thousands of years which related to his theory that both types of catastrophes happened cyclically over the greater span of the Great or Platonic year, the Precession of Equinoxes cycle. Which is something in excess of 24 thousand years long. The Egyptian year is three seasons long and each "Season" of the Great Year cycle was eight thousand years long": and you were supposed to get a destruction by fire in the "Summer" and a destruction by water in the "Winter" of the Great Year. The Egyptians maintained they had records which demonstrated observations of a full Precession cycle and a half had gone by: That is roughly as far back as Marshak's Cromagnons were supposedly making Astronomical tallies. My guess is that the Egyptians were interpreting rock art and the rock are does include depictions of constellations: and they were good enough Astronomers to figure out the rates of change in celestial bodies (So were the Mayas for that matter) And over that period they claim to have observed "Several" catastrophes: the Mayans say Four Worlds. The Egyptian Mythology does hint that the world is destroyed periodically but is re-created at the original Sacred Mound, which is the first part of the Earth to re-emerge from the waters.
Incidentally the mythic material that went into Plato's Atlantis dialogues is as old as Egypt itself, and part of the material can be traced to the documents known as The Pyramid Texts (According to an article by John Douglas Singer in PURSUIT.
Once again, the formation of the rift valley in this diagram is analogous to the sinking of Atlantis (and you can also see how the crumbs might be left behind) but this is an idealized composite diagram. In other words, the end result is typical of the Pacific ridge system with its high magma plume and fast spreading center generating a lot of new ocean crust (It may actually be doing this in fits and starts and "Pulsing", by the way; and violent vertical movements up or down could also be part of the "Pulsing") As noted above, the Atlantic version of this crossection has the high active magma plume gone and the ridge collapsed and inactive as a result.
The Atlantic seafloor again, and we can still make out the prominently large Azores platform area which has been dragged down by the collapse of the Mid-Atlantic ridge.
Belowm the Lucky Strike area explored by OCeanographers with a particular view as to the area's geology: Several structures are above-sea-level, subaerial lava flows. For one thing the "Lava Lake" is mostly a large flat lava pool, not like a submarine eruption in the form of deposit: those "Lambda" marks indicate subaerial types of basaltic volcanic debris (Breccia as indicated by the key) SOME of the lava structures are formed under water and hence are more recent than the land-like lava flows: in paricular the lighter grey patch toward the bottom right is a marine deposit, and beside it are a couple of small fields of submarine pillow lavas. That is of course a very small part of the larger field which was mapped and indicated here.
Many geologists independantly insist on a general downfaulting of the ocean beds at the end of the Pleistocene. Forrest (The Atlantean Continent, 1933) insisted that not only Atlantis but the entire North Atlantic floor sank three kilometers relative to the land areas at the end of the Ice Age: and several "Flood Geologists" likewise say something of the same nature. I am not insisting that the bottom fell out of the entire North Atlantic, but in fact that is a legitimate scientific theory and it IS possible that the ocean depths actually did sink down some hundreds of feet vertically after the continental ice sheets melted and the meltwater ran back into the sea: and the land also subsequently rebounded and regained altitude. So that basically at the end of the Ice Age there was a worldwidwe change in amplitude in the difference between the heights of the continents and the depths of the ocean bottoms. This was to different degrees in different areas but was most noticeable in the areas of the former continental glaciers. And the North Atlantic seabed had continental glaciers on either side so the change in vertical relief was more pronounced there.