Video #4: Atlantis - The Unique Geology of the Azores

Intro

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[Music]

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Atlantis, the unique geology of the Azores.

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[Music]

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In this episode, I'm going to attempt to  explain why the Azores Plateau is such a

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unique place from a geological context and why  this might present a case for a greater than

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130 metre sea level rise in the Azores since  the Last Glacial Maximum 20,000 years ago.

Supercontinent Pangaea

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To truly understand the isostatic mechanisms in  the region of the Azores Plateau, we have to look

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at the world as it was 200 million years ago, when  the supercontinent Pangaea began to separate.

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There have been a number of supercontinents  in Earth's history, with Pangaea being the

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most recent. Pangaea is the result of Earth’s  previous continental units converging into a

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new supercontinent. Once the convergence  had concluded, Pangaea remained more

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or less unchanged for 70 million years. So what caused Pangaea to break apart?

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It is thought that the start of the break  up began as magma surfaced at a point of

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weakness in the supercontinent, creating  a rift zone. This point of weakness would

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later become the Atlantic Ocean as  the rift zone continued to grow.

The Formation of the Plateau

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There seems to be some debate over exact time  scales, but approximately 20 million years ago

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something happened at the Azores triple  junction that caused the Azores hotspot

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to produce continental type crust, as opposed to  the oceanic type crust it had produced previously.

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The production of this continental type  crust continued for 13 million years,

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ending 7 million years ago. Over the last  7 million years, the continental Azores

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Plateau has slowly rifted apart as the Azores  Triple Junction has continued to diverge.

Why is The Azores Hotspot so Special?

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The Azores Hotspot isn't the only  hotspot or driver of continental drift,

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so what makes it so special? When looking at the  opposite side of the planet at the Pacific Ocean,

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the large body of water makes it clear that the  continental land masses are at this point in time,

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still heavily biased towards the  Atlantic side of the planet.

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This map, by Massimo Pietrobon, represents  Pangaea using the modern day continental units.

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Although the Azores Plateau wouldn't  have existed during the time of Pangaea,

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this map shows how central the Azores Hotspot  is in driving the continents apart.

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We know that oceanic plate boundaries tend to  subduct under continental plate boundaries,

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combine this with the fact that the continental  land masses are still biased to one side of the

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planet and the fact that all three plates of  the triple junction are divergent, it might

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be fair to suggest that the Azores Hotspot is the  primary driver of modern day continental drift.

A Lack of Data

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It's interesting to note how little is really  known about the Azores Triple Junction,

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considering it's potential significance in  understanding not only local phenomenon,

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but also continental geology on a global scale.  There doesn't seem to be any agreement on the

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exact location of the Azores Hotspot, some  geologists suggest there might be two hotspots

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under the plateau. There are even geologist that  suggest there are no hotspots under the plateau

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and that other geological mechanisms could explain  the nature of the divergent triple junction.

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After reading many papers I'm of the opinion  that there is indeed a hotspot under the plateau,

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which leads on to another reason why the  geology of the Azores Plateau can be considered

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unique. There has been very little movement of the plateau over the hotspot for at least

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20 million years since it's creation. Normally  you would see evidence of a tectonic plate moving

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slowly over a hotspot, whereas the Azores Plateau  seems to have stayed directly over the hotspot,

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with only a gradual migration of  only a few hundred kilometres.

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Again, this links back to my  argument that we might consider the

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Azores Hotspot to be the primary driver  in modern day continental drift.

Isostasy

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Although I believe there were a number of  geological mechanisms that may have been

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at play when the Younger Dryas came to an end  11,600 years ago, likely by some catastrophe.

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With regards to the Azores Plateau,  I'm going to focus on isostasy.

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We know that average global sea levels have  risen by approximately 130 metres since the

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Last Glacial Maximum, with the last 60 metres  taking place since the end of the Younger Dryas.

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This is almost certainly true on both sides of  the Atlantic, but the Azores along with other

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mid-ocean islands with steeply sided shorelines  are a little more difficult to characterise.

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We can see wave cutting that has taken place  since the end of the Younger Dryas at intervals,

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for the most part, that conform to what we see  on either side of the Atlantic, perhaps with some

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extra subsidence, but due to the steep shorelines,  shelf drop-offs and the build up of sediment,

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it's difficult to characterise older shorelines  by looking for evidence of wave cutting. There is

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clear evidence of wave cutting, hundreds of metres  below the accepted 130 metres, but it's difficult

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to say at what point over the last 7 million  years that these platforms were at sea level.

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Back in Episode 1, I briefly mentioned isostasy.  This picture nicely represents top loading

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isostasy from de-glaciation. The melting of  continental glaciers over the last 20,000

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years has transferred load from continental land  masses to the worlds oceans. Where ice has melted,

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the mantle rebounds causing the lithosphere and  crust to elevate. There is also a corresponding

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subsidence in oceanic crusts as the  load is transferred to the oceans.

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This top loading mechanism would certainly  have contributed to the subsidence of the

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Azores Plateau, possibly by more than 130  metres due to the geometry of the oceans,

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but I don't think it's enough to explain the  required 2000 metres for the Azores Plateau

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to have been above water, prior to  the end of the Younger Dryas.

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In the region of the Azores I believe that bottom  loading isostasy has had a larger effect on sea

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level rise than top loading isostasy. The main  driver for bottom loading isostasy below the

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Azores Plateau would be variations in the mantle  plume, specifically the Azores Hotspot, which is

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estimated to have a diameter of 200km. Increased  activity in the mantle plume has two effects,

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firstly there will be some additional uplift  due to the relative increase in pressure,

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secondly the crust thickens. As we know that  the crust is less dense than the material below,

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there will be a corresponding uplift  on the surface of the plateau.

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Unfortunately we don't have the tomographic  data to fully understand the modern day plume

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geometry of the Azores Hotspot, let alone  data to characterise variations of the past.

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This means that I cannot provide an estimate  on how past plume variations have effected

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the rise and fall of the Azores Plateau due to  pressure changes below. With regards to variation

Episodic Hotspot Activity

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in crustal thickness however, we do have access  to an interesting paper that could help explain

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large variations in sea level in the region of the  Azores Plateau over the last few million years.

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One of the hypotheses suggested in this paper, is  that there is episodic hot spot activity, which

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causes the crust to thicken to 2 or 3 times it's  normal thickness up to a maximum value of 16 km.

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This occurs in intervals of 3 to 5 million years,  suggesting this has happened at least once,

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possibly twice since the plateau was  fully formed 7 million years ago.

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This doesn't mean that the whole of  the plateau increased in thickness,

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more likely just the crust above the 200  km wide hotspot. Remnants of this localised

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thickening could be seen as some of the modern day  islands or sea mounts surrounding the plateau.

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I haven't just randomly placed a picture  of some tic tacs into this slide.

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It's an example of a living hinge that many people  around the world will be familiar with. The white

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plastic top of the tic tac container is made from  a single piece of plastic, the piece of plastic

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between the top and the lid is so thin it acts as  if it were a hinge, we call this a living hinge.

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In like manner the crust is so thin over the  Mid-Atlantic Ridge, that it may be acting as

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an enormous living hinge, allowing the hotspot  located under the Eurasian Plate to also lift

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the plateau on the side of the North American  Plate in times of increased magmatic activity.

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If this episodic hotspot hypothesis is true,

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given that the Azores Plateau for the  most part is now 2000 metres underwater,

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this would suggest that the plume is  currently in a period of low activity,

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I have found two papers that seem to back up this  statement. The first suggests that the plume,

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if not of a shallow origin, must be waning. The  second suggests that the hotspot is a present-day

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dying plume. Given the activity periods span  millions of years, then it's likely that the

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present day period of low activity was still  in place 11,600 years ago. Perhaps one day in

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the distant future activity will increase slowly  lifting the Azores plateau back out of the sea.

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The mechanisms at play would suggest that these  variations in the height of the Azores Plateau

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would take place over long periods of time,  conforming to the gradualist school of thought.

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I would definitely agree with this for the  upward motion of the plateau during periods

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of increased activity, but I also think there  are two potential mechanisms that could have

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caused rapid, cataclysmic subsidence in the  region at the end of the Younger Dryas.

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Firstly, it's looking more and more  likely that the Younger Dryas ended with

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multiple cometary impacts. Could the  Earth changes have been so great,

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causing a disruption to the plume below the  Azores Plateau. A sudden loss of pressure

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under the region certainly could have  been responsible for rapid subsidence.

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Secondly, if the plume was already in a period of  low activity 11,600 years ago, then the thickened

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crust would have been slowly melting back into  the mantle below. This downward movement may not

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have been in perfect isostatic equilibrium, the  earthquakes and various Earth changes that shook

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the world as the Younger Dryas came to an end may  have only just accelerated a regional cataclysm

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that would have happened regardless, but perhaps  many thousands of years into the future.

Conclusion

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My hunch is that the combination of top  and bottom loading isostasy is enough to

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explain a change in sea level of 2000 metres  or more since the end of the Younger Dryas.

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It is unlikely in our lifetimes that we will  have the necessary information to calculate

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past uplift from mantle upwellings  in the region of the Azores Hotspot,

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but in a later episode, likely quite far  into the future at this point, I would like

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to try and calculate how much a thickened  crust may have elevated the Azores Plateau.

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In the meantime, what other evidence do  we have for subsidence in the region?

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As I already mentioned in Episode 1, Randall  Carlson presents papers that detail core samples,

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these core samples suggest that the region of  the Mid-Atlantic Ridge could have been between

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approximately 3000 and 5500 metres higher than  they are today. It's definitely worth watching

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the Kosmographia Atlantis series as well as the  rest of the content produced by their channel.

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There are a number of interesting man-made  artefacts in the Azores that predate the

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Portuguese occupation of the islands. This  picture, from the Portuguese American Journal,

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shows a step pyramid on the western side of  Pico Island, it’s one of approximately 140.

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Academics have placed the age of this pyramid  somewhere between 1000 and 6000 years old.

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This would have been made many thousands of  years after the end of the Younger Dryas, so

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would not be an Atlantean construction. What I'm  more interested in is the apparent subsidence.

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We can't compare this to the Leaning Tower of  Pisa, where the foundation sunk into the soil

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below. The foundation layer of the step pyramid  still seems to follow the natural terrain,

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suggesting that the whole island must have  subsided my some degree over the last few thousand

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years. I crudely make the angle of subsidence  out to be approximately 9°, but some of this

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could be due to the camera angle, also this is  only one dimension of the pyramids subsidence,

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as it only shows one side in the photograph.  This pyramid, and the other 140 or so pyramids,

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would be a good excuse to take a trip out to  the Azores to try and determine if there is some

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mutual subsidence that has taken place  on the other pyramids of this region.

Outro

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I think this is probably a good place to stop with  Episode 4. I've had some good discussions with

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various people on the Graham Hancock Message Board  since I started to make this Atlantis series.

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I've had some interesting discussions with  Open Mind and Mike D seems to be a wealth

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of knowledge providing some good links to  various papers regarding the Azores.

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In the next episode I would like to present some  information from the Temple of Horus at Edfu

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regarding the Island of the Egg story, as this  draws close parallels to Plato’s Atlantis story.

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I know other people have presented  similar videos, but I will be linking

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this into other stories told around the  world that may link back to Atlantis.

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I was also approached by Keith Hunter,  the author of Occult Physics on the Graham

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Hancock Message Board. He's found some  interesting relationships regarding the

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placement of my proposed site for Atlantis and  other ancient sites such as the Great Pyramid.