Author Topic: Spain can claim the World's largest waterfall  (Read 12393 times)

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Offline steveT

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Spain can claim the World's largest waterfall
« on: December 20, 2007, 23:55 PM »
Dear anyone whose interested,

Some 5.5 million years ago the force of Africa colliding with Europe, closed the straits of Gibraltar, sealing off the Med, which then evaporated over 2000 years. The straits were then breached by the Atlantic and the basin filled up again over 100 years. This happened many times and resulted in massive salt accumulations. The Nile and Rhone created deep canyons as they cut down to the deep desert basin than had once been the Med ( I guess the Ebro did something similar but on a smaller scale). Many species migrated from one continent to another and to ‘island’ habitats, within the basin, some which are now islands others submerged areas of elevated sea floor. When the straits were breached the biggest water fall that we have evidence for, is believed to have existed - 70 km3 of water per day cascaded into a basin up to 3000m deep and 2 500 000 km2 in area! The width perhaps 5-10km …..wide and 300 times bigger than Niagara. I guess this record must also belong to Morocco….the Pillars of Hercules are really deserving of their name!

There are other ‘smaller’ mega water falls that would have been great to witness:

The collapse of the Dover Straits (in the past a ridge of high land linked what is now the sea floor between Dover and Calais) as part of 2 flood events 425,000 and 225,000 bp . It is believed the ‘Dover to Calais’ ridge held back an ice dammed lake on the southern  North Sea Plain,  it collapsed catastrophically, due to its weak structure ie chalk and perhaps moraine. These waterfalls/cascades resulted in the Thames, Rhine, Meuse and Seine flowing into a larger river within the Channel during times of glacial low sea level. Either waterfall/cascade probably did not exceed 10, 000km3 of water being released.

The collapse of the ice dammed lake Agassiz 8000bp, 700,000km2  in area and 75-150,000km3 in volume. This was held within the Laurentide Ice sheet that covered much of North America. It collapsed releasing most of this lake’s water into the Atlantic and raised global sea levels by 20-40cm almost immediately!

The overflowing of the Med into the deep basin (up to 2200m deep), which is now the Black sea around 7600 bp, due to sea level rise after the last ice age. This is an area of 450,000km2 and it is believed 43 km3 of water cascaded through the Bosporus per day for nearly a year (200 times as big as Niagara)! Though some scientists contest this event.

In the Tertiary the Red Sea closed ( ie no access to the Indian Ocean) and evaporated, leaving a deep basin that was later flooded by the Indian Ocean . The Red Sea is 450 000km2……up to 2500m deep very approx 500 000km3 in volume……another huge cascade.

steveT

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Spain can claim the World's largest waterfall
« on: December 20, 2007, 23:55 PM »

Offline Clive

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Re: Spain can claim the World's largest waterfall
« Reply #1 on: December 21, 2007, 00:40 AM »
SteveT,

Please come to the Grazalema summit in April.....

Clive :)
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Offline John C

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Re: Spain can claim the World's largest waterfall
« Reply #2 on: December 21, 2007, 01:07 AM »
Shouldn't Spain at least go 50/50 with Morocco on this one - assuming, that is, that modern political boundaries still held sway 5.5 million years back?

John  :santa_wink:

Offline nick

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Re: Spain can claim the World's largest waterfall
« Reply #3 on: December 21, 2007, 21:59 PM »
Excellent bit of writing Steve and good comment John

There's a short video here I posted ages back in Spanish of the event

http://www.iberianature.com/material/wildlife_nature_videos_spain.htm

And near the bottom of the page look for
When the Mediterrenan dried out
Nick
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Offline Technopat

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Re: Spain can claim the World's largest waterfall
« Reply #4 on: December 21, 2007, 22:22 PM »
Greetings All,
Reminds me that someone told me that the desert in Aragón which is shortly to become Spain's star attraction is apparently amazingly rich in geological deposits, apart from any other consideration.
Regs.,
Tp
Technopat's disclaimer: If this posting seems over the top and/or gets your goat (Sp. anyone?), please accept my apologies and don't take it personally - it's just my instinctive tendency to put my foot in it whenever/wherever possible. See also:
http://www.iberianatureforum.com/index.php/topic,266

Offline steveT

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Re: Spain can claim the World's largest waterfall
« Reply #5 on: December 22, 2007, 01:04 AM »
Dear Clive, Nick and all,

Clive thank you for your kind invitation ....... I will try to make it - I will know if this is possible in early January. Sorry I have not been able to write so regularly.......as I really enjoy the forum ...... along with the website. I've learnt so much and enjoy contributing ....I'm often mulling over new topics in my head when I'm off line too. Most people on the forum live in Spain and it's only fair to tell you that I left Spain a few years ago.........I have lived in Spain for many years.....and whilst there I travelled very extensively ( nature focused ).......but I'm now UK based. I visit Spain regularly and have friends over there and in many ways my heart has never left.....as you may have guessed.....I hope this ok.

steveT

Offline steveT

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Re: Spain can claim the World's largest waterfall
« Reply #6 on: December 22, 2007, 02:50 AM »
John ..... I agree 50/50......mind you if I remember correctly, 5.5m ya  is the very point that hominins evovle from apes and they were busy doing this several 1000km away in East Africa .....and designing in embryonic for that very concept of political boundary.

Regards steveT

 

Offline steveT

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Re: Spain can claim the World's largest waterfall
« Reply #7 on: December 22, 2007, 03:06 AM »
Dear all

The Ebro valley I've just read, is like the Rhone, Nile and Po and is at least in part a 2000m deep canyon, cut in the Miocene during the desication of the Med ( It's called the Messinian Salinity Crisis) and infilled in the Pliocene with sediments!!!! Incredible is'nt it!!!!!!

The  repeated desication of the Med locked up so much salt, as trapped sediments on the Med floor that the worlds seas are less saline than 5.5m ya ( not long ago really) and freeze now at a higher temp.

The desication also raised world sea levels by 10m....as the water that had been the Med  ended up as precipitation and ran in to the oceans of the world.

steveT





Offline lucy

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Re: Spain can claim the World's largest waterfall
« Reply #8 on: December 22, 2007, 13:20 PM »
Hi Steve, Your mention of salt has reminded me of the David Attenborough documentary about the Mediterranean, “The First Eden” – has anyone seen it? His narration of the birth of the sea is fabulous, giving a real sense of wonder, and he holds aloft a core of salt drilled out of the sea bed as evidence of its desiccation. The first episode is full of brilliant things, like the evolution of pygmy hippos and elephants on the newly created islands, the survival of a separate species of midwife toad on Mallorca, and the development of bird migration from Africa.

Offline Jill

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Re: Spain can claim the World's largest waterfall
« Reply #9 on: December 22, 2007, 17:47 PM »
I haven't seen the David Attenborough documentary, but I can remember, many years ago, watching a documentary about the flooding of the Med. It opened, as I recall it, with footage of a palaeolithic man in skins wandering along (in a ridiculously modern manner - as if he didn't need to be keeping a look out for dinner and sabre-toothed tigers)  in front of a huge rock face adorned with lush plants. Suddenly he stops. There, flowing out of the rocks right beside this (evidently) familiar path, is a trickle of water!

The second time we saw him taking his afternoon stroll there was a proper waterfall gushing over the path.

And then we were given shots of what appeared to be the Niagara Falls.

It was a very effective means of getting the info across to this particular viewer. In fact, it's the only part of the programme that I remember, apart form the footage of divers taking salt cores!

Offline steveT

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Re: Spain can claim the World's largest waterfall
« Reply #10 on: December 22, 2007, 19:59 PM »
Lucy and Jill,

I never saw the documentary ...... but I've got the book that went with the series.....it's 20 years old now! And it is where I first ever heard of this amazing event.

The latest BBC series ...... in touches on the event.....mentioning the pygmy elephant and the huge salt accumulations - showing a room size geod, with 1-2 metre crystals ( gypsum not salt in this case ), that a human can get into ...... !!!!

Just another point ........ sorry to go on......this my geography/geology getting the better of me.

.....if you go to the Baliarics recent sea level change stares you in the face......the 2 ends of Forentera were clearly submerged in the recent past. They are flat topped especially the the higher eastern end which off the top of my head is a 100 - 150m plateau.......this must be the result of wave action.......ie a wave cut platform( if you remember your old geography lessons).

The central plain of Mallorca looks like old sea bed ie wave cut platform.....north of the cicuit de Llucmajor there's a go example of a recently incised valleys, one you can see from the road ......as the sea fell/land rose and exposed the central plain of Mallorca deep valleys were cut. Infact many of the smaller calas all over the Baliarics are where deep cut valleys meet the sea.

Mahon is in one of these deeply cut valleys ...now flooded by the sea.

The area from Ibiza airport to Eivissa is a plain that was clearly under the sea in the recent past.

We know there was a bridge to the mainland at some point because of the mid wife toad and Myotragus the dwarf antelpe with stereoscopic vision of Mallorca ( both eyes at the front of the head) indicating lower relative sea levels.

What  I'm there is, is clear eveidence of higher sea levels too. When was this sea level rise/land fall ......I'm not sure......and how it relates to glacial sea level changes I'm not sure either ..... my guess is that other causes of sea level change may be involved .... especially in the case of Formentera due to height of the pateau at the eastern end........ie tectonic related....though I'm not sure.


steveT



Offline John C

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Re: Spain can claim the World's largest waterfall
« Reply #11 on: December 22, 2007, 23:53 PM »
I just can't see an opening without supplying a plug ......... if you want to see an artist's impression of the falls, complete with elephants, and some further information on the event take a look at pp18-19 in 'Nature Guide to the Andalusian Sierras' (Crossbill Guides),
John  :santa_rolleyes:

Offline Clive

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Re: Spain can claim the World's largest waterfall
« Reply #12 on: December 23, 2007, 00:17 AM »
Yes but John... Where could one buy that book from?

:)

http://www.wildsideholidays.com/index.php?action=page_display&PageID=74

Sorry... terrible, blatant plug..... But it is relevant to

 :sign:

Clive
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Offline steveT

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Re: Spain can claim the World's largest waterfall
« Reply #13 on: December 29, 2007, 00:14 AM »
Again only if your interested.....more on the central plain of Mallorca

The central plain of Mallorca which came up earlier, I've found out was formed in the Miocene during around this time of flood and then desication of the Med....5 - 6 mya. The high areas either side of today already existed. The plain of today was then a shallow sea of coral reef which occassionally suffered sea level rise and fall. Coral and sediment accumulated over time resulting in a flatish platform that was futher eroded by any sea level change. However during is formation sea level fall was predominant, resulting in reefs and sediments developing continually southwards and so  extending this platform of gently sloping land in the centre of Mallorca.
My guess is that the deeply cut valleys of the island were cut during this sea level fall ( 30m or more ).

steveT

Offline nick

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Re: Spain can claim the World's largest waterfall
« Reply #14 on: December 10, 2009, 15:09 PM »
Update to SteveT's old post (where are you Steve?)

Research has revealed details of the catastrophic Zanclean flood that refilled the Mediterranean Sea more than five million years ago.

http://news.bbc.co.uk/2/hi/science/nature/8404363.stm
Nick
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Spanish Civil War Tours in Barcelona
http://www.iberianature.com/
A guide to the environment, climate, wildlife, & nature of Spain
The Amazon/Forum Bookshop - lend us a hand
http://www.iberianatureforum.com/shop/index.htm
And also now The Natural History of Britain
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Re: Spain can claim the World's largest waterfall
« Reply #14 on: December 10, 2009, 15:09 PM »