Model Boat Mayhem
Mess Deck: General Section => Chit-Chat => Topic started by: nick_75au on January 24, 2010, 09:23:47 am
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My comment in the comparison thread was somewhat tongue in cheek but I've always wondered since high school geography about the causes of sea level rise, the Amazon for example dumps an estimated, in the past 20 years, sediment load delivered to the sea ranges from 4 to 10 times (10 to the power of 8 ) tonnes yr, plus all the other rivers around the world, and coastal erosion all must displace a massive amount of seawater, where is the geological process that removes material from the ocean?
Nick
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Where tectonic plates meet there are several things that can happen, including:
Two plates are moving apart. This will form a trench, like the one in the mid-atlantic.
Two plates collide and push up wards, this is how mountain ranges are formed. Also leads to areas of volcanic activity as the magma gets close to the Earths surface. Sediments are compressed and sedimentary rocks (like sandstone/mudstone) are formed.
The sediment can also be cooked under extreme pressure, forming metamorhic rocks like slate and shale.
Two plates meet and one slides under the other. This then draws a lot of matter under the surface layer of the Earths crust. Forming sedimentary or metamorhoic rocks. Organic matter can become coal or oil.
This is where the sediment ends up. It will pop up again in a few hundren million years as new mountains somewere.
Did you know that the Cambrian mountains in Northern Britain where once much higher than the Himalayas are today? Before erosion.
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Where tectonic plates meet there are several things that can happen, including:
Two plates are moving apart. This will form a trench, like the one in the mid-atlantic.
Two plates collide and push up wards, this is how mountain ranges are formed. Also leads to areas of volcanic activity as the magma gets close to the Earths surface. Sediments are compressed and sedimentary rocks (like sandstone/mudstone) are formed.
The sediment can also be cooked under extreme pressure, forming metamorhic rocks like slate and shale.
Two plates meet and one slides under the other. This then draws a lot of matter under the surface layer of the Earths crust. Forming sedimentary or metamorhoic rocks. Organic matter can become coal or oil.
This is where the sediment ends up. It will pop up again in a few hundren million years as new mountains somewere.
Did you know that the Cambrian mountains in Northern Britain where once much higher than the Himalayas are today? Before erosion.
Cambrian Mts,...have they moved that much,...last time i saw them they were in Wales,..S/W Britain,..or are you confusing them with the Grampian Mts,..or,.perhaps geography is not your strong point,Tiger O0
Wullie
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Yes I know nothing about geography.
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The Sun's energy output has been rising since it burst into existence. It is now 25% hotter than when it first started shinning. When the earth formed, it was on the outermost edge of the 'habitable' zone. In 4.5 billion years, as the HZ has moved outward, the Earth's position has effectively moved deeper into this.
Although the Sun will continue to shine and expand for another 4 to 5 billion years, in anything between 500 million to 1 billion years, the Earth will be unhabitable by all but the simplest microbes etc because the Sun's output will be such the Earth will be too hot.
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At some stage our sun will go super nova.
But about 1 bn yrs ago earth only had simple multi-cell life forms.
200m yrs ago the first mamals.
only 2.5m years ago we had genus Homo.
So in in 500m plus years, our species will not be life as we know it.
Scary perhaps. But on the geological timescale we are perhaps not that significant. And the rate of technological development far outstrips that of evolution.
Perhaps we will be capable of faster than light travel. Perhaps we will be the 'greys' of the future.
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The Sun's energy output has been rising since it burst into existence. It is now 25% hotter than when it first started shinning. When the earth formed, it was on the outermost edge of the 'habitable' zone. In 4.5 billion years, as the HZ has moved outward, the Earth's position has effectively moved deeper into this.
Although the Sun will continue to shine and expand for another 4 to 5 billion years, in anything between 500 million to 1 billion years, the Earth will be unhabitable by all but the simplest microbes etc because the Sun's output will be such the Earth will be too hot.
So although we are probably not helping matters , global warming would happen anyway..??
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Yeh.
But I was kinda hoping things would go pearshaped after
my grandchildren died.
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nick, over time water evaporates from the oceanic surface, and gets sucked into subduction zones, so in that respect sea levels stay stable, as ice melts it only displaces its own weight in water as a berg so again levels will not rise, however as glaciers melt and dump ice into the oceans, THAT will push levels up
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So although we are probably not helping matters , global warming would happen anyway..??
Ultimately, yes.
However the Gaia Theory suggests that the planet \ eco \ bio system will regulate the environment such as global warming.
http://www.gaiatheory.org/ (http://www.gaiatheory.org/)
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Ultimately, yes.
However the Gaia Theory suggests that the planet \ eco \ bio system will regulate the environment such as global warming.
http://www.gaiatheory.org/ (http://www.gaiatheory.org/)
Looking at it from an ecological standpoint. An environment cannot be destroyed, it can only be modified. Perhaps modified to a point where human life is no longer possible. But there will still be an environment.
At one point in the Earth's history the planet was totally degassed. The atmosphere disappeared totally. Nobody knows why/how. After this was the carboniferous period. The atmosphere was largely CO2. This is when the plants that form the coal and oil deposits of today lived. They locked up the carbon.
There was also another important development at this time. Oxygen modifying enzymes. The process of oxidization means burning. These oxygen modifying enzymes allowed life forms to use oxygen without oxidising (burning). That made oxygen breathing life possible. As a result we had more animal life than before. Started as simple animals and these evolved.
But in the extreme. If we cut down all the rainforests, and release all the locked up CO2 from fossil fuels, perhaps we will only be restoring the chemical balance of the environment to what it was 2 bn yrs ago.
And Hey! life goes on.
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At one point in the Earth's history the planet was totally degassed. The atmosphere disappeared totally.
No - I think you might be confusing the early, oxygen-less atmosphere which was altered by stromatolites and other early life forms, pumping out O2. There's always been "gas" there - though for a lot of the Earth's existence, it's not been an atmosphere we could use.
Andy
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The earth was DE-gassed. This was before the pre oxygen phase. The cause is not known but speculation includes a meteorric event or even a total global volcanic event, or planetary event.
There is evidence for a de-gassing.
But this in fact led to a basis for re-gassing as we see today.
The makeup of the gaseous environment before this even is uncertain. However, due to vocanic activity sulphur oxides were highly likely. These would not have supported life as we know it.
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Looking at it from an ecological standpoint. An environment cannot be destroyed, it can only be modified. Perhaps modified to a point where human life is no longer possible. But there will still be an environment.
At one point in the Earth's history the planet was totally degassed. The atmosphere disappeared totally. Nobody knows why/how. After this was the carboniferous period. The atmosphere was largely CO2. This is when the plants that form the coal and oil deposits of today lived. They locked up the carbon.
There was also another important development at this time. Oxygen modifying enzymes. The process of oxidization means burning. These oxygen modifying enzymes allowed life forms to use oxygen without oxidising (burning). That made oxygen breathing life possible. As a result we had more animal life than before. Started as simple animals and these evolved.
But in the extreme. If we cut down all the rainforests, and release all the locked up CO2 from fossil fuels, perhaps we will only be restoring the chemical balance of the environment to what it was 2 bn yrs ago.
And Hey! life goes on.
I thought that we, and all living things on this planet were "carbon based". One or two caveats ,of course. But keep removing CO2 and we'd be in deep doo-doo.
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Global warming.....
There used to be an Ice Age, it destroyed the dinosaurs.
These glaciers no longer cover the earth... The earth has become
warmer ever since...
There use to be dinosaurs... When you see dinosaurs again, you will know
that the earth will have reached one of the warmest states of it's climate potential.
If you want to see why the sea level is rising, just consider the tonnage displaced by this
http://drkruznutty.files.wordpress.com/2009/03/oasisheader.jpg
O0
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Correct Bryan.
By changing the balance of CO2 in the atmosphere we will change the environment. If these changes happened over a geological timescale then life forms could adapt (or extinctions occur) or evolve with the slow rate of change. However, burning all the fossil fuels has rather sped things up a lot.
Just after the planet re-gassed there was very little free oxygen in the atmosphere. The plants increased the available oxygen. I don't think however that we would return to a low/no oxygen environment. The problem with the CO2 relates the carbon cycle but also affects the water cycle, both of which will impact on all lifeforms.
There will be life Jim, but perhaps not as know it.
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Hi Umi
If I see a dinosaur again I will know it is time to...RUN! %%
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I am as concerned as the next man about this 'Climate Change', but I feel caution is required here.
They say that the Polar Ice is withdrawing and will disappear in the near future.
As a boy, (15) in 1958, sailing on trawlers fom Hull, I can recall sailing to the North of the North Cape of Spitzbergen (Svalbard) which must have been about 83 degrees North and the so called permenant ice was not there. It came back and has retreated again. So what is new.
I also recall much ado about the oil tankers with ice strengthened bows trying to force passage round the top of Canada to gain access to the Aleutians from the Atlantic to save passage time with the Alaskan Oil to the East Coast of the US.
This passage was free of ice in 1817. (See attached clipping which bears out being checked against Admiralty Records!!)
The emotive pictures of Polar Bears perching in ice floes is very emotive but not factual. There are more Polar Bears now than since records began. Just like sea gulls, they go where food is readily available - Human refuse & throw aways. They do not depend upon their age old quarry for food. Check the Canadian records for scavenging Polar Bears if you wish.
The Global Warming addicts are beginning to become unravelled. Witness the latest scam about the Himalayan Glaciers being melted by 2035. Completely discredited as the chap who write it now admits it was pure speculation.
There is much more, but please don't come back with more speculation. Just provable facts. Not the tripe pushed by the zealots.
Yorkiej
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The Himalayan glacier thing was explained as a typo. I tend to believe this is the case.
Even if it is not, it does not discredit the whole argument, based on a lot of data and years of research.
The problem with the global warming debate is that the arguments have become polarised (no pun intended).
This means you have more people at both extremes of the argument. And both extremes the arguments will not stand up to a full scrutiny. There are also some very powerful lobby groups who have vested interests, sometimes with very large financial interests involved, this guarantees biased views.
Putting aside the fine details of individual facts, or individual factual errors, or specific dates, and the point scoring of one side over the other. The global consensus is that continuing to burn fossil fuels at current rates is not a good idea.
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Wow, lots of interesting replies.
My understanding of plate tectonics was it was a neutral process as the mid ocean rifts as they opened new material "filled the gap" and old material returned to the mantle at the subduction zones.
What about all the extra material introduced from erosion?
Sea levels will not rise if the North Pole ice melts, its already displacing its own volume of water, its Greenland and the land based Ice elsewhere that are going to cause rises from polar melting.
Nick
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Hi Nick
Technically there is no extra material from erosion, it has just moved downwards with the flow of water. And, simply put, it becomes the old material that you mentioned.
It doesn't always make it to the mantle though. It can get pushed down and then up again. This is why you get folds in the earths crust, that can be seen in some rock strata.
Sometimes plates tilt, with maybe an end raising, and so what was once seabed becomes land. That is why sea fossils can be found in the mountains.
The plates can also rub up against each other, eg, one plate edge moving east, another west. This is the biggest cause of earthquakes. They don't slide smoothly past each other and every now and again there is a jolt.
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Trying to simplify this discussion a little. As an "old-fashioned" sort of navigator I had to learn some meteorology. Also just about every ship (especially British ones) used to send off a coded signal to the Met Office (nothing secret) every 6 hours, and all at GMT. So hundreds of signals were sent off from all over the world at the same time codifying the weather each ship had at that particular time. All this data very often led to extremely accurate weather forecasting. Certainly better than we get nowadays. Doing this did take some time, but it also engendered an interest in meteorology beyond just reporting all the gubbins happening at the time.
But to the nub of this note...over many years of observation, I concluded long ago that the seasons had and were "moving to the right". I would hazard that the seasons have moved by around a month over the last 30 years. Perhaps the mobility of the physical North Magnetic Pole has a part to play in this. But this sort of change can be misconstrued as "climate change". It isn't. Just because glaciers melt at the "wrong" time of (our) year means absolutely nothing. I mean, for heavens sake, the earth doesn't use a man-made calendar. So-called "climate change" has always been with us, and always will be.
However, none of the above doesn't excuse wilful pollution of the planet. There can be no excuse for that. But in the Grand Scheme of "things, mankinds contribution is still very small. One single volcanic eruption can, and does, cause more disruption than many years of human intervention. And so it will continue.........BY.
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The earth was DE-gassed. This was before the pre oxygen phase. The cause is not known but speculation includes a meteorric event or even a total global volcanic event, or planetary event.
There is evidence for a de-gassing.
But this in fact led to a basis for re-gassing as we see today.
The makeup of the gaseous environment before this even is uncertain. However, due to vocanic activity sulphur oxides were highly likely. These would not have supported life as we know it.
tigertiger?
I am intrigued about this 'de-gassing episode'. Are you talking about the Late Heavy Bombardment, which I did not think was associated with excessive atmosphere loss? If not, could you provide me with a link to any evidence or discussion of it?
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Our Prime Minister recently put forward that Australia should have a mandate in place nominating a defined % CO2 reduction that we would achieve & that was prior to Copenhagen >>:-( >:-o
Our NSW minister for energy went on a jaunt to Europe to "look a the cost of $ funds borrowing" in consideration for privatization off the NSW electricity industry
Me thinks there is a great source of hot air & lots of CO2...........emanating from the Houses of Parliament O0 :P ............Derek
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If, as is the case,that we,"Man"now believe that the Seas are rising,the temps are getting hotter,can anyone tell me,why we persist in trying to destroy this planet,Its all we,ve got,..by destroy, i mean,..ever since the first Atomic Bomb,was detonated in 1945....after that it was Test,after Test,after Test,...devices buried deep underground,..In America,Asia,Australia,then surface devices,...what i,d like to know is,could these "Test" have any bearing on what is happening now,..bearing in mind the Earthquake in Haiti, which according to reports was the shallowest earthquake ever,being a mere 10 miles down,...some of you have mentioned Tectonic Plates,..is it not possible that these underground Tests were done in the past,could alter the make up of these plates,..I,ve read in Books/magazines,about how California might..,someday, part company from the mainland,due to its position to the San Andreas Fault,or that a piece of the Canary Islands will one day fall into the sea,and create the biggest Tsunami ever,and that New York, will have Its "Day After Tomorrow"surely the shock waves from those blasts in the past had to alter something,
wullie
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Spot on Bryan (Reply 21)
My sentiments entirely.
Good sensible, objective observations.
As my Dear Mother used to say 'There's them as knows and there's them as thinks they knows'.
As I say ' You can't whack experience'.
Best regards
John
Yorkiej
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tigertiger?
I am intrigued about this 'de-gassing episode'. Are you talking about the Late Heavy Bombardment, which I did not think was associated with excessive atmosphere loss? If not, could you provide me with a link to any evidence or discussion of it?
You are right Dodgy Geezer.
I have just realised that I miss read the text book all those years ago.
I misread ‘the atmosphere was formed after the degassing of the planet’, to mean that, the atmosphere was re-formed after being ‘lost’.
What it actually means is that the hot lump of rock (Earth) was losing gas (degassing) as it cooled.
The remainder of the statement about the atmosphere, and the processes of change is I believe still correct.
The gases were mostly of the volcanic variety, not being conducive to life as we know it.