It's funny to think of granite as a light rock, because among the "common" rock types (the ones we use for construction, artwork, gravestones, etc.) it is actually one of the hardest and densest. It just serves as another reminder that we only live on the very thin surface of an entire rocky planet, most of which we don't (or barely) have physical access to.
It's light compared to basalt. It's denser than many sedimentary rocks because it has low porosity, but you can find sedimentary rocks denser than granite. For example, low porosity dolomite and anhydrite.
@@TheNightcrowsNest Technically if we want to get sematic about things the most common igneous rock, the term for the masses of solidified magma from volcanoes that never got erupted onto the surface and cooled slowly, which makes up continents and the one primarily made by subduction is actually called diorite and it's the igneous counterpart of the volcanic rock andesite. True granite is much more silica rich and is the igneous/plutonic counterpart for rhyolite both of which generally arise from a combination of crystal fractionalization (the process where less viscus/more mafic minerals precipitate out of magma) and crustal leeching where silica from surrounding rocks dissolves into magma intruding into the crust. diorite and other igneous rocks which cooled very slowly in large magma chambers i.e. plutons are sometimes called granite when talking to layperson audiences however they are compositionally distinct. For example the so called "black granite" is actually gabbro the igneous counterpart of basalt which primarily composes oceanic crust below the surface.
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The density difference is fairly small, but makes a big difference in terms of what stays on top or gets pulled down. Granite is 2.6-2.7 g/cm^3, Basalt 2.8-3.0
Yep. I've tried lifting one. Infact, we had to unload a single slab of granite 15x5ft. 3 people couldn't lift it, so we had to hire 3 more people so all 6 people lifted it with great difficulty. It's crazy heavy.
I've lifted granite as well as heavier materials (even solid gold!)💪... ok I'm talking pebbles and cobblestones of granite (and other rocks) and small amounts of gold (coins, rings nuggets.) One ton of feathers... is still one ton... it's just going to be more voluminous than that 1 ton chunk of granite...
For YEARS I had this question on mind, after seeing those maps with the continental shelf vs deep ocean and how the depth changed suddenly, but never had a talk with a geologist to ask it, thanks!
I remember first hearing about the plate tectonics theory in 4th grade in about 1966. It was so obvious to me lookin gat a globe that the Mid Atlantic Ridge mirrors the continents on both sides so "sea-floor spreading" was the theory presented. I never understood that granite can be leached out of the mantles peridotite until now. This video talks about the Great Alaskan Earthquake and includes some of this theory and how it applied in that situation: ua-cam.com/video/lE2j10xyOgI/v-deo.html
completely unrelated note: Granite is super hard and difficult to mine through and it is all across the Sierra Nevadas which is a very big mountain range in California so when they were building the Trans Continental Railroad across the Sierra Nevadas they had to dig through the mountains rather than go over them but that meant digging through granite. The Solution that was used was using Nitroglycerin which is very very explosive at each of the tunnels ends but that was still to slow so sometimes in extra large tunnels they would dig down and then out so there would be 4 parts of the tunnel being dug or exploded out at once
Thank you for this video! I was teaching tectonic plates for the first time recently, and was confused as to whether new continental crust could ever form at all, since I assume divergent plates can only form oceanic crust on the sea floor.
New continental crust is forming all the time. If it wasn't there wouldn't be anything above the ocean surface since erosion is also constantly happening. Divergent plate boundaries can produce continental crust, but it's mostly recycled material (mafic magma from below heats and melts existing felsic rock). These are actually where you tend to get the most explosive kind of volcanoes because silica-rich magma is a lot thicker and more viscous than mantle-composition magma. Look up Rift Valleys and Continental Rifting, along with Mantle Hotspots (think Yellowstone).
0:32 The image is a bit misleading: Actually the continental crust also goes downward (deeper than the sea crust), and "swims" on the underlying mantle like a ship in water.
Wait, does that mean Earth's surface was mostly smooth until after it got its water (which IIRC is assumed to have come from comets and such, not being there from the start)? And what about the topography of a place like Mars - does it mean Mars used to have a lot more water than what we've detected, or could it all have been formed by other processes (volcanoes, meteor impacts)?
No, it would've been akin to the moon - is the moon smooth? Planets are formed from a LOT of smaller rocks smashing and sticking together - what's the chance that'd result in a smooth surface? Even when the surface melted it was always being impacted and churned - by the time all of that reduced to the levels we experience now, the planet was mostly finished. And THEN it got smashed again by another massive object, which went on to form the moon. There was never a peaceful time during Earth's formation for it smoothen out - by the time there was, the planet had its own violent processes to keep roughing it up constantly.
@@ArawnOfAnnwn I'm saying mostly smooth, not perfectly smooth. Like, a small enough difference between average and minimum height that the amount of water we have could've covered the surface, maybe with the exception of a few volcanic islands. Could there have been a period in Earth's history, some time after the crash that formed the moon, when like 99% of the surface was covered in water? Or is the phenomenon described here just something that keeps dry land area from decreasing over time, rather than creating the dry land in the first place?
Indeed the topography of mars is one reason many were so certain we would find water there somewhere. Landers have targeted areas that look like they could have been ancient oceans in hopes of finding evidence of life.
Note that this video simplified things quite a bit even if its broadly true there are other factors at play for example the two hemispheres of Mars do have different elevations but the lower elevation Borealis basin is thought by some to potentially be due to a major impact from very early on in the solar system with the high plateaus of Mars such as Tharsis and Elysium being concentrated volcanic provinces. However yes Mars's topography is one reason to suspect water was once present in abundance and it still is its just the vast majority of Mars's water that hasn't been lost to space has long been sequestered into mineral hydrates largely as the planet cooled down increasing the fraction of mineral hydrates that could be supported before they reached saturation. This is in essence a major piece of the puzzle in terms of the newly emerging understanding of the deeper cycling aspects of plate tectonics on Earth enabled by seismic tomography the use of seismic waves to study the interior structure of the Earth as well as much older geological rock records over time. In essence the amount of water which can be converted into mineral hydrates is temperature dependent the higher the temperature of the rock the less water that rock can hold forcing the remaining water to return to liquid form and rise back to the surface driving volcanism like those seen around subduction zones. However Earth like Mars is cooling albeit much more slowly. When Earth was young virtually all of its water was likely in the oceans however over the last 4 billion years 3 times he current volume of Earth's oceans was sequestered away into the mantle a process which continues to this day and likely based on models is geochemically responsible at least in part for the convective cycling of what we call plate tectonics. In fact there is some building evidence to suggest it is this evolving geochemical process which has largely driven/constrained the ecological complexity of Earth's surface since it has been shown that among pelagic (open water) photosynthesizing microbe (those which fix carbon using sunlight as a source of energy via various chemical processes that provide a source of hydrogen for carbon fixation) aerobic photosynthesis the photosynthetic process which uses water as a source of molecular hydrogen for carbon fixation is actually the least metabolically efficient pathway because it requires higher energy photons of light than other anaerobic photosynthetic pathways (the two biggest examples being based around hydrogen sulfide or the use of metal ions such as iron to convert dissolved hydrogen ions into molecular hydrogen that can be combined with carbon dioxide to produce sugars. Oxygen among the elements which are not noble gasses has the second strongest electronegativity which means the amount of pull it naturally has to claim electrons from other atoms without any additional input of energy. It is the high electronegativity of oxygen which makes it so amazing at respiration as it reduces the amount of energy lost during respiration as oxygen does much of the work for "free" however the flip side is that all the energy needed to split electrons away from oxygen must be provided to use water as a source of hydrogen for carbon fixation. In quantum mechanics however only photons with sufficiently high energy can perform this job but such energetic photons can't penetrate as deeply into the sea. This is a problem because without a source of mineral nutrients near the surface such as continents passive upwards diffusion is the main mechanism nutrients such as phosphorus can rise in the water column to the layers where photosynthesis can occur. Thus phototrophs which can do their job with longer wavelengths that reach deeper into the sea such as infrared light can use up the available phosphorus will be able to naturally outcompete aerobic photosynthesizers. Thus the prognosis for aerobic photosynthesis to win out is poor unless another source abundant of nutrients is present or the seafloor is within the phototrophic zone of the ocean. There is geochemical evidence to suggest that prior to 3 billion years ago little if any land was exposed above the water meaning whatever continents existed back then (and we know some continental crust is that old since that is ho we were able to chemically check for whether there was dry land or not by using biases in oxygen isotope ratios of carbon dioxide chemically reacting with rock via air or when dissolved in seawater to gauge this question. Based on this timing and geochemical models of the mantle cooling the Great Oxygenation Event lines up suspiciously well with models of when continents began to rise out of the water opening up new sources of phosphorous not dependent on passive upwards diffusion. However there is another cooler bit related to a phase transition where enough lower density mineral hydrates can form form them to buoyantly start to rise towards the surface as thermodynamic modeling suggests the timing matches up with the Neoproterozoic oxygenation event and the associated Cryogenian glaciations. The geochemical composition of such magmas based on the known modern analog such this is the process that is feeding the volcanism associated with Mt. Paektu between North Korea and China and it has particular enrichments in elements derived from sea floor deposition most notably including phosphorus and these geochemcial signals are found in the flood basalts associated with the break up of the supercontinent Rodinia. Altogether this suggests that Earth's geosphere and biosphere have largely been driven by the effects of thermodynamics inhibiting the formation of mineral hydrate layers at the Mantle Transition Zone between the upper and lower mantle and driving plate tectonics. If this was the case then it appears complex life arose as soon as Earth's mantle thermodynamics allowed it to. This has some fascinating astrobiological implications since worlds without continents in the phototrophic zone would never be able to support an analog to the Great Oxygenation Event and thus any life would probably be kept simple by energetic constraints. For Mars the same processes which took around 3 billion years to unfold in Earth's mantle likely would have unfolded in the planets first billion years before the oceans vanished either into rock or space conditions which greatly constrain its habitable window, however this also means that the same processes would unfold far slower on planets much more massive to Earth as this is a consequence of the nonlinear relationship between surface area and volume and their consequences on heat exchange. If this is the case than the Universe might not be old enough for super Earth planets to have cooled into the habitable window for complex life though on the flip side that window should be able to last far longer all other things being equal. Well I have rambled off quite a bit more than I had intended though there is much more to say, for example did you know the cold dense subducted seafloor actually is the descending branch of mantle convection? Or that based on recent research what we call plate tectonics actually appears to extend far deeper from the surface down to the Mantle Transition zone as a system of basaltic convection cells with less dense "icebergs/glaciers" of continental rock buoyantly suspended within these denser cells of rock?
@@Dragrath1 well that sounds genuinely fascinating as far as I was able to follow (especially the bits with implications on the kinds of planets we could expect to find life in - if we have good evidence that life formed quickly after the right conditions were there, that implies the probability of it rising under the right conditions is relatively high! Or maybe I misunderstood and it's only relevant to the kind of life that likes oxygen, which wasn't the first on Earth? Even so, interesting if we ever hope to find anything complex on another planet). If it's not based on an article I hope you write one somewhere and not let it get lost in UA-cam comments :) Do you know if there's a single basic reason Mars cooled quicker to crystallize most of its water? Just that it's further from the sun, or is it more about different geology?
This is really cool. It directly answers two questions that I learned to ask when comparing Earth with other planets and moons in our solar system (how Earth's elevation profile got to be so bimodal, and why only the ocean floor is made out of basalt, when on the other rocky planets and the Moon almost everything is), and it also indirectly answers a question that I've had for a long time about Earth's early history (why we think that, early in its history, Earth had less continental crust). I wasn't sure I would ever get a good answer to any of those questions.
I like the new "Welcome to Minute Earth" intro than the old "Hi, this is ____ from Minute Earth" since by this point, we pretty much know the voice and "face" of every one of their team
I seem to remember reading that there is more trapped water under the North American continent than all the oceans combined. So it seems to me that there must be a more important mechanism than subduction to get the water there.
It can sometimes depend on what they mean by ‘water’ Hydrates are molecules that incorporate water into their crystal lattice, both trapping water and remaining solid. Gypsum or Plaster of Paris is one good example.
It has simply always been there. Well, it's a liiiittle more complex than that, but all the water trapped under Earth's crust has been there for longer than the Earth has had plate tectonics. More water enters as oceanic plates subduct, and leaves where they diverge.
@@IgnisDomini97 your correct about the water always have been there but not becuse of "subducting plates" that water has been trapped beneath the crust forever and just didnt escape during the bursting of the subterranean oceans when the midoceanic ridge was formed. HPT
Interesting. Granite forms a huge part of Singapore’s geology (we even used to have granite quarries, and one of them is now a nature park); given our relative proximity to the Pacific Ring of Fire, I wonder if that’s where all our granite ultimately came from.
Singapore and western part of Peninsular Malaysia is part of land that sheared off Gondwana, like just a sliver of land, all the way to Iran, in a process called the Cimmerian orogeny. The sliver of land collided with the Asian continent, way before India made the same move. In a way, it was a test run for India's great collission.
Very interesting. In March of 2020 a geology conference was supposed to meet and decide if a tectonic plate in the Pacific should qualify as an eighth continent, despite being under water. Then Covid hit and I don't know if the decision was made.
I never really noticed how much thumbnails and titles change shortly after videos are created. For Example, this video: Original Title: Where Do Continents Come From? Revised Title, within the same day: Earth Used to be Naked Second Revised Title, also less than a day later: Why Continents Are High
There is a leap from a mid-ocean subduction zone to colliding with a continent. I think I figured it out, but it would be nice if you clarified how this happens.
That won't really matter because in 1 billion years there won't be any water (or macroscopic life) left on Earth due to the sun getting hotter/brighter (Note: the sun getting hotter is extremely gradual and not the cause of climate change).
No. Eventually when the Earth's core cools enough, plate tectonics will cease. There will be no more volcanoes or subduction. Erosion from wind and water will gradually wear down the surface until everything is below water. Without a molten metal core, the Earth's magnetic field will disappear and the solar winds (high energy particles produced by the sun) will gradually tear away our atmosphere. The water will all evaporate and be carried away, until we're left with a lumpy dry surface with nothing but rock and soil and some thin atmosphere retained by gravity. This is what happened to Mars.
Rock is heavier and densier then water and earth spins what results in a centrifugal force (I learnt this in a video 'what if earth stops spinning, or slows down rotating). This force gives our planet an egg-shape ; an oval which bulbs out at the equator with 20-40 km and is flattened at the poles. This also effects continent-building together with the tidal-forces of sun and moon. The oceans, wether and rivers also have an eroding effect on mountains and continents. We are on a relative thin layer floating on melted rock, and it is continue moving. That we have continents at all is because earths inside is melted because of friction, if earth cooled down and became solid , 2 things can happen ; 1) the oceans erode the continents away resulting in a blue planet covered with an overall 200m deep 'sea'. 2) more likely, the ocean water seeps into the inner of the planet, it no longer turns in steam and flows just lower and lower, this will result in a rocky dry surface all over the earth. some scary thoughts.
You left out the smashing of earth and the planetary body theia which is one of the main reasons earth, which is an inner planet, has such abundance of water and the reason there is this granite in the first place. Everything was pretty spot on though just a few things were missing out
I live in St Cloud, MN. I saw a very old picture around 1900 that called my town "Granite City". There are many granite mines, and businesses that sell only granite products (countertops, tombstones) So, either the granite was already here, or when the glaciers made all of our lakes, deposited large amounts of granite in my state. Not all of it came from volcanoes.
Minnesota has some VERY old rocks! It's geologic history spans some 3.5 billion years, and part of its bedrock is indeed igneous (from the cooling of magma and lava). The state forms the southern edge of the Canadian Shield, which is sort of the original "nucleus" of North America - it's a vast area of igneous and metamorphic rock that formed during Precambrian time and involved a ton of volcanic activity. Minnesota may not be the place to see an active volcano today, but it definitely was a few billion years ago!
Well, most of the current exposed land mass was under water at some point in time during the history of Earth. Like the story of Noah, and having most of the Earth under water, there has been much movement of the Earth. The plates have moved greatly since Pangaea. That a lot of the exposed land mass has seen volcanic activity. The glaciers brought rocks and minerals to other areas too.
As soon as you mentioned that most of the continental crust is made of granite, I was WAITING for that pun at the end haha great stuff
The pun was basically a granite-ee (sorry)
Not very dense, are you? 😉
I laughed way too hard at that pun 😂
A very gneiss pun
What's a granitee?
It's funny to think of granite as a light rock, because among the "common" rock types (the ones we use for construction, artwork, gravestones, etc.) it is actually one of the hardest and densest.
It just serves as another reminder that we only live on the very thin surface of an entire rocky planet, most of which we don't (or barely) have physical access to.
It's light compared to basalt.
It's denser than many sedimentary rocks because it has low porosity, but you can find sedimentary rocks denser than granite. For example, low porosity dolomite and anhydrite.
@@H0A0B123 but they said "common" I haven't heard of any of those rock minerals in which you have described.
Crazy to think we probably know more about other planets than what's a few km under our feet
@@TheNightcrowsNest they just mean readily available at the earths surface.
@@TheNightcrowsNest Technically if we want to get sematic about things the most common igneous rock, the term for the masses of solidified magma from volcanoes that never got erupted onto the surface and cooled slowly, which makes up continents and the one primarily made by subduction is actually called diorite and it's the igneous counterpart of the volcanic rock andesite. True granite is much more silica rich and is the igneous/plutonic counterpart for rhyolite both of which generally arise from a combination of crystal fractionalization (the process where less viscus/more mafic minerals precipitate out of magma) and crustal leeching where silica from surrounding rocks dissolves into magma intruding into the crust. diorite and other igneous rocks which cooled very slowly in large magma chambers i.e. plutons are sometimes called granite when talking to layperson audiences however they are compositionally distinct. For example the so called "black granite" is actually gabbro the igneous counterpart of basalt which primarily composes oceanic crust below the surface.
This is actually a surprisingly interesting topic! Thanks for making this, MinuteEarth!
100% agreed!
100%
yup
Are you a bot?
@@psgamer-il2pt nope
*MinuteEarth be over here answering questions we never even had!*
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Ok
🍎
If we didn't have water wouldn't the stuff we call oceanic crust _be_ our land?
sorry, i'm poor
You forgot to pin the comment
I never thought of granite being low density. Have you ever tried to lift up a large slab of it.
The density difference is fairly small, but makes a big difference in terms of what stays on top or gets pulled down. Granite is 2.6-2.7 g/cm^3, Basalt 2.8-3.0
I don't always move mountains, but when I do, I prefer the lighter granite ones.
Yep. I've tried lifting one.
Infact, we had to unload a single slab of granite 15x5ft.
3 people couldn't lift it, so we had to hire 3 more people so all 6 people lifted it with great difficulty.
It's crazy heavy.
try lifting a slab of neutronium then lol
I've lifted granite as well as heavier materials (even solid gold!)💪... ok I'm talking pebbles and cobblestones of granite (and other rocks) and small amounts of gold (coins, rings nuggets.)
One ton of feathers... is still one ton... it's just going to be more voluminous than that 1 ton chunk of granite...
I had never heard of this before, I always thought the continents were there since Earth’s cool down and that was it. What a fascinating video !
Cue the plate tectonic videos for more detail.
@@michaeldeierhoi4096 *Queue
@@smurfyday r/confidentlyincorrect
For YEARS I had this question on mind, after seeing those maps with the continental shelf vs deep ocean and how the depth changed suddenly, but never had a talk with a geologist to ask it, thanks!
I remember first hearing about the plate tectonics theory in 4th grade in about 1966. It was so obvious to me lookin gat a globe that the Mid Atlantic Ridge mirrors the continents on both sides so "sea-floor spreading" was the theory presented. I never understood that granite can be leached out of the mantles peridotite until now. This video talks about the Great Alaskan Earthquake and includes some of this theory and how it applied in that situation: ua-cam.com/video/lE2j10xyOgI/v-deo.html
completely unrelated note: Granite is super hard and difficult to mine through and it is all across the Sierra Nevadas which is a very big mountain range in California so when they were building the Trans Continental Railroad across the Sierra Nevadas they had to dig through the mountains rather than go over them but that meant digging through granite. The Solution that was used was using Nitroglycerin which is very very explosive at each of the tunnels ends but that was still to slow so sometimes in extra large tunnels they would dig down and then out so there would be 4 parts of the tunnel being dug or exploded out at once
Cool story. Have you talked with your doctor about the symptoms and spectrum of autism?
@@ghost2coast296 super unprompted
@@Anhilare I'm guessing Ghost2Coast thinks OP is on the spectrum, for some reason. 🤷
@@ghost2coast296 have you talked to your doctor about your irrational thinking and antisocial behavior?
@@ghost2coast296 acts like autism spectrum is a bad thing 😂😂😂😂😂
Thank you for this video! I was teaching tectonic plates for the first time recently, and was confused as to whether new continental crust could ever form at all, since I assume divergent plates can only form oceanic crust on the sea floor.
New continental crust is forming all the time. If it wasn't there wouldn't be anything above the ocean surface since erosion is also constantly happening.
Divergent plate boundaries can produce continental crust, but it's mostly recycled material (mafic magma from below heats and melts existing felsic rock). These are actually where you tend to get the most explosive kind of volcanoes because silica-rich magma is a lot thicker and more viscous than mantle-composition magma.
Look up Rift Valleys and Continental Rifting, along with Mantle Hotspots (think Yellowstone).
i've been following this channel since the beginning, 2:30 was the best pun by far
0:32 The image is a bit misleading: Actually the continental crust also goes downward (deeper than the sea crust), and "swims" on the underlying mantle like a ship in water.
Yeah, I see what you mean. I guess they made that image so for simplicity sakes 🤷♂️
rlly informative! love this channel
Wait, does that mean Earth's surface was mostly smooth until after it got its water (which IIRC is assumed to have come from comets and such, not being there from the start)?
And what about the topography of a place like Mars - does it mean Mars used to have a lot more water than what we've detected, or could it all have been formed by other processes (volcanoes, meteor impacts)?
No, it would've been akin to the moon - is the moon smooth? Planets are formed from a LOT of smaller rocks smashing and sticking together - what's the chance that'd result in a smooth surface? Even when the surface melted it was always being impacted and churned - by the time all of that reduced to the levels we experience now, the planet was mostly finished. And THEN it got smashed again by another massive object, which went on to form the moon. There was never a peaceful time during Earth's formation for it smoothen out - by the time there was, the planet had its own violent processes to keep roughing it up constantly.
@@ArawnOfAnnwn I'm saying mostly smooth, not perfectly smooth. Like, a small enough difference between average and minimum height that the amount of water we have could've covered the surface, maybe with the exception of a few volcanic islands. Could there have been a period in Earth's history, some time after the crash that formed the moon, when like 99% of the surface was covered in water? Or is the phenomenon described here just something that keeps dry land area from decreasing over time, rather than creating the dry land in the first place?
Indeed the topography of mars is one reason many were so certain we would find water there somewhere. Landers have targeted areas that look like they could have been ancient oceans in hopes of finding evidence of life.
Note that this video simplified things quite a bit even if its broadly true there are other factors at play for example the two hemispheres of Mars do have different elevations but the lower elevation Borealis basin is thought by some to potentially be due to a major impact from very early on in the solar system with the high plateaus of Mars such as Tharsis and Elysium being concentrated volcanic provinces.
However yes Mars's topography is one reason to suspect water was once present in abundance and it still is its just the vast majority of Mars's water that hasn't been lost to space has long been sequestered into mineral hydrates largely as the planet cooled down increasing the fraction of mineral hydrates that could be supported before they reached saturation. This is in essence a major piece of the puzzle in terms of the newly emerging understanding of the deeper cycling aspects of plate tectonics on Earth enabled by seismic tomography the use of seismic waves to study the interior structure of the Earth as well as much older geological rock records over time.
In essence the amount of water which can be converted into mineral hydrates is temperature dependent the higher the temperature of the rock the less water that rock can hold forcing the remaining water to return to liquid form and rise back to the surface driving volcanism like those seen around subduction zones. However Earth like Mars is cooling albeit much more slowly. When Earth was young virtually all of its water was likely in the oceans however over the last 4 billion years 3 times he current volume of Earth's oceans was sequestered away into the mantle a process which continues to this day and likely based on models is geochemically responsible at least in part for the convective cycling of what we call plate tectonics.
In fact there is some building evidence to suggest it is this evolving geochemical process which has largely driven/constrained the ecological complexity of Earth's surface since it has been shown that among pelagic (open water) photosynthesizing microbe (those which fix carbon using sunlight as a source of energy via various chemical processes that provide a source of hydrogen for carbon fixation) aerobic photosynthesis the photosynthetic process which uses water as a source of molecular hydrogen for carbon fixation is actually the least metabolically efficient pathway because it requires higher energy photons of light than other anaerobic photosynthetic pathways (the two biggest examples being based around hydrogen sulfide or the use of metal ions such as iron to convert dissolved hydrogen ions into molecular hydrogen that can be combined with carbon dioxide to produce sugars.
Oxygen among the elements which are not noble gasses has the second strongest electronegativity which means the amount of pull it naturally has to claim electrons from other atoms without any additional input of energy. It is the high electronegativity of oxygen which makes it so amazing at respiration as it reduces the amount of energy lost during respiration as oxygen does much of the work for "free" however the flip side is that all the energy needed to split electrons away from oxygen must be provided to use water as a source of hydrogen for carbon fixation.
In quantum mechanics however only photons with sufficiently high energy can perform this job but such energetic photons can't penetrate as deeply into the sea.
This is a problem because without a source of mineral nutrients near the surface such as continents passive upwards diffusion is the main mechanism nutrients such as phosphorus can rise in the water column to the layers where photosynthesis can occur. Thus phototrophs which can do their job with longer wavelengths that reach deeper into the sea such as infrared light can use up the available phosphorus will be able to naturally outcompete aerobic photosynthesizers. Thus the prognosis for aerobic photosynthesis to win out is poor unless another source abundant of nutrients is present or the seafloor is within the phototrophic zone of the ocean.
There is geochemical evidence to suggest that prior to 3 billion years ago little if any land was exposed above the water meaning whatever continents existed back then (and we know some continental crust is that old since that is ho we were able to chemically check for whether there was dry land or not by using biases in oxygen isotope ratios of carbon dioxide chemically reacting with rock via air or when dissolved in seawater to gauge this question.
Based on this timing and geochemical models of the mantle cooling the Great Oxygenation Event lines up suspiciously well with models of when continents began to rise out of the water opening up new sources of phosphorous not dependent on passive upwards diffusion. However there is another cooler bit related to a phase transition where enough lower density mineral hydrates can form form them to buoyantly start to rise towards the surface as thermodynamic modeling suggests the timing matches up with the Neoproterozoic oxygenation event and the associated Cryogenian glaciations. The geochemical composition of such magmas based on the known modern analog such this is the process that is feeding the volcanism associated with Mt. Paektu between North Korea and China and it has particular enrichments in elements derived from sea floor deposition most notably including phosphorus and these geochemcial signals are found in the flood basalts associated with the break up of the supercontinent Rodinia.
Altogether this suggests that Earth's geosphere and biosphere have largely been driven by the effects of thermodynamics inhibiting the formation of mineral hydrate layers at the Mantle Transition Zone between the upper and lower mantle and driving plate tectonics. If this was the case then it appears complex life arose as soon as Earth's mantle thermodynamics allowed it to. This has some fascinating astrobiological implications since worlds without continents in the phototrophic zone would never be able to support an analog to the Great Oxygenation Event and thus any life would probably be kept simple by energetic constraints.
For Mars the same processes which took around 3 billion years to unfold in Earth's mantle likely would have unfolded in the planets first billion years before the oceans vanished either into rock or space conditions which greatly constrain its habitable window, however this also means that the same processes would unfold far slower on planets much more massive to Earth as this is a consequence of the nonlinear relationship between surface area and volume and their consequences on heat exchange. If this is the case than the Universe might not be old enough for super Earth planets to have cooled into the habitable window for complex life though on the flip side that window should be able to last far longer all other things being equal.
Well I have rambled off quite a bit more than I had intended though there is much more to say, for example did you know the cold dense subducted seafloor actually is the descending branch of mantle convection? Or that based on recent research what we call plate tectonics actually appears to extend far deeper from the surface down to the Mantle Transition zone as a system of basaltic convection cells with less dense "icebergs/glaciers" of continental rock buoyantly suspended within these denser cells of rock?
@@Dragrath1 well that sounds genuinely fascinating as far as I was able to follow (especially the bits with implications on the kinds of planets we could expect to find life in - if we have good evidence that life formed quickly after the right conditions were there, that implies the probability of it rising under the right conditions is relatively high! Or maybe I misunderstood and it's only relevant to the kind of life that likes oxygen, which wasn't the first on Earth? Even so, interesting if we ever hope to find anything complex on another planet).
If it's not based on an article I hope you write one somewhere and not let it get lost in UA-cam comments :)
Do you know if there's a single basic reason Mars cooled quicker to crystallize most of its water? Just that it's further from the sun, or is it more about different geology?
OMG I love that Emily Elert is back narrating again!!!
" mom , where do continents come from ? "
" The bird of plate tectonics carries the baby continents ."
" Oh "
"AND SMASHES THEM ALL TOGETHER"
I found this channel 7 days ago and I love your videos
This is really cool. It directly answers two questions that I learned to ask when comparing Earth with other planets and moons in our solar system (how Earth's elevation profile got to be so bimodal, and why only the ocean floor is made out of basalt, when on the other rocky planets and the Moon almost everything is), and it also indirectly answers a question that I've had for a long time about Earth's early history (why we think that, early in its history, Earth had less continental crust). I wasn't sure I would ever get a good answer to any of those questions.
It’s been soooo long Emily narrated a video. I almost thought she was gone
We were excited to have her back too! Who knows? She might make the occasional appearance on the channel from time to time.
@@MinuteEarth also great that Kate is the director on this!
How do you guys know all this?!
@@FirestormX9 bcuz they went to school-
@@Corruptedhope do you know what the question is referring to or whom about?
Another great video from MinuteEarth! Thanks for making our jobs as geography teachers a whole lot easier.
The thumbnail got me acting unwise
Yo, you're funny
So glad to heat Emily’s voice again! It has been awhile. Hope she will narrate more video! 😊
Why continents are high? ⛰️
Why continents are high? 🚬
Never tought of this question but it has been answered anyways ❤️
I'm glad that minute earth finally started posting content that sounded right.
Love those puns
I highly appreciate how accurate the title match the content
I like the new "Welcome to Minute Earth" intro than the old "Hi, this is ____ from Minute Earth" since by this point, we pretty much know the voice and "face" of every one of their team
Your videos are always so fun to watch! Thank you!
"Jesus christ Rick what are you, a boulder ? A rock person ?"
Rick would be proud of that joke at the end
One of the best UA-cam Channels...!!! NOT just a, Good Great Science Channel, I always look forward to your, Earth and Space Science Videos 🪨🌊🌍
I seem to remember reading that there is more trapped water under the North American continent than all the oceans combined. So it seems to me that there must be a more important mechanism than subduction to get the water there.
It can sometimes depend on what they mean by ‘water’ Hydrates are molecules that incorporate water into their crystal lattice, both trapping water and remaining solid. Gypsum or Plaster of Paris is one good example.
It has simply always been there.
Well, it's a liiiittle more complex than that, but all the water trapped under Earth's crust has been there for longer than the Earth has had plate tectonics. More water enters as oceanic plates subduct, and leaves where they diverge.
@@IgnisDomini97 your correct about the water always have been there but not becuse of "subducting plates" that water has been trapped beneath the crust forever and just didnt escape during the bursting of the subterranean oceans when the midoceanic ridge was formed. HPT
Interesting. Granite forms a huge part of Singapore’s geology (we even used to have granite quarries, and one of them is now a nature park); given our relative proximity to the Pacific Ring of Fire, I wonder if that’s where all our granite ultimately came from.
Really? Never knew that granite was so important.
Singapore and western part of Peninsular Malaysia is part of land that sheared off Gondwana, like just a sliver of land, all the way to Iran, in a process called the Cimmerian orogeny. The sliver of land collided with the Asian continent, way before India made the same move. In a way, it was a test run for India's great collission.
@@mfaizsyahmi Damn this is interesting. So a thin sliver of land collided with Asia even before India did
All the continents are made of granite so yeah, it's pretty important.
Very interesting. In March of 2020 a geology conference was supposed to meet and decide if a tectonic plate in the Pacific should qualify as an eighth continent, despite being under water. Then Covid hit and I don't know if the decision was made.
It isn’t often I learn something completely new! Well done!
Love this ❤️❤️
Thank you for simply explaining what my Earth sciences professors had trouble conveying in my university courses.
Keep going minuite earth team
This answered so many questions I have never thought to ask, wow
That's such a cool phenomena, water is so amazing
The number of times the title of this video has changed is honestly wilddd. Get the algorithm on your side I guess
Great video and best pun I've heard in a long time. Well done
That was such a concise and informative video! Great for science/geology needs without academic backgrounds!!
This video explained the solution of a problem which I did not know we had, in a way I did not really understand
I love this explanation
Precise and crisp.
* looks at thumbnail * “No way is that Teardrop from BFDI?!?”
It is
You really made me understand that topic very smoothly. Thaank you. It was a really nice video. Keep it up. I really enjoyed it
The puns 😂. You guys rock.
Also the granites are crazy cute with their balloons
Exactly
They're so flippin' cute
Solid video. Am a B.S. of Geo student, and there isn't anything jumping out at me as wrong.
I had this doubt for so many years.
Gave a like because you explained it away.
Wow, I have learned several times about plate tectonics but now I finally understood this part. Thanks!
Emily is back!
best short form content I've seen in a long time
I never really noticed how much thumbnails and titles change shortly after videos are created.
For Example, this video:
Original Title: Where Do Continents Come From?
Revised Title, within the same day: Earth Used to be Naked
Second Revised Title, also less than a day later: Why Continents Are High
I see several channels do this.
I suspect search/recommendation engine hacking.
@@musaran2 yeah, Veritasium did a whole video on it.
@@musaran2 Come, used, naked, high. Search engine optimization. Got it.
Emily is back!! 🥳
Everyone wave to Sam Bankman-Fried (aka SBF) at 3:01 ! Def. had a high-impact role.
Ms. Emily! You’re back!🌼 I haven’t heard from you in a while… I hope everything’s okay
I was just researching this yesterday!!!
Love it!😍
I love this channel
Adorable! Thank you for your video!
There is a leap from a mid-ocean subduction zone to colliding with a continent. I think I figured it out, but it would be nice if you clarified how this happens.
@@ThompsoniusIV thanks for the information.
There is a lot of information glazed over and missing
Thank you this is really neat to see! Loved the animations, too.
Best sponsor ever!
Wow, that is so cool! Thank you, guys! :D
Finally, a new video!
How incredible!🙌🏼
at 1:08 arent the tectonics plates made of solid rock? wouldn't that just be the land if there was no water? am Ii missing something?
wow I learned much more to plate tectonics in this video
minute earth video is 3 mins long inflation is gnarly
This is something I’ve always wondered! Thank you!
So it took 4 billion years to form 30% dry land does that mean in 4 billion years there will be barely any ocean, only a small but really deep one?
That won't really matter because in 1 billion years there won't be any water (or macroscopic life) left on Earth due to the sun getting hotter/brighter (Note: the sun getting hotter is extremely gradual and not the cause of climate change).
@@jouaienttoi I thought the sun is growing bigger in 4 billion years, am I wrong?
No. Eventually when the Earth's core cools enough, plate tectonics will cease. There will be no more volcanoes or subduction. Erosion from wind and water will gradually wear down the surface until everything is below water. Without a molten metal core, the Earth's magnetic field will disappear and the solar winds (high energy particles produced by the sun) will gradually tear away our atmosphere. The water will all evaporate and be carried away, until we're left with a lumpy dry surface with nothing but rock and soil and some thin atmosphere retained by gravity.
This is what happened to Mars.
Finally some accurate geology popular science content
Loved it. I did not know that this was the reason landmass did not sink to the core
Japan is actually a piece of continental crust that has moved out towards the sea. Not all of it was built from volcanos.
I am interested in this topic, thanks 😊
Hey Emily, good to have you back
YOOOO EMILY'S BACK!!!!
Now I know why my geology professor was so eager to tell us about the water “trapped” in the crust!
Every Minute Earth video for me: Come for the puns, stay for the awesome and interesting knowledge
Rock is heavier and densier then water and earth spins what results in a centrifugal force (I learnt this in a video 'what if earth stops spinning, or slows down rotating). This force gives our planet an egg-shape ; an oval which bulbs out at the equator with 20-40 km and is flattened at the poles. This also effects continent-building together with the tidal-forces of sun and moon. The oceans, wether and rivers also have an eroding effect on mountains and continents. We are on a relative thin layer floating on melted rock, and it is continue moving.
That we have continents at all is because earths inside is melted because of friction, if earth cooled down and became solid , 2 things can happen ; 1) the oceans erode the continents away resulting in a blue planet covered with an overall 200m deep 'sea'. 2) more likely, the ocean water seeps into the inner of the planet, it no longer turns in steam and flows just lower and lower, this will result in a rocky dry surface all over the earth. some scary thoughts.
Thanks for your puns😁 You always make the videos interesting👏
Love you videos
Thanks for your sharing
Cool video !!👍
-Why Continents Are High ?
-Because they are stoned .🥴
This video rocks!
Every video I watch from MinuteEarth, always ends with a single pun...
nice reminder to be thankful we have such cool beaches
You left out the smashing of earth and the planetary body theia which is one of the main reasons earth, which is an inner planet, has such abundance of water and the reason there is this granite in the first place. Everything was pretty spot on though just a few things were missing out
I'm halfway through collecting all the Infinity-Thumbnails!
I live in St Cloud, MN. I saw a very old picture around 1900 that called my town "Granite City".
There are many granite mines, and businesses that sell only granite products (countertops, tombstones)
So, either the granite was already here, or when the glaciers made all of our lakes, deposited large amounts of granite in my state. Not all of it came from volcanoes.
Minnesota has some VERY old rocks! It's geologic history spans some 3.5 billion years, and part of its bedrock is indeed igneous (from the cooling of magma and lava). The state forms the southern edge of the Canadian Shield, which is sort of the original "nucleus" of North America - it's a vast area of igneous and metamorphic rock that formed during Precambrian time and involved a ton of volcanic activity. Minnesota may not be the place to see an active volcano today, but it definitely was a few billion years ago!
Well, most of the current exposed land mass was under water at some point in time during the history of Earth.
Like the story of Noah, and having most of the Earth under water, there has been much movement of the Earth. The plates have moved greatly since Pangaea. That a lot of the exposed land mass has seen volcanic activity. The glaciers brought rocks and minerals to other areas too.
DREAR-TOP BFDI ‼️‼️‼️
Emily is back! She's back!
Its amazing to have emily back
30 second in: this continental crust is mostly granite
Me: Well, I know what the pun at the end of the video is going to be.
Continents are high because weed doesn't grow on the ocean
Yeah for real, weed doesn't have the same affect under water. 😊
THANKYOU 🙏🏻🙏🏻🙏🏻