@@stevenbaumann8692 Yeah. And they are found in a particularly hypersaline environment within Shark Bay, Western Australia. What creationists who like to raise this point in an attempt at a living fossil own don't bring up is that the Precambrian stromatolite reefs were huuuuuge. These cyanobacterial mats had no predators and few competitors and so vast stromatolite reefs ringed the ancient continents. Now the remaining colonies tend to eke out existences in areas where the environment is actively hostile to potential threats (gastropods and foraminfera) and is high enough in pH to enable the bacteria to secrete the calcium carbonate that binds them into these rock-like blocks.
Just got back from an excursion to southwest Utah and saw some great stromatolites within the Navajo sandstone! Great explanation of carbonate minerals! Great video!
Something you said gave me an idea. You were talking about how certain organisms had the world to themselves for a long time - at least before life diversified. In the process of diversification, new, complex systems of behavior were introduced, both active and predatory, and passively as a result of background chemistry. So - an increase in diversity can lead, quite mechanically, to a natural limit to diversity. Not enough leads to stagnation and extinction. Too much leads to crowding and extinction. What then is the functional limit of diversity with regard to complexity?
Wow what a great thought train and question! I don't know, I have never thought about it that way. I'd love to hear more opinions of others, so if anybody knows the answer or list of possible answers to this question, please reply in this thread :D Thanks!
The theory of island biogeography (qv) treats equilibrium species diversity as a function of habitat area, extinction rates, and immigration rates. It is used in conservation biology to predict extinction probabilities for small populations. A general rule of thumb is that when you shrink habitat area, you shrink population sizes and increase the likelihood of extinction. However, evolutionary diversification can lead to large numbers of specialist species with small populations in biodiverse places like tropical forests and tropical coral reefs, and those species may have high evolutionary turnover.
@@ellenmcgowen - Are such considerations applicable to the Earth as a whole, or do they necessarily require variables such as immigration and habitat size? I would think that the evolution of new species would function to limit the space available to existing species. But what is the relationship? Does a linear increase in the number of species result in a linear statistical probability of any one of those species going extinct? If that is the case, the number of potential species would be self-limiting. If, however, there was a geometric rise in extinction probability, too much diversity could result in catastrophe for all. If the pool is too crowded, compatible organisms would be less able to randomly run across each other and perpetuate their species, would they not?
@@brentwilbur The equilibrium species diversity has a power law relationship to habitat size, i.e. roughly linear on a log-log plot. This was originally an ecological timescale model for isolated areas and to go to an evolutionary timescale model you need to bring in other elements from things like speciation models, metapopulations and disturbance regimes. Unfortunately it's been a few decades since I was reading in this area and I don't recall the details. But when you put together disturbance regimes and speciation you should get an upper limit to species diversity, which tends to be higher for less disturbance. Species diversity becomes limited because packing more species into an area results in a larger number of species with very small populations, and those tend to go extinct more quickly.
There are a lot of Precambrian carbonates. The Kona, Randville, part of the Gordon, etc. but those are Paleoproterozoic. They also tend to have a lot of silica in them. Carbonate rocks really don't come about until circa 3.2 Ga and became somewhat common 2.5 Ga. Us tectonic guys think the appearance of carbonate rocks has more to do with the start of plate tectonics than life. We also have stromatolites in BIF. The Kona dolostone has beautiful stromatolites.
That was interesting - thank you for sharing! Says a musician, who loves to widen his horizon by watching videos like yours. Greetings from Dortmund, Germany and God bless
Rachel: Here’s a wild question from an earth bound geologist. What do we know of the presence of extra terrestrial carbonates? I figured you might have some insights. I recall reading an article about a crater on Mars (Jezero sp? crater) that had the apparent signature of carbonates and was in association with what appeared to be fluvio-lacustrine deposits. Any thoughts? Your video was superb and made me ponder some of the Proterozoic and possibly older carbonates I’ve observed in the Brooks Range of Alaska.
I saw a Cripple Creek, Colorado geology map that suggested the gold producing volcanics cut through a Precambrian migmatite and metamorphosed limestone. I was suspicious of the lime. That would make a great geology video.
I asked GPT4 and it suggested that oil and natural gas could form abiogenically from abiogenic calcium carbonate through this process: CaCO3 -> CO2 under high pressure and temperature. CO2 + 2H2 -> CH4 + 2H2O (Sabatier reaction). That gives us natural gas. Methane can then undergoes further reactions to form more complex hydrocarbons such as oil. Of course, just because a reaction can theoretically happen doesn't mean it has happened in any meaningful quantity, but I find it fun to speculate.
The main problem I see with this reaction happening underground is the lack of a significant source of hydrogen, the most volatile gas. You could get it from splitting water, which requires a lot of energy, but CO2 and H2O are far more likely to percolate through the rocks, causing metamorphism and formation of mineral ores. CH4 likewise is far more likely to percolate upward until it collects in a trap or escapes to the surface than to polymerize. I wouldn't expect to find significant reserves of abiogenic hydrocarbons anywhere, especially compared to biogenic hydrocarbons.
We know for sure that Precambrian carbonates often formed abiotically, without life involved, but we don't know how the larger pebbles where formed. That is interesting. Thank you for these insights into the past, of things, places, and times where no one ever been och experienced.... yet.
Hey thanks for the deep dive! I asked about this a few months ago because ... well frankly my (outdated) geophysicist background was lacking in geochemistry and mineralogy, and you gave a pretty good answer, but a real detailed explanation in video form is awesome!
I usually prospect much higher up, but it's winter, so I have been confined to lower altitudes. Among them, I have come across some gypsum that is very colored. The coloring is localized to an area that could, more or less, be covered by three twenty acre claims. What I know of it, so far, is that it is mostly sedimentary. The only evidence of the color coming from below that I have found is one place in a drainage where I found a lot of pyrite in really thin seams. It came in a formation that was tilted up, when most of the rest around it lay sort of flat. I just happened across it because I like to poke around and randomly came from doing that on one side of the hill that matched with the seam in the drainage. Otherwise, you see a lot of stuff that looks rich from sulfides, but appears sedimentary upon examination. The gypsum is very crystalized. It comes banded, with sulfide layers. The layers aren't flat. They get twisted. This could be because of pressure from below. It could also be because it was a low point in an ancient sea. The sulfides could be there because they collected at the low point. Pressure, or other, could have formed the pyrite. It could also be the tip of a skarn deposit. There are lava flows less than a mile away. They are due to Laramie intrusives. A porphyry body could easily have blown nearby. I just wonder, if that was so, would the sulfidization up high appear so sedimentary still? In some, not everywhere, it does look like it could have been shot through by hydrothermal fluids that were completely barren, especially where they gypsum is not soft. I can't send you a picture, but you can see Gypsum, Colorado on Google Earth. Right across from the airport, on the north side of I-70, you can see the stained area. I'm just curious what the probability is that there could have been any porphyry involvement? I see it described on the internet how ancient sea floors could collect sulfides. I wonder if this area is too limited for that? How small it is? Maybe that is the common thing, though? I don't have enough experience, except to vacillate back and forth.
You refer to the first egreed upon signs of life 3.5 b years ago. Have there been any updates on earlier possible dates? What about the claims of 4 b or even earlier?
Yep, there are claims of 4 billion year old signs of life, but instead of rigid fossilized structures like stromatolites, the 3.9+ billion year old life signs are all (to my knowledge) chemical signatures in rocks rather than physical. This means that the fossil of the organism(s) that caused that signature is gone, but it left behind a chemical fingerprint of some sort. A common chemical signature we look for is stable C isotope ratios. If the C isotope ratios are very 'light' (more depleted in the heavy C isotope), this could mean photosynthetic life was present and caused the rocks to have that signiture. But there is currently a lack of knowledge regarding abiotic processes that could cause this, so we cannot say for certain that it had to be life, that's just the only thing we know that currently causes such signatures. I hope that makes sense :)
My favourite precambrian deposit is the oceans the moon gave us 3 billion years ago. Forget "the moon forming impact" it's proven impossible to model it forming by such a scenario. And that was only proposed when they claimed that " moonrocks" from Apullo had the same chemistry and isotopic ratios as Earth rocks. Which they don't because of constant bombardment by high energy protons from solar wind and cosmic rays. We now know that the moon once had a thick ice crust and it blew off when the Earths magnetic field decoupled from the moons, and it lost its Atmosphere, 3 billion years ago, and that's why the moon is covered by Cryovolcanic features. That are 99% NOT Meteorite craters. And we now have Oceans.
Girl, Girl, Girl! I see why you fangirl over Kevin Peter Hand, and now I'm joining the club😁 i downloaded his book and have been listening to his dreamy voice explaining my fav subject, the spectacular ocean worlds of the outer solar system. I would have loved to be in that airport security line watching his brilliance in action; no, even better, if only i could have been the tsa agent doing that pat down☺️ is that a bottle of salt water on your pocket, or are you just happy to see me?😉 I love your channel, and you are an amazing teacher and brillant scientist; thank you for the suggestion on Alien Oceans too, its been facinating doing a deep dive into oceans beyond 🙄😄✨💖✨
Yes!! I'm so glad you've been enjoying that book! It's one of my favs! And he has done some incredible work in the astrobio field! I love the airport story as well hahaha ;D
O totally recommend visiting Bacalar in Mexico. Not too touristy, but touristy enough for a great time, but *stramotolites* it's amazing to kayak with them?
There is nothing more attractive than an intelligent, strong and confident woman. This girl is that, and also good looking, and also explains awesome and interesting knowledge about how we came here and why things are the way they are. I cant describe the massive crush I have with this girl.
My guess before listening: No, limestone didn't form before life. In fact, I'll guess that the first limestone didn't form until after photosynthesis evolved. I think the main way we currently precipitate carbonate depends on the active transfer of carbon from the surface waters to the ocean depths by life. But I'll also guess that the direct evidence is missing, because that's still two billion years before the Cambrian, and even half a billion is enough to have the rocks be pretty rare. Oceanic crust gets recycled, continental surfaces erode, and even plutonic rocks get metamorphosed or invaded by newer plutonic activity.
Mine was given to me by the american chemical society (ACS) but I believe you can buy one from the ACS website! :) Here's a link to their store webpage: www.store.acs.org/eweb/ACSTemplatePage.aspx?site=ACS_Store&WebCode=storeCatList&catKey=944d7d91-5947-42f3-aa4f-a5e0d897a8b3 I am not sure if they carry that particular blanket anymore, but they do have lots of cool periodic table items :D
Yep, calcareous ooze is another term for it. It tends to be called calcareous ooze when it is being deposited (so modern carbonate muds for example), whereas once preserved in rocks we tend to call it micrite. But I've noticed the usage of these terms change from professor to professor haha ;)
I'm not sure that there are any biochemical reactions that can't happen without life. It's just that life is good at creating conditions that favor biochemistry. Conditions have to be just right for limestone formation to take place, so while abiotic limestone formations *CAN* form, those formations will be small and rare. Limestone is a rather delicate mineral it is dissolved in even slightly acidic water and is destroyed under high pressures and temperatures, turned into other minerals as it is cooked. So it is unlikely that any small abiotic limestone formation to survive the hundreds of millions of years since biotic limestone formations became dominant. And after that, any abiotic limestone may be impossible to distinguish from the majority of limestone that was once a part of a living thing.
Wonderful video geo girl... Iam sorry because...I am not watching your videos from last 2 months... Because...iam also making UA-cam shorts 🙃🙃🙃 But I always love your video ✨✨💖💖💖
Are these dissolved ions in seawater, Rachel, the reason why skeletons over time dissolve in deep water in places such as the abyssal planes? Why there are no skeletons around the Titanic's wreck for example.
Absolutely! The deeper the water, the colder it is and the more dissolved CO2 the water can hold, this causes acidification and carbonate dissolution. The depth at which calcite dissolves in the ocean is called the carbonate compensation depth (CCD) and the depth at which aragonite dissolves is called the aragonite compensation depth (ACD). The ACD is shallower than the CCD because aragonite is less stable at cooler T, higher P water than calcite is even though they are the same composition, they have different atomic structures which make their stability fields different. Skeletons are mostly made of calcium carbonate (like calcite or aragonite) or calcium phosphate, which also dissolves in deeper water that contains more CO2, so all skeletons dissolve in the deepest parts of the ocean. Hope that makes sense :)
I shouldn't watch Geo Girl videos when I've got a couple of glasses of wine in me. Instead of really taking in the content, I just keep thinking "Smart chicks are _so effing hawt."_ 🤪😛😍 Oh well, I think I learned something anyway.
the bed in the dorm room don't help none. (I feel a bit guilty myself, since Geo Girl has come to enjoy my more "intelligent" comments over the months that I've been watching her videos.)
Warmer water holds less CO2 than colder water and this creates a situation where equilibrium with repest to CO2, HCO3-, and CO32- leans toward the HCO3- and CO32- side of the equation which causes an increase in alkalinity and the precipitation of calcium carbonates :)
How does this story connect with water pipes and taps often tend up slowly getting a layer of carbonate like stuff. Roman aquaducts had to be cleaned out periodically. Bacteria and algae play a clear role in our own anthropocene.
Well this is a little disappointing since I just read we got some carbonate samples from Mars and we should have it here on Earth in 10 years. I’m hoping it’s not abiotic.
While I did focus on marine environments, the precipitation and dissolution information in this video applies to carbonates forming in nodules or veins in rocks as well ;)
@@GEOGIRL You are our sciencey types, our torch. We count on you to lead us out of the darkness of ignorance, and the mire of pronunciations like _zoo-ology._
Holy crap! I'm a 65 year old geologist (by training) and I come here to learn new stuff. Well done young lady! Keep up the good work!
That is so cool! Thanks so much for the comment and encouragement :)
Wow we got them stromatolites here in west Australia. 3.5 billion years.🤯
Try and tell the religious that's where we get our oxygen from and not allah.
That would be in Shark Bay would it not?
@@nicholasmaude6906 no. Those are living stromatolites.
@@stevenbaumann8692 Yeah. And they are found in a particularly hypersaline environment within Shark Bay, Western Australia.
What creationists who like to raise this point in an attempt at a living fossil own don't bring up is that the Precambrian stromatolite reefs were huuuuuge. These cyanobacterial mats had no predators and few competitors and so vast stromatolite reefs ringed the ancient continents.
Now the remaining colonies tend to eke out existences in areas where the environment is actively hostile to potential threats (gastropods and foraminfera) and is high enough in pH to enable the bacteria to secrete the calcium carbonate that binds them into these rock-like blocks.
Fascinating stuff! I appreciate that you do a good job of presenting material in a way that's comprehensible to a non-geologist like me.
Just got back from an excursion to southwest Utah and saw some great stromatolites within the Navajo sandstone! Great explanation of carbonate minerals! Great video!
Oh that's sounds like so much fun! Cool! ;D
@@GEOGIRL One day I'd like to hop over to Shark Bay in Western Australia and see our living stromatolites there :)
I love your content. As a fellow educational content creator, I am really impressed with your videos and style. Thanks for all your work.
Thank you so much! And best of luck with your content journey as well! :D
youve got this perfectly synced up with my sediment/stratigraphy class going in on carbonates
Something you said gave me an idea. You were talking about how certain organisms had the world to themselves for a long time - at least before life diversified. In the process of diversification, new, complex systems of behavior were introduced, both active and predatory, and passively as a result of background chemistry. So - an increase in diversity can lead, quite mechanically, to a natural limit to diversity.
Not enough leads to stagnation and extinction. Too much leads to crowding and extinction. What then is the functional limit of diversity with regard to complexity?
Wow what a great thought train and question! I don't know, I have never thought about it that way. I'd love to hear more opinions of others, so if anybody knows the answer or list of possible answers to this question, please reply in this thread :D Thanks!
The theory of island biogeography (qv) treats equilibrium species diversity as a function of habitat area, extinction rates, and immigration rates. It is used in conservation biology to predict extinction probabilities for small populations. A general rule of thumb is that when you shrink habitat area, you shrink population sizes and increase the likelihood of extinction. However, evolutionary diversification can lead to large numbers of specialist species with small populations in biodiverse places like tropical forests and tropical coral reefs, and those species may have high evolutionary turnover.
@@ellenmcgowen - Are such considerations applicable to the Earth as a whole, or do they necessarily require variables such as immigration and habitat size? I would think that the evolution of new species would function to limit the space available to existing species. But what is the relationship? Does a linear increase in the number of species result in a linear statistical probability of any one of those species going extinct? If that is the case, the number of potential species would be self-limiting. If, however, there was a geometric rise in extinction probability, too much diversity could result in catastrophe for all. If the pool is too crowded, compatible organisms would be less able to randomly run across each other and perpetuate their species, would they not?
@@brentwilbur The equilibrium species diversity has a power law relationship to habitat size, i.e. roughly linear on a log-log plot. This was originally an ecological timescale model for isolated areas and to go to an evolutionary timescale model you need to bring in other elements from things like speciation models, metapopulations and disturbance regimes. Unfortunately it's been a few decades since I was reading in this area and I don't recall the details. But when you put together disturbance regimes and speciation you should get an upper limit to species diversity, which tends to be higher for less disturbance. Species diversity becomes limited because packing more species into an area results in a larger number of species with very small populations, and those tend to go extinct more quickly.
There are a lot of Precambrian carbonates. The Kona, Randville, part of the Gordon, etc. but those are Paleoproterozoic. They also tend to have a lot of silica in them. Carbonate rocks really don't come about until circa 3.2 Ga and became somewhat common 2.5 Ga. Us tectonic guys think the appearance of carbonate rocks has more to do with the start of plate tectonics than life. We also have stromatolites in BIF. The Kona dolostone has beautiful stromatolites.
I'm sitting looking at a lump of oolitic limestone I use as a door stop!
@@capt.bart.roberts4975 sweet!
Lincoln Center in NYC is faced with oolitic limestone.
@@dancingnature that's cool!
That was interesting - thank you for sharing! Says a musician, who loves to widen his horizon by watching videos like yours. Greetings from Dortmund, Germany and God bless
Rachel: Here’s a wild question from an earth bound geologist. What do we know of the presence of extra terrestrial carbonates? I figured you might have some insights. I recall reading an article about a crater on Mars (Jezero sp? crater) that had the apparent signature of carbonates and was in association with what appeared to be fluvio-lacustrine deposits. Any thoughts? Your video was superb and made me ponder some of the Proterozoic and possibly older carbonates I’ve observed in the Brooks Range of Alaska.
Extremely interesting talk,thanks
I saw a Cripple Creek, Colorado geology map that suggested the gold producing volcanics cut through a Precambrian migmatite and metamorphosed limestone. I was suspicious of the lime. That would make a great geology video.
In Belen, NM you can find both travertine and Pennsylvanian era Calcium carbonate.
They mine travertine there for industrial uses.
I asked GPT4 and it suggested that oil and natural gas could form abiogenically from abiogenic calcium carbonate through this process:
CaCO3 -> CO2 under high pressure and temperature.
CO2 + 2H2 -> CH4 + 2H2O (Sabatier reaction).
That gives us natural gas. Methane can then undergoes further reactions to form more complex hydrocarbons such as oil.
Of course, just because a reaction can theoretically happen doesn't mean it has happened in any meaningful quantity, but I find it fun to speculate.
The main problem I see with this reaction happening underground is the lack of a significant source of hydrogen, the most volatile gas. You could get it from splitting water, which requires a lot of energy, but CO2 and H2O are far more likely to percolate through the rocks, causing metamorphism and formation of mineral ores. CH4 likewise is far more likely to percolate upward until it collects in a trap or escapes to the surface than to polymerize. I wouldn't expect to find significant reserves of abiogenic hydrocarbons anywhere, especially compared to biogenic hydrocarbons.
We know for sure that Precambrian carbonates often formed abiotically, without life involved, but we don't know how the larger pebbles where formed. That is interesting. Thank you for these insights into the past, of things, places, and times where no one ever been och experienced.... yet.
Thank you so much for this informative video. Keep up the good work.
Hey thanks for the deep dive! I asked about this a few months ago because ... well frankly my (outdated) geophysicist background was lacking in geochemistry and mineralogy, and you gave a pretty good answer, but a real detailed explanation in video form is awesome!
i did not know lime stone could form without life thankyou for a great video i liked watching this video
Thanks for the video!
Of course! :)
I usually prospect much higher up, but it's winter, so I have been confined to lower altitudes. Among them, I have come across some gypsum that is very colored. The coloring is localized to an area that could, more or less, be covered by three twenty acre claims.
What I know of it, so far, is that it is mostly sedimentary. The only evidence of the color coming from below that I have found is one place in a drainage where I found a lot of pyrite in really thin seams. It came in a formation that was tilted up, when most of the rest around it lay sort of flat. I just happened across it because I like to poke around and randomly came from doing that on one side of the hill that matched with the seam in the drainage.
Otherwise, you see a lot of stuff that looks rich from sulfides, but appears sedimentary upon examination. The gypsum is very crystalized. It comes banded, with sulfide layers. The layers aren't flat. They get twisted. This could be because of pressure from below. It could also be because it was a low point in an ancient sea.
The sulfides could be there because they collected at the low point. Pressure, or other, could have formed the pyrite. It could also be the tip of a skarn deposit.
There are lava flows less than a mile away. They are due to Laramie intrusives. A porphyry body could easily have blown nearby. I just wonder, if that was so, would the sulfidization up high appear so sedimentary still? In some, not everywhere, it does look like it could have been shot through by hydrothermal fluids that were completely barren, especially where they gypsum is not soft.
I can't send you a picture, but you can see Gypsum, Colorado on Google Earth. Right across from the airport, on the north side of I-70, you can see the stained area. I'm just curious what the probability is that there could have been any porphyry involvement?
I see it described on the internet how ancient sea floors could collect sulfides. I wonder if this area is too limited for that? How small it is? Maybe that is the common thing, though? I don't have enough experience, except to vacillate back and forth.
Great content ! Thanks !
(Sadly) there is too much evaporite here in the desert of Nevada (and other places). Makes waterproof layers in the soil, etc.--
You refer to the first egreed upon signs of life 3.5 b years ago. Have there been any updates on earlier possible dates? What about the claims of 4 b or even earlier?
Yep, there are claims of 4 billion year old signs of life, but instead of rigid fossilized structures like stromatolites, the 3.9+ billion year old life signs are all (to my knowledge) chemical signatures in rocks rather than physical. This means that the fossil of the organism(s) that caused that signature is gone, but it left behind a chemical fingerprint of some sort. A common chemical signature we look for is stable C isotope ratios. If the C isotope ratios are very 'light' (more depleted in the heavy C isotope), this could mean photosynthetic life was present and caused the rocks to have that signiture. But there is currently a lack of knowledge regarding abiotic processes that could cause this, so we cannot say for certain that it had to be life, that's just the only thing we know that currently causes such signatures. I hope that makes sense :)
@@GEOGIRL Thanks for the clarification. Its nice to see so much engagement with the comments btw
My favourite precambrian deposit is the oceans the moon gave us 3 billion years ago.
Forget "the moon forming impact" it's proven impossible to model it forming by such a scenario. And that was only proposed when they claimed that " moonrocks" from Apullo had the same chemistry and isotopic ratios as Earth rocks. Which they don't because of constant bombardment by high energy protons from solar wind and cosmic rays.
We now know that the moon once had a thick ice crust and it blew off when the Earths magnetic field decoupled from the moons, and it lost its Atmosphere, 3 billion years ago, and that's why the moon is covered by Cryovolcanic features.
That are 99% NOT Meteorite craters.
And we now have Oceans.
Thanks geo girl
Of course ;)
Girl, Girl, Girl! I see why you fangirl over Kevin Peter Hand, and now I'm joining the club😁 i downloaded his book and have been listening to his dreamy voice explaining my fav subject, the spectacular ocean worlds of the outer solar system. I would have loved to be in that airport security line watching his brilliance in action; no, even better, if only i could have been the tsa agent doing that pat down☺️ is that a bottle of salt water on your pocket, or are you just happy to see me?😉 I love your channel, and you are an amazing teacher and brillant scientist; thank you for the suggestion on Alien Oceans too, its been facinating doing a deep dive into oceans beyond 🙄😄✨💖✨
Yes!! I'm so glad you've been enjoying that book! It's one of my favs! And he has done some incredible work in the astrobio field! I love the airport story as well hahaha ;D
O totally recommend visiting Bacalar in Mexico.
Not too touristy, but touristy enough for a great time, but *stramotolites* it's amazing to kayak with them?
There is nothing more attractive than an intelligent, strong and confident woman. This girl is that, and also good looking, and also explains awesome and interesting knowledge about how we came here and why things are the way they are. I cant describe the massive crush I have with this girl.
Oh, interesting topic!
My ears are still ringing from that Cambrian explosion.😵
Amazing topic
Excellent!
My guess before listening: No, limestone didn't form before life. In fact, I'll guess that the first limestone didn't form until after photosynthesis evolved. I think the main way we currently precipitate carbonate depends on the active transfer of carbon from the surface waters to the ocean depths by life.
But I'll also guess that the direct evidence is missing, because that's still two billion years before the Cambrian, and even half a billion is enough to have the rocks be pretty rare. Oceanic crust gets recycled, continental surfaces erode, and even plutonic rocks get metamorphosed or invaded by newer plutonic activity.
Newly subbed - this is awesome.
Thanks! So glad you enjoyed it ;D
Easily distracted man says is that an element bed spread and where can I get one?
Ha ha Rachel has 2 of them…..
Mine was given to me by the american chemical society (ACS) but I believe you can buy one from the ACS website! :) Here's a link to their store webpage: www.store.acs.org/eweb/ACSTemplatePage.aspx?site=ACS_Store&WebCode=storeCatList&catKey=944d7d91-5947-42f3-aa4f-a5e0d897a8b3 I am not sure if they carry that particular blanket anymore, but they do have lots of cool periodic table items :D
@@GEOGIRL Big bang shower curtains? Love your vids, as soon as I strike it rich , your the third academic on my list to support.
My strat/paleo instructor called carbonate muds “calcarious ooze”.
Yep, calcareous ooze is another term for it. It tends to be called calcareous ooze when it is being deposited (so modern carbonate muds for example), whereas once preserved in rocks we tend to call it micrite. But I've noticed the usage of these terms change from professor to professor haha ;)
@@GEOGIRL Mine was a retired petroleum geologist. He said he got bored in his retirement, got his doctorate, and started teaching. 🤣
I'm not sure that there are any biochemical reactions that can't happen without life. It's just that life is good at creating conditions that favor biochemistry.
Conditions have to be just right for limestone formation to take place, so while abiotic limestone formations *CAN* form, those formations will be small and rare.
Limestone is a rather delicate mineral it is dissolved in even slightly acidic water and is destroyed under high pressures and temperatures, turned into other minerals as it is cooked. So it is unlikely that any small abiotic limestone formation to survive the hundreds of millions of years since biotic limestone formations became dominant. And after that, any abiotic limestone may be impossible to distinguish from the majority of limestone that was once a part of a living thing.
Thanks!
Thank you so much! ;D
Getting rid of "gutpile" and going with Ooids and Pisoids as new garage band name.
Wonderful video geo girl...
Iam sorry because...I am not watching your videos from last 2 months...
Because...iam also making UA-cam shorts 🙃🙃🙃
But I always love your video ✨✨💖💖💖
Thank you! Glad to see your comments again ;)
most welcome geo girl.. 💖✨✨🙃🙃
What are the different industrial uses of calcium carbonate that doesn't harm living organisms?
Are these dissolved ions in seawater, Rachel, the reason why skeletons over time dissolve in deep water in places such as the abyssal planes? Why there are no skeletons around the Titanic's wreck for example.
Absolutely! The deeper the water, the colder it is and the more dissolved CO2 the water can hold, this causes acidification and carbonate dissolution. The depth at which calcite dissolves in the ocean is called the carbonate compensation depth (CCD) and the depth at which aragonite dissolves is called the aragonite compensation depth (ACD). The ACD is shallower than the CCD because aragonite is less stable at cooler T, higher P water than calcite is even though they are the same composition, they have different atomic structures which make their stability fields different. Skeletons are mostly made of calcium carbonate (like calcite or aragonite) or calcium phosphate, which also dissolves in deeper water that contains more CO2, so all skeletons dissolve in the deepest parts of the ocean. Hope that makes sense :)
@@GEOGIRL So basically below the ACD and CCD the sea is basically very cold, CO2 super-saturated carbonic acid with a pH of about 5?
I shouldn't watch Geo Girl videos when I've got a couple of glasses of wine in me. Instead of really taking in the content, I just keep thinking "Smart chicks are _so effing hawt."_ 🤪😛😍 Oh well, I think I learned something anyway.
the bed in the dorm room don't help none.
(I feel a bit guilty myself, since Geo Girl has come to enjoy my more "intelligent" comments over the months that I've been watching her videos.)
Limescale in the kettle springs to mind
What about CaCO3 coming from the weathering of Precambrian Metamorphic Marble or Igneous Carbonatites?
New to me neat.
I am confused. Why would it precipitate from warm beach water, when warm water can hold more solute?
Warmer water holds less CO2 than colder water and this creates a situation where equilibrium with repest to CO2, HCO3-, and CO32- leans toward the HCO3- and CO32- side of the equation which causes an increase in alkalinity and the precipitation of calcium carbonates :)
@@GEOGIRL I should have remembered about equilibrium constants. Thanks.
How does this story connect with water pipes and taps often tend up slowly getting a layer of carbonate like stuff. Roman aquaducts had to be cleaned out periodically. Bacteria and algae play a clear role in our own anthropocene.
Interesting. Liked and shared.
I think "ooid" is pronounced "-oyd."
👏🏻 Rachel 👏🏻
Was there a change in how Girvanella is interpreted?
Well this is a little disappointing since I just read we got some carbonate samples from Mars and we should have it here on Earth in 10 years. I’m hoping it’s not abiotic.
Oolites? I oolike it!
That's interesting, I don't think I learned the term pisoids in sed class. Peloids and ooids, but not pisoids.
Heck yeah, carbonate minerals
Wow.. the oldest rice crispy treats.. not very crunchy though
Limescale!
Love your stuff! But, um, “ooid” isn’t pronounced “oo-id”, it’s “oh-oyd”. It comes from Greek and means “egg-like”.
Assuming there was never life on Mars, will there be limestone and carbonate minerals?
Wow, what a chemical soup before the creatures ate it up and gave us marble!
😎
👍👍👍
Sadly, there is little marble on Mars.
I'm so happy Geo-Girl didn't get any jab related injuries like Physics Girl did.
@TalesOf Gore ...
Go EFF yourself!
Diana's LONG COVID is because of... COVID!
Scared of needles, or just hate science? Why you here, bro?
You should explain "cycle of rocks 🪨" ,also.
You are using the name carbonates too loosly. What about carbonates in veins?
While I did focus on marine environments, the precipitation and dissolution information in this video applies to carbonates forming in nodules or veins in rocks as well ;)
Are you kidding me with the 'ew-ids' again? It's 'oh-oids'.
I am sorry, my prof always said ooids the way I say it, so I am just used to that. I will try to be better next time :)
@@GEOGIRL You are our sciencey types, our torch. We count on you to lead us out of the darkness of ignorance, and the mire of pronunciations like _zoo-ology._
My favourite Precambrian deposit? Thea.