FYI: Catastrophic flooding helped carve Martian valleys, not just rivers of water Scientists studying Mars now reckon flooding from lakes contributed to around a quarter of the planet's land erosion and not just continuous flows of water that had been assumed to be the cause. In a paper that prompts a rethink of the Red Planet's ancient landscape, researchers from The University of Texas at Austin used data …
Almost 4 Gy ago, that's still in the Archean, isn't it? Like right at the beginning. There was no life around on Earth at that point in time (ok, some life, this is why we do not call it the Azoikum any longer). Even the stromatholites here on Earth are younger, maybe some cyanobacteria were around already, not sure about the dating of those.
Ok, but that also means that simple life could have evolved on Mars at that time. No little green men, but maybe green algeae.
The Martians were already hydraulic engineers. As I see it:
- oh noes, we need water, what shall we do?
- ah, plenty of water in those gaudy rings around Saturn. Let's send some home!
- great idea; Saturnian iceberg lands, makes a big lake-sized hole, and fills it up at the same time.
- win win, let's do it.
- only... be careful not to land one on the rim of a previous lake, right? That could be an issue.
- nah, she'll be fine...
When I was in grad school in geology back in the mid-'70s one of the professors in the department had NASA funding to study earth-analogues of Martian fluvial features. The features of interest were predominantly fluvio-glacial (jokulhlaups) in origin, so much the type of processes this article's ascribing the features to.
"That's the theory about the formation of the English Channel, being scoured out by a catastrophic event."
That's covered in a really interesting exhibition:
https://www.rmo.nl/en/exhibitions/temporary-exhibitions/doggerland/
Current thinking is that the UK and Ireland used to form part of mainland Europe, the area joining them is now referred to as Doggerland. At the end of the last Ice Age sea levels rose, gradually forming the North Sea. Towards the end of that period part of the coast of Norway collapsed, causing a tsunami which reshaped the area to form the North Sea as we know it know.
Apparently you can find archeological artefacts from Doggerland on some reclaimed areas fairly close to where I live, so planning to go there and have a gander.
The catastrophic lake breach scenario will be familiar to anyone who knows the geological history of Washington state in the U.S. During the last ice age, huge lakes formed repeatedly in western Montana behind ice dams in northern Idaho. When the ice dams melted during warm periods, vast volumes of lake water were released across the state of Washington, gouging out channels such as Grand Coulee and leaving ripples on the landscape that are miles long.
Yep. That was my thought. And it's not just Washington. Indeed, the largest glacial floods were apparently further East draining into -- at various times -- the Mississippi, St Lawrence or Arctic drainages. See https://en.wikipedia.org/wiki/Outburst_flood. Similar floods occurred in Asia during the last deglaciation.
What I'm not sure of is whether the geological (areological?) signatures of glacial floods would be easily recognized from orbit or whether perhaps they require boots/wheels on the ground observations.
Yep. That was my thought. And it's not just Washington. Indeed, the largest glacial floods were apparently further East draining into -- at various times -- the Mississippi, St Lawrence or Arctic drainages. See https://en.wikipedia.org/wiki/Outburst_flood. Similar floods occurred in Asia during the last deglaciation.
I really do enjoy reading about past climate changes.
This planet has undergone significant climate calamaties & will continue to do so.
its interesting reading how some of these changes allowed early humans to leave Africa and how it displaced communities in other areas.
In my view this planet does what it does and life works around it, which is not easy to stomach when it directly impacts your way of life.
My pet theory is that nature has had billions of years to create humans yet has only done so geologically recently. If you want to spread life beyond this globe you need the tools to do so. Humans are the only forms of life in the known galaxy able to go from 1 planet to another. I think nature wants to spread its DNA to other planets & we are natures tool for doing so.
The sooner we succumb to natures will the better.
Maybe this planet is changing for the worst or there will be some catastrophic object from space headed our way & life's only chance is for us to spread life in this planets DNA image to other planets.
I have thought on similar lines. Another thing that Nature could be doing is using humans to free up all of the CO2 that has been locked up in fossil fuels and raise the levels of CO2 to help out the plants. Let's face it plants were nearly at starvation level when the CO2 had dropped to 200ppm and 2000ppm would be much better level for plants.
> to free up all of the CO2 that has been locked up
Be careful what you wish for, the end of that road is Venus, a runaway CO2 hell with temperatures which would melt lead! Plants wouldn't appreciate...
CO2 is only beneficial in certain amounts. Over that it's Game Over.
Quite wrong actually. Venus is 95% CO2 and it is not the CO2 that makes it hot but the amount of just well gas. Venus has a surface pressure 90 times greater than Earth. If you measure the temperature on Venus 54km up at the same pressure as the surface of Earth then the temperature is the same as Earth. Which shoots a hole in the 'greenhouse effect'.
Even if all the CO2 locked in ALL fossil fuels is released back into Earth's atmosphere we will never become a Venus. We will never even get back to the atmosphere we had a billion years ago because so much of the CO2 has been locked up in limestone by little sea creatures.
It is always possible to get any wrong answer you like by missing out things from your calculation. In this case it is at least water vapour: 20ppm on Venus, variable between ~0 and 30,000ppm in Earth's atmosphere.
You cannot do atmospheric warming effect with spherical cow models if you want right answer. Of course, if you want wrong answer such models are ... convenient.
> I think nature wants to spread its DNA
Don't mix up correlation and causation. Life is fragile, and the life forms (plants, animals) which have survived long enough to be noticeable are those who actively try to perpetuate their genome. That's why you get all antsy when you see a suitable sexual partner: If your parents and grand-parents weren't so interested in sex you wouldn't be here, would you, and you inherited that from them. Those uninterested had no offspring.
Now what does an ecosystem ("Nature") want? Just to cram as many different life forms in a given situation as possible, usually by creating interdependencies (food chains, symbioses or parasitism). It definitely doesn't push anybody to go to space. What pushes you there is your own need for new territories and opportunities.
Why did the old Europeans leave for those new, uncivilized and dangerous Americas? Because they offered more opportunities than their homelands. The more desperate and/or adventurous took the leap and left to start a new, hopefully better life in those new lands of infinite possibilities. Similarly, when and if humans leave Earth to start a new life on some other planet, it will because they hope they will get a better chance there. Better life, less taxes, a chance to become somebody.
However there are many examples of life doing impulsive things that it almost seems we are driven to go somewhere else.
The first move from the sea onto land. Even now many fish leave the environment there are ideally suited for and cross the boundary between sea and land and vice versa. Eels, Lungfish, Sharks, Catfish, Channidae and the ones that have gone the other way, Manatee (once elephants,) Comodo Dragons, Sea Snakes, Cetaceans many of which seem to be trying to get back on land (whale dolphin beachings.)
Many animals that have ended up on the Pacific Islands that launched themselves off into the wild blue yonder to make a life in isolated places.
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