I’m laying awake, not able to figure this out.
If our civilization were to be left untouched for thousands of years then over time it’d get covered in dirt. Some future generation would have to “dig up” our civilization in the same way we dig up artifacts from the ancient past.
Where does that dirt come from? Is it floating around in the atmosphere? Or does it get created somehow (ie. organic matter decomposing)?
My understanding is that older artifacts are buried deeper, which may not be the correct understanding. But is there some relationship to dirt vs time?
So many questions.
In: 18
Okay so, if you walk down a path in the dirt the path will get deeper because your compacting and pushing the dirt aside. And you clean and sweep your color right? The wind carries dirt to your things but you remove it.
Now of you love around sand this is a more active process because the wind picks up sand like crazy and it’s harder to brush away.
Not all ruins are covered in dirt…it depends on the location. Either the landscape in the area changes and dirt is “brought” in from another location, or – as you mentioned – it is created.
Dirt can be transported from other areas via events like flooding. (Ruins can even be submerged in a body water, and then be submerged under silt over many years.)
Dirt can be “created” by decaying organic matter…that’s what makes up the majority of soil, after all. Other sources are volcanic eruptions spewing magma and ash, earthquakes, and even erosion breaking down rock into sand.
Over hundreds of years, rocks break down into tiny grains, and these small grains, mixed with plant and animal matter — decayed roots, leaves, dead bugs and worms, and other organic matter thrown in, along with water and air — is what we call dirt or soil.
Sediment from flooding (before dams were common floods were more common) covers the land with dirt from time to time.
There are a few potential reasons why various sites ended up buried:
* They’re buried by the surrounding environment. This can be due to things like shifting desert (Amarna in Egypt), centuries of vegetation turning to soil (Chichen Itza in Mexico), or an abrupt cataclysm burying the city (Pompeii in Italy).
* The site was intentionally buried by humans. This is most common in the cases of tombs, barrows, tumuli, and so on. Occasionally, it could be because a site was intentionally razed, making it far less of a challenge for nature to bury it.
*The site got buried by continued habitation. This is most common in the Fertile Crescent, where mud brick was the most common material. As mud brick buildings gradually eroded (or got destroyed in war) and got rebuilt, it gradually raised the elevation of the city over millennia, forming what archaeologists call a [tell](https://en.wikipedia.org/wiki/Tell_(archaeology%29).
If your civilization isn’t being slowly buried, it’s being eroded. Wind and water work hard to break off bits of rocks and soil and manmade structures. That’s erosion, basically. So some places do get buried, but the rest will get eroded.
So why are all the sites where we dig up ancient civilizations the buried ones? Because the other ones got eroded away over time – they’re gone, scattered in a trillion little pieces downstream.
Think of all the mountains being constantly scoured by wind and rain and being worn down…all that dust is swept by the wind to other places.
Basically all the mountains and hills are being made shorter and everything below them are being filled in.
The Arbuckle Mountains in Oklahoma are said to be the oldest mountain range in the world, and they are very small now compared to “newer” mountain ranges like the Rockies.
Another example of sand being moved from one place to another by wind is the Caribbean Islands. These islands were formed *entirely* by sands blown west from the Sahara desert! That’s an incredibly far distance – all the way across the Atlantic Ocean.
Overall, it is really mind-boggling how much dirt and sand is moved by the wind from one place to another all around the world.
On a smaller scale, abandoned places can become overgrown with plants and vines (and sometimes trees), which eventually decay and turn to dirt – in which other plants take root, die, and turn to dirt – thereby becoming buried in that fashion as well.
Real ELI5: Your room gets dusty in one week if you don’t clean it, now imagine what kind of dust there is after nobody’s been cleaning it for two thousand years.
The dust comes from space and erosion, and gets whipped up into the air by winds and such.
Vegetation creates a lot of soil.
For example: most roads are built with dirt sloped sides to carry water away. Nevertheless have a look to an old road and you can see how the grass has created a 20cm tall dirt wall on the sides. Idk if it happens everywhere, but here in Italy they have to periodically scrape the road side with a dozer to remove that dirt buildup. I guess it grows 1 cm of dirt per year.
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