Earth as a whole is essentiallly a closed system right? Nothing leaves except what we send into space and (presumably) no material enters earth except the some space debris.
Where does all the earth/dirt come from to consistently bury historical structure under ground across the world?
In: Planetary Science
It’s not that everything gets buried, it’s that stuff which happens to get buried is available for us to find. Moreover, people tend to live in places where sediment is being deposited (flood plains where floods deposit sediments; cities where people are constantly dumping trash and building rubble) and not in places which are being eroded (the tops of mountains.)
Theres plenty of archaological sites that arent buried but the ones that get buried stay the best preserved. Sites on the surface would also get dismantled for new building materials . In some cases sites are buried for disasters like volcanoes, floods, landslides, etc but its also possible some were intentionally buried by ancient civilizations to either protect them or for use again later
there is plenty of dirt in the world on not much to bury comparatively
Have you ever seen a sidewalk that was freshly edged after grass/etc started pushing soil over the edge and then growing in that soil? That process, but for decades or centuries, or even thousands of years.
Also: wind can blow sand, floods can bury stuff with mud, volcanoes, etc.
Like this: [https://youtube.com/shorts/lUotZuduqOM?si=L3J9q9waMXf3KGOQ](https://youtube.com/shorts/lUotZuduqOM?si=L3J9q9waMXf3KGOQ)
Anything worthy that wasn’t buried , was either stolen, destroyed by nature (wind, floods, rains, tides etc) or were discovered long ago since they were easy to find on the ground.
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Moreover, structures underground were better preserved than those above.
One explanation is survivorship bias.
Many historical structures have been destroyed. Broadly speaking, anything above ground stood a high chance of being repurposed, demolished or exposed to weather etc etc. So much of what we discover tends to be buried because much of what wasn’t buried was destroyed.
Things get buried over time, sometimes deliberately. It is really only in post-industrial times (say 1800s) that we have large earth moving equipment or the broad availability to transport lots of material over long distances. Prior to that, the easiest way for most humans (ie not rich) is to repurpose nearby materials and burn/bury the stuff that isn’t useful. Then build over it. No one was going to spend resources to do much more.
we’re closed to mass but not to energy, which is a lot of why we have a weather system.
that weather gets intense and floods happen, burring what was there.
There’s three parts to this.
The first is while earth is a closed system, its a system in motion. Erosion and deposition move sand and dirt and even rock around the earth and reshape the land. You might not notice it on a human timescale, but over thousands of years you can see much more notable changes.
The other is survivor bias. Most ancient structures and artifacts are destroyed by nature or by humans who move in over them. The ones that are abandoned and buried are better preserved to be found later, so thats why the bulk of our ancient artifacts and buildings are buried, though not all are. Just to take an example, New York City is around 400 years old, yet you are unlikely to find many buildings that are even 100 years old because humans continually demolish old buildings in favor of new and better ones, or fires happen.
And finally, some of the most important archaeological sites for learning about ancient people and cultures are from places of burial or tombs, which of course, tend to be underground.
I think there’s three things.
1. If you demolish an old falling down building, you then cover over the top of the remaining debris to start your new building on a flat solid ground.
2. Everything is moving down-hill usually from wind and water. And in modern times, farmers ploughing fields. Most buildings are built down on flat land. Over long periods of time material from higher points are distributed over the lower land.
3. Dirt is being created from plant matter. If a tree grows, then dies, then decomposes, all those leaves that have fallen along with any parts of the dead tree will add a small amount of dirt which wasn’t there before. Basically the world is a composter.
It’s very easy to put dirt on top of something.
It’s a lot lot harder to put dirt underneath something.
Probably because of mudfloods. Oh and we like to built on top of stuff, just to show we can.
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