How do archaeological ruins get buried?

At this moment a construction crew is in the process of excavating the foundation for a new apartment building across from my house. In the process, they have uncovered a lot of Roman ruins (this is pretty common where I am in Switzerland), which then has turned the build site into an archaeological dig for the last several months. It’s very cool to watch and see what they find. So far it’s just the usual stuff: bits of stone wall, miscellanous pieces of red brick, remnants of fire pits, etc.

Most of this stuff seems to be appearing about 2-3 meters below the surface. I have always wondered how these ruins end up underground. In particular,

  1. what natural processes are responsible for putting 2-3 meters of organic matter on the objects in question? I have a few ideas but am not certain, and

  2. what are the socioeconomic phenomena that allow the ruins to remain untouched for long enough for them to get buried? I mean, a few abandoned stone walls for retaining livestock I can maybe understand, but how does one ignore an entire ampitheatre for 2000 years?

any archaeologists out there?

I’d guess that after a natural disaster such as a mudslide or an earthquake in which most sructures are destroyed/lost, the people living there just build over the ruins and continue on with life.

Is it possible that some structures are always known to the people living in the area and are visited thus keeping everything from being buried (Stonehenge) and that ‘lost’ towns/cities just get buried naturally…?

Cecil knows the answer.

thanks jovan. I had tried searching the SD archives under ‘archaeology’, but not, unfortunately, ‘archaeological’…

An interesting answer. I hadn’t thought of the accumulating trash angle.

Robert - I’m a professional archaeologist, who specializes in exactly what you are talking about. I work for a large firm in Boston Massachusetts and my area of expertise is excavating industrial sites where human and archaeological remains are found. What area of Swiss are you in. I may be able to tell you quite a bit about the dig, through our network. I am also open to any Q’s you may have. I’ll write a reply to your Q’s, in a second post…so if you have any further Q’s let me know…

Land slides, volcanic eruptions, desert shift, desertification, inhabitants didn’t like their first mud home so they tore it down and built a second one in the same location because they liked the view. A river shifted and covered a settlement, then shifted again and I discovered their midden (trash area) when excavating for a new walmart.
In a settlement you have to account for much the same things we do now. Where to put the waste and where to put the trash. Manytimes that was in puts specially designed for that purpose. And when a pit got too full they would fill it in and move a home, and sometimes an entire settlement around where they were putting their trash. It is a little more complicated than that, but in a nutshell, those are major factors.

Well, as per the amphitheater - that does not usually happen. But let’s take something well known such as a Mayan Temple. First of all, it was built in the middle of a forest, and not just any forest, a rain forest. Therefore things grow very quickly, including concealment vines and the like. And a new theory recently surfacing was that the ancients actually let the vines and such grow on the temples to give them a bit of concealment from outside intruders, mainly post conquistadores. But there are a variety of reasons for consealment of settlements, and I’ll direct you to the above info for some of them.

IANAA, but this is what I have observed:

When I lived in the desert, I noticed that sand tended to accumulate around unattended structures. A house that is unoccupied for a long time will eventually fall down. (There are a lot of old “shells” still standing, but they’re not going to last 1,000 years.) Once they fall, they’ll get filled with blowing sand and vegetation will start to grow on them. Over time, they will be buried and appear to be just a bump in the desert floor.

Now I’m living in a very wet area. I see a lot of wooden-framed houses that are deteriorating and are covered with vegetation. Much of the vegetation is brush (e.g., blackbury bushes – “kudzu of the North”). Saplings also shoot up through them. (There’s an old tin shed out back that has a sapling growing on its roof. I’ll have to demolish it when we have longer stretches of sunny weather.) The growing stuff, fungus, insects, etc. will bring structures to the ground after a while. Moss will cover it, and other things will grow in the moss. These plants will die and fall over the site, to be replaced by other plants. After a while, the structure will be completely buried under decayed vegetable matter and dirt.

That’s great Antiquarian. Thanks

I live in Nyon, on Lake Geneva, about 25 km NE of Geneva. I doubt this current dig will be very noteworthy, as every single new foundation dug in central Nyon comes up with something Roman. The archaeological teams just come, document everything, (presumably remove any important pieces), and then tear it all up and build over it. However, that said, a parking lot project was completely scuttled about 30 years ago when they found a well-preserved basilica (which is now the local Roman museum), and a housing project was stopped in 1997 when they found a 40 meter ampitheatre. Nothing like that next to my house I’m afraid.

I guess Cecil’s column answered my first question about the burying process, but I am still curious about the second one. I mean, assuming there wasn’t some catyclysmic event, the ampitheatre must have been buried over many centuries. Didn’t anyone at some point notice a half-buried ampitheatre? Or the basilica must have been pretty impressive in its time, how could someone ignore it for such a long time?

Another question I just thought of is very specific to the dig near me. As I mentioned in the OP, most of the ruins are old walls of some kind. However, they are all no more than 2 feet high - not enough to do any wall-type functions I can think of. Would these have originally been higher, or were they meant to be so short?

Not that not all places of human habitation get buried. Depending on local conditions, a site might get built up or worn away. Ancient cities can be complete eroded away by wind, rivers and such. The latter make really lousy arch. digs. So the best places to find stuff are where things are buried well and of course that’s what you hear about.

I saw a documentary once on a “lost” city of central Asia. It had been besieged by Ghenghis Khan, didn’t take the offer to surrender and was obliterated. Since the city was on a flat windy plain and made of mud brick, there isn’t much there at all now. The image of the host standing on a flat, nearly smooth spot where a grand city of 10s of thousands once stood is burned into my brain. So we really don’t know a whole lot about that place since there’s virtually nothing to dig up.

whoops, looks like our posts crossed…

A quick dig found this:

which should answer your second Q.

Most likely, the basilica was destroyed and built over giving no heed to it’s prior value by the medieval developer. It happened more than you’d think. Same thing with the amphitheater. Someone probably built over it and didn’t give it much thought. You’d be surprised how often it happens. I was on a dig outside Toledo Spain where they found a Moorish outpost that produced some of the most rare moorish artifacts I have encountered. Why was it discovered so late as it were? Because the people who built over the find did not give any heed to the moorish culture, infact they despised the infidels. It happens. any further Q’s just let me know.

I’ve noticed the same thing in a different climate. My grandparents’ own the original family homestead in Idaho, and as a kid there were still a few buildings standing from an abandoned part of the farm that dates to around 1900. Now, twenty years later, most of the stuff has fallen down and is overgrown with weeds. In fact, it’s hard to tell that much of anything was in the area, and this only took a decade or two. I can see how a couple thousand years would allow this stuff to be buried pretty completely.

This makes me think of Colha in Belize. Colha was located in an area with lots of chert and became the centre of the stone tool industry in the Maya world. There are piles of debitage that are metres deep.

As to your 2nd question, IANAA but I’d imagine it may have something to do with the fact we’re probably one of the first generations to have this level of ample free time on our hands with which to pursue our intellectual curiosities. My guess is that ancient peoples saw the ruins but were so busy just with their day to day struggles to stay alive that digging up some ruins just had no logical benefit to them. Their animals were more susceptable to disease since they had no meds, their crops more susceptable to pests and weeds since they had no pesticide, herbicide or fertilizer and, in short, this kept them busy as hell just trying to eek out a living.

The ruins were around them but they were of little interest since investigating them didn’t make life any easier. Again, just MHO.

The post about the city Ghengis Khan destroyed gives another reason why the buildings get buried… there is a confirmation bias in the question because the buildkings which don’t get buried (for whatever reason) are relatively quickly destroyed, so it seems that ancient buildings get buried.

Is it also a factor that whenever something sticks up off of the ground, dust and plants accumulate around them?



I’ve always assumed that stream aggradation was a significant factor, whenever the settlement was in a valley. Cecil touched on this, but not much. Anyway, streams deposit sediments (that come from upstream), and the stream itself rises as these sediments build up.

The thing is that, as a geologist, I’ve only dealt with geologic time, so I’m not sure how significant this process is in the time blip that is human history. Does anybody have insights on this?

Sediment transport works on two levels. The first is closer to geologic time - the a naturally functioning stream constantly moves sediment. The amount of sediment that the stream can carry is determined by many factors, including the slope, channel cross section, velocity, and sinuosity (how “crooked” it is). In this instance, the stream itself will reach an equilibrium - if there isn’t enough sediment in the stream, it will erode the banks to increase the bed load; if there’s too much, it will deposit sediment in the channel. This kind of balance is responsible for carving out canyons and creating deltas, but it’s gradual enough that it doesn’t necessarily effect human settlements.

The more immediate method sediment aggradation is from flood waters. When you get a lot of water travelling downstream very quickly, it picks up an enormous amount of sediment. Eventually, it reaches a place where it will back up (a confluence with a larger river, for example). When this happens, the water slows down and spreads outward, losing most of its energy. This energy loss causes it to drop the huge sediment load - a couple of feet isn’t unusual for a large event. These events recur on timescale thats more compatible with human history. The frequency depends greatly on the climate and the particular watershed being considered, but they can certainly happen several times in a few hundred years.

Thanks Antiquarian. Interesting blurb on Nyon. I am originally from the US, so I find all this Roman history around me to be quite exciting. In my home town, the oldest building dates to 1786. Around here, they have cheeses older than that!

Any insight into my question about the height of the walls thay are uncovering?

That’s one of Cecil’s better lines :slight_smile:

True. Also, let’s remember that as mentioned before, “historic preservation” was not a priority in most of the world until very, very recently. In continuously-inhabited areas, the normal course of events would be that new construction would involve building on the old structure’s foundations, or even right on top and around them whole – e.g. the original chapel would become the crypt of the cathedral – up to and including actually burying the old structures with fill in order to level the terrain for the new construction. Material from the old building would be “recycled” for use in the new.

Really large and conspicuous exposed structures would stand a better chance of being reused more or less intact in new roles (e.g. Hagia Sophia, or the Pantheon); those that fell into disuse would be at risk of being turned into “urban quarries” (much of the Roman Forum and Colosseum).