WHY DO COINS BURY THEMSELVES?

i was wondering why coins bury themselves over time,when rocks are usually pushed to the surface from the frost and the freezing durring the winter?

  Gravity

I've tried to explain this phenomenon before but some people are stuck on weird science. It all has to do with density. each type of coin has a specific density as does the soil it falls on. Once it penetrates the grass roots area this plays more prominently into the system. The coin will reach a place within the soil matrix where it's same specific density is reached. this same system can be demonstrated with liquids using liquids of varying densities differing densities will create separate layers. If you pour a liquid into this layered environment all will be mixed for a short period but it will al settle out again into separate layers with the added liquid seeking out a similar density level as its self. If none are found it will form a new level. So it is a coin dropped onto the soil will sink until the surrounding soil equall its specific density. As to why stones are forced to the top from a frost freeze action. It is the same. Although most stones are harder than surrounding soil the relative density can be less.

I've tried to explain this phenomenon before but some people are stuck on weird science. It all has to do with density. each type of coin has a specific density as does the soil it falls on. Once it penetrates the grass roots area this plays more prominently into the system. The coin will reach a place within the soil matrix where it's same specific density is reached. this same system can be demonstrated with liquids using liquids of varying densities differing densities will create separate layers. If you pour a liquid into this layered environment all will be mixed for a short period but it will al settle out again into separate layers with the added liquid seeking out a similar density level as its self. If none are found it will form a new level. So it is a coin dropped onto the soil will sink until the surrounding soil equall its specific density. As to why stones are forced to the top from a frost freeze action. It is the same. Although most stones are harder than surrounding soil the relative density can be less.

Huh?

  I think he was explaining how gravity works.  Any object with
weight will sink until it reaches a layer of density that keeps the
object from sinking farther.
  Natural gold is extremely dense.  When you pan for color the
gravel looks much denser to the eye but when you keep bumping
the pan while you allow the lighter sands and gravel to run over
the riffles even the ultra fine particles of gold will settle under
everything else.
  Sometimes coins, unless they are on edge, won't get very far
down but every year the soil above is being replenished with dust,
plant matter and leaf mulch.  The longer in the ground the deeper
they get without any external force.
  You can easily see this by looking at old sidewalks or curbs.  The
ground level eventually gets several inches above the paved layer.

I've tried to explain this phenomenon before but some people are stuck on weird science. It all has to do with density. each type of coin has a specific density as does the soil it falls on. Once it penetrates the grass roots area this plays more prominently into the system. The coin will reach a place within the soil matrix where it's same specific density is reached. this same system can be demonstrated with liquids using liquids of varying densities differing densities will create separate layers. If you pour a liquid into this layered environment all will be mixed for a short period but it will al settle out again into separate layers with the added liquid seeking out a similar density level as its self. If none are found it will form a new level. So it is a coin dropped onto the soil will sink until the surrounding soil equall its specific density. As to why stones are forced to the top from a frost freeze action. It is the same. Although most stones are harder than surrounding soil the relative density can be less.

Huh?

Try it your self, try using different coins and different liquids with different densities. Like oils of different types and Honey and syrups etc. You'll see them set up layers, then toss a coin in and see if it sinks all the way to the bottom or if you have a liquid that is just as dense as the coin, it will stop at that layer. Same thing with stones or rocks, at least until the bigger rocks reach the upper four feet in a frost zone, then it can be both moved up and or down in the soil matrix at varying points of time throughout the year.

I wont try to discuss the relationships between sizes and weights. 

  MD:  Have you experimented with clad vs silver in the heavy
syrup/honey test.  I think that would be interesting for all to
hear about.

MD Dog,
Wow I always thought the coins felt a bit "down".  
J/K.

Now but seriously I think you got it quite right.

  Uh-oh, MD, we forgot to take the specific gravity of gasses
into the formula.  This may take all day.

  MD:  Have you experimented with clad vs silver in the heavy
syrup/honey test.  I think that would be interesting for all to
hear about.

nope sure haven't, but it does sound like an interesting thing to experiment with.

  Uh-oh, MD, we forgot to take the specific gravity of gasses
into the formula.  This may take all day.

Feel free to work on that last leg. Me I don't really care but just like to hunt them and dig them up. 

MD-dog, I got the chance a few years ago, to see this first-hand, in a perfectly stratified park-scrape in a late-1800s San Francisco park.  They were scraping to make ready for astro-turf, and it was a rare occasion to be in on various levels of the scrape.   The park was essentially un-hunted, because it was in a blighted neighborhood that local md'rs avoid (tending to go to the cleaner upscale parks, unless they want to punish themselves with clad and wino-caps).  

The top 6" was very stratified:  Ie.: clad within the top several inches, '50s/60s coins starting at 4 to 5", '40s losses at 6" or so, '20s/'30s losses at 7", etc...   What was interesting, is that ........ if a person were merely to look at the age verses depth speed, of the top few decades, he could assume that ........ if that speed of burial continued, then by logical conclusion, a coin that was 100 yrs. old, would be a foot or more, right?  But we noticed that once the scrape got down to 10" to 12" deep, where we could dig un-disturbed coins (which were now very shallow d/t the scrape), we could see that barbers lost in the teens, and seateds lost in the 1870s, were nearly identical in depth (with maybe a slight 1" difference).  That meant that once coins got to a certain depth, the sinkage rate slowed and then, I guess, stops.   Below a certain point (when the scrapes got to 1.5 ft. or whatever), the soil was completely sterile.   So yes, there does seem to be a point where, in un-disturbed turf, coins tend to slow and stop their depth drop.

That's awesome Tom I wish you could have gotten pics it would have been really cool to be able to see it demonstrated in that way. Thanks for the post non the less, I'm just jealous I didn't get to see that.
 

But then you have to take in account of wind, water, etc., erosion, removing the upper layer. Personally, I think that they are just self conscious.

I've tried to explain this phenomenon before but some people are stuck on weird science. It all has to do with density. each type of coin has a specific density as does the soil it falls on. Once it penetrates the grass roots area this plays more prominently into the system. The coin will reach a place within the soil matrix where it's same specific density is reached. this same system can be demonstrated with liquids using liquids of varying densities differing densities will create separate layers. If you pour a liquid into this layered environment all will be mixed for a short period but it will al settle out again into separate layers with the added liquid seeking out a similar density level as its self. If none are found it will form a new level. So it is a coin dropped onto the soil will sink until the surrounding soil equall its specific density. As to why stones are forced to the top from a frost freeze action. It is the same. Although most stones are harder than surrounding soil the relative density can be less.

Huh?

Huh, hell pay attention.

It's a highly logical phenomanon, Spock.


Coins gravitate. Dirt levitates.

So MD Dog you are saying that 'soil density' would explain why I found items 125 years old at one site only a 1/2 inch deep, but in another different area 20 year old items were only 4 inches deep?  That's pretty cool, and there should be some use I could put that knowledge to.

So MD Dog you are saying that 'soil density' would explain why I found items 125 years old at one site only a 1/2 inch deep, but in another different area 20 year old items were only 4 inches deep?  That's pretty cool, and there should be some use I could put that knowledge to.

I'm not sure how you could put that knowledge to use RGINN ?  Maybe if you could quantify the specific density of targets before hand and then have a way of matching it to soil conditions at your site you could make educated guesses aka estimates about depths of certain types of targets. But all that would be more work than it may be worth. Personally for what it's worth I still just swing, detect, dig. 

very intresting I never knew that  thanks for the lesson

  Huh  ? ? ?

ground gets wet, opens up a
bit and coin starts going down,
over a few years it gets deeper!

Now I wish I would have paid attention in animal biology.

Now I wish I would have paid attention in animal biology.

Or at least geography.

  I think the highlight of this thread was made be Tom in CA.
1' 5'' is the magic number for detector development.

You're probably right MD.  I was thinking more in regard to non metallic targets.  I can find all the metal.  Soil density was very obvious, but perhaps I could apply this to corroborate C-14 datings, maybe.  (I think they're unreliable)  I pay attention to every idea on here, and file the info away.  I went to college once, but mostly remember the student union.  Cool info, anyway.  Thanks.

Coins may sink in certain situations, such as loose sand, but for the most part just the opposite is true.  Any Paleontologist knows that dinosaur bones did not sink to the amazing depths. What has happened is the deposit of new soil on top of old.  (Please do not talk to me about the great flood and Noah!) This fact explains why in certain areas such as pine barrens, where there is little new soil deposited each year, old coins can be found relatively shallow.  In other ground conditions such as upland forests, where each Autumn layers of decomposing leaves add inches to the soil, coins will be found much deeper.

Grass typically grows over coins.  Grass dies and decomposes.  It becomes soil.  New grass grows.  This grass dies and decomposes, and so on. 

Traffic such as walking or sports activities will mat down the soil and push coins deeper. 

Heavy downpours will upset the soil, where the weight of metals will allow coins to sink.   Sometimes the size of the coin will inhibit this.  A heavy half dollar, for example, will usually be found much shallower than a dime.  It depends on the density of the soil.

I hope this does not creat to much controversy.

  I know how coins get deep in Texas.  When we get a long
dry spell the ground will actually crack open.  Years back I
ran my coil over a crack and got a good signal.  So I got
down eye-level peering into the crack.  Sure 'nuff at the
bottom, about 8" down, was a copper on edge.  Turned out
to be an Indian head, the first one I ever found.

  lastleg

  Dear SWR:

    D-Tex BFO Coinshooters are hard to find.  Keith Willis in
Gilmer, TX has parts and pieces you could use to construct
a viable replacement.  No soil was between the coil and the
coin to impede the signal.  I believe the coin was tilted so
that just enough of the surface was 'seen' by the bfo.
  Unless you have used one of the remarkable detectors I
don't blame your skepticism, in fact I encourage it.

  lastleg

I agree to a lot of the comments here...it IS related to the specific gravity of the surrounding medium.  Without too much technical terminology here it could also be that the coin or piece of jewelry could settle down onto some roots, group of stones, or anything else to prevent it from settling any deeper.  I myself found a few older coins settled only an inch or two(or interlocked)into/or onto a root matrix.  Until the roots break down, and dissappear...the item should NOT go any deeper.  Roots could act like a shelf, keeping the item stationary. If metal detecting under a house for example that had no cellar... you may find coins and jewelry did'nt settle more than an inch or two because of not having the elements to bury it further such as rain, wind, snow, bieng walked upon, or any other activity.  On the other side of the coin(sort to speak) if the coin fell into very loose mud or very free and loose sand at the beach it could probably sink a few feet or MORE over a time, also standing on edge could also drive it deeper as well.... I guess it all depends also on the surrounding conditions...Just a couple of other things to ponder!   

Deepseeker 1   

[Law of Superposition]

Coins may sink in certain situations, such as loose sand, but for the most part just the opposite is true.  Any Paleontologist knows that dinosaur bones did not sink to the amazing depths. What has happened is the deposit of new soil on top of old.  (Please do not talk to me about the great flood and Noah!) This fact explains why in certain areas such as pine barrens, where there is little new soil deposited each year, old coins can be found relatively shallow.  In other ground conditions such as upland forests, where each Autumn layers of decomposing leaves add inches to the soil, coins will be found much deeper.

Grass typically grows over coins.  Grass dies and decomposes.  It becomes soil.  New grass grows.  This grass dies and decomposes, and so on.  

Traffic such as walking or sports activities will mat down the soil and push coins deeper.  

Heavy downpours will upset the soil, where the weight of metals will allow coins to sink.   Sometimes the size of the coin will inhibit this.  A heavy half dollar, for example, will usually be found much shallower than a dime.  It depends on the density of the soil.

I hope this does not creat to much controversy.

Neil,  you are correct, "Deposition of Soil"(Law of Superposition) is what basically is responsible for depth of any artifact(IN UNDISTURBED SOIL).   Some settling of course intially does happen, but then it is the accumulation of dirt/debris that becomes soil on top of the object as we all have seen from watching Archies on TV excavate sites...........

Of course we are talking about undisturbed areas, not beaches with tidal flow, fields and any other disturbed areas, artifacts can be deep or on top.

Lesson #3 on this website explains:  http://cap.binghamton.edu/strats.php#  Here is some of the text from that site:

A variety of environmental factors contribute to the deposition of sediments on the surface of the earth, including erosion by physical and chemical weathering, wind, glaciers, flooding, and volcanic activity. A heavy buildup of sediments is often found in valleys and the flood plains near rivers, where people have tended to settle. As human activities in these areas continue over the years, evidence of their activities are sometimes left in the soil. As sediments are deposited, evidence of these human activities are buried. Over time, newer evidence of human activities are deposited on top of the old, which will in turn be buried by new sediments. The result is that the newest deposits are usually found nearest the current soil surface, and the soil with the oldest materials is found at the lowest depths. The study of soil(and rock) levels is called Stratigraphy.

The most obvious analogy to stratigraphy is a multi-layer cake. The first layer is layed down first. Then another layer is place on top of that. More importantly, if you cut a slice in that layer cake, you would be able to see the layers built up on top of one another.

  Different episodes of sedimentary deposition can be seen as different layers of soil, both in color and texture (soil type). Sometimes large-scale events such as forest fires, volcanic explosions, or catastrophic flooding mark a specific point in time (and a layer in the soil). If we know when a certain event happened, such as the explosion on May. 18th, 1980 of Mt. St. Helens and its widespread fallout of ash, and we can identify it as a layer in the soil, we can group all the artifacts and materials in a layer to that period in time. Of course, archaeologists do not usually know the exact date of an event. Relative Dating Techniques

  When excavation starts on a site, archaeologists carefully remove the layers (strata) of soil to reveal artifacts and features. As they cut into the soil, they painstakingly note the color and texture of each layer. After completing the excavation of the site, drawings of the walls (profiles) of the excavated areas are all combined into one large map. This gives archaeologists a view of the entire site's soils and can show where artifacts lie in time and space. Each layer is given a code to identify it. When archaeologists cannot get dates from absolute dating methods such as radiocarbon or thermoluminescence, they must rely upon relative dating. By comparing soils from nearby sites or different areas at one site, the levels can be placed in sequence from the earliest levels at the bottom to the most recent levels at the top. This concept is called the "Law of Superposition." When artifacts or features are found, they are grouped with all other artifacts found in that soil level. Artifacts found in the same soil level are believed to be of the same time period. They were deposited at that level at the same point in time. Therefore, an artifact in an upper stratum is considered to be more recent than one found at a lower depth. The study of soil(and rock) levels is called Stratigraphy.
  Sometimes, there are clues that can give a more specific date to a stratum. Some artifacts have properties that identify when it was made, such as the shape and size of a projectile point, or the color and glaze of a piece of ceramic. These not only give us a more proximate date for the artifact, but a date for all other artifacts in that same layer of soil, and all artifacts and features found in matching soil types in different areas of the site, and other nearby sites. Sites found in the historic period often yield artifacts that can be dated in this manner, as we have a written record to match up with the material record.

Disturbances
While the Law of Superposition is an important method used for dating the artifacts found on a site, archaeologists must also determine if that site has been disturbed in anyway. Most archaeological sites are subject to a wide array of disturbances. External forces such as erosion, gravity, earthquakes, burrowing animals, plant/root growth, human-made structures, chemical alteration, and many other natural or human made activities can change, move, or mix up the original layers of stratigraphic levels. This could be the result of a natural disturbance, such as a root or an animal burrowing into the ground. Humans can create the same effect by digging holes or pits. Artifacts that are moved into or fall in those spaces would then be found in a lower stratigraphic level than where they were originally deposited. In these cases, an artifact can possibly be found below an older level.

Usually, disturbances are superficial and contained in one area of the site. In the case of larger events, a site's integrity can be destroyed, especially when soil levels have been turned over or moved.

Because it is so important for archaeologists to be able to recognize subtle differences in soil color to determine disturbances, archaeologists must take careful and precise notes.

Don

Deposition of Soil"(Law of Superposition) also explains the ancient cities atop "mounts", as old cities were built where older ones once stood.

  Dear SWR:

    D-Tex BFO Coinshooters are hard to find.  Keith Willis in
Gilmer, TX has parts and pieces you could use to construct
a viable replacement.  No soil was between the coil and the
coin to impede the signal.  I believe the coin was tilted so
that just enough of the surface was 'seen' by the bfo.
  Unless you have used one of the remarkable detectors I
don't blame your skepticism, in fact I encourage it.

  lastleg


My 1st detector  a D-tex Pro BFO with I believe an 8 inch coil & I also had an opyional 24 inch coil 4 it IT WOULD GO DEEP

I think it has alot to do with the size and soil they are lost in.  In some areas folks can find old coins on top of the ground.  Other areas not so lucky.  Also if a coin is dropped in a yard with alot of foot travel would help compress that coin into the soil.   Finding a coin you lost in a grassy yard  is hard enough to find even if you know where you dropped it.  So give up on that coin and 30 yrs pass with all the kids playing and what not.  That coin would be under the soil. I do think alot depends on the types of soil tho.  Woods soil is less compacted.  Then the specific gravity of the metal would come into play more.  It would most likely sink into the less compacted soil.  Be covered up with yrs of leaf litter and just be covered up.

I've tried to explain this phenomenon before but some people are stuck on weird science. It all has to do with density. each type of coin has a specific density as does the soil it falls on. Once it penetrates the grass roots area this plays more prominently into the system. The coin will reach a place within the soil matrix where it's same specific density is reached. this same system can be demonstrated with liquids using liquids of varying densities differing densities will create separate layers. If you pour a liquid into this layered environment all will be mixed for a short period but it will al settle out again into separate layers with the added liquid seeking out a similar density level as its self. If none are found it will form a new level. So it is a coin dropped onto the soil will sink until the surrounding soil equall its specific density. As to why stones are forced to the top from a frost freeze action. It is the same. Although most stones are harder than surrounding soil the relative density can be less.

 Bingo.!.  That's it .  The more one under stands about soil science the more good finds they can pull out.

I've tried to explain this phenomenon before but some people are stuck on weird science. It all has to do with density. each type of coin has a specific density as does the soil it falls on. Once it penetrates the grass roots area this plays more prominently into the system. The coin will reach a place within the soil matrix where it's same specific density is reached. this same system can be demonstrated with liquids using liquids of varying densities differing densities will create separate layers. If you pour a liquid into this layered environment all will be mixed for a short period but it will al settle out again into separate layers with the added liquid seeking out a similar density level as its self. If none are found it will form a new level. So it is a coin dropped onto the soil will sink until the surrounding soil equall its specific density. As to why stones are forced to the top from a frost freeze action. It is the same. Although most stones are harder than surrounding soil the relative density can be less.

 Bingo.!.  That's it .  The more one under stands about soil science the more good finds they can pull out.

Based on this theory, a coin sitting on a piece of balsa wood, which has very low density, will sink through the balsa wood?  This theory is valid on liquid or gases, but not on solid objects such as coins.

So you take a glass jar and put some dry sand in it, and carefully lay a dime on top and put the lid on the jar. Keeping the jar indoors on a shelf, would the coin ever settle any farther down?

My opinion follows:

On a beach with normal large silica grains and much percolating water, a coin should mix downward into the sand until either there is no more mixing forces or the density is approximately balanced to the surrounding matrix. That could be 14 inches or more, to the point it is beyond detection. In this scenario it doesn’t matter the coin age as the mixing action is rapid, a matter of hours, days, or perhaps seasons. If soil grains are small and/or the soil is not as wet as at the beach, or the soil matrix contains many buried pebbles/rocks, then the final depth of a sinking artifact would not be as great (less mixing and more resistance) and take longer (slower vertical movement).

In nearly any soil, in the wet season, coins should likewise mix downward, at least into the root zone by physical processes (that is, precipitation, foot or animal traffic, wind action, lawnmowers, ground vibrations). A coin should mix downward 1-3 inches after one or two rainy seasons assuming a supporting root system or humus base (offering some resistance). Depending on the soil density (compactness) and its porosity/permeability to vertical water transport and/or propensity to being disturbed, a coin dropped in a field will be displaced downward to a point by the pull of gravity and should go no further. There is evidence that coins are often found deeper than would be expected by mechanical processes alone - that another action is at work, perhaps at random, altering the soil matrix enough to allow gravity to work the coin deeper.

I’d submit that there is a more significant action going on unnoticed in almost all soil matrixes. In a word, relics descend deeper or in some cases are brought back toward the surface by a nifty biological action – namely, unseen critters in the soil.

 It may be hard to believe their effectiveness, but earthworms, ants, and rodents work overtime to mix the soil, and in the process transport coins/artifacts down deeper into the soil. Burrowing animals displace large objects downward, and can carry smaller object upward to the surface. So, we have to consider not only mechanical but biomechanical soil turnover, as I suspect these are the prime redistributors of buried objects in the soil.

Bioturbation is a real and moderately rapid effect (over the span of years). Once an artifact hits the ground it is subject to downward transport as well as deposition of soil over it. A 1994 study with a single earthworm found that after two years mammal bones had been vertically displaced downward 9 inches and laterally by six inches by the worm. Large rodents like gophers work hard to redistribute soil matrixes and tend to move smaller objects (1-2” in diameter) through their burrowing efforts toward the surface.  Rodent activity can also bury surface objects under excavation mounds which can raise the ground surface. Their tunneling work can mix artifacts into the soil down to a working depth of 2 feet or more.

Likewise, earthworms working in the soil will cause deposited coins to sink further than expected by density alone. The mechanics of breaking apart the soil and the biological action of mound building by rodents, ants, and earthworms can cause artifacts to be buried deeper without raising the level of the ground, though deposition of soil can raise the ground level. The artifact depth finally obtained through bioturbation depends upon the depth mixed by these soil critters, their relative abundance, and the time allowed. It is estimated that surface soil can be completely mixed downward by gopher-action within about seven years or less.

Through the soil movement of earthworms and ants alone it is estimated that the first six inches of soil is mixed and displaced every fifty years or more. Earthworms move dirt to the surface at the estimated rate of about 0.10 to 0.40 inches per year. Rodent activity has been measured to bury artifacts at a rate of as much as 2.2 inches per 100 years.  One study found that within seven years, artifacts on the surface had become buried by zooturbation (critter action) to a depth of about one inch.

The net effect of this burial and mixing is to redistribute coins and other artifacts further down into the soil. Rodent tunneling can stratify objects based not on density but rather by activity zones, such that one study found a relic settling depth of 8 inches and another at about 20 inches, corresponding to two levels of gopher burrowing activity. Smaller artifacts tend to be moved toward the surface (smaller than the rodent tunnels) and larger artifacts tend to mix downward thus creating separate zones sorted by size.

Other phenomenon was observed in which objects are buried without mixing. A layer of lime was laid down on a grassy field followed six years later by a layer of coal cinders. Ten years later a trench dug into the soil found the lime 3 inches deep into the ground and the coal layer was 1 inch beneath the surface, all still with the layers stratified. Thus layers moved downward into the soil and were buried as a layer, without mixing. This is the process by which buried artifacts of older cultures can be found beneath younger cultures, though mixing does and can occur.

The upshot is, artifacts and coins will sink both due to gravity acting through a water leached soil medium and by mechanical mixing such as from farming, wind deposition, frost heaving (that is, water layer at some depth freezes and expands thus forcing soil above it upward and soil beneath it downward. The ice layer (called an ice lens) can grow larger with capillary movement of liquid water from below, the net displacement upward can be significant enough to break pavement and lift the soil into mounds), tree uprooting, soil creep (down slope), foot or vehicle traffic, and further by bioturbation from rodents, ants, earthworms and the like that bury surface objects but also force deeper into the soil root-level artifacts, notably by mixing larger objects downward and smaller objects toward the surface.

I'd estimate that it would then be correct to expect coins dropped 50 years ago to be deeper than a coin dropped 10 years ago - all things being equal. If critters are present, and they usually are, energy is being expended that will mix the coin deeper - unless otherwise impeded. The actual sinking depth is likely only to be consistent within similar soil matrixes and with similar critter mixing actions and at similar critter working depths. What constitutes the final relic depth is going to be localized to the area in the proximity of the find, where soil variables that hinder/enhance vertical movement are generally similar and critter activity is about the same. With so many variables working in a dynamic soil, it should not be surprising if younger coins are located deep in the ground and older coins are found near the surface, or both are found at the same level. Which was the predominate force: was it the action of earthworms and gophers or was it the internal soil consistency and available leaching action of water that caused the final coin depth. Likely it was a combination of influences that over time acted in conjunction with gravity on the coin - but you'd be hard pressed to determine the culprit that put that Barber dime only 2 inches beneath the surface and that clad coin at 7 inches. Varying soil conditions and critter workings combine in unique and differing ways that makes predicting the final resting place of coins and relics more complicated than one might first assume.

Jack

  Thank you Mister alope.  Well said.

  lastleg