Found layer of petroleum below my soil/horse manure in my barnyard

Cleaning up under my barn where my horses hang out, I dug about 10” down and found clay with what appears to be a layer of oil. It’s black and just at the surface of the red clay soil. I’ve been using the manure I collect here for my compost so I’m disappointed to find this underneath it all. What do you guys recommend I do?
My thoughts are to shovel that layer away and toss it. Then what? What should I begin to replace it with? My horses and chickens spend a lot of time in this area. It’s about 30’ x 40’. Thanks for your help!

Maybe you're rich now?  

How thick is the oily layer?  Does stuff grow in those areas?  Maybe the oil isn't a problem?...

First off, just because it looks oily doesn't necessarily mean that it's petroleum, so it may need testing.
Second, look around and see if there's any chance there's some sort of buried and forgotten tank around that could in fact, have leaked oil.
Some forms of oil are far more toxic than others - gasoline is really bad, particularly if it contaminates your well, as one example.
Old oil from changing oil filters is not so bad and responds *really* well to wood chips inoculated with mushroom spawn - I believe oyster mushrooms have been used very successfully by Paul Stamets who's written a book called, Mycelium Running.
There are also natural oils - fats from dead animals, fats excreted, fats in nuts, and clay will stop it from infiltrating and possibly slope has caused it to concentrate in one area. Do some more exploring and post what you find and maybe we can help some more!

Oh, and welcome to permies, Susan!

Was gonna say if oil you can do mushrooms, oyster mushrooms but that is already stated.  I have seen whole areas cleaned up by mushrooms!

Do you have fracking in your area?

Jay Angler wrote:Second, look around and see if there's any chance there's some sort of buried and forgotten tank around that could in fact, have leaked oil.

^ This ^

It's unlikely you have actual oil deposits on your land only a 12 inches from the surface (Not impossible, though! In the middle east, some oil used to be literally on the surface like ponds. If you do, contact an oil company and make some cash).

If this barn pre-dates you living there, I would speculate someone changed their car's, truck's, or tractor's oil semi-regularly in the barn and just (irresponsibly) let it soak into the dirt. Does that seem to reasonably fit the circumstances?

Weird and possibly unfortunate..

I am pretty certain irresponsible fuckwits have dumped oil during oil changes on my property; there is a long history of logging and farming involving heavy equipment, and I have found old oil filters in various places.

Never found any sign of the oil, though, despite having a serious hardpan clay layer..

I figured/hoped over time it would have been diluted/washed away/down and/or broken down..


How big an area are you finding this oil layer in, the whole 30x40? More?

How long is a plausible minimum time since oil or fuel could have been spilled there?

Susan,

Please ignore all calls to get rich quick from the oil and please don’t call an oil company to try to sell oil.  Let me explain.

While you own the land, you actually only own the surface rights.  The mineral rights were most likely sold off long ago and are owned by a company long sways.  If they found surface oil on your property they might be highly inclined to explore for more oil on your property.  Assuming they find none, they would then have to return the land back to its original state, which generally means bulldozing to “restore” land they tore up.  Also, if you have any trees in their way, during exploration, those too would likely go and it’s hard to simply restore a tree.

I am saying this because my region, Southern Illinois, has both oil and coal.  Fortunately, my land is adjacent to an old, well restored strip mine.  It is so well restored that I only know about the old mine because people who have lived here for decades told me about it.  The strip mine today simply looks like a valley between two hills.  I say I am fortunate because if the land had any promise of holding coal, it would have been mined long ago.

But there have been people in the region that had their property explored for oil.  A company came in, built an oil drilling pad and then a loud Diesel engine ran day and night for months before deciding the effort was not worth the cost.  They did considerable damage to the surface that simply could not be repaired by bulldozing.

Long post, but I hope you catch the gist.  If that is natural oil, you don’t own it, an oil company does.

Eric

I agree with Jay about having it tested.  

I also really like the idea of mushrooms!

An Eric's advice is spot on!

Something in the back of my mind says that maybe it was put there for a reason.  Seems like I remember something about oiled floors.

Some speculation about why it may have been put there might not hurt before getting rid of it.  Maybe there was a spring or something that kept the floor wet and the oil was the solution.

Since it was 10" down, to me, your manure would be okay to compost.

Here are some pics of the site. I added water to the clay and of course it just sits there. I need better drainage here.
I don’t know about fracking in my area. It’s probably like someone mentioned where a previous owner drained their oil there.

I suspect that you are seeing the remains of a natural biological process.

http://askanaturalist.com/what-is-this-oily-sheen-on-the-marsh/

The manure and bedding decomposing can produce oil like substances, which can be trapped in areas of high concentration. I suspect that the clay layer acts like a barrier.

Hard to say for certain without better photos and a more in depth exploration of the site, but I wouldn't be too concerned.

Thanks for all of your input. Michael, that sounds plausible. If I see anything else suspect, I’ll post again.

Michael Cox wrote:I suspect that you are seeing the remains of a natural biological process.

http://askanaturalist.com/what-is-this-oily-sheen-on-the-marsh/

The manure and bedding decomposing can produce oil like substances, which can be trapped in areas of high concentration. I suspect that the clay layer acts like a barrier.

Hard to say for certain without better photos and a more in depth exploration of the site, but I wouldn't be too concerned.

If it's really oil/fuel/petroleum based... it should burn. Maybe test a small(!) sample in a safe container/location, with a blowtorch or similar heat source?

D Nikolls wrote:If it's really oil/fuel/petroleum based... it should burn. Maybe test a small(!) sample in a safe container/location, with a blowtorch or similar heat source?

Yes, but even if it's a totally natural oil from animal fats or plant decomposition, it will still burn like vegetable oil lamps or Inuit seal fat lamps. I guess from that point of view, the oil industry is based on a "natural" product of decomposing plants, but it's form was changed by pressure over millennia and isn't something we can easily replace at the rate we are currently using it. There's a reason that mushrooms can so easily rehabilitate lands poisoned by oil spills - they're a pretty old organism compared to humans also!

Jay Angler wrote:

D Nikolls wrote:If it's really oil/fuel/petroleum based... it should burn. Maybe test a small(!) sample in a safe container/location, with a blowtorch or similar heat source?

Yes, but even if it's a totally natural oil from animal fats or plant decomposition, it will still burn like vegetable oil lamps or Inuit seal fat lamps. I guess from that point of view, the oil industry is based on a "natural" product of decomposing plants, but it's form was changed by pressure over millennia and isn't something we can easily replace at the rate we are currently using it. There's a reason that mushrooms can so easily rehabilitate lands poisoned by oil spills - they're a pretty old organism compared to humans also!

Hm. I am used to surface level oil-looking sheens that definitely don't burn, like the ones linked above.

So perhaps one could say, this test would tell one whether it *might* be oil/fuel/petroleum based, or that it is definitely not?

It might not be that they drained the oil there, but that the farmer had a machine with a steady slow oil leak, and the machine was parked there when not in use, for many years.  This vector of oil deposit is fairly common on farms.  Not saying that this is the case for you, but it is a possibility.

D Nikolls wrote:

Hm. I am used to surface level oil-looking sheens that definitely don't burn, like the ones linked above.

So perhaps one could say, this test would tell one whether it *might* be oil/fuel/petroleum based, or that it is definitely not?

Yes - it's sort of like people saying, "I don't like chemicals in my food" and all I can picture is my old chemistry teacher saying, "salt is a chemical"! Where does one draw the line between petroleum based oil vs sunflower seed oil which in common speech, are both called "oil"? I just needed to know that there are oil-looking sheens out there that don't burn.  I did not mean to sound critical!