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I enjoy sorting through micro-matrix. Between the times that I'm able to spare a Saturday to drive 3 hours to the Peace River to sift for larger fossils, I like to have some micro-matrix on hand so I can easily scratch the itch when I feel the need to hunt for fossils--even if it is only from the comfort of my office desk. I'm currently working on a project involving micro-matrix (which I'll write-up on TFF once it is complete). This project requires a large number of specimens and so I've collected about five 5-gallon buckets of micro-matrix which now reside in the corner of my home office. Whenever I need a break from working on the computer I can easily grab a cupful of micro-matrix, my omni-useful dental probe, and my well-worn iris decorated paper plate and take a short plunge into the world of tiny fossils.

 

I've recently taken steps to optimize my productivity while sorting micro-matrix so I thought I'd post them here in case any micro-fossil hunters find any utility in my method. Here is my usual setup for sorting micro-matrix--I used to pour out a large amount of micro-matrix onto my plate at one time but I now sprinkle a narrow, nearly complete, ring of micro-matrix around the edge of my paper plate. I use two different colored cups to keep track of which cup I'm pulling from and which cup I'm discarding from. I used to use two blue plastic Solo cups but it's no fun when you get them mixed up and start sorting your discards instead of fresh micro-matrix. Color coding has solved that issue permanently.

 

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I purchased a nice large magnifying lens ringed in 100 LED lights which provide nice even lighting in the field of view. The model I purchased is usually made for those doing detailed crafts like needlepoint or those whose vision is not what it was when they were younger so they can minimize eye strain while reading or doing crossword puzzles. As this model is specifically meant to be used while seated, it comes with a heavy weighted base and an adjustable arm so I can move the lens around and adjust the height over my plate for optimal focus. I used to scan micro-matrix  using my photographer's loupe which had became rather outdated and useless once I went digital and stopped processing chemically developed slide film. The problem with this is that holding it in front of one eye with the other eye closed for extended periods caused only one eye to focus abnormally close and after a session of micro-fossil hunting my vision would end up blurred for hours afterward--not ideal in any way. The large lighted lens was not inexpensive but being able to see my micro-matrix clearly with both eyes providing some stereoscopic depth and no residual eye strain made the purchase well worth the cost. Though the camera could not quite figure out where and how to focus while viewing through my magnifier, you'll get some idea of how I see my micro-matrix under well-lit magnification.

 

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I've sorted many gallons of micro-matrix using just this method with great success. I'm an engineer by trade (computer programming to be specific). I'm always on the look out for ways to optimize my process allowing me to more efficiently search through my micro-matrix to find the tiny prizes hiding within. One of the things that limits my efficiency while sorting is the size range of the items in my micro-matrix. When I collect micro-matrix in the field I use a pair of stacked sifting screens. The top screen has 1/4" mesh and screens out any pieces larger than this approximate dimension. The sifter under that has a piece of metal window screen placed inside it. The mesh spacing on this screen is approximately 1/20". The separate piece of screen material allows me to lift this out of the bottom sifter and flush some of the fine sand through this tighter mesh before dumping it into my collecting bucket. So my collected micro-matrix consists of pieces roughly between 1/4" and 1/20". The mixture of different sized pieces can be seen in the last photo above where larger chunks of black phosphatic pebbles and shell hash mingle with smaller pieces of rock and sand.

 

While sorting through this micro-matrix my search image has to encompass larger shark teeth and ray tooth plates all the way down to tiny drum fish "button" teeth, Dasyatis stingray teeth, fish incisors, and tiny baby shark teeth. I'm pretty good at keeping all of these search images in mind while working through the micro-matrix but consider the scenario of being out on a South African safari and trying to keep an eye out for a heard of African Elephants, a clan of Meerkats, as well as looking out for Dung Beetles rolling by. You might be able to be on the alert for any of these African photo-ops but it would be hard not to know if you'd overlooked something somewhere.

 

I remembered visiting the Florida Museum of Natural History (FLMNH) up in Gainesville a little over a year ago and getting a spectacular tour of the work area where specimens were being prepped and micro-matrix from the Thomas Farm dig site was currently being processed. Dr. Hulbert explained to me and my wife how the bagged micro-matrix from the field was washed through a stacked set of sifting screens with different mesh sizes before being placed in a drying rack where continuous air flow sped up the drying process. I also recently learned that each project (Thomas Farm, Montbrook, etc.) have their own sets of screens to avoid any cross contamination that might make for interesting mix-ups of fossils.

 

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I started looking online to compare various sets of sifters. I found several models of different sizes (diameters) and different ranges of mesh sizes. Some were geared toward geological surveys to classify the particle size of soils, some were made to prepare specialized potting soil mixes to remove fine powders to make well-draining soil for things like bonsai planting, the set I finally decided on was, among other purposes, intended to assist in gold panning--something I'd not considered before. The idea was to grade the material scooped out of a stream into narrow size ranges. The heaviest particles in each size class should be the gold and so it should be easier and more efficient to separate the valuable gold flake from the surrounding materials. Learn something new every day.

 

I picked up the 9-piece set which conveniently are sized to fit over a 5-gallon bucket. My shipment arrived just after lunch today and I was able to do some experimentation. Here is the model I purchased: https://www.amazon.com/gp/product/B008EWOL8I/

 

The sifting screens came plastic wrapped and boxed stacked in order. Unfortunately, the mesh size was not printed on any of the individual screens so before I mixed any of them up I got out my label printer and made labels for all of the mesh sizes: 1/2", 1/4", 1/8", 1/12", 1/20", 1/30", 1/50", 1/70", 1/100"

 

Here is the complete set staked on a 5-gallon bucket.

 

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Here are the the first four screens to get an idea of the steadily decreasing spacing. You can easily see the range from the 1/2" mesh screen to the finest 1/100" screen that looks more like cloth than screen. Stacked on the bucket, it is easy to pour in a cup of micro-matrix and swirl around the material allowing all of the pieces to fall to their own level based on their size.

 

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Everything easily fell through the 1/2" mesh screen and there really is no reason for passing it through this screen as my collection in the field used a 1/4" mesh screen to exclude pieces larger than this. Only a small amount of material was caught by the 1/4" mesh screen below it. These are pieces that initially slipped through the 1/4" mesh while collecting it in the field but did not find the same orientation when being passed through my new sifting stack. It was quite easy to pour this small amount out on my plate and remove any large visible fossils that have nowhere to hide.

 

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Once this coarse material was dumped into my red discard Solo cup, I loaded up my blue Solo cup with the material from the 1/8" mesh screen. This probably accounted for the bulk of the material passed through the sifter stack. It was interesting to sort through micro-matrix with a much tighter range of sizes. The uniformity of the gravel made it very easy to go through the ring of micro-matrix on the paper plate. My method is to be methodical. I use my dental probe to pull down a small amount of material and spread it out evenly on the plate so it is on a single level and no pieces are covering (and hiding) any others. It is then a simple matter to scan this section of the material for fossils and pull those to the size. After this, the non-fossil material is pushed lower down on the plate and the next small amount of micro-matrix is pulled down and again spread out and searched. Bit by bit it is possible to work through an entire plate rotating as I go till I've reached the other end of my nearly circular line of micro-matrix. I place the lit of my collection box next to my plate (tucked under a bit) and with a single finger I can push any fossils up the sloped edge of the paper plate and into the lid. Occasionally, this lid then gets carefully emptied into the little storage box.

 

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The process is then repeated with each sifting screen. The amount of material at each level varies and the composition of the micro-matrix I collected would likely have a much different composition from micro-matrix collected in different environments. At the next level (1/12") you can see the particle size getting finer on the plate (though still quite uniformly sized). The types of fossils being spotted in these finer distillations of the micro-matrix do tend to vary. In the 1/8" mesh above you will see some larger shark teeth and ray tooth plates. The 1/12" mesh now turns up smaller shark teeth, fish incisors, the little dasyatid ray teeth with their two-pronged little roots, and even a small ganoid gar scale.

 

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At the next stage we are now down to 1/20" mesh size and the micro-matrix is getting still finer. It is quite efficiently searched as there are no large pieces to cover and hide this finer material. This size range yields some tiny shark teeth (Rhizoprionodon and baby teeth from other species). Little "Barracuda" teeth are starting to become more prevalent and the little dasyatid teeth continue down to this size range. I need to start relying on the optical zoom and "microscope" capabilities of my little point-and-shoot camera to try to capture these ever smaller finds.

 

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Continuing further down my diminishing stack of sifters, we are now at the 1/30" mesh size and the amount of material at this level is pretty small. I had tried to remove most of this fine material by using a 1/20" mesh size window screen as my bottom sifter when collecting the micro-matrix. This smaller material is just what was holding onto something larger while wet or didn't get completely cleared in the field during collection.

 

There is so little of this that I ditch my methodical method of laying a ring of micro-matrix around the edge of the plate and just dump it into a pile in the middle of the plate. Some shaking and tapping spreads this out well enough and I switch to my higher magnification photo loupes (a 4X or a 10X) and do a quick visual scan to see if anything interesting pops out. Here is what it looks like zoomed in with my camera.

 

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Mostly, we are approaching the sand grain size at this point so it is mostly sand, fine shell hash, and a few tiny bits of black phosphatic material. A quick search did come across a tiny little oddity that looks like a microscopic version of something Queequeg would have launched at Moby Dick. Anybody recognize this? The tip of my dental pick for scale--it's tiny whatever it is.

 

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Below this, the remaining screens down to 1/100" mesh just pick up tiny amounts of what is basically dust. You can see from the coloration that this is mostly composed of a tan silica sand with a peppering of black phosphatic dust. The greater amount of sandy material at this granularity tends to inhibit searching for anything novel but I'm assuming if my micro-matrix contained something like very fine shark dermal denticles that they might start appearing at this level (or the one above). So far nothing of interest has appeared at this ultimate dregs level in the sifting process. It is quite nice to have this sandy material removed from interfering with the previous coarser sifting grades.

 

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It takes a bit more time to run the micro-matrix through the stacked sifters and collect each grade in turn for searching but I believe that effort is more than made up for by the efficiency gained in searching through the micro-matrix one size-class at a time. The chances of missing a tiny fossil being obscured by a larger piece of the micro-matrix are mostly eliminated by this pre-classifying before sorting through each grade in turn. I'm happy with my purchase and I believe it will not only aid my sorting through micro-matrix as a diversion when I get tired of typing long posts on TFF but it may also help me in the field while I'm collecting micro-matrix. I'm thinking of using the 1/50" through the 1/100" mesh screens instead of my 1/20" piece of window screen mesh. Though I will likely end up taking back home more sand in the process, I'm hoping that I might discover some interesting truly microscopic micro-fossils that I've been missing up until now.

 

Hope this illustrated accounting of my new optimized micro-matrix sorting may be of some use to others on the forum who know the joy of tiny prizes hiding out of sight in a plastic Solo cup.

 

 

Cheers.

 

-Ken

 

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Hi have you tried a digital microscope connected to a computer?Even less eye strain and they are cheap and cheerful now,mine is 5mp.

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Ken

I think your barbed fossil is a catfish pectoral spine. 

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I use a similar method for searching matrix. I divide my material into 2 sizes, larger than 1 millimeter and smaller than 1 millimeter. The larger I use various power reading glasses and a strong LED light (picture attached). I will spread a small amount on a white paper plate and move the material toward the bottom of the plate with a small paintbrush as I search. The paintbrush is also used for picking up the fossils that I'm keeping and placing them in a small box.

 

For smaller than 1 millimeter I will spread the material to the edge of the plate similar to how you do it and then search with a binocular microscope, rotating the plate as I go. I spend about a half hour to hour a day doing this, usually during news time on TV.

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5 hours ago, Yvie said:

Hi have you tried a digital microscope connected to a computer?Even less eye strain and they are cheap and cheerful now,mine is 5mp.

 

Celestron.jpg

https://www.amazon.com/Celestron-Handheld-Digital-Microscope-Pro/dp/B00CMJ1I08

 

Yup. A while back I picked up a Celestron 5MP "digital microscope". Basically, a webcam with a ring of LED lights and a lens to allow close focus. Mine came with a little stand but I ended up building another support out of PVC tubing to support the camera with a wider base which would allow my paper plate to fit under it. I figured that would allow me to see my micro-matrix magnified full screen on my large computer monitor. It did actually work--though I had to make sure the camera was oriented correctly in my new mounting jig. If it got rotated slightly then "down" on my paper plate no longer corresponded to down on my computer screen. A misalignment made positioning and moving my dental probe tricky for someone like me with no sense of coordination.

 

I tried this for a couple of hours but in the end I gave up on it as an aid to helping me sort micro-matrix. There was just enough delay in transmitting the video back to my computer for display that it made working with my dental probe cumbersome due to the visual lag. The other issue that sealed this method's demise though was that the lens in this inexpensive camera lacked any sort of adjustable aperture to allow for an increased depth of field. Despite my attempts at changing the LED brightness or adjusting the ambient room lighting, the shallow depth of field remained problematic limiting what I could keep in focus on the screen. If, at the time, I had pre-sorted my micro-matrix like I'm now doing to grade the material to a more uniform size it's possible I might have been able to establish a well-focused image but the visual hindrances have mostly kept this toy in the drawer to the side of my desk.

 

For a while I would break out this scope and use it to try to photograph some of my tiniest micro-fossils, again I was plagued by focus issues but it worked for images beyond the "microscope" setting of my old digital point-and-shoot camera. I've since broken down and purchased a nice 100mm macro lens for my DSLR camera. Together with the Helicon focus stacking and remote control software I can now create well-focused images of both my tiny micro-fossils as well as much better images of my larger fossils with incredible depth of field beyond camera lens optics but easily obtained through photo stacking software. It takes a bit of time to setup my tripod and connect my camera to the computer so the Helicon Remote can control the camera to generate these images but the results are well worth the effort for the results obtained.

 

http://www.heliconsoft.com/

 

 

5 hours ago, Al Dente said:

Ken

I think your barbed fossil is a catfish pectoral spine. 

 

Indeed, it appears to be such. I'm familiar with the larger (dorsal?) spines which turn up with regularity while sifting fossils on the Peace River or picking through plates of micro-matrix. I hadn't seen the barbed tip of a pectoral spine before. This one obviously came from a very young catfish as it is, quite literally, microscopic. Here's a photo I dug up from a paper online which matches well--mystery solved!

 

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3 hours ago, Al Dente said:

I spend about a half hour to hour a day doing this, usually during news time on TV.

 

While listening to the TV news or as a substitution for that activity? :)

 

I found decades ago that listening to what is considered "news" on the TV or radio or to a lesser extent reading about it in newspapers (remember them?) or magazines depressed me and invoked homicidal tendencies when I learned about the co-members of my own species abusing each other or the planet on which they reside. In the end, for my sanity, I had to adopt a news firewall and now practice purposeful blissful ignorance as a way of life. I've found that I don't need to go as far as taking up the monastic life with Buddhists in Tibet to keep my mood serenely peaceful and my blood pressure near 120/70--I just need to disassociate myself from that which I don't need to know about and couldn't control if I did know. Thankfully, the planet is populated with people who are willing and equipped to deal with issues of the day while I try to make the world a slightly better place in more subtle ways. Not taking the time to stay informed of the latest mass shooting, bombing, or out-of-state warehouse fire (irrelevant, but with flashy visuals) leaves me more time also for typing these long postings on TFF. :P

 

EDIT: From Stephan Pastis--one of my favorite online comics. I prefer to get my news filtered through comic strips.

 

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Cheers.

 

-Ken

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  • JohnJ pinned this topic

Ken,

Thanks for this most excellent breakdown of your micro-fossiling techniques.  

Your thread has been pinned.   @digit

Regards,

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Nice guide Ken.:dinothumb:

 

Tony

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Coming from a gold prospector, your assessment on the sizing of material is spot on. The closer you can get the grain sizes of material to be worked the better it will stratify. If all the material is the same size, gold will always win out.

And who says size doesn't matter?

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21 minutes ago, Fossildude19 said:

Your thread has been pinned.

 

My first "pinning"--thanks. I've gotten so much from this forum that I'm always looking to give back in any way I can. I'm nowhere near as knowledgeable as many on this forum (in fact, most of my fossil knowledge was derived from reading the postings of other members here). I try to find ways to contribute and, as you can clearly tell, I'm an inveterate story teller and so I try to impart my experiences to this forum--either collecting in the field or working on what's been collected. Though I'd never have made it as a photo journalist, I do think in pictures often and I like to illustrate my posts when possible to convey my story.

 

My hope is that my modest success in optimizing my method of sorting micro-matrix might give others some ideas which might benefit them.

 

 

Cheers.

 

-Ken

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I agree with depth of field,someone on our British forum mentioned using a polarising filter but I haven't tried that yet,but I do use an led light powered by the computer for side illumination.I'll have to have a play with my canon.Thanks for the info.

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Thanks for this info.  I am more like al dente... I screen to two different fractions, not your 5 or 6.  The other thing I do differently is I sort on a blank 5 x 8 piece of cardstock.  I have a pile of unised mailings form someone from the distant past that are blank on the back.  I fold the top (long side) and bottom up and then draw lines in at about 3/8 inch.  I also have lines on the short sides that say, do not put matrix outside these lines.  The folded up edges keep matrix on the card as well.  The lines create 'alleys' parallel to the long axis of the card  so that when I am looking through the microscope (I sort through my binocular scope) I can just scan along the parallel alleys I have drawn and slowly move from side to side, jumping down one alley each time.  NO need to move the rocks to know I have looked at them.  I also try to spread rocks thin enough so that I do not need to move them out of the way of each other.   

 

I will try to post a photo over the weekend, but I am on my lunch break at the office now. 

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Illuminating fossils with polarized light to effectively produce polarized light microscopy might be interesting. I've seen this technique used mostly with thin film sections in optical mineralogy. Doing a google image search for "optical mineralogy" will return some fascinating (and beautiful) images.

 

If you are instead referring to just placing a polarizing filter in front of the camera lens then I'm not sure what benefit this might bring. I use my polarizing filter for my DSLR camera to remove the glare and aid color saturation when taking photos of reflective surfaces in bright sun (the surface of a body of water being the prime example). I guess this could possibly have some beneficial effect but my view of micro-fossils through a camera's lens has never been marred by any lighting that a polarizer might resolve.

 

The thought did just occur to me that when using the Helicon Remote software to control my Canon DLSR (a 5D Mark II) that the software puts the camera into "live view" mode so that I may view the focus on my computer's LCD screen. This is useful while also using the software to nudge the camera lens focus motor one step at a time to achieve precise control over the nearest and farthest points of the focus when setting up for shooting a stack of photos with different focal planes which are later combined by the Helicon Focus software into a single image with a super-optical depth of field. Pumping what is, in effect, realtime video through the USB cable to my computer tends to eat up my camera's battery during extended photo sessions but I suppose that if I could find an external power supply for my camera and rearrange the photo setup in my office, I might be able to reproduce a higher quality version of the functionality of my cheaper Celestron "digital microscope". I don't recall seeing any particular delay when viewing my Canon DSLR through the software (though I may just not be noticing it as I'm only staging specimens for photos rather than sorting through a plate of micro-matrix). I have much better control over the depth of field on this setup as well as my macro lens has the adjustable aperture diaphragm to control the f-stop.

 

While viewing tiny specimens in realtime (or nearly so) on my computer screen can be useful--especially for micro-photography, I think I still prefer the low-tech solution of a brightly lit large diameter magnifier while sorting. This is the specific model I'm using but there are hundreds of models available online:

 

http://www.firststreetonline.com/Home+Solutions/Magnification/High+Power+Page+Magnifier.axd

 

 

Cheers.

 

-Ken

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12 minutes ago, jpc said:

I will try to post a photo over the weekend, but I am on my lunch break at the office now. 

 

Would love to see your setup when you get a chance to post photos. See how other people attack the same problem can provide novel ideas even if the entire method is not used.

 

I do find that most of the specimens that I'm particularly interested in from this micro-matrix tend to be found in one or two of the sifting screens (mainly the 1/8" and 1/12" screens) and the full complement of 9 screens is indeed overkill. The fractioning of my micro-matrix into multiple different particle sizes is informative in being able to isolate one size class to pay special attention to micro-fossils of a certain scale. I can foresee using specific combinations of these screens to optimize my micro-matrix collection in the field so I can take home just the appropriate size class of micro-matrix for the specimens I am in search of. A few of these screens will likely receive the lion's share of attention and use but I like having the full complement to be able to experiment. Different types of fture micro-matrix from different localities may direct my attention to micro-fossils of different size classes.

 

 

Cheers.

 

-Ken

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Dr Steve Sweetman has been sieving a beach on the Isle of Wight,discovered 48+ New species.Happy hunting!!

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Nice! He was off my fossil radar--just looked him up online. Looks like he has tapped into exposures there from around 130 mya containing dozens of species from dinosaurs, lizards, frogs and salamanders to some of the early small mammals. Says he's sieved through tons of sediment to find these microscopic fossils. Sounds like a kindred soul who I could talk to for hours over a pint or two.

 

Cheers.

 

-Ken

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Ken, I use almost the exact method you use.  have a set of the same sieves you have, however I normally do not go down any smaller than .5 mm on my screening. I start with the 1/4, then sift out any thing smaller than 1mm. then I sift it down to .5. 

 

I often use the sieves with large chunks of matrix. I set them out in the yard with the matrix in them and let the rain break the chunks down. This sometimes can take more than a year, but some of the finds are amazing.

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41 minutes ago, sixgill pete said:

....

 

I often use the sieves with large chunks of matrix. I set them out in the yard with the matrix in them and let the rain break the chunks down. This sometimes can take more than a year, but some of the finds are amazing.

 

I don't have the patience to wait a year.  :P  However, I agree with your results.  I'll use the outdoor water hose to gently shower my matrix.  There is a noticeable difference in how many more fragile specimens survive the sift/sort process.

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20 minutes ago, JohnJ said:

 

I don't have the patience to wait a year.  :P  However, I agree with your results.  I'll use the outdoor water hose to gently shower my matrix.  There is a noticeable difference in how many more fragile specimens survive the sift/sort process.

 

I do sometimes with the softer matrixes, "help" them along with the water hose. But the harder matrixes, mother nature is the best dissolver. Sometimes clay / dirt mix matrixes I just leave in a large container of rainwater to soften them before washing.

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Great info in above postings.

 

There are fascinating specimens waiting to be discover at the micro level.  We all borrow on other techniques then usually modify them for our own use.

 

I've had a set of  4 stacking sieves for decades.  Light weight and indestructible. These were considered 'the standard' for reporting to various departments for mining applications, etc.

 

I get matrix and either use 'as is' or dissolve it using acids.  Then sift through the series of sieves and sort under low power with the microscope.  I usually keep the light off and use a fiber optic light that can be adjusted at different angles from the side. This oblique angle gives more relief and easier to find specimens...especially the smallest.

 

These are specimens various sizes of Late Devonian and Early Carboniferous shark teeth.

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About a year ago I had the honor of meeting up with @ynot at Shark Tooth Hill in Bakersfield, CA. It had rained heavily the week before (even washing out some of the roads over at the Ernst Quarries. Tony brought along his 1/4" shaker-table sifting screens so that we could check the matrix that we removed while looking for larger shark teeth to see if any smaller ones were hiding (which they were--we recovered quite a few from the sifting screen). The matrix that fell through the sifting screen was collected in a couple of 5-gallon buckets to be searched for micros once I was back home. The rain hampered the collection of micro-matrix as it left the matrix rather damp and the little lumps of clumpy matrix that passed through the sifting screen looked like a very unappetizing dried cat food.

 

I carted the two full 5-gallon buckets back to my brother-in-law's house where I had access to a hose and a fine mesh colander. Emulsifying the muddy matrix and then straining it reduced the 10 gallons of matrix enough to fit into 2 gallon size zip-top bags (after drying). There was still a lot of chunky matrix hiding the fantastic variety of micro-fossils and I attempted to soak and strain it again. After being completely dried out the second washing dissolved much more of the matrix and I was left with about a quart size baggie of concentrated matrix (containing some really nice shark teeth and other micros). My guess is that the matrix contained a lot of silty clay-like material and the first contact with water formed a gel-like coating on the matrix nuggets inhibiting further breakdown by the water. The intervening drying likely caused the nuggets to shrink and develop cracks which allowed a second soaking to penetrate and dissolve away more of the matrix. As an experiment, I allowed the paltry remaining bag of concentrated matrix to dry again in the sun but a third soak didn't seem to remove any significant amount of material so I figured I was down to just harder chunks that would not dissolve with water. I experimented with small batches of micro-matrix (after I had sorted through and pulled out all the micro-fossils I could see). I added a bit of acetic acid (vinegar), hydrogen peroxide, and other chemicals I thought might break down the matrix without dissolving away everything. Never found anything that would dissolve the remaining matrix to see if there were any last micro-fossils hiding within. I was surprised though how well a soak-dry-soak routine did. The micro-matrix I collect from South Florida is basically shell hash and phosphatic, silica, and carbonate based rocks without any clay that would need to be dissolved and removed. Basically, a wash to float away residual vegetative matter like tiny leaf fragments, a good drying on a tarp in the sun, and some sifting to remove the residual sand is about all that is needed. And now I have more than enough sifters to perform whatever type of sifting I need.

 

 

Cheers.

 

-Ken

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@FossilDudeCO - I tagged somebody for this. This is good to know when dealing with this matrix material. I too had some from south Florida (the shelly phosphatic mix) and it breaks down fairly easily. The material I had did have some clay constituents, and it's fairly heterogenous, so some chunks have more clayey texture and some pieces are very loosely consolidated and friable - they break apart readily without being soaked or strained. The latter is easier to work with, but the former seems to have more treasures concealed (vertebrates). I find the loose very-shelly or beachy stuff is almost all Miocene and Pliocene inverts and the clay-ey stuff has the mammals and later Pleistocene goodies.

 

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