Optimizing micro-matrix sorting

[Yvie]

Just had a thought freeze thaw might help,it certainly breaks down our local cliffs!

 

The rain probably helps if its the acid rain that some areas get,how many fossils dissolve in it?

[digit]

We use the freeze-thaw method (leveraging [literally] the phenomenal power of the expansion of the liquid to solid phase of water) to help pry apart siderite nodules from Mazon Creek. Usually, the fossil within is more of a cast (or sometimes just a faint shadow) of the fossilized item so little damage can be done by the process. I'm wondering what effect freeze-thaw would have on the porous and usually fragile shark tooth roots of the specimens from Shark Tooth Hill. For other fossil matrices I would expect the freeze-thaw might indeed help in separating fossils from their surrounding matrix. I guess your mileage would vary depending on the type of matrix. Definitely a good technique to try on a sample.

 

 

Cheers.

 

-Ken

[sixgill pete]

3 hours ago, Yvie said:

Just had a thought freeze thaw might help,it certainly breaks down our local cliffs!

 

The rain probably helps if its the acid rain that some areas get,how many fossils dissolve in it?

 

 

Freeze thaw is great for opening concretions. But when you are searching for micro fossils in large chunks of matrix (hard or soft) the object is to dissolve the matrix and clean it away leaving only the fossils. It could help by breaking the chunks into smaller pieces, but you still have to wait for the matrix to dissolve away. 

[Herb]

this is a very nice post, digit. The only thing I would add is a #100 screen to flush out most larger true microfossils ( conodonts, forams, ostracods and scolecodonts)  , and all but the smallest forams. A #200 sieve will allow only silt and clay particles to pass. 

[Bob Saunders]

Very much good reading. I bought a shaker with a fine screen for like fine confectioners sugar over pastries $5.95 in the bakery goods section.  Looking forward to try it. I also have an old like a gold very fine mesh coffee filter that I can cut up for the screen. The type that replaces a paper filter and no idea what size the weave are. I assume that many are using the depression concave microscope slides to view and save the micros? I will need to order some. I also have very small bottles that had tiny watch repair parts in assortment kits. 

[Bob Saunders]

we like thrift stores. I found a Metrokane rabbit wine funnel new in the box. It has a very fine micro mesh screen to catch wine sediment. 4 3/4 inch tall 2 5/8th wide. Not promoting the brand as their is surely others, but if you are needing something like this to catch micros it may help. 

[digit]

I enjoy picking micro-fossils and with my volunteer work with the FLMNH I now get to do it virtually every day (will be starting a new batch later this morning). The finest that I pick is caught by their brass-screen mesh that is finer than what they call their window-screen matrix. It's catching probably 1/30" (or just under 1 mm) diameter material. Below that in Florida any micro-fossils tend to be drown out in a sea of fine silica sand. I looked at some 1/50" material (~ 0.5 mm) but it is only fine sand with no observable whole fossils (but some tiny fish tooth fragments). At #100 (1/100" or around 0.25 mm) there is nothing to be seen in Florida matrix other than very uniform silica sand grains.

 

I know northerners make good use of these finer mesh sizes to filter clay from decomposed slates to search for truly microscopic fossils this could be great fun to see what is hiding in the silty clay. It gets tricky to handle sub-millimeter size micro-fossils from Florida and I can't imagine how difficult it would be to move and store really fine fossils. I'm guessing you might actually need to store them on the slides as you'd never find them again if you put them away in something like gem jars.

 

My stack of green sifting screens that fit over a 5-gallon bucket get nearly daily use and are one of the best purchases I've made. Can't recommend them enough to anyone picking through micro-matrix looking for fossils. How else are you going to optimize your micro-matrix picking so you can find things like tiny rajid (skate) teeth that are less than a millimeter?

 

 

Cheers.

 

-Ken

 

 

[Bob Saunders]

Thanks for your info. On my post about micros the picture of the red jar cap shows a crinoid columnal that looked like a tiny grey dot to the un-aided eye. As a watchmaker I have a stick of Rodico for picking up fine lint from watch movements and took a piece and rolled it to a point. Watching with the stereo scope I picked up the piece and put in a covered container. That is cought the edge of the tube and it fell in. The farm field clay in my area is usually calcified like in our lightning stones, and can hardly be dissolved to look for objects. I sets of drill bits from 2 mm to 40 mm. I used my scope with the metric measure and checked the accuracy of it. 

[digit]

I just had to search for 'Rodico' looks like really useful stuff for a watchmaker. I bet I can find a use for it even though I don't wear a watch.

 

I've seen tiny micro fossils picked up and moved by using a very fine artist's brush dampened in water.

 

The larger micro-fossils (down to around a millimeter) I can usually pick up and move to the appropriate bead storage jars on a plastic tray that I use for classifying/organizing my finds with my fingertip. Light pressure is often all that is needed to be able to carefully lift a micro-fossil. Often my fingertips are too dry to be able to get the micro-fossil to temporarily adhere long enough to get a hold of it. Licking your fingertips and then rubbing them to make sure they are not too damp gets a bit tiresome (not to mention unhygienic) and so I've taken to using a fingertip moistener often seen in offices that deal with lots of paperwork. It works really well to develop just enough tack to allow tiny bits to be lifted safely and delicately and is quicker than using the paint brush method.

 

Cheers.

 

-Ken

 

[jpc]

I wonder if that stuff leaves an unpleasant coating of goo on the fossil.  I use tweezers.  I have picked up thousands of micros with quality (Swiss Made, for example) fine tweezers, and have only lost maybe three fossils due to the watermelon seed effect.  I have developed a good feel for how much pressure to use and have never (that I can recall) crushed a fossil.  Quality tweezers are good because at this scale you want the ends to meet nicely.  I have also used the paintbrush moistened in my mouth, as well as the dry paintbrush.  The problem with moistening a paintbrush is that you need to work to dislodge the fossil from the hairs.  If you use a slightly worn paintbrush (size 0 or smaller), where the bristles do NOT come together at a point, you can scoop up the fossil in the bristles by sliding them towards the fossil; some bristles go under, but most go around and above.  The fossil gets lightly pinched in the bristles.  

[digit]

The pink material in the fingertip moistener is reminiscent of a lip balm (and likely include some ingredients in common). The instructions are to moisten your fingers with it and rub them together till they are dry. This works out any moisture and leaves behind just an ever-so-slightly tackiness that aids in adhering tiny micro-fossils. I can pick them up securely with the very lightest of touches--barely making contact. I generally pick up fossils with my index finger and then close in with my thumb to secure them as I move them to the appropriate jar. The tackiness is just enough to allow me to lift it off the plate but not really enough to allow me to swing it over to the jar without being held in place with a second finger. I do not even leave a hint of a fingerprint on the gray construction paper that I use to cover my picking plate so I don't believe I'm leaving any unpleasant goo on the fossils.

 

I've tried working with fine tweezers (maybe just not having the proper quality and precision). Hard for me to find the right pressure to apply without crushing delicate fossils or doing the watermelon squirt. There is obviously no "correct" way of handling micro-fossils and we all find a way that works well for us and the tiny bits we are working with. I suggest the tacky stuff here because it took me a while to think of it as a solution and it is one that works remarkably well for me and so may benefit others looking for a solution.

 

 

Cheers.

 

-Ken

[JohnJ]

1 hour ago, jpc said:

I have also used the paintbrush moistened in my mouth, as well as the dry paintbrush.  The problem with moistening a paintbrush is that you need to work to dislodge the fossil from the hairs.  If you use a slightly worn paintbrush (size 0 or smaller), where the bristles do NOT come together at a point, you can scoop up the fossil in the bristles by sliding them towards the fossil; some bristles go under, but most go around and above.  The fossil gets lightly pinched in the bristles.  

 

I have used these techniques with great success and little damage.  

[LabRatKing]

I find an aspirator designed for Drosophila handling works great.

 

Though they are super easy to make and you probably have everything you need just laying around, I use the older model of the one pictured. (it has aluminum angle tubes and a brass mesh recessed anti-inhalation check.)

[digit]

This would work well for picking up a bunch of micro-fossils to be sorted through at a later time. In my picking process for the Montbrook micro-matrix I'm working with I have an array of small plastic jars that are probably something like 3 cm in diameter that are sitting on a plastic tray. They sell these for crafty people who do bead work to organize their tiny beads. I figured what works well for keeping beads organized should work well for micro-fossils of around the same size.

 

 

I cut small pieces of paper where I can write the type of fossil destined for each of these containers--gar scales, fish teeth, shark teeth, fish verts, invertebrate fragments, coprolites, turtle phalanges (yes, I get numerous "turtle toes"), etc. and curl them into each of the jars so I can remember where I'm dropping various types of micro-fossils. Each little jar has a lid but I'm not permanently storing them in these little jars so the lids are unscrewed and placed under the jars to raise them up in the tray. When I've finished a batch of matrix I can decant the contents of these little jars into tiny zip-top bags or gelcaps as needed to organize these when I return them to the FLMNH for further sorting and cataloging in the collection.

 

The tray of little labeled jars is near the plate that I'm picking from so I only need to transport the micros a short distance without dropping them and drop them into the appropriate jar to keep the finds categorized. A fruit fly aspirator would work really well for picking up micro-fossils but for my process I'd then have to empty the aspirator jar and move them a second time into their little jars while categorizing them into the broad categories I separate the finds into. Certain fossils like dasyatid or rhynchobatid teeth or the copious ganoid scales of the gars are pretty specific but other jars hold a diversity of shark teeth or fish teeth that I do not bother separating taxonomically.

 

I pick the finer material on the plate moving bits around with a little shepherd's crook of a dental probe known as "single ended explorer". These are made by G. S. Dental and may be obtained online from a retailer named for a large South American river for a ridiculously low price with free shipping (US$12.95 for a pack of 5).

 

 

They are really excellent for pushing the various bits of matrix around on the picking plate in order to get a better view and also work really well to pull the selected micro-fossil to the side and push away other bits of matrix so that the area around the fossil is clear and easy to pick up without also getting unwanted bits. Using tweezers or an aspirator bottle would necessitate me putting down the dental probe. With the probe in one hand and slightly tacky fingertips on the other I can quickly shuffle off any fossil bits to the appropriate jar in the tray without letting go of the probe. Very efficient when I have to deal with fossils that are so common that I may pick dozens off a single picking plate with just a narrow ring of matrix spread out along the edge. If I am not as efficient as possible I'd never get through batches that have insane densities of things like dasyatid teeth.

 

 

 

Cheers.

 

-Ken

 

 

[Coco]

On 07/12/2020 at 4:20 PM, digit said:

I'm guessing you might actually need to store them on the slides as you'd never find them again if you put them away in something like gem jars.

 

I store my current smaller shells in capsules : https://www.shutterstock.com/fr/image-photo/empty-capsules-medicine-background-175480682

 

Coco

[digit]

Indeed. Gelcaps are used by the FLMNH to store tiny fossils. Sometimes the specimens are so small that it is impossible to write a collection number on the fossil itself and the number is instead written on the gelcap in which it is stored.

 

I have the great opportunity to volunteer my time with the FLMNH. In addition to going into the warehouse to sort through bags of fossils from the field after having been washed, dried, and repacked sorting out bones to be cataloged from the scrappy bones that get packed away and archived, I am also able to volunteer at home picking through batches of matrix that are collected in sandbags and washed through screens, dried, and repacked. I sometimes pick batches that are what we call "window-screen" micro-matrix which is between 1/4" and about 1/20". We also have batches that are much finer and are between 1/20" and about 1/50" which we call "brass-screen" matrix (and I have dubbed "nano-matrix").

 

My process for working these batches is to separate it into size classes by running it through my stack of screens. I process each size class separately which makes it easy to go through the larger coarse material quite quickly without risking smaller fossils hiding among the larger bits of matrix. I can pick the larger sizes using my floor mounted lighted magnifier but when I get to the really fine stuff (1/20" and smaller) I need to switch to my camera-microscope to pick. I separate the picked fossils into the different categories I mentioned above (gar scales, shark teeth, fish verts, etc.) and when I've finished picking through a batch I need to gather up and pack the fossils to return them to the museum. I generally pack the contents of each of my little bead jars into tiny zip-top bags that are also used by craftspeople especially people working with beads.

 

 

Within each of those tiny bags I will often separate out special finds. For fish teeth I separate out triggerfish (Balistidae) teeth because a student here at UF is interested in writing a paper on the triggerfish fossils of Florida. Occasionally, I will find some of the rarer shark teeth like catshark (Scyliorhinidae), Tope Shark (Galeorhinus sp.) or Hound-shark (Mustelus sp.) that I want to be easy to locate without having to search through all of the miscellaneous shark teeth in the little bag. These I pop into the little gelcaps to keep separate. I drop the filled gelcaps into the tiny bag with the rest of the fossils and put all of the tiny bags in the larger zip-top bag that the original sample of matrix came in with the label containing information on the sample. There are several sizes (0, 00, 000) of gelcaps available and they can be purchased from a variety of online sources for not a lot of money.

 

Cheers.

 

-Ken

 

 

 

[Bob Saunders]

Many moons ago in grade school for my science project my mother asked the pharmacist for empty pill capsules. I filled each one with her spices and put them on cardboard with the names. For the few I may get, I just mentioned it to my wife and she had half a bottle of empty capsules from her working days. 

[Rockin' Ric]

Hey Ken, I'm laughing as I read your post. I did not know you had posted this until now. I got started micro sifting 3 months ago only because I was sifting for Cretaceous shark teeth on a local creek. I was using the standard 1/4" mesh and often wondered what got through the mesh so one day I started sifting where I created a pile big enough to bucket and haul through the woods to my vehicle. Before that I sifted out the sand with a kitchen sieve and when I got home spread gravel to dry. The next step was to cup it up when dry and do as you did on a paper plate like you have shown which had me laughing. Obviously you came up with this first and amazed how often people think a like? I'm definitely taking some of your optimization techniques to heart. It's a whole world when it comes to micro fossils. I'm just as excited to find fossil treasures at home as well as on the creek! Thanks!

[digit]

Glad you found some useful ideas. That's pretty much the point of sharing information here on the forum.

 

Fossil sites can be totally different when looked at on the micro scale. In addition to juvenile versions of larger fossils there are species that never get large enough to see without sifting micro-matrix.

 

Looks like some nicely fossiliferous matrix you've got there--I'm envious (no Cretaceous in Florida).

 

 

Cheers.

 

-Ken

[nutty_canuck]

I have to comment on this. I took an amazing trip in September and ventured into VA and south into NC to hunt teeth. In NC I went as far as Top Sail, then slowly drove back up to VA. while I was in top sail I started to think about strainers and what could be used. Went into a dollar mart and purchased two nesting plastic containers and a paring knife. the containers were approx 2.5 inches deep and when nested they fit together nicely leaving at least 2 inches of room for the sifting. Not being home where i could use a drill and bits. I sat in my motel room and with the paring knife and proceeded to drill holes into the bottoms of the containers. yes it was time consuming and hard on the hands turning and pushing.  the containers were about 12 inches by 8 inches (guessing may have been larger) and I placed holes as close as i could in my rough invention.

 

The top holes had to range between 1/2 and 3/4 inch (too big I realized later), and the bottom holes i tried to keep under between 1/4 and 1/8.  this worked very well to my surprise.  I didn't find many teeth on topsail nor as i ventured up the coast. However, in VA where my cousin lives and works, is close to 2 places. WestmoreLand park and another (kinda private) area where his house is located.

 

While in VA  the second strainer became very useful in finding micro teeth as they were trapped. If i built another set I would use a 1/2 inch top drill bit  and a 1/8 for the bottom. these strainers were cheap to buy and easy to make. the nice thing were they are fairly light to swing for hours and not get sore. it does take a bit of practice to swooosh them but after the hang of it they worked very nice.   on the day before i had to fly home, my cousins girlfriend took me the private area near their house and i was able to really concentrate on finding the micro teeth. had a ball collecting these ones that are as small as 2MM. I was stoked and she was surprised at them. I will take a picture or (few) of the small display I was able to make after returning home.

 

I envy you guys that have this hobby and these fossils in your back yards.  cheers

 

 

[digit]

Hah! That made my morning! I can picture you sitting in your hotel room "sculpting" your bespoke sifters. I can see your member name is well chosen.

 

You were obviously channeling your inner MacGyver when you made these. I'm assuming you no longer have them at hand but would love to see photos of your creation if still available for photos.

 

https://en.wikipedia.org/wiki/MacGyver_(1985_TV_series)

 

I've seen photos and videos of folks using a wide range of objects for sifting from spaghetti strainers to shallow metal dishes with holes punched in for grilling veggies on a BBQ grill. When I am collecting bulk micro-matrix out in the field I use two larger (roughly 18" x 18" or 0.5 m x 0.5 m) sifting screens with a wooden frame, metal mesh screen stapled onto the bottom and floats (pool noodles) zip-tied on for buoyancy. I bring one sifter with 1/2" x 1/2" mesh and another with 1/4" x 1/4" mesh as well as a loose piece of window screen material (approximately 1/16" x 1/16" mesh). I stack the two sifters with the one on top holding back the larger material (either larger than 1/4" or 1/2" depending on the order I stack the screens). The loose piece of window screen sits in the lower sifter and allows the finer sand and silt to be washed away resulting in the intermediate (usually 1/4" down to 1/16") material to be gleaned and tossed into a bucket for later picking. These sifters are large and a bit bulky but work excellently when collecting larger amounts of matrix from an area not too far from a car (those buckets can get heavy). I suggest to anybody collecting bulk material this way to bring two buckets and fill them half full. It is easier on your back if you can balance the load side-to-side and easier on your hands as those bucket handles are not meant for weightlifting. I wrote this up some years back but it is still my primary technique for harvesting bulk micro-matrix:

 

http://www.thefossilforum.com/index.php?/topic/51286-collecting-cookiecutter-shark-micro-matrix/

 

If you are looking for something that is lighter and more portable and possibly used for just classifying gravelly matrix in the field and picking the small fossil out directly rather than bulk harvesting of micro-matrix material, then I'd go for some of the purpose-built stackable sifters/seives. I own a set of the green plastic ones with stainless mesh from 1/2" down to 1/100" which is a wide enough size range for virtually any application. They fit over a 5-gallon bucket which can be handy.

 

    

 

You can also get smaller (~8" or 20 cm diameter) sieves online that are used in geological work classifying the grain sizes of soils (and other purposes). A quick internet image search for the phrase "geological sieves" will turn up a wide variety of sizes, compositions, prices and suppliers. The nice thing about these is they are light, portable, and very sturdy and would easily fit into a suitcase when traveling. They would work well dry sifting as well as wet sifting when you are digging in a river or at the beach. They are stackable as well and so you can put a few together and toss material in the top and have it classified into different size classes with a few shakes.

 

 

Cheers.

 

-Ken

 

[nutty_canuck]

I have no idea what sharks these came from except the 2 long pointy ones I think are sand shark. Those 2 I found on topsail island.  I wish I did take a picture of the strainers.  cheers and thanks for this site!! very informative.

 

[nutty_canuck]

"They are stackable as well and so you can put a few together and toss material in the top and have it classified into different size classes with a few shakes. "

 

Ken, that is exactly what i did with the 2 I made, the larger stuff stayed in the top section, and the smaller bits fell into the second trap. I would screen the top first. look it over for the larger samples, then set it aside and screen the smaller ones by placing the large holed strainer below the small holed one. as the sand would wash out the 1/2inch holes. worked very well. (and as said, fairly light to hold all day)

 

cheers

Edited January 3, 2021 by nutty_canuck

[IsaacTheFossilMan]

Very informative post, thank you very much, I intend to learn from this little guide! Also, hey - fellow software engineer haha! I'm currently only a hobbyist software engineer, not in any form of work in that end! @digit

[digit]

Gained information and insight is best when it is shared. My methods are not the only way of doing things but I'd evolved and optimized them to suit me and I share them here in case it makes someone else's path to an optimal method a bit shorter.

 

I've been retired for some time and used my software engineering skills to benefit coral reef research for a few decades. These days if I do any programming it is for my own use/amusement.

 

 

Cheers.

 

-Ken