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seperating smallest microfossils from sand


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Do microfossils come as small as the grains of sand, and if so, how do you separate them?

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WhodamanHD

According to the most knowledgeable source of Wikipedia, microfossils are considered to be around .0001 mm to 1 mm, it also says a grain of sand is about .0625 to 2 mm. As to how to separate the small ones, I would imagine painstakingly with a microscope and tweezers, but I've never done it. Others will probably have better ways...

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I use a small paintbrush to pick microfossils.

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I use a dental pick for sorting and wet it to lift the fossils out of the matrix.

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Matrix a teaspoon at a time in a glass dish

B&L Zoomscope

Needle pointed tweezers

 

Warning, it can be addictive. 

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Oxytropidoceras

I prefer to use a very fine 00 grade artists sable brush for microfossils as it avoids crushing the more fragile ones.  However, there is nothing wrong with using a variety of tools, e.g. different paint brushes and needle pointed tweezers, for different types of microfossils.

 

Some interesting web pages about this topic.

 

Lesson Six - Sorting Vertebrate Microfossils

http://digfieldschool.org/wp-content/uploads/2013/08/Lesson-6-Microfossils-Final.pdf

http://digfieldschool.org/digboxresources/

 

Also, there are some Fossil Forum pages;

Collecting Microfossils Without Breaking The Bank

http://www.thefossilforum.com/index.php?/topic/30904-collecting-microfossils-without-breaking-the-bank/#comment-340110

 

Collecting Microfossils Without Breaking The Bank Part 2

http://www.thefossilforum.com/index.php?/topic/30907-collecting-microfossils-without-breaking-the-bank-part-2/

 

Collecting Microfossils Without Breaking The Bank: 2015 Edition!

http://www.thefossilforum.com/index.php?/topic/55894-collecting-microfossils-without-breaking-the-bank-2015-edition/#comment-594962

 

Yours,

 

Paul H.

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Thank everyone. Looks like it's just the tediously picking them out under a microscope then. I was kinda hoping there was an easier way. Maybe they settle to the bottom faster after mixing in water, or running water into the container and floating most of the sand out as the container overflows and the fossils sink to the bottom. But I guess I'm not that lucky. Hahaha. Well, ok then. 

 

So so far I have magnifying visor and loupe, then a 500X digital microscope. Guess I'll try it out and see just how small I can find. 

 

Thanks for for all the tips. 

 

Oxytropidoceras, thanks for all the links. I'll go through each of them to see what else I can learn. 

 

Snolly, yes it can be. Started with someone telling me about micro sharks teeth in Post oak creek, and I found some. But a few weeks ago I was back in Post Oak Creek and using a loupe, I found the vert I had in my other post, then later I found another while looking through the sifted gravel back at the house. 

 

Now one I need a sturdier mount for my digital microscope that the little thing it came with. 

 

Thanks again y'all

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@Tex

I like to search with the magnifying visor to pick the fossils out. I spread a small amount on a 8x11 card stock paper sheet (white) and search with a dental pick from one side to the other.(some prefer a paper plate.) A good desk lamp helps too.

I use the microscope to make pictures of what I find. (and get a better view of what I found.)

 

As for collecting matrix....

I use a 1/4 inch screen stacked onto a window screen to collect matrix. This will wash out nicely leaving a clean sand to search.

The window screen is set on a 1/2 inch screen for support.

 

Please post pictures of Your finds.

Good luck! 

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26 minutes ago, Tex said:

Thank everyone. Looks like it's just the tediously picking them out under a microscope then. I was kinda hoping there was an easier way. Maybe they settle to the bottom faster after mixing in water, or running water into the container and floating most of the sand out as the container overflows and the fossils sink to the bottom. But I guess I'm not that lucky. Hahaha. Well, ok then. 

 

 

About the only thing soaking in water is good for is when the soil has lots of clay or shale in it. Some of it can dissolve into the water a bit and be sloshed away. Also if there is a lot of organic matter hydrogen peroxide will break it down so it isn't hiding fossils and some of will float. I don't think any of that really applies much to POC.

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  • 1 month later...

there is no easy way, just painstaking searching under a microscope. I use a fine artists brush with all the bristles except 2-4 bristles left to pick them with

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ok, thank you. I haven't had a lot f time to get back to it, but thank you for the tip. Hopefully I can get the time to try it out soon. Got pleanty to pick through.

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  • 2 weeks later...

sorry for the late comment.

 

I suggest to work only on samples, which contain at least 20 microfossils/organic objects per1g in the fraction 100-2000µm.

 

Every marine beach has a spot with such a richness. Just go at low tide close to the waterline and take the stuff lying ON the sand, not the sand itself !

Fossil material needs to be chemically cracked down and washed over a sieve, e g. 100µm 

 

Picking with a brush every minute another interesting microfossil or organic object is fun and not strenuous at all.

 

Samples from the deep sea and e.g. Upper Cretaceous chalks commonly contain hundreds of objects per1g in the fraction 100-2000µm. In the deep sea the remnants of planktonic organisms cause almost all sedimentation.

 

maybe you need to get rid of the empty sand samples you may have got :)

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  • 2 weeks later...

I sprinkle a very small amount of well-dried washed residues into a small, heavy glass dish, flat-bottomed, with a low rim.  Working under the scope at 25x, starting at one edge of the sample, I use a standard dissecting needle to move individual grains of material away from the center of the small pile.  The needle with a 45-degree angled tip works especially well.  When I find a micro, I gently touch it with the tip of the needle -- static electricity will cause it to adhere, and I then move it to a new "pile" at the edge of the dish.  When I have completely worked through the sample in this way, I move the little pile of micros to a small vial for storage, using a moist sable brush, typically a 00.

 

Using the needle takes a bit of experience to get the right amount of static attraction.  When I first pick up the needle, it typically has too much attraction -- you end up with a ball of particles on the tip.  The trick is to rub the needle on a small, hard-rubber cork -- this greatly reduces the amount of static attraction, so you can easily pick up just the particle you want to save, but can easily release it on the "save pile".

 

Currently working on Holocene sands from Morro Bay, CA, Cretaceous samples from TX, Pennsylvanian and Permian samples from TX, OK, and KS, and Devonian samples from various localities in the eastern US and Canada.  The Cretaceous samples from the Gulfian of TX (e.g., the Pecan Gap Chalk) are incredibly rich -- in some samples, about half of the particles from washed residues are forams!

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  • 4 weeks later...

I sometimes come across very fragile micro fossils such as plant spores or some are just too tiny to pick up with my fine tweezers, or things that are an awkward shape that is in danger or 'pinging off'. I do not use water as I find it too 'clingy' Just use the end of your tweezers after brushing the end lightly on your face, the tweezers will pick up the oil from your skin then you can easily pick up and transfer the isolated item over to a jar and knock them off really easily. Of course you can use the end of a pin or whatever you prefer, I always put my sample in a glass petrie dish or its lid as plastic creates a static build up and then everything sticks to everything else or it just jumps around or out of your container.

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