Collecting Microfossils Without Breaking The Bank: 2015 Edition!

[billheim]

Administrators and moderators, my apologies for starting a new subtopic on Herb's EXCELLENT discussion of washing clay to get fossils. I read the instructions for newbies and so I'm going to start a new thread to continue the 2012 discussion by the same name.

Herb, Nice job on your 2012 article. I do exactly the same thing and agree that if you live in Ordovician rock you have lots of clay to extract with plain water and awesome collections of microfossils to show for it.

Here's how I do it. Rather than posting the same info that's already online (again apologies to the moderators), here is some photos and descriptions of my technique from the hills of Cincinnati, Ohio, USA where we have Late Ordovician clay.

http://www.drydredgers.org/fieldtrips/bonwell5.htm

Bill

[Auspex]

This is very much value-added content; thank you!

[Coco]

Hi,

I can see on your pics that cleaned sediment keeps a little clay Inside. To perfect the wash of the sediment, you can do well to dry what you washed before putting back in the water. The clay decompresses very well when it is very dry before being put in the water. You shouldn't hesitate to dry well before putting back in the water, and that as often as necessity, the result would be better

Coco

[billheim]

Hi,

I can see on your pics that cleaned sediment keeps a little clay Inside. To perfect the wash of the sediment, you can do well to dry what you washed before putting back in the water. The clay decompresses very well when it is very dry before being put in the water. You shouldn't hesitate to dry well before putting back in the water, and that as often as necessity, the result would be better

Coco

Good idea, coco. I'll try that. It will take longer, but some of my samples have tough clay and will benefit from this. Others are almost entirely mud and clean up nicely with about 10 rinses.

Bill

[Mediospirifer]

Some of the shale I've worked with softens with boiling alternated with drying. It's time consuming!

[Coco]

Hi,

I have forgotten to tell you that using some water + hydrogen peroxide on the well dried clay accelerates of process.

Coco

[squali]

Thanks for the post. I have found a lot of enjoyment in the micro world since Herb's

first post. Always looking for new ideas.

I agree with using hydrogen peroxide to break down tough clay.

If the material is dry it only takes a few minutes. When the phizzing stops it's done.

Be advised to try it on a scrap specimen to see if the fossils would be disturbed.

[Herb]

Nice, Bill. Use a little Calgon dishwasher detergent while you are soaking the material. Calgon is a de-flocculating agent and will help break up the clay.

[billheim]

Nice, Bill. Use a little Calgon dishwasher detergent while you are soaking the material. Calgon is a de-flocculating agent and will help break up the clay.

Another great tip. Thanks Herb!

When I began fossil hunting around 1990, I began by washing my fossils in laundry detergent. It worked better than plain warm water. People were commenting that my fossils always smelled so nice and I didn't know what they meant until I realized it was my laundry detergent. I was a happy housekeeper. :-)

Then I realized my bryozoans were too and span. They were coming out white! Bryozoans are not colorfast! I realized calcite finds some detergents a little harsh.

I don't have as much concern about phosphates. Some people use acidic acid to clean phosphatic microfossils but I'm clumsy and have burned my skin enough times to know I can't do it. I So I maybe I'll try Calgon.

In my collaboration on the phosphatic microfossil taphonomic study with Ben Dattilo and Rebecca Freemen, I'm now observing the amount of phosphate compared to calcite at different Cincinnatian Series sites to help determine how phosphates accumulate over time. Since the traditional method to extract phosphatic fossils from carbonate facies has been dissolution in acid, we need more data - at least in my opinion. So having clays that I can dissolve in plain water has been a benefit.

But for all my other microfossil extractions, I'll try some Calgon and let you know how it goes.

Bill

Edited July 28, 2015 by Auspex