The QCC Posted September 10, 2015 Share Posted September 10, 2015 Photo1The smaller piece was used to make the cross section and was approx 8.7mm in diameter.The larger piece was approx. 15mm long and 6mm in diameter. This piece was used to make the trans (along its length) section.This photo was taken using a Canon SX50 HS. The Canon SX50 can focus at ridiculously close distances. In this case 4.6mmAlthough I photographed using Crossed Polars, the Crinoid specimen in not birefringent. I tried using Darkfield illumination to see if more details could be brought out. Photo 2 (Top) shows the cross section using Crossed Polarized light at 4x magnification.Photo 2 ((Bottom) I switched microscopes and inserted a 9mm Darkfield stop. Photo 3 (Top) shows the trans section using Crosed Polarized light at 4x mag.Photo 3 (Bottom) was photographed with the 9mm Darkfield stop inserted. Photo 4 shows a small area of the trans section at 10x.The Crinoid Stems were purchased from the Rock Shed.Photo 5 4 Link to comment Share on other sites More sharing options...
Auspex Posted September 10, 2015 Share Posted September 10, 2015 I am glad that you are showing us your work! It is a scientific discipline that, though aware of it, I have never explored. Thank you! "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
ZiggieCie Posted September 11, 2015 Share Posted September 11, 2015 The interior detail is amazing. Thank you. Link to comment Share on other sites More sharing options...
abyssunder Posted September 11, 2015 Share Posted September 11, 2015 Excellent!Eminent differences when using Darkfield.Thanks for sharing! " We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. " Thomas Mann My Library Link to comment Share on other sites More sharing options...
MarcoSr Posted September 11, 2015 Share Posted September 11, 2015 Very interesting post. Great images. Great detail. Marco Sr. "Any day that you can fossil hunt is a great day." My family fossil website Some Of My Shark, Ray, Fish And Other Micros My Extant Shark Jaw Collection Link to comment Share on other sites More sharing options...
The QCC Posted September 12, 2015 Author Share Posted September 12, 2015 Thank you. I plan on making more fossil thin sections. A new and hopefully better microscope is coming. Link to comment Share on other sites More sharing options...
Blastoid Posted October 28, 2015 Share Posted October 28, 2015 Wonderful work, thanks for sharing! You should try some crinoid stems from Arkona, they have a gorgeous symmetrical central cavity and superb preservation! Some of the discs have a halo of stubby spines and a thin iridescent pyrite crystal coating; an image of these, without polishing, would be gorgeous. 2 Link to comment Share on other sites More sharing options...
squali Posted November 21, 2015 Share Posted November 21, 2015 Very interesting post. Thanks for taking the time to share it with us. Could you give a description of how you make the thin sections? They are beautiful photographs. It's hard to remember why you drained the swamp when your surrounded by alligators. Link to comment Share on other sites More sharing options...
The QCC Posted November 21, 2015 Author Share Posted November 21, 2015 How I make thin section slides. Briefly. The thin section process is destructive so I photograph the specimen. for reference. The fossil is cut in thin, 2-3mm, slices using a wet tile saw. One surface of the slice is ground flat by hand on a glass lapping plate using, 100, 320, 600 and 1200 grit silicon carbide paper. The smooth flat side is bonded to a frosted petrology glass slide using Epoxy 300. The slide is then fastened to a home made holder and ground on a wet flat lap machine using successively finer grit diamond discs. The final grind and polish is done by hand on 1500 grit silicon carbide paper and 10,000 grit diamond paste. The linked pages show an early version of my process. 4 Link to comment Share on other sites More sharing options...
Auspex Posted November 21, 2015 Share Posted November 21, 2015 Very informative; thank you! "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
squali Posted November 22, 2015 Share Posted November 22, 2015 Thank you very much for your excellent response. The dedication involved in accomplishing your photographs Is quite evident. I'm curious to know about thin sections of Sediments like glauconite and silty marine clays with high salinity. Are thin sections of unconsolidated sediments even performed? It's hard to remember why you drained the swamp when your surrounded by alligators. Link to comment Share on other sites More sharing options...
The QCC Posted November 22, 2015 Author Share Posted November 22, 2015 I have not worked directly with clay, but have slides of Ledikite and some sandstones in a clay matrix. I have played around with friable material. My method is to soak the specimen in Elmer's Glass glue. It is a thin liquid that permeates through the material and hardens crystal clear. Not adding any colour to the material. Creating a hard specimen I can cut and grind. This is an image of Ledikite with the lambda plate in place. I believe a clay in liquid suspension placed on a slide and "cured" could be a candidate for micro photography. Clay varies in size from .1 to 50 microns. The ideal thickness for a thin section is 30 microns. I did something similar with sand. 4 Link to comment Share on other sites More sharing options...
sdsnl Posted November 25, 2015 Share Posted November 25, 2015 O_O Thanks for all the info, you are such an expert! Link to comment Share on other sites More sharing options...
The QCC Posted December 14, 2015 Author Share Posted December 14, 2015 The same Crinoid stem, but a different microscope and camera. These photos were taken with a Canon XS (1000D) and a Zeiss Stemi 305 edu stereo microscope with a DIY polarizer kit. Photos 1-3 are thin section views of a transverse slice. Photos 4-5 are a cross section view. Photo 5 has the Darkfield stop in place. Photos 6-7 are a close-up of the lower left corner. Photo 7 has the Darkfield stop in place. 1 Link to comment Share on other sites More sharing options...
squali Posted December 15, 2015 Share Posted December 15, 2015 That is fantastic. Is the coloration due to minerals? It is hard to imagine not fracturing the specimen during polishing. Are there polishing scratches visible or are they crystal growth? Thanks again for posting. It's hard to remember why you drained the swamp when your surrounded by alligators. Link to comment Share on other sites More sharing options...
The QCC Posted December 15, 2015 Author Share Posted December 15, 2015 The specimen is really and truly fractured. A thin slice is cut from the middle and ground and polished down to 40 microns. The darkfield photos show some polihing scratches, but mainly the crystal structure. The colours result from being viewed through crossed polarized filters. The intensity of the colours change as the specimen is rotated through 90 degrees. 1 Link to comment Share on other sites More sharing options...
Blastoid Posted December 23, 2015 Share Posted December 23, 2015 Remarkable. Do you have a gallery of prints? A bit of fossilized dinosaur bone, or a scrap of similarly-cellular armored fish from Arkona would be amazing to see. Do you do custom work, or give talks on your work? Link to comment Share on other sites More sharing options...
The QCC Posted December 23, 2015 Author Share Posted December 23, 2015 Thank you. I make thin sections of rocks and fossils as a hobby.. My gallery is rather basic. 1 Link to comment Share on other sites More sharing options...
abyssunder Posted February 2, 2016 Share Posted February 2, 2016 Beautiful! Congrats! " We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. " Thomas Mann My Library Link to comment Share on other sites More sharing options...
JohnBrewer Posted February 3, 2016 Share Posted February 3, 2016 Fascinating. Enjoyed your link showing your method. John Map of UK fossil sites Link to comment Share on other sites More sharing options...
bookishgeologist Posted April 14, 2016 Share Posted April 14, 2016 I've never seen someone make thin sections out of crinoid stems before! I have access to thin section machines at my university... this is something I may try to do, considering I have a stem staring at me from across my desk... do you think the same thing could be done to a horn coral fossil? I have a few of those as well. Also, you're taking them down to 40 microns or 30 microns? What thickness would you recommend for best examination? (Sorry for all the questions, this thread has totally blown up my curiosity!) Link to comment Share on other sites More sharing options...
The QCC Posted April 14, 2016 Author Share Posted April 14, 2016 Thank you all for the nice posts. It is appreciated. I made some thin sections of horn coral in December 2015. Unfortunately, my equipment is not really capable of 30-40 micron thick sections. My grinder is a standard jewelry 6" flat disc machine. I can get sections down to about 80-70 microns, then I finish them off by hand as best I can. Ideally, 30-40 microns is the target for a polarizing microscope, but I have good results in the 90-50 micron range. 1 Link to comment Share on other sites More sharing options...
bookishgeologist Posted April 18, 2016 Share Posted April 18, 2016 Thank you all for the nice posts. It is appreciated. I made some thin sections of horn coral in December 2015. Unfortunately, my equipment is not really capable of 30-40 micron thick sections. My grinder is a standard jewelry 6" flat disc machine. I can get sections down to about 80-70 microns, then I finish them off by hand as best I can. Thank you!!! I'm totally thrilled!!! I'll be sure to share anything I make!!!! Link to comment Share on other sites More sharing options...
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