Fossil diatom from Oamaru

[hkv]

Fossil diatom from Oamaru. 500X mag on a 19" screen.

Diatom-1.jpeg (417.05 KiB) Viewed 33486 times

Diatom-3.jpeg (422.72 KiB) Viewed 33486 times

[DonSchaeffer]

These photos are extraordinary. They look like sculptures made out of plastic.

[charlie g]

Beautiful work, thank hkv.

Any idea how old this sample is ( aprox age)?

Your image captures are quite elegant. charlie g

[MichaelG.]

Exquisite imaging … please share your secrets

Probably the nearest I have ever seen to a convincing representation !

… You have brightened-up what had the makings of a miserable day.

MichaelG.

[hkv]

Thank you Charlie! They date from late Eocene to early Oligocene; 32 – 35 million years ago.

Beautiful work, thank hkv.

Any idea how old this sample is ( aprox age)?

Your image captures are quite elegant. charlie g

[hkv]

Here is another one.

Diatom-4.jpg (326.85 KiB) Viewed 33397 times

[hkv]

No secrets really. SEM imaging of a sample from Oumaru. Gold sputtered, high vacuum mode. 8kV EHT. Colored in photoshop. I try to find colors that would be true in real life using light microscope, but not always possible of course. It is sort of a guess work.

Exquisite imaging … please share your secrets

Probably the nearest I have ever seen to a convincing representation !

… You have brightened-up what had the makings of a miserable day.

MichaelG.

[hkv]

Thank you Don, yes, the resolution and characteristic of SEMs give a great 3D-effect.

These photos are extraordinary. They look like sculptures made out of plastic.

[charlie g]

Wonderful microscopy, hkv, again..bravo and thanks.

Two silly questions for you: 1) the depth of field for your SEM instrument can crisply capture the entire height and depth of a diatom frustle...never a concept of'image stacking with SEM at this magnification?

2) does your SEM setup have a nuisance of 'dust in the optical path'...or is it simply the challenge ( no doubt a big challenge) of an incredibly clean/ debris free sample grid?

Thanks for the age estimate! https//www.bsgf.fr>bsgf> bsgf190034>bsgf190034 " Thai amber : insights into early diatom history" by V Girard, 2020. Estimated diatom origins near Triassic-Jurassic boundary.

charlie g

[MichaelG.]

No secrets really. SEM imaging of a sample from Oumaru. Gold sputtered, high vacuum mode. 8kV EHT. …

I honestly thought it was the best piece of Optical Microscopy stacking that I had ever seen

… No mention of SEM on your equipment list

MichaelG.

[hkv]

1. A SEM has better depth of field than normal light microscopes. You can also decide the working distance you want and the compromise will be the resolution that suffer when you need more depth of field. I theory, you could do focus stacking, but is normally not needed. These are "single shots" if you know what I mean.

2. Nor sure I understand your question. There cannot be any dust in the optical path. In fact, there can be no molecules at all as the electron beam travels in more or less perfect vacuum. The problem with SEM, just as with light microscopy, is to get a good clean sample so that you can image the subject/specimen you want without a lot of debris on top or next to it. For these images, I did not do any preparation using a stereo scope to carefully place or arrange the diatoms. As you can see, it looks like a fairly dirty collection of debris and diatoms, but I liked the look sort of. Makes it more interesting to look at than a perfectly isolated diatom outside it's habitat. Some people would disagree of course. Also, based on the knowledge I have from light microscopy, I tried to color the pieces in a natural way. I really dislike the colouring scheme many use for SEM images with purple, orange, pink, etc just to make them pop. I am glad actually that MichaelG thought this was a light micrograph!

Wonderful microscopy, hkv, again..bravo and thanks.

Two silly questions for you: 1) the depth of field for your SEM instrument can crisply capture the entire height and depth of a diatom frustle...never a concept of'image stacking with SEM at this magnification?

2) does your SEM setup have a nuisance of 'dust in the optical path'...or is it simply the challenge ( no doubt a big challenge) of an incredibly clean/ debris free sample grid?

Thanks for the age estimate! https//www.bsgf.fr>bsgf> bsgf190034>bsgf190034 " Thai amber : insights into early diatom history" by V Girard, 2020. Estimated diatom origins near Triassic-Jurassic boundary.

charlie g

[hkv]

Sorry Michael. I have now updated my list of equipment

No secrets really. SEM imaging of a sample from Oumaru. Gold sputtered, high vacuum mode. 8kV EHT. …

I honestly thought it was the best piece of Optical Microscopy stacking that I had ever seen

… No mention of SEM on your equipment list

MichaelG.

[KurtM]

I was thinking the same thing: "DANG I know that Olympus BX of his has great optics, but this looks just like SEM!!"

Wonderful stuff, thanks for posting it here!

[Sure Squintsalot]

Scale bars, good sir.....just pretty pictures without 'em.

[Phill Brown]

The great thing about SEM is knowing what structures you should be seeing.
Do mammal fossils pre date fossil diatoms?
I only have Miocene samples.

[hkv]

No, I will never put scale bars on my images. Just like street photographers does not put the street name on their work... Nor do I put ISO, Aperture or exposure time. I believe a photograph should be clean without signatures or other distracting elements. In a scientific paper I fully can understand the value of scale bars, but not for micrographs in general.

Scale bars, good sir.....just pretty pictures without 'em.

[hkv]

The great thing about SEM is knowing what structures you should be seeing.
Do mammal fossils pre date fossil diatoms?
I only have Miocene samples.

Yes, if I recall correctly, animals dates back over 600 million years ago during the Ediacaran Period and the Cambrian Period. Mostly simple and soft-bodied animals back then. Diatoms first appeared during the Jurassic Period, around 180 million years ago. Someone, correct me if I am wrong.

[Hobbyst46]

Fascinating images, hkv.

[Phill Brown]

The great thing about SEM is knowing what structures you should be seeing.
Do mammal fossils pre date fossil diatoms?
I only have Miocene samples.

Yes, if I recall correctly, animals dates back over 600 million years ago during the Ediacaran Period and the Cambrian Period. Mostly simple and soft-bodied animals back then. Diatoms first appeared during the Jurassic Period, around 180 million years ago. Someone, correct me if I am wrong.

Quick search on the misinformation superhighway says Mammal and diatom fossil records start around 200 million years ago.

[JWW]

I saw these on Facebook. Incredible images Håkan and exquisitely colored in Photoshop. The best I've ever seen for sure. Thanks for sharing.

-JWW

[zzffnn]

Such beautiful work, Hakan! Thank you for sharing.

[hkv]

I saw these on Facebook. Incredible images Håkan and exquisitely colored in Photoshop. The best I've ever seen for sure. Thanks for sharing.

-JWW

Thank you!

[hkv]

Such beautiful work, Hakan! Thank you for sharing.

Thanks!

[Sure Squintsalot]

What is the field of view on these images?

[Phill Brown]

I'll kick off with 275 microns ish across the round diatom.

[Sure Squintsalot]

A beer says less than 2 fifty.

I suspect the scale bar wasn't recorded when it was scanned. Aesthetics or something.

[hkv]

A beer says less than 2 fifty.

I suspect the scale bar wasn't recorded when it was scanned. Aesthetics or something.

The good thing about SEMs is that they record all data. Here is an extract from the EXIF:

Code: Select all

Store resolution = 6144 * 4608
Reference Mag = Out Dev
Mag =    559 X
Image Pixel Size = 87.31 nm
Width = 536.4 µm

Reference Mag = Out Dev means the magnification is in relation to the size of the screen used, meaning 19".

The full image width (x-axis) has a 536.4 µm field of view so I would say the diatom is around 300 µm.

[Phill Brown]

Sticking with 275.

[hkv]

Sticking with 275.

So I checked the exact figures. The diatom is 3625 pixels in diameter. 3625/6144*536.4 = 316.48. A big boy.

[Sure Squintsalot]

Is that Carl ZEISS EVO LS 10 Lab6 your own or do you have regular access to it?

I've often wondered about a used table-top SEM.... seems that for the cost of a decent modern optical system, you could get lucky with a basic SEM.