I have a few SEM micrographs in hand but I couldn't tell exactly what is those samples. Could anyone help me to identify or maybe suggest the nature of these samples (including the minerals)? These samples were collected at a tropical small island, ranging from coastal to inland. The major composition of these samples were essentially CaCO3, except the 2nd sample collected from high elevation area (quartz and ulvospinel). Alternatively, you can also help me by inviting or suggesting more experts who worked closely in this field. I thank you in advance for your efforts and contributions.
Hello Chin,
I examine diatoms once and the 3rd and 4th structures are very similar with that creatures. First one is also may same but i am not sure.
I cannot understand the second one but it seem like there is a huge contamination that may be lipid or solvent.
Have you coat your samples? If not, contamination on second image should have burn under electron beam. This may give a clue.
In short, these are organic living creatures except 2nd. And ceramics structures can be observed.
Hope this answer can lead you.
Good Luck!
Thank you for your useful suggestion. The 1st sample is a dead coral sample collected from the shore. But I am not sure about the elongated structure, is it also a type of diatom? Yes, I do coated my samples with Pd. Lipid or solvent? or could it possibly be halite?
To the left of the first image, I see a diatom which might be the species of the genus NItzschia or Bacillaria, I guess. Round-elliptic object to the top of the image would be also a diatom valve (which means half of a diatom frustule), yet it is difficult to tell what species it would be.
I also think the pictures could be of diatoms, broken ones that is. The second one is most distinct - perhaps a phytholith?
Yes, in the first image, I can see diatoms : on the left, and on the background (in the dark part of the picture). For the second picture, I don't know.
For the two last, it could be diatoms also, but I am not certain. It should be also a piece of foraminefera test ...
Hello Chin, On the first one it could be aragonite needles and calcite crystals . Is there no magnesium at all ?
So in addition tour your diatoms (or forams –am not an expert) you have aragonite needles and calcite crystals. If you have enough material you should make XRD. It is not necessary to separate the products so you will also have informations abt diatoms (mainly amorphous silica) or forams (calcareous)
Hi Chin, I am suggesting that you perform EDX mapping on your samples if your SEM has the facility. This could help you to easily identify the elemental composition and contermination in your samples
The first picture includes several frustules. The material appears poorly oxidized or rinsed. The magnification of othrr samples is low, i don't think these are apical pore field but need more detail at higher magnification. The xray analsis is a good method i used in a rg paper available under my profile (zimba and bates). Best, pzimba
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