I need a reliable chart for thermal alteration index assesment. It must have references for at least spores, algae and acritarches.
Your help would be appreciated.
The attached colour and colour description charts are valid for all palinomorphs.
You may find other indications at http://www.biologydiscussion.com/palynology/parameters-used-in-exploration-of-hydrocarbons/64737 .
I also attach a comparative chart of different thermal maturity indexes and an example taken from this paper:Article Optical thermal maturity parameters and organic geochemical ...
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Thank you for your replies Mr Bencini and Mr Idan.
Actually, I do not think the same color chart applies to all palynomorphs.
Parameters like the size and morphology may influence the color saturation or rather the amount of light going throught the palynomorph.
I would be happy to share some of my work on some slides and show you the Palynofacies from some clean samples (only core samples). I may be a beginner in the field because I worked on no more than 60 samples so far, but I noticed a clear color saturation between different palynomorphs (on the same slide).
Thank you for your comment Yacine Mokri, and your previous comments Mr Bencini and Mr Idan. It shows the problem with this topic, there is a lot of personal believe and interpretation involved, leading to very different schemes. Just comparing the schemes submitted by you both, Bencini & Idan, we see significant differences. So who is right???
And you are fully right, Yacine Mokri, that different palynomorphs show different colours at the same maturation levels. Pollen are different from spores, which are different from algae, or dicocysts or acritarchs. And even within each group we see clear differences, depending on wall thickness, density and thickness of ornament, preservation (chemical & microbial alteration). So you have to use very similar types of palynomorphs to have good colour correlation. And because the kerogen we study is from sedimentary rocks, which are mostly recycled to some degree, you can have similar types of palynomorphs in different colours in one sample, due to recycling of higher mature material in your less mature sample. So you see, it's pretty complex.
Unfortunately also the documenting of our results brings additional uncertainty, because the colour of our photoplates depend on the specific of microscope, magnification, lightning system and so on. Therefore the same sample will show three different pictures in three microscopes. And if you take paper, the colours in ptinted papers are effected by printing, in digital documents colours are effected by your system, programs or the settings of your screen.
Working with Vitrinite reflectance and palynomorph colours for several years now, I realized also an age dependence of palynomorph colours. So stratigraphy is another point making it more complex.
So it's even more complicating. And the dream of a simple TAI chart working for everything is finally gone, I guess. Sorry Cristiana.
On the other hand palynomorph colours are just a fast initial tool to determine maturation on a relative rough scale (immature, low/medium/upper oil or gas) and for this we can ignore a lot of the difficulties above.
As one solution, I would like to encourage you to work with the palynomorph darkness index (PDI) from Goodhue & Clayton, which might be a good way out of the troubles with the previous colour analysis schemes.
cheers
Hartmut
Thank you for your reply Mr. Jaeger.
You gave pretty much all the inconvenients/downsides of using TAI for maturity assessment. I had some time since I posted this question to look more into this, and indeed, it is as you say: lots of palynomorphs with all kinds of shapes, wall thickness, size,... without even taking into account other (external) factors.
Having a lot of tasmanites in my samples, I chose to focus more on those when possible, and only individuals in the range of 40 to 60 microns. thanks to that, I manage to get consistent measurements (and get rid of the "subjective color" syndrome haha), but I always use other parameters for reference (Tmax, VR).
I read about DPI, but I never tried it before. Does it require any extra equipment (We have a motorized microscope coupled to a CCD for VR and fluorescence measurements).
Also, I try to read papers from famous authors (and others), but do you have interesting ones in particular to suggest? I would be grateful if you could point me out some good publications and books.
Thank you for your help Mr. Jaeger,
Sincerely
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