Dear Mr. Lghmour,

for the clay, silt and sand particle size you can take the classical approach making use of sieve analysis, settling tubes (pipette analysis of the mud or hydrometer)or make use of the CAMSIZER. If the gravel size range plays a significant part you must separate it from the smaller grain size fraction and weight it. If you have no adequate set of sieves for the larger grain size intervals you must group these gravel size particles and measure it with a caliper or try and evaluate them by an image analysis. You have to measure the length, width and height. In this case you don not only obtain grain size results but you are also able to describe the shape in terms of roundness and sphericity. It is helpful for sedimentological interpretations.

I wish you much success

H.G.Dill

Thank you very much Mr. Dill for your help and for this detailed explanation, I hope I can do the same for you in the near future.

please excuse me because I have two more questions :

- concerning the analysis of images, can I use this method for gravel and pebbles (i.e. size > 2 mm), if so, how can I proceed and by which software will I do this analysis?

- for frequency and cumulative curves, are they sand-specific? or can I use them for other fractions?

awaiting your answer, thank you

best regards

To describe the image analysis which not only enables you to determine the grain size but also the morphology of the grains and their chemical composition so as to be able to give an overview of the composition and the texture it would exceed the scope of this Q&A communication. It depends on the techniques you have at hands and the devices installed.

For frequency and cumulative curves you can use the common mathematical techniques and also calculate the parameters such as median, sorting...These are not particle-size sensitive, because you want to describe your entire sediment load.

H.G.Dill

To add to Harald G. Dill 's excellent and helpful answer, if you proceed with image analysis I have found the free opensource ImageJ software to be a very useful tool for grainsize and textural analysis. Ensure you set the scale correctly, and analyse a statistically significant number of grains. I don't see any reason why you couldn't use this method on images of pebble size clasts, as long as you set the scale appropriately.

Bonjour Mohammed Lghamour

Afin de déterminer la distribution des grains de vos échantillons alluvionnaires tu peux utiliser 2 méthodes normatives: la première est celle de l'analyse granulométrique par tamisage pour les particules ayant des tailles supérieurs à 0.080 mm. Pour les particules de taille inférieurs à 0.080 mm, l'analyse s'effectue par sédimentation.

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Dear Mohammed Lghamour

In order to determine the grain distribution of your alluvial samples you can use 2 normative methods: the first is that of Grain size analysis for particles with sizes greater than 0.080 mm. For particles smaller than 0.080 mm, the analysis is carried out by sedimentation.

Dear Mohammed,

In case of sedimentological studies on claystone samples, as known with predominance of the clay size fractions, there will be a lack of applying the classical approach of sedimentological parameters.

Hence, this approach could be useful:

https://doi.org/10.1016/j.clay.2018.06.027

Thanks and best regards !

Mahmoud E. Awad

For coarse material: pebble count (grid or transect line, using a granulometer).

I thank you very much for your support my colleagues :

- For Mr. Harald G. Dill , Thank you very much for your advice and very useful comments. for our case here in Morocco, the only material we have here is the series of sieves, we do not have other more efficient and faster materials such as CAMSIZER or others. for the moment I have done the analyses of the fine fraction, it remains for me to analyze the pebbles, in this way you spoke of image analysis for this type, what kind of image I will use? how? and by which software I will proceed? it is open source?

- For Mr. Mardi McNeil , thank you very much for learning about ImageJ, I found it very interesting and efficient, my last question is can we use it in the case of mixed samples not separated? and does it work with all types of images? ( for the tutorial I saw, they work with a SEM image, and I want to use it for the pebbles).

- For SI Abidi Abdelfattah , thank you very much for your intervention, I worked by the method you mentioned, that's what we have in our hands for the moment, see you at the faculty.

- For Mr. Mahmoud E. Awad , thank you very much for your advice, really the very fine fractions present analysis problems, although this is not my treatment objective, but I think I will use sedimentometry to determine their sizes.

- For Mr. Corrado Cencetti thanks for your interaction, I didn't quite understand what you mean by (grid or transect line, using a granulometer) .

They are Wolman pebble count methods (see:

https://andrewsforest.oregonstate.edu/sites/default/files/lter/data/studies/gs002/Wolman_Pebble_Count.pdf

https://dep.wv.gov/WWE/getinvolved/sos/Documents/SOPs/PebbleCount_Methods.pdf

Article The Pebble Count Technique for Quantifying Surface Bed Mater...

You can use sieves (AFNOR or phi series) following methods described in this free book :

Book Analyses granulométriques. Principes et méthodes

Fournier J., Bonnot-Courtois C., Paris R., Le Vot M. 2012. Analyses granulométriques, principes et méthodes. CNRS, EPHE, 102 p.

Then, you can also use the package 'G2SD' R-CRAN

https://cran.r-project.org/web/packages/G2Sd/index.html

https://cran.r-project.org/web/packages/G2Sd/G2Sd.pdf

or this interface : https://regisgallon.wordpress.com/r-software/g2sd-r-interface/

and this reference : https://journals.openedition.org/geomorphologie/10513

Fournier J., Gallon R.K., Paris R. 2014. G2Sd: a new R package for the statistical analysis of unconsolidated sediments. Géomorphologie, relief, processus, environnement, 20(1), 73-78.

Kind regards

Jérôme