Dear Mr. Basu,

it makes no difference whether you prefer the PAAS-normalized data to the chondrite-normalized ones or vice versa. I recommend a rather pragmatic approach. Browse the pertinent literature and find out which application is used most frequently. For your discussion it is mandatory to have data for comparison. In my opinion, this is "economic" geology sensu lato.

Best regards

H.G.Dill

Dear Dr Basu

For geochemical study of shales, most researchers prefer chondrite normalised REE pattern. Therefore, the data can be readily compared with the data of literatures. But to understand the exact nature of source (provenance)  and inter-sample variations of sources, it is better to normalise with a standard that is similar to the probable source. And in these cases normalisation with PAAS or UCC would give better results.

Best regards

Nurul Absar

Thank you Dr. Dill. I also feel that normalization procedure does not make any difference. Still in literature especially for provenance related issues Chondrite normalization is found to be preferred by researchers.  

Thank you Dr. Absar, You have correctly pointed out that PAAS or UCC would give better result in studying provenance. But in literature I find even in provenance studies Chondrite-normalization is given more preference.

Although the REE concentrations in shale/coal have been normalized to chondrite in some investigations of REE distribution patterns, this is not advisable as the normalization standard should have been affected by similar fractionation processes to the samples being normalized. In order to investigate how REE concentrations in shale/coal are fractionated, the standard materials used for normalization should have a similar genetic origin to shale. In a different context, this is why basaltic rocks are usually normalized to standard basalt values (such as P-MORB and N-MORB). It is therefore advisable that the REE in coal/shale are normalized to an average value for sedimentary rock, such as the Upper Continental Crust , North American Shale Composite, Post-Archaean Australian Shale.

Thank you Dr. Dai. I understand your explanation for basaltic rocks. But it may not be true in case of normalizing shale with PAAS or NASC. If we consider near-quantitative transfer of REEs from provenance to basin, the REE distribution pattern (and therefore fractionation) of shale (fine siliciclastics)  is mainly a function of provenance composition. However, I agree with normalizing shale with UCC, as the exposed upper crust is the source of all siliciclastic sediments.

Thank you Dr. Kechiched. Actually overwhelming use of chondrite normalization in sedimentary geochemistry evoked the question.

I recommend Harald's answer

Best Regards

Can any one send me normalization process in excell sheet by PAAS and UCC?

I also recommend Harald's answer.

For Proterozoic sedimentary rocks sometimes chondrite and other Std normalised diagram may show different REE pattern due to recycling of sedimentation during Archean-Proterozoic transition. So you can prefer either PAAS or PCS for petrogenesis.