Geochemistry of the Cheremkhovo and Lower Prisayan Formations from the Jurassic Irkutsk Coal-Bearing Basin: Evidence for Provenance and Climate Change in Pliensbachian–Toarcian
Round 1
Reviewer 1 Report
General comment
A submitted paper is written well and described the authors’ suggestions for provenance and environmental change which would influence for occurrence of the Irkutsk coal-bearing formation. A traditional interpretation method likely CIA, PIA and other scatter plots of chemical components seems to be useful for evaluation of climate change qualitatively. It would be recommended, therefore, that the paper would be valuable for acceptance to the journal with minor revision since there are several minor careless mistakes in the text. Additionally, the reviewer gives the authors suggestion to examine of comparison for their REE data to PAAS and/or NASC normalized by CI chondrite in the future. It is furthermore recommended to explore a multivariate statistical analysis likely PCA because they obtained the large dataset of multiple chemical components shown in Appendix A. The specific comments including the careless mistakes are summarized in the attachment.
Comments for author File: Comments.pdf
Author Response
Offered comments are accepted. The reviewer can see it in the attachment. The authors will consider the proposed comparison for REE data to PAAS and/or NASC normalized by CI chondrite and a multivariate statistical analysis in the future.
Author Response File: Author Response.pdf
Reviewer 2 Report
The English expression needs some improvement and I have made some suggestions in the attached document which I hope the authors will find to be useful.
I am somewhat surprised that the authors have used XRF for trace element analysis as ICP-MS and ICP-AES have much better sensitivity. Maybe a short explanation is required.
Although the title of the paper emphasizes the role of geochemistry I feel that the authors have ignored the considerable petrographic information that they have available. I would like to see more use made of this information when discussing potential source rocks and depositional environments and discussion of the agreement (or lack of) between the geochemical and petrographic indicators.
Comments for author File: Comments.pdf
Author Response
Offered comments are accepted and find it useful. The reviewer can see it in the attachment. X-ray fluorescence spectrometry was chosen because of low-cost and high speed for total analytical procedure compared to other multielement analytical methods. Petrographic studies of the Irkutsk basin rocks are fully consistent with the data of previous studies. The geochemical studies generally confirm it but give more detailed information.
Author Response File: Author Response.pdf