Geochemical Characteristics and Depositional Environment of Coal-Measure Hydrocarbon Source Rocks in the Northern Tectonic Belt, Kuqa Depression

Round 1

Reviewer 1 Report

The authors have submitted an interesting manuscript. The manuscript is within the scope of the journal.
The methodology and theoretical background are well written.
The methods and materials used in this article are appropriate.
The experimental results and conclusions are sufficiently presented and discussed.
The illustrations and figures are good.

Minor revision:
1. I suggest the authors extend the introduction; it is very short.
2. I suggest the authors change the division of chapter 3. From my point of view, there are many subchapters. Unification is needed.
3. In references, the DOI should be added for individual sources if possible.
4. All abbreviations should be properly explained in the manuscript.

I suggest accepting the paper, but my comments should be resolved.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

The paper presents organic geochemical data of source rocks from Kuqa Depression, Tarim Basin. The authors can find my notes and comments in the attached file. In general, I was not able to understand why was this study conducted on the first place. Numerous repetitions of text and figures, together with the grammatical and stylistic problems make the text hardly readable and even more difficult to understand. I started to correct the language but eventually I gave up as it appears I will need to re-write the whole manuscript. There are so many misinterpretations of the data that I actually question the whole design and conclusions of this study. I have the feeling that the authors just slide on the surface of their data and discuss only the most obvious results. It will be much more important and interesting to see a discussion on the spatial and vertical variation of the geochemical parameters.

I think a major re-design,  complete re-writing of the text and language correction through official editorial service is needed prior to accepting for publication.

Comments for author File: Comments.pdf

Author Response

We apologize for the poor language of our manuscript. We worked on the manuscript for a long time and the repeated addition and removal of sentences and sections obviously led to poor readability. We have now worked on both language and readability and have also involved native English speakers for language corrections. We really hope that the flow and language level have substantially improved. Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

The manuscript “Geochemical characteristics and depositional environment of coal-measure source rocks in the northern tectonic belt, Kuqa Depression” present an interesting set of organic geochemistry data for the possible source rocks of hydrocarbons. Data appears robust and the topic is interesting. The research can be adequate for Applied Sciences.

Before more substantial things, I truly recommend to present the submitted manuscript with pages and lines numbered, which will facilitate the reviewing process. It is also disagreeable to receive a manuscript with parts highlighted with a yellow background. But let’s go on…

I found 3 main things that deserve author’s attention:

1)      Written English. Problems with written English appear since the title. I know the term “coal-measure source rocks” has been used, but it can be confusing. One can read it as the source for a coal measure or the coal measure as a source for hydrocarbons. Unless we are dealing with the recycling of previous coal deposits (an awkward idea, anyway), only the second hypothesis makes sense. Hence, it is wise to write in the title what the coal measures are sourcing. They are source rocks for what?

It seems that the vocabulary used by the authors is somewhat limited, making the manuscript unpleasant to read. For example, the term "source rocks" appears 9 times in the abstract and 160 times in the paper. Adding up, we find "source rock" 48 times.

But there are many other problems, indicated in the annotated manuscript.

2)      Stratigraphic/sedimentologic descriptions and interpretations. The text focusing on issues of stratigraphy/sedimentology, from the introduction to the discussion passing through the setting, does not appear to be solid and suggest a poor knowledge of these scientific components. At some point it is mentioned that “The depositional environment of source rock samples is mainly a continental delta and shallow water environment, as shown in Figure 7.” But Fig. 7 only suggests the presence of mainly terrestrial and estuarine material. Hence, there’s no reason to mention continental delta in these terms. A delta is a depositional accumulation that forms where the sediment discharge overcomes the environmental capacity to mobilize these sediments. Can be in coastal or lacustrine settings and has nothing to do with estuaries (although estuaries may include the so-called ebb and flood deltas).

3)      Oxidation and organic matter enrichment. It is written in section 4.3 (Controlling factors of source rock development), and later emphasized in the conclusions, that “the partial oxidation environment is more advantageous to the enrichment of organic matter”. This is somewhat surprising. In general, oxidation accounts for the decomposition of the organic matter. Possible reasons for an enrichment with more pronounced oxidizing conditions must be presented. And it is also necessary to consider the possibility of independent environmental factors affecting the ratio Pr/Ph. Actually, looking at the plot, it seems that the samples are clustered in 2 groups. If these groups have any environmental meaning that justify their isolation, the relation TOC-Pr/Ph is lost.

Considering these issues, I suggest major revision before acceptance in Applied Sciences.

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

 No further comments

Author Response

Thank you for your review.

Reviewer 3 Report

I recognise that the authors took into consideration the comments and suggestions that I made before. I have no futher suggestions.