Dear Dr. Duan,

Thank you for submitting your manuscript entitled "Origins of the hydrothermal dolomites in Middle Permian, Sichuan Basin (SW China): Implication for the relationship with the Emeishan Large Igneous Province" to PLOS ONE .

Following a careful assessment by independent reviewers and thorough evaluation of their comments, I find that your study presents a meaningful and potentially valuable contribution to the understanding of hydrothermal dolomitization and its geological context within the Emeishan Large Igneous Province. The manuscript aligns well with the scope of the journal and demonstrates scientific merit.

However, to improve the clarity, rigor, and overall presentation of the work, a Major Revision is recommended . The reviewers have provided constructive feedback, which I believe, if addressed thoroughly, will significantly enhance the quality and impact of your manuscript.

Please submit your revised manuscript by Sep 13 2025 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org . When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

• A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
• A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
• An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols . Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols .

We look forward to receiving your revised manuscript.

Kind regards,

Rizwan Sarwar Awan

Academic Editor

PLOS ONE

Journal Requirements:

When submitting your revision, we need you to address these additional requirements.

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at

https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and

https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

2. In your Methods section, please provide additional information regarding the permits you obtained for the work. Please ensure you have included the full name of the authority that approved the field site access and, if no permits were required, a brief statement explaining why.

3. Please include a complete copy of PLOS’ questionnaire on inclusivity in global research in your revised manuscript. Our policy for research in this area aims to improve transparency in the reporting of research performed outside of researchers’ own country or community. The policy applies to researchers who have travelled to a different country to conduct research, research with Indigenous populations or their lands, and research on cultural artefacts. The questionnaire can also be requested at the journal’s discretion for any other submissions, even if these conditions are not met.  Please find more information on the policy and a link to download a blank copy of the questionnaire here: https://journals.plos.org/plosone/s/best-practices-in-research-reporting. Please upload a completed version of your questionnaire as Supporting Information when you resubmit your manuscript.

4. We note that the grant information you provided in the ‘Funding Information’ and ‘Financial Disclosure’ sections do not match.

When you resubmit, please ensure that you provide the correct grant numbers for the awards you received for your study in the ‘Funding Information’ section.

5. We note that your Data Availability Statement is currently as follows: [All relevant data are within the manuscript and its Supporting Information files.]

Please confirm at this time whether or not your submission contains all raw data required to replicate the results of your study. Authors must share the “minimal data set” for their submission. PLOS defines the minimal data set to consist of the data required to replicate all study findings reported in the article, as well as related metadata and methods (https://journals.plos.org/plosone/s/data-availability#loc-minimal-data-set-definition).

For example, authors should submit the following data:

- The values behind the means, standard deviations and other measures reported;

- The values used to build graphs;

- The points extracted from images for analysis.

Authors do not need to submit their entire data set if only a portion of the data was used in the reported study.

If your submission does not contain these data, please either upload them as Supporting Information files or deposit them to a stable, public repository and provide us with the relevant URLs, DOIs, or accession numbers. For a list of recommended repositories, please see https://journals.plos.org/plosone/s/recommended-repositories.

If there are ethical or legal restrictions on sharing a de-identified data set, please explain them in detail (e.g., data contain potentially sensitive information, data are owned by a third-party organization, etc.) and who has imposed them (e.g., an ethics committee). Please also provide contact information for a data access committee, ethics committee, or other institutional body to which data requests may be sent. If data are owned by a third party, please indicate how others may request data access.

6. Thank you for stating the following in the Acknowledgments Section of your manuscript: [We thank the constructive comments from the reviewers. This research was funded by National Natural Science Foundation of China (Grant No. U19B6003). Guoxiang Chi and Hairuo Qing are thanked for their contribution to fluid inclusion analysis and the determination of the properties of dolomitized fluids. This work are also supported by the research group “Geologia Sedimentària” (2021 SGR-Cat 00349) funded by the Generalitat de Catalunya, and the DGICYT Spanish project PID2021-122467NB-C22, the Natural Science Foundation of Chongqing Municipality (CSTB2023NSCQ-MSX1022), and the Natural Science Foundation of Sichuan Province (2022NSFSC1177).]

We note that you have provided funding information that is not currently declared in your Funding Statement. However, funding information should not appear in the Acknowledgments section or other areas of your manuscript. We will only publish funding information present in the Funding Statement section of the online submission form.

Please remove any funding-related text from the manuscript and let us know how you would like to update your Funding Statement. Currently, your Funding Statement reads as follows: “The authors received no specific funding for this work.”

Please include your amended statements within your cover letter; we will change the online submission form on your behalf.

7. We note that Figure 1 and 3 in your submission contain [map/satellite] images which may be copyrighted. All PLOS content is published under the Creative Commons Attribution License (CC BY 4.0), which means that the manuscript, images, and Supporting Information files will be freely available online, and any third party is permitted to access, download, copy, distribute, and use these materials in any way, even commercially, with proper attribution. For these reasons, we cannot publish previously copyrighted maps or satellite images created using proprietary data, such as Google software (Google Maps, Street View, and Earth). For more information, see our copyright guidelines: http://journals.plos.org/plosone/s/licenses-and-copyright.

We require you to either (1) present written permission from the copyright holder to publish these figures specifically under the CC BY 4.0 license, or (2) remove the figures from your submission:

1. You may seek permission from the original copyright holder of Figure 1 and 3 to publish the content specifically under the CC BY 4.0 license. 

We recommend that you contact the original copyright holder with the Content Permission Form (http://journals.plos.org/plosone/s/file?id=7c09/content-permission-form.pdf) and the following text:

“I request permission for the open-access journal PLOS ONE to publish XXX under the Creative Commons Attribution License (CCAL) CC BY 4.0 (http://creativecommons.org/licenses/by/4.0/). Please be aware that this license allows unrestricted use and distribution, even commercially, by third parties. Please reply and provide explicit written permission to publish XXX under a CC BY license and complete the attached form.”

Please upload the completed Content Permission Form or other proof of granted permissions as an ""Other"" file with your submission.

In the figure caption of the copyrighted figure, please include the following text: “Reprinted from [ref] under a CC BY license, with permission from [name of publisher], original copyright [original copyright year].”

2. If you are unable to obtain permission from the original copyright holder to publish these figures under the CC BY 4.0 license or if the copyright holder’s requirements are incompatible with the CC BY 4.0 license, please either i) remove the figure or ii) supply a replacement figure that complies with the CC BY 4.0 license. Please check copyright information on all replacement figures and update the figure caption with source information. If applicable, please specify in the figure caption text when a figure is similar but not identical to the original image and is therefore for illustrative purposes only.

The following resources for replacing copyrighted map figures may be helpful:

USGS National Map Viewer (public domain): http://viewer.nationalmap.gov/viewer/

The Gateway to Astronaut Photography of Earth (public domain): http://eol.jsc.nasa.gov/sseop/clickmap/

Maps at the CIA (public domain): https://www.cia.gov/library/publications/the-world-factbook/index.html and https://www.cia.gov/library/publications/cia-maps-publications/index.html

NASA Earth Observatory (public domain): http://earthobservatory.nasa.gov/

Landsat: http://landsat.visibleearth.nasa.gov/

USGS EROS (Earth Resources Observatory and Science (EROS) Center) (public domain): http://eros.usgs.gov/#

Natural Earth (public domain): http://www.naturalearthdata.com/

8. If the reviewer comments include a recommendation to cite specific previously published works, please review and evaluate these publications to determine whether they are relevant and should be cited. There is no requirement to cite these works unless the editor has indicated otherwise. 

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

Reviewer #1: Yes

Reviewer #2: Yes

**********

2. Has the statistical analysis been performed appropriately and rigorously? -->?>

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Have the authors made all data underlying the findings in their manuscript fully available??>

The PLOS Data policy

Reviewer #1: No

Reviewer #2: Yes

**********

4. Is the manuscript presented in an intelligible fashion and written in standard English??>

Reviewer #1: Yes

Reviewer #2: Yes

**********

Reviewer #1: 

The manuscript titled “Origins of the hydrothermal dolomites in Middle Permian, Sichuan Basin (SW China): Implication for the relationship with the Emeishan Large Igneous Province” by Zheng et al. presents an interesting and compelling study of the spatial relationships that is often observed in structurally-controlled, hydrothermal dolomite bodies. The manuscript is well-presented and provides strong field, petrographical, and geochemical observations. I will comment here that much of this manuscript is based on types of data that we have been collecting for several decades now – both in the Sichuan Basin and worldwide. I understand that many of the more novel analytical techniques can be quite costly (e.g., clumped isotopes, U-Pb geochronology etc.) and my purpose here is not to delay a manuscript for these reasons – this manuscript very well may be an ideal fit for PLOS ONE. However, I would strongly suggest the authors make a clearer statement in their “Introduction” of the key research gap they are addressing and why this has not been previously feasible during the past ~20 years of research. Note that there are also a small number of English language editing that is required, but I will not focus on this for the purposes of peer-review.

I sign this peer-review and choose not to make these comments anonymous because I do have a small number of recommendations to my own work and that of collaborators that work on these deposits. I will start by stating that the authors should not be so reliant on the works by Davies and Smith Jr. (cited 5 times in the manuscript and 3 times in the reference list). “All researchers should be aware that Davies and Smith were the ‘Editors’ of the AAPG special publication in which their manuscript was published, which is a conflict of interest.” (pers. comm. H. Machel). The authors cite the ‘introduction’ to this special publication (Smith and Davies, 2006), the actual controversial article (Davies and Smith, 2006), and then a ‘reply’ article that is largely irrelevant to this study (Davies and Smith, 2007). Line 255, for example, cites 2 of these publications for a statement where there are several 10’s of other papers that are more relevant.

The work by G. Davies was largely based on the Cambrian hydrothermal dolomites in the Western Canada Sedimentary Basin (WCSB) – to which I was one of three Ph.D. studies that were conducted to dispel some of the myths perpetuated by this work. The authors should be aware that Koeshidayatullah et. al (2020a, 2020b) focus on a single outcrop in the WCSB – thus, it is maybe not the best reference to basin-scale, regional processes. Stacey et al. (2021 – GSA Bulletin; Fig. 9) present similar trends and correlations in the δ13C and δ18O data that the authors demonstrate here – however this study was also based on a single outcrop and the rest of the data was compiled from the literature (see works by V. Vandeginste). We published 5 papers from my Ph.D. research, focusing on more regional trends where we actually went and sampled each of these localities. I suggest that the authors read McCormick et al. (2023 – Basin Research; Fig. 9), where I show the exact same trends that the authors are presenting in this manuscript. Much of my other research has focused on this transition between this ‘Rd3 and Sd’ in zebra textures and dolomite breccias, which the author may choose to read at their own discretion. All the comments that I have provided on the manuscript are meant with good intentions and are provided to help bolster the author’s presentation of their work.

(1) Need to define “hydrothermal” dolomite at the beginning of the Introduction.

• I would suggest using the definition from Machel and Lonnee (2002), where you can also cite the Davies and Smith (2006) paper as most researchers in this field understand the discrepancy.

• Remove citations to Smith and Davies (2006) and Davies and Smith (2007) unless there are specific details from these papers that you want to present or discuss in this manuscript.

• Note that in is not always the case that HTD forms in “shallow-buried” strata. Every case study differs slightly, avoid such broad generalizations at the start of the manuscript without citations. The authors also do not define what “shallow” is. These definitions will differ within every subdiscipline of the geosciences.

Machel, H. G., & Lonnee, J. (2002). Hydrothermal dolomite—A product of poor definition and imagination. Sedimentary geology, 152(3-4), 163-171.

Davies, G. R., & Smith Jr, L. B. (2006). Structurally controlled hydrothermal dolomite reservoir facies: An overview. AAPG bulletin, 90(11), 1641-1690.

(2) I really like how the authors present a clear list (i to iv) at the end of the Introduction stating their research goals and objectives. However, a manuscript needs to present more than just a documentation of these aspects. What broader scientific problem are you trying to address, why has this not been studied before or why were previous studies insufficient, and what are the broader implications of your work? Why do these, very strong, observations matter? Both within the Sichuan Basin and worldwide?

(3) The authors use “replacive dolomite” and “dolomite cement” as their petrographical classifications. Both of these are interpretations, and thus, present some challenges in how the manuscript is presented. Almost every HTD paper nowadays refers to the grey, finely crystalline dolomites as “replacive” – this is somewhat common knowledge at this point, so I broadly agree that this is acceptable. However, it not necessarily a fact that all saddle dolomites are “cements” – these can also form through recrystallization and grain-boundary migration, as you demonstrate with your Rd3. Why not just call this ‘non-planar, saddle dolomite’ in the abstract, and use the abbreviation ‘Sd’ as you do throughout the manuscript? It is entirely valid if you want to interpret these as cements later on in the manuscript, but for observations, it would be best to use purely descriptive terms.

• Line 146.

• Note that you also describe Rd3 as a textbook non-planar, saddle dolomite in lines 164-168.

• Please simply use the term “zebra texture” in Line 170 and in the figure caption for Fig. 3.

(4) If there are any leftover powders, it would be excellent to include some XRD data in this manuscript. This is relatively straightforward data to collect and interpret. Thin-section confirmation of dolomite is a good start, but there is no way to know if these samples were contaminated with small amounts of calcite cements (or other diagenetic phases). For future studies, I would strongly suggest that the authors conduct XRD on all their powders before geochemical analyses.

(5) The authors do an excellent job of presenting their petrographical and geochemical results. These are concise and to the point, and easily understandable for the reader. Well done!

(6) The authors have collected both d18O ratios and fluid inclusion homogenization temperatures from the same samples. Clearly, they also need to calculate the d18O values of the diagenetic fluid! I would like to see a plot of the d18O(fluid) values for each of these locations as well. There are many many different isotopic fractionation equations – some are more relevant for low temperature and normal marine fluids, and others are more ideal for high temperatures. I would suggest using Horita (2014):

Horita, J. (2014). Oxygen and carbon isotope fractionation in the system dolomite–water–CO2 to elevated temperatures. Geochimica et Cosmochimica Acta, 129, 111-124.

(7) I would like to see the authors present a conventional “paragenetic sequence” type diagram as an added figure. These geological settings are quite complex, and much of this manuscript focuses on the Rd3 to Sd transition – but it would be useful to place these in context of all the other phases you have recognized.

(8) A major criticism I have is that the Discussion is quite limited. In my opinion, this needs to be much much more thorough, with further discussion of how these processes operate within the Sichuan Basin and then with a clear discussion of other sedimentary basins worldwide. In fact, there is almost no mention to other work on these systems elsewhere. Currently, the Discussion is ~3.5 pages – I would suggest taking these ideas much further and adding significantly more depth here. I have provided a few additional comments below that may help bolster these ideas.

(8a) Lines 324 to 327: Much of the discussion of the fluids up to this point has been local to each datatype, but there is a great opportunity to synthesize your ideas and present a little bit more rigor. I think the authors need to present some more rigorous discussion here of how these fluids are migrating and undergoing fluid-rock reactions. What are the temporal relationships here?

• First, it is incorrect that “The dolomitized fluids of Rd3 and Sd in NW Sichuan Basin are most likely coeval Permian seawater, which is characterized by relatively low temperature, low salinity, and low 87Sr/86Sr ratios.”. It is very likely that the fluids could be ‘derived‘ from seawater – but you still need to explain how the fluids got to 120C and ~8 wt% NaCl!

• I see how you are trying to frame this in the following section (5.3 Dolomitization mechanisms and implications for the ELIP control), but I do think some revisions are needed here. You are presenting these two models as either (A) hydrothermal fluids along faults or (B) thermal convection of seawater. The more realistic way to present these ideas is that it is a continuum between these endmembers, rather than an ‘either/or’ statement.

• Consider whether you are mixing two endmember fluids in this system, or if it is a single fluid that is evolving along a flow path through fluid-rock reactions. In either of these cases, how specifically do you interpret these processes to occur? What is the timeline of these events? Are the dolomites in the SW coeval to those in the NW? Or is there some variability in the timing of these reactions? In our U-Pb study from western Canada, we demonstrated that dolomite recrystallization proximal to the hydrothermal fluid source post-dated the more seawater-derived dolomitization distal to the hydrothermal fluid source.

(8b) I would like to see an additional section of the “Discussion” (after Line 374) that presents how these relationships within the Permian strata should influence how other researchers consider the dolomitization processes in the underlying strata? Should we also expect to see these regional trends in the underlying strata? There are many other HTD bodies of varying ages in the Sichuan Basin – which are almost always tied to the ELIP. Note that there are several U-Pb papers from this basin that have dated (U-Pb geochronology) the HTD bodies in the underlying strata. I would like to see a little bit more in the discussion about how these processes might impact others working on this basin, but with possible through the lens of ‘guidance for those working on other stratigraphic intervals’. Would you expect the Cambrian strata to have a more ‘hydrothermal fluid’ signature than the Permian strata? What of the dolomitization temperatures?

Jiang, H., et al. (2025). Rock-bufferred versus fluid-buffered geochemistry of structurally-controlled, hydrothermal dolomite bodies: Insights from the Sichuan Basin, China. Sedimentology.

Li, K. et al. (2023) A comparison of hydrothermal events and petroleum migration between Ediacaran and lower Cambrian carbonates, Central Sichuan Basin. Marine and Petroleum Geology.

Pan, L., et al. (2020) LA-ICP-MS U-Pb geochronology and clumped isotope constraints on the formation and evolution of an ancient dolomite reservoir: The Middle Permian of northwest Sichuan Basin (SW China). Sedimentary Geology.

Pan, L., et al. (2021) Diagenetic conditions and geodynamic setting of the middle Permian hydrothermal dolomites from southwest Sichuan Basin, SW China: Insights from in situ U–Pb carbonate geochronology and isotope geochemistry. Marine and Petroleum Geology.

Yang, T. et al. (2022) Fault-controlled hydrothermal dolomitization of Middle Permian in southeastern Sichuan Basin, SW China, and its temporal relationship with the Emeishan Large Igneous Province: New insights from multi-geochemical proxies and carbonate U–Pb dating. Sedimentary Geology.

Zou Y., et al. (2023). Carbonate U-Pb geochronology and clumped isotope constraints on the origin of hydrothermal dolomites: A case study in the Middle Permian Qixia Formation, Sichuan Basin, South China. Minerals.

(8c) Following this section of the Discussion, the authors should then discuss the relevance of their study to other sedimentary basins worldwide. I have provided some ideas and similarities to the HTD system we worked on in western Canada. There are also three authors on this manuscript that are very familiar with other examples of these HTD reactions in Europe, so it would be great to include some discussion here of how this case study compares to those from these other regions.

Figure 3: The inset diagrams are extremely small, especially when the authors are placing 3 of these SEM images side by side. I would suggest revising these figures to maybe show Fig. 3A-F as one figure, and then the SEM images as a separate figure. Make these images a bit larger and make sure that the text is legible.

Figure 5-7 (optional): Consider reversing the X-axis on the Th, salinity, and Sr isotope plots to show the “SW” datapoints towards the left, and the “NW” datapoints towards the right. This would result in more consistency with your d18O plot.

Reviewer #2: This manuscript presents a detailed petrographic and geochemical study of Middle Permian dolomites (specifically types Rd3 and Sd) from the Sichuan Basin, China. The authors aim to determine the origin of these dolomites and establish their relationship with the Emeishan Large Igneous Province (ELIP). Through an integrated analysis of core, outcrop, petrography, fluid inclusion microthermometry, and stable (C, O) and radiogenic (Sr) isotopes, the study concludes that the formation of these dolomites was directly controlled by the ELIP.

This is a well-researched and well-written paper that makes a valuable contribution to the understanding of large-scale dolomitization processes linked to igneous activity. The dataset is comprehensive, and the conclusions are well-supported by the evidence.

**********

what does this mean? ). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy

Reviewer #1: Yes:  Dr. C.A. McCormick

Reviewer #2: No

**********

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/ . PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org . Please note that Supporting Information files do not need this step.

Attachments

Attachment

Submitted filename: Reviewer Recommendation.docx

Origins of the hydrothermal dolomites in Middle Permian, Sichuan Basin (SW China): Implication for the relationship with the Emeishan Large Igneous Province

PONE-D-25-31227R1

I am pleased to inform you that your manuscript entitled “Origins of the hydrothermal dolomites in Middle Permian, Sichuan Basin (SW China): Implications for the relationship with the Emeishan Large Igneous Province” has been judged scientifically suitable for publication in PLOS ONE. It will be formally accepted once all outstanding technical requirements have been addressed.

During the proofing stage, please ensure the following:

1. Carefully check the spelling and grammar throughout the manuscript.
2. Review all figure captions for clarity and consistency — for example, revise Figure 8 to read:
   “Schematic model illustrating the dolomitization mechanism of the study area.”

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

An invoice will be generated when your article is formally accepted. Please note, if your institution has a publishing partnership with PLOS and your article meets the relevant criteria, all or part of your publication costs will be covered. Please make sure your user information is up-to-date by logging into Editorial Manager at Editorial Manager®  and clicking the ‘Update My Information' link at the top of the page. For questions related to billing, please contact billing support .

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Rizwan Sarwar Awan

Academic Editor

PLOS ONE