Mantle Magmatic Activity and Source Material Supply for the Jinchuan Cu–Ni Deposit in Northern China Revealed by Seismic Tomography

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors The article is quite interesting. It is devoted to the problem of the origin of one of the largest nickel-copper deposits in the world, Jinchuang, which, nevertheless, is enclosed in a very small intrusive. An extensive literature is devoted to this deposit, nevertheless, the authors have found their place with scientific novelty. The authors investigated the mantle-crustal processes that led to the formation of such a unique deposit. The authors used computed tomography, which is practically not used for such objects.

This is what made the article original. They found low- and high-velocity anomalies in the upper mantle and lower crust. Their main conclusion is valid: the functioning of the mantle plume, timed to the collapse of the Rodinia supercontinent, with the rise of residual mantle material and its interaction with the sublithospheric mantle, led to the formation of such an ore giant.

As a result, a gap has been filled in understanding the underlying causes of the formation of giant nickel-copper deposits in small intrusions such as Norilsk-Talnakh, among others.

Computed tomography cannot be trusted - it is not qualitative, but quantitative data. Therefore, the conclusions are consistent with the presented evidence and arguments, and answer the main question of the underlying causes of the formation of giant mineralization.
The first disadvantage of the article is that there is little information about the deposit itself - only general words and an incomplete summary of geochronological definitions. If the article is devoted to a deposit, it would be necessary to provide its geological scheme and characteristics using the latest publications.

There is no "Methodology" section in the article at all - this is unacceptable.
The conclusions of the article provide information only about various anomalies at depth under the deposit. And where is the model of its formation from the standpoint of geodynamics? This is the main response of the study and it should be the main one in the conclusions.
The references are mostly relevant, but one can only note that a third of the articles are in Chinese, which does not quite correspond to the international status of the journal. The list of references is poorly designed: abuse of capital letters. There is an opportunity to significantly improve the article.

Author Response

Dear Reviewer,

We sincerely thank you for your constructive and detailed comments on our manuscript. Your feedback has been very valuable for improving the quality and clarity of our paper. Below, we respond point-by-point to your concerns:

1. Comment:

“The article is quite interesting… The authors investigated the mantle-crustal processes … They used computed tomography … This is what made the article original.”

Response:

We thank the reviewer for recognizing the novelty and originality of our work and the application of computed tomography to this deposit. We appreciate your positive evaluation.

2. Comment:

“Their main conclusion is valid: … with the rise of residual mantle material and its interaction with the sublithospheric mantle …”

Response:

We are grateful for your support of our main conclusion and are pleased that you find our interpretation valid.

3. Comment:

“The first disadvantage of the article is that there is little information about the deposit itself … it would be necessary to provide its geological scheme and characteristics using the latest publications.”

Response:

We agree with the reviewer. In the revised version, we have added a detailed description of the Jinchuan deposit, including its Geological and Geophysic Setting, supported by the latest publications. We have also included a geological map and schematic cross-section (new Figure 2) to provide the reader with a clear understanding of the deposit.

4. Comment:

“There is no ‘Methodology’ section in the article at all – this is unacceptable.”

Response:

We fully agree. A comprehensive “Method” section has now been added to describe the dataset, analytical methods used in our study. This will help readers better understand our approach and ensure transparency of the results.

5. Comment:

“The conclusions … provide information only about various anomalies at depth … And where is the model of its formation from the standpoint of geodynamics?”

Response:

We appreciate this important suggestion. In the revised conclusions, we have emphasized the geodynamic model of deposit formation. Specifically, we now discuss how plume-related mantle upwelling, supercontinent breakup dynamics, and lithosphere-asthenosphere interactions contributed to the unique mineralization at Jinchuan. A conceptual model figure (we have improved Figure 11 ) has been added to illustrate these processes.

6. Comment:

“The references are mostly relevant, but one can only note that a third of the articles are in Chinese … The list of references is poorly designed …”

Response:

Thank you for pointing this out. We have revised the reference list carefully. The formatting has been standardized according to journal guidelines, and the misuse of capital letters has been corrected. Where possible, we have added additional international references to balance the proportion of Chinese-language sources, while still retaining key local studies that are essential for understanding the deposit.

Once again, we sincerely thank the reviewer for their valuable comments and constructive criticism. We believe that the revisions have significantly improved the clarity, completeness, and scientific contribution of the manuscript.

 

 

Respectfully,

Jianyu Zhao , Shigang Duan*, Rong Peng

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The present work studies the relationships between the magmatic activity of the mantle and Cu-Ni sulfide deposits in a region of China.

The way to consider it is through the tracking of P-waves achieved in seismic tomography studies.

The interest of the work, aside from the study through tomographic seismology, is to understand the richness of the sulfide intrusions in a little-studied area of China that is linked to magmatic intrusions.

The work is well-written with a presentation that is not very polished, which undervalues the interest of the work. Corrections that should be made:

Line 37. Insert a map of China with the mentioned location and its geological analysis.

Line 79. Explain what the study of P-waves signifies.

Figure 2. Insert a scale of the map.

Line 190. Place the location of the Baiyin ore district on a map.

Line 254. Indicate what LA/SM means.

The bibliography does not conform to the journal's standards.

 

additional comments

What is the main question addressed by the research? Explain the genesis of the deposit being studied and relate it to large-scale deep magmatic processes.

Do you consider the topic original or relevant to the field? Do you? It is original given the lack of knowledge about the area studied.

Does it address a specific gap in the field? Please also explain why this is/is not the case. The importance relates to the application of tomography to the study.

What does it contribute to the subject area compared to other published literature? The contribution relates to the description of the area, given the lack of knowledge about it. The bibliography is scarce, and the existing literature is in Chinese.

What specific improvements should the authors consider regarding the methodology? Line 79. Explain the meaning of P-wave analysis. Line 254. Indicate what LA/SM means.

Are the conclusions consistent with the evidence and arguments presented? And do they address the main question posed? Please also explain why this is/is not the case. They are consistent, although knowledge of certain analyses is assumed, but not provided.

Are the references appropriate? The bibliography does not comply with the journal's standards.

 Any additional comments on the tables and figures. Line 37. Insert a map of China with the mentioned location and its geological analysis. Figure 2. Insert map scale. Line 190. Plot the location of Baiyin ore district on a map.

Author Response

Dear Reviewer,

We would like to sincerely thank you for your valuable and constructive comments, which have helped us to substantially improve the quality of our manuscript. Below we provide detailed responses to each of your suggestions.

We greatly appreciate your recognition of the originality and relevance of our work, especially regarding the application of seismic tomography to study Cu–Ni sulfide deposits in China. We have carefully revised the manuscript to address all your concerns.

 

Comment (Line 37): Insert a map of China with the mentioned location and its geological analysis.

Response: We have added a new figure (Fig. 1) showing the location of the study area within China, together with a simplified geological map.

 

Comment (Line 79): Explain what the study of P-waves signifies.

Response: We have revised the text to include a clear explanation of the significance of P-wave tomography, emphasizing its ability to image velocity anomalies that reflect variations in lithology, temperature, and partial melt in the mantle.

 

Comment (Figure 2): Insert a scale of the map.

Response: We have added a scale bar to Figure 2 for clarity.

 

Comment (Line 190): Place the location of the Baiyin ore district on a map.

Response: We have marked the Baiyin ore district on the revised geological map (Fig. 5, Fig. 9 and Fig.10) for reference.

 

Comment (Line 254): Indicate what La/Sm means.

Response: La/Sm is the ratio of lanthanum (La) to samarium (Sm) among the rare earth elements, usually expressed as a chondrite-normalized value (La/SmN). This ratio effectively reflects the fractionation between light and middle rare earth elements. A high La/Sm typically indicates mantle plume activity or crustal contamination, which may contribute additional ore-forming materials, whereas a low La/Sm generally reflects a depleted mantle source, related to oceanic-type or mantle-derived melts. In this study, we apply previously reported La/Sm parameters of the Jinchuan deposit to demonstrate that the ore-forming material of the Jinchuan deposit is genetically linked to mantle plume processes.

 

Comment: The bibliography does not conform to the journal’s standards.

Response: We have reformatted all references according to the journal’s guidelines and corrected the capitalization issues.

 

Additional Reviewer Questions

Q1: What is the main question addressed by the research?

A: The main question is to explain the genesis of the Jinchuan deposit and relate it to large-scale deep magmatic processes linked to mantle plume activity during the breakup of Rodinia.

 

Q2: Does the study address a specific gap in the field?

A: Yes. The application of seismic tomography to investigate ore-forming processes is rare, and our study fills a significant gap by providing new insights into the deep geodynamic setting of Cu–Ni sulfide deposits in small intrusions.

 

Q3: Are the conclusions consistent with the evidence?

A: Yes. The revised conclusions are consistent with the tomographic results and geodynamic interpretation.

 

Q4: Any additional improvements?

A: We have polished the language, improved the presentation of figures, and clarified the methodology. These revisions enhance the clarity and readability of the manuscript.

 

We sincerely appreciate your constructive comments, which have significantly improved our manuscript. We hope the revised version meets the journal’s standards.

 

 

Sincerely,

Jianyu Zhao , Shigang Duan, Rong Peng

 

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Comments to article

The article is very interesting and valuable. However, it should be modified and supplemented with some data to be more clear and completed.

1. 2 – Lack of scale bar on the map
2. Lack of chapters of the ‘Geographical location of the study area’ and ‘Materials and Methods’.
3. There is no information about the type of magmatic deposit that is the subject of this article. What type of deposit is this? Is it an igneous, syenite, diorite, or gabbroic intrusion? Mineralization can occur in various types of igneous intrusions. This information is not provided in the introduction, which is very general and does not provide the reader with a clear understanding of the deposit type and its structure. Moreover there are no chapters ‘Geographical location of the study area’ and ‘Materials and Methods’ in which these information could be placed. The Authors write only about deposit which ‘is characterized by its small-sized intrusions, large metal reserves, high ore grades, and high mineralization efficiency’. The only information about the type of intrusion appears in the 'Discussion' section in Figure 9, where ‘Gabbro stratum, Ultramafic cumulate and Continental food basalt’ were mentioned.
4. Figures 1, 4, 5, 6 and 7, 8 were probably made by Authors, however there is no information how they were prepared. The method of figures preparing including type of equipment and software should be placed in ‘Methods’ chapter.
5. Chapters: ‘2. P-wave seismic tomography’ and ‘3. The process of mantle magma activity’ include the results of Authors research. So this chapters should be called 'Results' and the chapters 2 and 3 should be marked as subsections. Moreover, Figures 1, 4, 5, 6 and 7, 8 were probably made by Authors, so that they should be placed in ‘Results’ chapter.
6. The 'Discussion' section is very general, containing rather general information and citing figure taken from the reference. In this section, the Authors should present a discussion of their own research results and, based on them, present a view on the relationship between mantle magmatic activity and the supply of source material for the Jinchuan Cu-Ni deposit. They should prepared their own figure presented their theory on the relationship between mantle magmatic activity and the supply of source material.
7. The 'Conclusions' section is also very general. Only information on the identified anomalies is presented. There is no conclusion on the relationship between these anomalies and the impact of magmatic activity on the supply of source material for the Cu-Ni deposit.

In conclusion, the article is worth of publication, but should be reorganized and supplemented with some chapters and data, especially type of magmatic intrusion. It needs major correction to be completed.

Comments for author File: Comments.pdf

Author Response

Dear Reviewer,

We sincerely thank you for your constructive and valuable comments on our manuscript. Your suggestions have greatly helped us to improve the quality and clarity of our work. We have carefully revised the manuscript according to your comments, and our detailed responses are as follows:

Comment 1: Lack of scale bar on the map.
Response: We appreciate your suggestion. We have added scale bars to all relevant maps (Figures 1, 4, 5, 6, 7, and 8) to improve clarity and readability.

Comment 2: Lack of chapters ‘Geographical location of the study area’ and ‘Materials and Methods’.
Response: Thank you for pointing this out. We have added a new chapter entitled “Geological and Geophysic Setting” to describe the regional geological background and location of the Jinchuan deposit. In addition, we added a “Methods” chapter, where we describe the seismic tomography dataset, processing methods, and figure preparation process.

Comment 3: Lack of information about the type of magmatic deposit.
Response: We agree with your suggestion. In the new chapter entitled Geological and Geophysic Setting, we clearly state that the Jinchuan Cu-Ni sulfide deposit is hosted in a small-sized ultramafic-mafic intrusion, mainly composed of gabbro, pyroxenite, and ultramafic cumulates. This information helps clarify the geological setting and mineralization type.

Comment 4: Figures 1, 4, 5, 6, 7, and 8 lack methodological information.
Response: Thank you for highlighting this point. We have revised the Materials and Methods section to include details on how these figures were generated, including the data source, software (GMT and CorelDraw), and processing steps. This ensures transparency and reproducibility.

Comment 5: Chapters ‘2. P-wave seismic tomography’ and ‘3. The process of mantle magma activity’ should be reorganized as ‘Results’.
Response: We agree. We have reorganized the manuscript structure. These two sections have now been included in a new chapter entitled “Results”, with subsections (2.1 P-wave seismic tomography, 2.2 Mantle magmatic processes). Figures 1, 4, 5, 6, 7, and 8 have also been moved to this Results section.

Comment 6: The ‘Discussion’ section is too general and should focus on the relationship between mantle magmatic activity and source material supply.
Response: Thank you for this valuable suggestion. We have significantly revised the Discussion section. Based on our tomographic results, we now discuss in detail the link between deep mantle anomalies, magmatic upwelling, and the supply of ore-forming materials to the Jinchuan Cu-Ni deposit. Furthermore, we have prepared a new figure (Figure 11 in the revised version), which illustrates our proposed genetic model and the relationship between mantle magmatic activity and source material supply.

 

Comment 7: The ‘Conclusions’ section is too general.
Response: We agree and have rewritten the Conclusions. The revised version now explicitly highlights: (1) the identified mantle anomalies, (2) their implications for magmatic processes, and (3) how these processes supplied ore-forming materials for the Jinchuan deposit.

We appreciate your valuable comments. The manuscript has been reorganized and substantially improved according to your advice. We believe these changes enhance the scientific quality and clarity of our paper.

 

Sincerely,
Jianyu Zhao , Shigang Duan, Rong Peng

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

Review of the manuscript titled “Relationship between Mantle Magmatic Activity and the Source Material Supply for the Jinchuan Cu-Ni Deposit” submitted to the Journal “Applied Science”.

- Title: Highlight “Northern China” which is the deposit location, and Highlight the use of “3D seismic imaging method”.

- Lines 18-19: This sentence “In this study, we utilize P-wave velocity structure imaging… across the North China region” should be revised.

- According to journal guidelines, the abstract should be a single paragraph with a total of about 200 words maximum, which is not respected in the case of this manuscript.

- It is requested to follow the article structure as defined by the journal in “Instructions for Authors” (Abstract, Keywords, Introduction, Materials and Methods, Results, Discussion, and Conclusions sections.)

- The section “2. P-wave seismic tomography” can be devoted to present a literature of review about P-wave seismic tomography, anterior studies…, and do not include the main results.

- A map (satellite, topographic,…) highlighting the location of the study area is required.

- It is recommended to separate the methodology from results, into two distinctive sections.

- More details about the seismic tomography (methodology, mathematical formula, materials used…) are needed.

- Lines 82-83: reformulate the sentence “The imaging results are show… velocity seismic tomography”. It is inaccurate.

- More interpretation of Figure 1 is needed.

- The map (Figure 2) is missing a scale.

- Identify the Jianchuan deposit on the map (Figure 2).

- Map (Figure 3) is missing a scale, north arrow and legend.

- Highlight the seismic tomography sections in Figures 5 and 6 on the previous maps (Figure 4).

Author Response

Dear Reviewer,

We sincerely thank you for your careful reading of our manuscript and for your valuable comments. We have carefully revised the manuscript according to your suggestions. Below, we provide a detailed point-by-point response.

Comment 1: Title: Highlight “Northern China” which is the deposit location, and Highlight the use of “3D seismic imaging method”.
Response: Thank you for the suggestion. We have revised the title to: “Mantle Magmatic Activity and Source Material Supply for theJinchuan Cu-Ni Deposit in Northern China Revealed by Seismic Tomography. ”

Comment 2: Lines 18-19: This sentence “In this study, we utilize P-wave velocity structure imaging… across the North China region” should be revised.
Response: We revised the sentence to improve clarity:
“Using P-wave seismic tomography, we imaged the crust and mantle beneath the Qi-lian–Longshoushan area, revealing a deep low-velocity anomaly at ~400 km depth, in-terpreted as residual mantle plume material.”

Comment 3: Abstract length exceeds 200 words and should be a single paragraph.
Response: We have rewritten the abstract to a single paragraph with fewer than 200 words, in accordance with the journal’s guidelines.

Comment 4: Follow the article structure as defined by the journal (Abstract, Keywords, Introduction, Materials and Methods, Results, Discussion, and Conclusions).
Response: The manuscript has been reorganized to fully follow the required structure.

Comment 5: Section “2. P-wave seismic tomography” should be a literature review, not contain main results.
Response: We have revised Section 3 to include a review of previous studies on P-wave seismic tomography. The main results have been moved to the “Results” section.

Comment 6: A map (satellite, topographic, etc.) highlighting the location of the study area is required.
Response: We have added a satellite-based map (Figure 1) to clearly show the location of the Jinchuan Cu-Ni deposit.

Comment 7: Methodology and results should be separated into two distinct sections.
Response: The manuscript has been revised to separate methodology and results into two independent sections.

Comment 8: More details about seismic tomography (methodology, mathematical formulas, materials used, etc.) are needed.
Response: We have expanded the “Methods” section to include detailed descriptions of the seismic tomography method, data sources.

Comment 9: Lines 82-83: reformulate the sentence “The imaging results are show… velocity seismic tomography”.
Response: We corrected the sentence to:
“Through the inversion, 11 P-wave velocity tomographic images at different depths were obtained (Figure 4 and Figure 6), providing important insights into the litho-sphere–asthenosphere structure and the processes of deep material migration.”

Comment 10: More interpretation of Figure 1 is needed.
Response: We have expanded the description and interpretation of Figure 4 (the original Figure 1) in the revised manuscript, explaining its geological significance in more detail.

Comment 11: The map (Figure 2) is missing a scale.
Response: We have added a scale bar to Figure 3 (the original Figure 2).

Comment 12: Identify the Jinchuan deposit on the map (Figure 2).
Response: The Jinchuan deposit has now been marked and labeled in Figure 3 (the original Figure 2).

Comment 13: Map (Figure 3) is missing a scale, north arrow, and legend.
Response: We have revised Figure 5 (the original Figure 3) to include a scale bar, north arrow, and legend.

Comment 14: Highlight the seismic tomography sections in Figures 5 and 6 on the previous maps (Figure 4).
Response: We have updated Figures 4 and 6 (the original Figures 1 and 4) to highlight the positions of the tomography profiles shown in Figures 7 and 8 (the original Figures 5 and 6).

 

We thank the reviewer again for their constructive suggestions, which have helped us improve the clarity, structure, and quality of our manuscript.

Sincerely,
Jianyu Zhao , Shigang Duan, Rong Peng

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors mostly took into account the comments, which greatly benefited the article. I would like to wish that Figure 2 was made in color. There are problems with the reference list: names in capital letters and names without abbreviations.

Author Response

Dear Reviewer,

We sincerely thank you for your constructive comments, which have greatly helped us improve the manuscript.

Regarding Figure 2, we have revised it and presented it in color to the greatest extent possible, while ensuring that the figure remains clear, scientifically accurate, and suitable for both online and print formats. We believe the revised figure more effectively conveys the intended information.

As for the reference list, we have carefully checked and corrected the formatting issues, including the capitalization of author names and the use of abbreviations. The references now follow the journal’s style requirements.

We greatly appreciate your valuable suggestions and your recognition of our work.

Sincerely,

Jianyu Zhao , Shigang Duan  , Rong Peng

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have collected suggestions that have improved the paper.

Author Response

Dear Reviewer,

We sincerely thank the reviewer for the positive evaluation in the second round. We are glad that the revisions have improved the quality of our manuscript. In this revision process, we carefully considered and incorporated the reviewer’s suggestions, which significantly enhanced the clarity and overall quality of the paper.

We greatly appreciate the reviewer’s valuable input and time dedicated to improving our work during the review process.

Sincerely,

Jianyu Zhao , Shigang Duan, Rong Peng

Reviewer 3 Report

Comments and Suggestions for Authors

Comments:

The manuscript has been vastly improved by the revisions.

The Authors have reorganized the manuscript structure. These two sections have now been included in a new chapter entitled “Results”, with subsections (2.1 P-wave seismic tomography, 2.2 Mantle magmatic processes). Figures 1, 4, 5, 6, 7, and 8 have also been moved to this Results section.

In addition, the Discussion and Conclusions chapters have been supplemented.

In its current form, the article is suitable for publication.

Comments for author File: Comments.pdf

Author Response

Dear Reviewer,

We sincerely thank you for your careful evaluation of our manuscript and for your positive comments regarding the revisions. We are pleased that the reorganization of the manuscript structure, the inclusion of new subsections in the “Results” chapter, and the supplementation of the Discussion and Conclusions sections have improved the quality of the paper.

We greatly appreciate your recognition and encouragement, and we are glad that the manuscript is now considered suitable for publication.

Sincerely,

Jianyu Zhao , Shigang Duan  , Rong Peng

Reviewer 4 Report

Comments and Suggestions for Authors

I would like to congratulate the authors on the revisions they have made, which have significantly improved the quality of the manuscript. However, the quality of some Figures (e.g., 2, 3, 5, 11) should be improved. For example, the content of Figure 11 is illegible and unreadable.

- Many of the references used are very old. Update your references. I suggest this recent paper related to seismic investigation: https://doi.org/10.62593/2090-2468.1044 

Author Response

Dear Reviewer,

We sincerely thank you for your constructive comments, which have greatly helped us improve the manuscript.

Regarding the figures, we have enriched Figures 2, 11, and others with additional details to improve clarity. Specifically for Figure 11, the figure is intended to highlight the evolution of the mantle plume after supplying ore-forming materials. Due to subsequent tectonic evolution, the original mantle plume has partly collapsed, leaving behind the low-velocity anomaly observed in deep seismic tomography. Moreover, compression of the lithospheric mantle has caused the original magma conduits to disappear. We believe the revised figure now better conveys these processes and their significance.

Concerning the references, we have carefully updated the reference list, adding more recent studies on seismic tomography and mantle plume imaging, while maintaining scientific relevance to our work. We have also studied the paper you kindly suggested. However, as its focus on specific methodologies differs from our study, we have not cited it directly, though we have incorporated the relevant insights into our discussion.

We greatly appreciate your careful review and valuable suggestions, which have significantly improved the clarity and completeness of our manuscript.

Sincerely,

Jianyu Zhao , Shigang Duan  , Rong Peng