Review Reports

Round 1

Reviewer 1 Report

The manuscript entitled " Parameters for the formation of the Dobroe gold deposit (Yenisei ridge, Russia): evidences from fluid inclusions and S–C- isotopes" is studied. The Dobroe deposit with 10 t gold reserves is one of the gold mines located within Yenisei Ridge Orogenic Belt. The authors stated that the Dobroe gold deposit was formed by water–carbon dioxide and carbon dioxide–hydrocarbon fluids in the temperature range from 180 to 360 °C, pressure – from 0.8 to 1.3 kbar and salinity from 1.5 to 15.0 wt. % (NaCl – equiv.). They used gas chromatography–mass spectrometry techniques for analyzing fluids. It is showed that ore–forming fluids consist of H₂O, CO₂, N–, S–, Cl–compounds and hydrocarbons, which are potentially capable of transporting ore elements. They concluded that total content of hydrocarbons in the fluids of the Dobroe deposit is less than in the fluids of large gold deposits and this is an important factor of determining of the scale of the ore deposit.

It is not clear that how hydrocarbon compounds can affect the scale of mineralization? There isn’t meaningful difference between ore forming fluids in gold bearing zone and fluids in barren zone. How it could be interpreted?

The manuscript revealed many data on the formation of the Dobroe gold deposit, Russia, and can be attractive and interesting for many readers of Minerals. So, I can suggest the manuscript to be published after some modification that are suggested in attached pdf file and attention to the comments at the end of this letter.

 Comments:

1.      Page 2, line 55-56, the problem to be solved by this research is not well defined. Please, explain the problem more specifically.

2.      Page 3, Fig1a, the location of the deposit is not clear by arrow. It is better to show it more precisely.

3.      Figs 1b and 1c are transposed. Actually, fig.1b is the geological map.

4.      Fig. 1, the size of symbols in the legend and those that are used in the map should be the same, but in cases of 14 and 15 are not the same size.

5.      Fig. 1, where is the position of this fig.1c in the fig.1b? Why the color of RF2gr here is different with that of fig. 1b?

6.      Page 8, Table 1, all abbreviation used in the Table 1 should be explained at the bottom of the Table, such as Th, Teut and so on.

7.      Page 11, Fig. 6, please, use similar term for FIs. What do you mean with two phase FIs? Is it type A FIs?

8.      Page 16, line 454, it is not clear that how hydrocarbon compounds can affect the scale of mineralization?

9.      On the basis of Figs. 7 and 8 and related data, there isn’t meaningful difference between ore forming fluids in gold bearing zone and fluids in barren zone. How it could be interpreted?

 

Comments for author File: Comments.pdf

Author Response

Dear Reviewer, 

The authors of the manuscript “Parameters for the formation of the Dobroe gold deposit (Yenisei ridge, Russia): evidences from fluid inclusions and S–C isotopes” would like to thank you for careful reading of the work and valuable comments. We have tried to take all of them into account during the manuscript revision in order to improve the article.   

Please find our responses to your comments in the file enclosed.

Best regards,

Elena Shaparenko

Author Response File: Author Response.pdf

Reviewer 2 Report

Dear authors,

FI part of your manuscript needs to be re-written. I also sent my comments.

Best

Comments for author File: Comments.pdf

Author Response

Dear Reviewer,

The authors of the manuscript “Parameters for the formation of the Dobroe gold deposit (Yenisei ridge, Russia): evidences from fluid inclusions and S–C isotopes” would like to thank you for careful reading of the work and valuable comments. We have tried to take all of them into account during the manuscript revision in order to improve the article.   

Please find our responses to your comments in the file enclosed.

Best regards,

Elena Shaparenko

Author Response File: Author Response.pdf

Reviewer 3 Report

This manuscript Shaparenko E. et al. “Parameters for the formation of the Dobroe gold deposit (Yenisei ridge, Russia): evidences from fluid inclusions and S–C isotopes) are is the result of careful research of fluid inclusions by traditional hermobarogeochemical methods (Homogenization temperatures, salinity and pressure of fluids) including less used Raman Spectroscopy and and GC–MS analysis. Summary of fluid inclusion microtermometric data for typical Gold–bearing zone and Barren zone is considered in the paper. Of cause, results on geological setting, mineral assemblages, and quartz types are described. Composition of fluid inclusions in quartz is confirmed by statistically significant data that permit the role of CH4 and N2 in ore forming process. The author try to use for grnetic model the contents (rel.%) and numbers (in parentheses) of volatiles extracted by mechanical shock destruction of minerals from the Dobroe deposit (according to GC–MS) are presented in the paper. Carbon isotopic composition (δ13C) of carbon dioxide in fluid inclusions and Sulfur isotopic composition of sulfides The paper is really successful for finding principally new knowledge because one of the main approaches to the study of the gold deposit because of original approach. Moreover, this authors display new criteria to distinquish god deposits with small and huge resources. F.e. “Water–carbon dioxide (A) inclusions from the barren and ore zones are dominated by CO2, while carbon dioxide–hydrocarbon type (B) inclusions are dominated by CH4. The total content of hydrocarbons in the fluids of the Dobroe deposit is significantly (from 7 to 11 times) less than in the fluids of large (Au>100 t) gold deposits.

This manuscript is a well written, illustrated and insightful review that provides condition for a development of theory of ore forming processes, in general. However I have main comments. I hope these comments could be useful to improve this nice manuscript.

Line 25-30Gold has always played …producing gold (331 t in 2021) [2]

Reviewer: This well known data is not related to main topic of the paper can be easily deleted.

Line 31 – 59. In Introduction,

Reviewer: The magmatic and sedimentary metamorphic models should be explained carefully by comparison of arguments. What similar or same methods were previously used to resolve the key genetic problem. Please, complete manuscript by recent world wide references discussed this problem.

Line 97-98 Fig.1

Reviewer: I am afraid, the shrift in the maps is to small. Please, increase it for pleasure of the readers.  

Line 135 – 137. Fig.

Reviewer: Please, increase the size of the photos

Line 295. Table 1. Summary of fluid inclusion microthetrmetric data from the Blagodatnoye gold deposit.

Reviewer: “microthetrmetric” or microtermometric?

Line 527 – 528. The range of δ34S variations in pyrite significantly expands – from +3.2 to +17 ‰.

Reviewer: Could be this data interpreted an as ground seawater influence?

In my opinion, the manuscript can be considered as an original paper with excellent data for fluid inclusions in quartz of the gold deposit. The theoretical model should be more argued. I think, the manuscript can be accepted with minor revisions of genetic model in the Minerals.

 

Author Response

Dear Reviewer,

The authors of the manuscript “Parameters for the formation of the Dobroe gold deposit (Yenisei ridge, Russia): evidences from fluid inclusions and S–C isotopes” would like to thank you for careful reading of the work and valuable comments. We have tried to take all of them into account during the manuscript revision in order to improve the article.   

Please find our responses to your comments in the file enclosed.

Best regards,

Elena Shaparenko

Author Response File: Author Response.pdf

Reviewer 4 Report

Major revisions:

1. The strata in the gold orefield are not mentioned in the text. Please add. And the host rocks of the gold orebodies should be given.

2.The mineralization stages in the gold mineralization should be divided. The studied quartz samples belongs to which mineralization stage?

3.Adivse to add some photographs for the gold ores with two types of quartz. Please illustrate which type of quartz is close to gold mineralization or both.

4. The mineralogy of quartz 1 and 2 is better to be shown in the Part 2” Samples and methods”

5. The formulas for the salinity and fluid pressure calculations should be given.

6. The homogenization temperatures, salinity and pressure of secondary fluid inclusions can not represent the property of the ore-forming fluids.

7. The gas phase of 48 individual inclusions in quartz, the individual inclusions mean primary inclusions or secondary fluid inclusions.

 

Minor revisions:

Several revisions have given in the revised manuscript.

Comments for author File: Comments.pdf

Author Response

Dear Reviewer,

The authors of the manuscript “Parameters for the formation of the Dobroe gold deposit (Yenisei ridge, Russia): evidences from fluid inclusions and S–C isotopes” would like to thank you for careful reading of the work and valuable comments. We have tried to take all of them into account during the manuscript revision in order to improve the article.   

Please find our responses to your comments in the file enclosed.

Best regards,

Elena Shaparenko

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Dear authors,

Thanks for the revised manuscript. 

All the best