Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This manuscript entitled “Timing of ore mineralisation in deposits of the Baikal-Muya belt and the Barguzin-Vitim super-terrain (Transbaikalie)” aims at dating of Au ores from the Yubileinoe, Irokinda and Uryakh deposits located in the Baikal-Muya fold belt and Pb-Zn ores from the Ozernoe deposit in the Barguzin-Vitim super-terrain, Transbaikalia, Russia.

Four deposits located in different terrains in the wider area of the Early Carboniferous-Early Permian Angara-Vitim batholith have been studied by 40Ar/39Ar dating of pyrite-encapsulated sericite.

It is an interesting short paper that falls within the aims and the scope of the journal.

However, there are some issues to be addressed.

Authors should demonstrate that the samples studied (only one from each deposit? (Line 220)) are representative of the respective mineralizations. I would also expect the inclusion of additional data to support a more robust conclusion, rather than relying on a 'working hypothesis' (line 270)

The size of the Figures 2, 5, 7, 9, 10, 13 and 14 can be reduced.

Author Response

Comment 1. Authors should demonstrate that the samples studied (only one from each deposit? (Line 220)) are representative of the respective mineralizations. I would also expect the inclusion of additional data to support a more robust conclusion, rather than relying on a 'working hypothesis' (line 270).

Reply 1. Samples for dating were not randomly collected samples, they belong to particular stage of mineralization and thus represent age of this stage. All ages obtained for dissiminated mineralisation are older and all ages obtained for vein-type mineralisation are younger. We extended discussion on this topic. We also extended discussion of our 'working hypothesis'.

Comment 2. The size of the Figures 2, 5, 7, 9, 10, 13 and 14 can be reduced.

Reply 2. The size of the figures is reduced.

Reviewer 2 Report

Comments and Suggestions for Authors

Dear authors,

Here is my review of the Manuscript ID: minerals-3268944, entitled “Timing of ore mineralization in deposits of the Baikal-Muya belt and the Barguzin-Vitim super-terrain (Transbaikalie) by Vadim A. Vanin et al.

The subject of this paper is the presentation of new results of ⁴⁰Ar/³⁹Ar dating of pyrite separates from quartz veins encapsulated sericite from three deposits in the Baikal-Muya Belt (BMB) and one deposit in the Barguzin-Vitim super-territory of the Central Asian Orogenic Belt (CAOB) and a review of available geochronological data for other deposits located in a spatial association with the Early Carboniferous-Early Permian Angara-Vitim batholith. These authors concluded that the studied deposits were formed during two stages, in contrast to the gold deposits located to the northern and southern parts, which were formed in the Silurian-Early Carboniferous and Jurassic-Early Cretaceous, respectively. In my opinion it can be published in the Mineral Deposits journal after major revision.

Comments to authors

2. Geological characteristics of the deposits, line 75:

I suggest separating the mineralogical from geological characteristics.

Table 1: I think that this table can be more informative, providing more characteristics of the Transbaikalian deposits, as they are described; for example, the mineralogy in mineralized veins.

Discussion, Lines 279-282:  The processes associated with the formation of granitoids provided a source of heat and possibly fluids for the mineral genesis system. However, the source of gold was within the host rocks [24], as established, for example, by Pb isotopic studies of ores from the Mukodek ore field [31].

Please, re-write and give your opinion regarding the appearing carbonate and marble as host rocks (Table 1)

In general, in the section of the discussion the arguments for the proposed interpretation of the results (Lines 267-279) are missing. Also, the published data (geochronological, mineralogical and geochemical data) on Transbaikalian deposits should be discussed, such as in the cited reference by Litvinovsky et al., [No 7] on the Origin and evolution of overlapping calc-alkaline and alkaline magmas: The Late Palaeozoic post-collisional igneous province of Transbaikalia (Russia) (Table 1).

 Please, check again the Figures, some references are cited only for a few in figures, but in others a reference is missing, for example Figure 2, Figure 5, Figure 7. ………

Figure 4. Examples of pyrites of the second generation from different ores of the Yubileinoe deposit: Please, re-write and describe clearly Fig. 4a and Fig. 4b.

The highlights are missing. Please, add highlights to the revised paper.

Best wishes

Comments on the Quality of English Language

English Language can be improved

Author Response

Comment 1. Geological characteristics of the deposits, line 75: I suggest separating the mineralogical from geological characteristics.

Reply 1. Another reviewer also had question to this description in annotated pdf file. So, we rephrased this part.

Comment 2. Table 1: I think that this table can be more informative, providing more characteristics of the Transbaikalian deposits, as they are described; for example, the mineralogy in mineralized veins.

Reply 2. We added tonnage of minerals and mineral assemblages.  

Comment 3. Discussion, Lines 279-282:  The processes associated with the formation of granitoids provided a source of heat and possibly fluids for the mineral genesis system. However, the source of gold was within the host rocks [24], as established, for example, by Pb isotopic studies of ores from the Mukodek ore field [31].

Please, re-write and give your opinion regarding the appearing carbonate and marble as host rocks (Table 1)

Reply 3. Marbles were erroneously mentioned as host  rocks for Irokinda in Table 1. We removed this. Carbonates are only significant in one deposit - Uryakh, which has the lowest gold resources. Probably the presence of interlayered terrigenous (gold-bearing) and carbonate (gold-free) rocks was the reason for the low tonnage. We have included it in the discussion.

Comment 4. In general, in the section of the discussion the arguments for the proposed interpretation of the results (Lines 267-279) are missing. Also, the published data (geochronological, mineralogical and geochemical data) on Transbaikalian deposits should be discussed, such as in the cited reference by Litvinovsky et al., [No 7] on the Origin and evolution of overlapping calc-alkaline and alkaline magmas: The Late Palaeozoic post-collisional igneous province of Transbaikalia (Russia) (Table 1).

Reply 4. We added into discussion more extended description of the Angara-Vitim batholoith based on Litvinovsky et al.

Comment 5. Please, check again the Figures, some references are cited only for a few in figures, but in others a reference is missing, for example Figure 2, Figure 5, Figure 7. ………

Reply 5. We added references to the figures.

Comment 6. Figure 4. Examples of pyrites of the second generation from different ores of the Yubileinoe deposit: Please, re-write and describe clearly Fig. 4a and Fig. 4b. 

Reply 6. Fig 4a and 4 b represent two ore types. You were right that Fig. a show rounded pyrite of the first generation, whereas Fig. b shows rectangular pyrite of second generation. Corrected in the figure and in the text. 

Comment 7. The highlights are missing. Please, add highlights to the revised paper.

Reply 7. Highlights are added.  

Reviewer 3 Report

Comments and Suggestions for Authors

This manuscript gives a comprehensive dating work for the deposits in far east Russia. Most data are reliable and have high quarlity, although some of the age have large error. There are some major comments here for consideration:

(1) There is a lack of introduction on the geological background.

(2) More information should be presented in the Figure 1, such as the lithologies in the figure and main economic metals of each deposit. Where is  the ore body in Figure 2?

(3) It is recommended that change "vein-like ore" to "disseminated ores" for clearity.

(4) It is very likely that the vein type ore formed coeval with the disseminated ores, as seen in most orogenic rocks, although analytical results give different ages. 

(5) The ore-forming model proposed by the authors is not conclusive. What kind of batholith underwent such long cooling time? Additionally, the nature of the batholith and the exsolved fluid need more research as different metals are associated with various type of magma fertility.

(6) The language of the manuscript should be well polished by a native expert.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

This manuscript gives a comprehensive dating work for the deposits in far east Russia. Most data are reliable and have high quarlity, although some of the age have large error. This manuscript presented a review of the age data for these deposits and proposed a two stage model for the mineralization. But the evidence for the two stage model is not so compelling.More geological information, like the fluid property, may be useful in discussion. Moreover, the language of the manuscript should be well polished by a native expert.

Major comments are as follow:

(1) Introduction to the geological background is not enough.

(2) There are some mistakes of spelling in Figure 1 and confusive words in Figure 9. You should mark the metal assemblages of each deposits in Figure 1.

(3) Why do you think the Angara-Vitim granite batholith provide fluid and metal for gold and Pb-Zn mineralization? It is very weird that one batholith is responsible for different types of mineralization? $0 million years of hydrothermal activity is also impossible.

(4) It is suggested that "Veinlet-disseminated" ores should be named as "isseminated" ores for clarity.

(5)  The language of the manuscript should be well polished by a native expert.

(6) Other comments are listed in the noted PDF file.

 Thus, I would recommend a moderate revision for the manuscript. 

Author Response

Comment 1. Introduction to the geological background is not enough.

Reply 2. We added tonnage as the reviewer requested.

Comment 2. There are some mistakes of spelling in Figure 1 and confusive words in Figure 9. You should mark the metal assemblages of each deposits in Figure 1.

Reply 2. We examined Figure 1 for the spelling mistakes and do not see any. Probably the reviewer means names of some deposits. We will appreciate if he or she will name the spelling mistakes. Russian names can be (and were) translated differently in various sources. We also examined other figures and corrected typos. 

Comment 3. Why do you think the Angara-Vitim granite batholith provide fluid and metal for gold and Pb-Zn mineralization? It is very weird that one batholith is responsible for different types of mineralization? $0 million years of hydrothermal activity is also impossible.

Reply 3. We do not suggest that the Angara-Vitim granite batholith provide metal, we suggest that  (citation from our text) "The processes associated with the formation of granitoids provided a source of heat and possibly fluids for the mineral genesis system. However, the source of gold was within the host rocks." We do not say that the batholith was one event that provided heat for duration of 40 million years (if $ in the comment was a typos for 4). The Angara-Vitim batholith is a historical name for various granites that emplaced between about 320 and 280 million years ago. Clarification on this topic is added to Discussion.

 

Comment 4. It is suggested that "Veinlet-disseminated" ores should be named as "disseminated" ores for clarity.

Reply 4. Done. Changed to disseminated.

 

Comment 5.  The language of the manuscript should be well polished by a native expert.

Reply 5. We submitted the manuscript to professional English-editing service.

 

Comment 6. Other comments are listed in the noted PDF file.

Reply 6. We made changes accordingly.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Authors have addressed my comments and suggestions.

 

Author Response

Comment 1. Authors have addressed my comments and suggestions.

Reply 1. Thank you for your efforts. 

Reviewer 2 Report

Comments and Suggestions for Authors

Dear authors,

The revised Manuscript ID: minerals-3268944, entitled “Timing of ore mineralization in deposits of the Baikal-Muya belt and the Barguzin-Vitim super-terrain (Transbaikalie) by Vadim A. Vanin et al., was substantially improved. However, please check again the sections of geological and Mineralogical characteristics, because there is a gap between No 1 and No 3 sections.

Kind regards

Author Response

Comment 1. The revised Manuscript ID: minerals-3268944, entitled “Timing of ore mineralization in deposits of the Baikal-Muya belt and the Barguzin-Vitim super-terrain (Transbaikalie) by Vadim A. Vanin et al., was substantially improved. However, please check again the sections of geological and Mineralogical characteristics, because there is a gap between No 1 and No 3 sections.

 

Reply 1. Thank you for this. Two paragraphs were missing there. We corrected this mistake and also went through the text again using Deep L artificial inteligence English editing.