The Carbonate-Hosted Tullacondra Cu-Ag Deposit, Mallow, Ireland

Round 1

Reviewer 1 Report

The article presents the results of geochemical-mineralogical and geological-prospecting  studies within the carbonate-hosted Tullacondra Cu-Ag deposit in Irish Midland. It contains an interesting description of ore mineralization. The issue may be of interest to researchers dealing with sediment hosted deposits. The article, however, requires minor corrections and additions. The following notes that require adjustment are listed below.

• In the Geological setting chapter, a schematic lithological profile or geological cross-section of the studied area should be additionally included.
• Figure 1A is difficult to read. It should be at least twice as large and made in color.
• In chapter 3. Materials and Methods, the information on the standards used in mineralogical research should be completed. This chapter describes the methodology of geochemical research, among others on ICP-MS and ICP-AES of various elements (including Co, Ni, Cd, REE and others), but the results of these works are not presented in the article at all. Therefore, in chapter 4.4. Geochemistry should add a few sentences about the distribution of other elements in the deposit as well. Also noteworthy are the upper limits of quantification for Cu and Ag, which were 10,000 and 100 ppm, respectively. Therefore, in the discussion of geochemical results throughout the article, where higher levels of Cu and Ag are given, the source of information should be provided (e.g. line 225).
• In Fig. 3 A and B the blue axes – Elev., are very faintly visible. Please change to a different color. In addition, there are errors in the description to Figs. 3A and B. Fig. 3A relates to Cu a 3B Ag.
• In chapter 4.2. from verse 301 to 316 there is a description which is essentially repeated in the next chap. 4.3 Sulfides and sulfosalts texture. This should be sorted out, it is best to leave the description in 4.3 and remove a similar part from 4.2.
• Figures 5 and 6 in their present form are poorly legible. They should be stretched over the entire page or the layout and description used for Figure 7 should be retained.
• In chap. The geochemistry presented for the main oxides basically reflects the composition of the studied rocks, and to a small extent the variability of the distribution of metals in them. The description should be extended to include correlations between other metals in the mineralized zones.
• 10 shows the lack of pyrite in the syn-depositional stage. What about framboidal pyrite?
• In the whole study, the form of silver was basically not identified. Is it in the form of isomorphic admixtures or inclusions in Cu sulphides? Or maybe there are own Ag minerals present that have not been identified. Moreover, the authors point to slight admixtures of As and Pb in pyrite (verse 300). Please specify what these are.
• In Table A2 for sample M73-11-510 (Old Red Sandstone), the authors indicate as ore mineral chalcopyrite present in an amount below 1%, and in Table A3 for the same sample, only 6 ppm Cu was determined. Are you sure that chalcopyrite is present here and not another mineral?

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Author Response

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Reviewer 2 Report

The paper proposes a preliminary study on the poorly documented Tullaconda Cu-Ag deposit in southern Ireland. The Authors offer a geological and metallogenic reconstruction of the deposit, highlighting its differences with the classical Zn-Pb Irish-type deposits, and suggesting that it could be also akin to sediment-hosted copper-type. The paper fits well into the scopes of Minerals. The structure and methods of the study, written in good English, appear appropriate and the geological reconstruction of mineralized bodies and the metallogenic reconstruction of mineralizing events are well supported by results. The interpretation at the district scale, in relation to the structural evolution of the area is convincing. Some parts of the work, however, need in my opinion some improvement, in particular:

1) an integration of the paragraph of previous studies on the deposit, especially as regards ore mineralogy and Ag minerals;

2) to display the available SEM-EDS data, even if semi-quantitative, especially for phases such as tennantites-tetrahedrites;

3) to display the Ag vs As and Sb geochemical correlations;

3) a revision of the text of the paragraph on paragenetic sequences and, possibly, of Figure 10, to distinguish the two stages (Cu-Ag and As-Sb) of the main mineralizing event.

See the attached file for more detailed annotations and some suggestions.

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Author Response

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Reviewer 3 Report

This research provides very interesting insights on the Tullacondra Cu-Ag deposit in Ireland mainly based on borehole data and geochemiscal analyses of host rocks and the mineralization.

Yet, the data provided are very limited and at the same time very limited work is done on the petrography of the mineralization and the samples analyzed. The manuscript could be largely improved if the geochemical data aquired is coupled to ore nad host rock petrography. For instance, the authors do not discriminate between primary host rock geochemistry (and the corresponding major element geochemistry and correlation coefficients) and possible changes related to the ore forming system.

You may find more comments in the attached pdf

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Author Response

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Reviewer 4 Report

Dear Authors,

Your manuscript contain valuable new data on a by far less studied deposit type of Ireland. The arrangement of Your manuscript is logic and the documentation is mostly  correct. The interpretation is moderate, which is OK, but may be developed. For example, I missed a short discussion about the deposit type/model, i.e. comparison with sediment hosted Cu deposits (they commonly form during rifting, see e.g the redbed model). Besides, I have some minor comments and suggestions listed below.

-Introduction: simple but correct, the main questions are highlighted, the aims of the study are well described
-chapter 2.1.: the host rock of the Pb-Zn dposits is hard to recognise, please, clarify, which of the above mentioned formations host the mineralisation.
-chapter 2.1.: please, write exactly the geotectonic environment of Irish-type deposit formation (i.e. rifting? like in case of SEDEX?)
-chapter 2.1.: please, briefly define the connection of Irish-type deposits to magmatic activities. This may have importance when evaluating the genesis of Cu-Ag deposits.
-chapter 2.1.: what do we know about the geotectonic environment of Cu-Ag deposit formation? are they syngenetic with the host sedimentary series? are they related to continental rifting?
-chapter 4.1.: please, make it clear, if the ore concentration data presented in this chapter are results of this study or earlier ones?
-chapter 4.1: is mineralised zone 3 related to a fault? please, make this clear
-fig 3: it is hard to observe mineralised zone 3 on these sections, please, try to highligh them somehow. In figure caption, it is ver hard to distinguish the signs of mineralised zone 1 and 2, please, try to solve this issue.
-chapter 4.3: do we know anything about the time and spatial relationship of the three textural types? (disseminated, dissolution seam hosted and vein hosted). Please, clarify, which mineralised zones contain which texture type(s)?
-chapter 4.4: you write a lot about correlation of different elements, but mention correlation coefficient only on fig 9. Please, give this value throughout the text, where You mention correlation (that would support Your statements very much).
-chapter 5.1, lines 472-476: i.e. silicification as a characteristic alteration related to mineralisation? 
-chapter 5.1, lines 481-486: do You mean other Cu-Ag mienralisations or Irish-type Pb-Zn mineralisations also? Please, clarify!
-chapter 5.2, lines 509-510: what kind of later fluid circulation could cause this remobilisation? Do You have any evidence for it in the vicinity?
-chapter 5.3, lines 527-534: what could be the cause of the mentioned zonation?
-line 543: this whould be chapter 5.4.
-lines 587-589: please, list point-by-point the differences
-chapter 6, lines 617-619: what could cause the two different mineralising pulses?

 

Author Response

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Round 2

Reviewer 1 Report

The authors took into account the comments and corrected the
original version of the article.

Author Response

Dear Reviewer 1,

We appreciate your time reviewing our paper again. 

Sincerely,

Andressa

Reviewer 3 Report

Most of the comments made during the first review are addressed. Minor grammar and spelling revisions are required. 

Please see attached file for more details.

Comments for author File: Comments.pdf

Author Response

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