Mineralogy and Geochemistry of Nephrite Jade from Yinggelike Deposit, Altyn Tagh (Xinjiang, NW China)

Round 1

Reviewer 1 Report

Any paper dealing with nephrite will attract considerable interest. In particular, your research   gives interesting data both on minerals and whole rocks from a deposit that is still little investigated.  I only added in the manuscript   a very few comments. Figures and tables are perfectly provided.  However, I think that   is not necessary to list the distribution of   the cations in the different   sites of tremolite and pargasite (Table 2 and 3).  Actually it is   only the result of a calculation and does not derive from the refinements of the structural sites by a crystallographic study of the amphiboles. I suggest to simplify the tables and report only the cations sequence.  This makes the tables more readable.

The manuscript should be considered for publication only after a minor revision.

Comments for author File: Comments.pdf

Author Response

Dear Reviewer:

Thanks for the comments concerning our manuscript entitled “Mineralogy and Geochemistry of Nephrite Jade from Yinggelike Deposit, Altyn Tagh (Xinjiang, NW China)” (ID: 780702). Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have studied comments carefully and have made correction which we hope meet with approval. Please see the attachments.

Once again, thank you very much for your comments and suggestions.

Best regards

Ying Jiang

Author Response File: Author Response.pdf

Reviewer 2 Report

Abstract

Reading the abstract only doesn’t really explain the goal of the manuscript. In the abstract, we understand that the nephrite deposit is situated “on the margin of the Precambrian dolomitic marble adjacent to diorite”. And after this sentence, all the abstract is about multiple analysis showing that the nephrite is of dolomitic origin. What is the point of the manuscript then? There is no doubt in this abstract since the second sentence than the nephrite is dolomitic, so why bothering to make all these analysis? I guess it is to understand the different phases of formation? If so, it could be much clearer.

It would also be interesting that the abstract would clearly indicate what is new about this work, and not just summarize the results. It would be useful to state what is the contribution of this manuscript, in relation to previous knowledge, that makes it worth reading. There are some hints at the end of the introduction.

Introduction

The introduction contains too many references to specific works in China while there is a plethoric worldwide bibliography about nephrite, easily accessible. There are many reviews and books about nephrite that should be cited instead of works about specific deposits, to attest the vast distribution of nephrite worldwide: the general literature about nephrite should be expanded and/or more diverse.

At the end of the introduction, we understand why this research was conducted: to document this nephrite deposit, poorly studied so far. It would be important that the authors also synthetize what are the remaining questions about this nephrite deposit and how they plan to elucidate these questions. This would also be helpful in the abstract. Since the references 20-22 are already studying this deposit, but are in Chinese or unpublished, it would be helpful to clearly state that this article is finally something like the publication of a summary of what is known about this deposit since nothing was known prior to these non accessible works.

Line 42: Maybe more generalist publications about the definition of nephrite instead of the references 1 and 2 that are case studies.

Line 46: There are much more generalist studies of use of nephrite among several past cultures that could better suit this kind of citation, for example Keverne 1991 Jade, among many others.

Line 49: There are many other (and more generalist) references for the widespread distribution of nephrite in the world than the reference 8.

Line 57: There are many more references for the distribution of D-type nephrite worldwide.

Line 68: Reference [20-22] finally explains the reason for this article : up to now, the literature about this nephrite deposit is purely in Chinese and most of it is unpublished dissertations. It finally explains the reason for this article in English.

Lines 69-70: This reason for the study could integrate the abstract.

Lines 74-75: a reference would be interesting for this historical statement, if it does exist.

Line 75: “until” does not seem to be right word here.

Line 76: Is a reference available for that information about the price?

Lines 79-81: this would be interested in the abstract also, so that the reader knows why this article is of interest.

Geological background

Globally it is quite difficult to follow the description of the geological background because of changes in colors and names between the figures 1 and 2, and even between 2b and 2c. The K-feldspar bearing rock from 2b seems to become plagioclase bearing in 2c. The Precambrian dolomitic marble, light orange in fig. 1 becomes two different orange colors in fig 2b, and then take back its light orange color from fig. 1 in fig. 2c (if I understood well). But in fig 2b there is no dolomitic marble at the location of 2c. The text also indicates different ages from the fig. 2b for the Bashikuergan and Altyn Tagh Groups. Well, it is really difficult to follow the authors in this part of the article because of all these little issues that accumulate or the lack of precision of the text that could use the exact terms employed in the figure so that the reader has not to make all the links himself.

Lines 113-115: the age are not concordant with the ages given in Fig. 2b. If it is these Bashikuergan and Altyn Tagh Groups that contain the dolomitic marble that is of major importance in this study, it would be interesting to clearly state it, and precisely explain to which formation this dolomitic marble belongs. Because “clastic sedimentary rocks” is not evident at all that this is the dolomitic marble.

Lines 115-116: the definition of the Kurukeyasi gneissic suite (K-feldspar granite) is not consistent with the legend of fig. 2c which is “plagioclase amphibolite”. Please explain, make direct links between the figure and the text, by using the same terminology.

Figure 1: what are the No of nephrite deposit useful for? It is not used at all in the article. Removing this numbers would simplify the figure.

Figure 2a: Please indicate the type of all faults on the figure when it is stated in the text, and check the accordance between text and figure. Please indicate a legend for the different limits between units that seem to be of different line thickness, and different color, so there is probably a meaning behind these different thicknesses (if not, make it all same thickness). The red line could be traced more precisely on the limit, so that we do not see any more the underlying black thin line.

Figure 2b-c: the link is difficult to make between the Fig. 2b and 2c since the Fig. 2b indicates only diorite in the area supposed to be represented in 2c, but in 2c we see 3 different types of rocks. The fault visible in fig. 2c is not visible on Fig 2b at the pint indicated by the blue star. Please check on the coherence between the text and the figure 2 for ages of rocks, type of feldspars, type of faults, and also between sub-figures 2b and 2c. Also in the Fig. 1, Fig. 3 and in the text it is written “dolomitic marble” and in Fig. 2c it is “dolomite marble”.

Samples and Methods

The description of the samples is not straightforward. The text states that the samples H, collected on the field, are mainly light yellow (but the fig. 4a is greenish-yellow) and that, on the contrary, the samples purchased are of gem-quality. This sentence compares the samples H and Q in a strange way. What does gem-quality means, since the samples H are only described through their color? Does it mean more green? But after, we read that 3 of the 6 purchased samples are light yellow. And Fig. 4 does not show samples that seem to be less gem-quality, with more impurities than we can see on Fig. 5 for Q-3 for example.

Nowhere is indicated that thin sections have been prepared, but given the fig. 6 and the petrographic description, it seems that this is the case. Please add it in the methods.

Lines 136-137: Maybe “Samples Q-1, Q-2 and Q-3 are greenish-yellow while Q-4, Q-5 and Q-6 are light yellow”?

Table 1: Please add Vickers hardness (the measurement really performed) and keep conversion into Mohs as the usual hardness scale. But Vickers is not directly comparable to Mohs.

Line 179: Please indicate at the very beginning of the paragraph that this is for isotope analysis, as you did for the other paragraphs.

Results

The results chapter is very clear, I only suggest some minor modifications

Line 217: indicate figures where this replacement are visible if any.

Figure 6. Indicate that 6b is part of 6a (in the caption and as a square in Fig 6a). Indicate if possible the sample for each photo (for example the allanite is probably from H-5?).

Line 241 : caption of Fig. 6h : I don’t understand the word lineated here. I don’t see on the picture how the tremolite is lineated.

Figure 7: Fig 7c and 7i. the focus is not very good. It would be interesting to know also which photo comes from which sample.

Line 251: the maxima for SiO2 in Table 2 is 59.74.

Lines 287-289 and Table 5: maybe there is more to say on this result. Since the color is probably related to these transition metal elements. And you will discuss it in the discussion.

Line 291: allanite is also visible on fig. 6g.

Lines 296-298 and Figure 9: What is the interest of normalizing to 2 different references, since the goal is only to compare the samples between each other through normalization.

Figure 10: the color/shape codes are quite numerous because of numerous nephrite sources. A convex hull for S-type and D-type would help the reader I guess, or other way to show the two types. Or maybe all the S-type in a single color, and the D-type in another color, with only changing shapes for the different sources. And a third color for the samples from this study, would help to easily find them in the middle of the plot.

Table 7: A clearer separation between D-type and S-type would be useful. This table should be in the discussion part, since it is not a result from the authors, but is very useful for the discussion.

Discussion

The whole discussion is oriented towards defining whether the studied nephrite is D-type or not. But it has already been demonstrated elsewhere, even in the introduction it is already written. The article presented here introduces more analytical elements to confirm that, but it is only a confirmation (the geological study itself doesn’t allow much doubt). This work also goes further, by explaining the different phases of the formation. These are the two points to highlight in my opinion.

Lines 334-337: this is not “mineralogical characteristic” like the beginning of the paragraph introduce, but a gemological one. Please relocate this sentence elsewhere.

Line 341-342: same here, color is not a mineralogical characteristic. Should be placed with the other sentence about the color of D-type nephrites, after the paragraph about mineralogy.

Line 349-350: at this point of the article, you have already written several times than the nephrite you study is from D-type, by citing the PhD dissertation and so on. No need to emphasize that here. Just confirm that the mineralogical associations of the samples studied here confirm this D-type attribution.

Lines 374-379: useless to repeat all this. We already read that you compile this dataset in the Results chapter. This sentence can be shorten a lot, something like “As summarized by the compilation of data presented in Table 6 and Figure 10, D-type nephrites tend to have…”

Line 401: Is “delicate” the right word here?

Line 404: lack the word “been” in the sentence.

Lines 420-421: an hypothesis about the origin of such fluids? Is there other local differences from the other Hetian deposits that could explain this?

Lines 445-460: a large literature is available on the causes of coloration in nephrite, most of them pointing towards Fe (2+), Mg, Cr. This literature cannot be ignored in this part of the discussion. Examples but there are many more:

Feng, X., Zhang, Y., Lu, T., Zhang, H., 2017. Characterization of Mg and Fe contents in nephrite using Raman spectroscopy. Gems & Gemology 53.

Fritsch, E., Rossman, G.R., 1987. An update on color in gems. Part 1: Introduction and colors caused by dispersed metal ions. Gems & gemology 23, 126–139.

Fritsch, E., Rossman, G.R., 1988. An update on color in gems. Part 3: Colors caused by band gaps and physical phenomena. Gems & Gemology 24, 81–102.

Liu, Y., Deng, J., Shi, G., Lu, T., He, H., Ng, Y.-N., Shen, C., Yang, L., Wang, Q., 2010. Chemical Zone of Nephrite in Alamas, Xinjiang, China. Resource Geology 60, 249–259. https://doi.org/10.1111/j.1751-3928.2010.00135.x

Line 463: exquisite? I don’t understand what this means in this context.

Conclusion

The conclusion, reporting the results and the conclusion about the D-type nature confirmed by geology, observations and analysis, is very concise. It could be enlarged with reflection about the input of this article in the regional/global field of nephrite studies. It could also begin by one or two sentences about the questions initially present before this work, the lack of work on this part of the Hetian nephrite belt.

Author Response

Dear Reviewer:

Thanks for the comments concerning our manuscript entitled “Mineralogy and Geochemistry of Nephrite Jade from Yinggelike Deposit, Altyn Tagh (Xinjiang, NW China)” (ID: 780702). Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have studied comments carefully and have made correction which we hope meet with approval.

Once again, thank you very much for your comments and suggestions.

Best regards

Ying Jiang

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

This is a largely improved second version of the manuscript. The authors have carefully and seriously follow the advice and proposition of the reviewers, by makin quite a big amount of work especially on broadening the literature cited.

The geological part is much clearer with the new figures.

I just noted one point that remains unsolved:

• The authors state in their cover letter that the preparation process of thin sections has been added but I did not find it anywhere in the revised version. The new last paragraph of the method is not a thin section preparation, since the thickness is 1 cm. This is the preparation of the polished slabs for figure 4, useful to see the color. But this is not the production of the thin sections on which the photomicrographs of figure 5 have been done (which are not 1 cm thick but rather 30 microns)

I recommend to publish this manuscript with a sentence added to the thin section preparation.

Author Response

Dear Reviewer，

Considering your suggestion, we have added the preparation process of thin sections in the methods section (Line 194-196 in the revised version). These sentences are as follows: 

“Samples H-1~H-5 were cut into small slabs, and polished thin sections were prepared for petrographic observations. Samples Q-1~Q-6 were cut to uniform-sized (5×2×1 cm) polished slabs to facilitate the color comparison (Figure 4). ”

We appreciate for your warm work earnestly, and hope that the correction will meet with approval.

Best regards,

Ying Jiang