Searching Mass-Balance Analysis to Find the Composition of Martian Blueberries

Round 1

Reviewer 1 Report

Review of the manuscript entitled:

Searching Mass-Balance Analysis to Find the Composition of Martian Blueberries

This work presents a novel and sophisticated approach to find the composition of Hematite-based Martian blueberries that were found by the Opportunity rover into Eagle Crater. Although the analysis of these hematite spherules has been addressed in multiple previous works (as commented by the author), in this research a new analytical approach is applied for their investigation, providing enhanced results. The article is very well written and structured. The proposed method is convincing, and the obtained results are solid. I believe its content could be of interest for the scientific community and more in particular to the readers of the Minerals journal. Therefore, I suggest its publication after a few minor revisions that are mostly concerning the introduction section. Details are provided below:

·         In the affiliation sections the main author presents two emails ([email protected] and [email protected]). Considering the two emails are very similar, I am wondering if one of them is the results of a typo.

·         Page 2, lines 49-51: the authors mention 7 Science papers in which the presence/characterization of hematite blueberries is discussed. However, only 6 of these papers are presented in the reference list. Please add the missing one.

·         Page 2, line 75: “This extra constraint is effectively narrows”. I believe the word “is” can be removed from the sentence.

·         Page 2, line 76: “weight percentages too high values”, I believe the word “too” should be replaced by “to”.

·         Page 2, lines 81-92: I would suggest replacing the bullet structure of this section by a regular paragraph describing the novelty of the applied data-analysis approach and the purpose of the overall study.

·         Page 3, lines 95-96: the sentence is not clear, please rephrase.

·         Page 12, line 466 (and below): I suggest changing Table 5a and Table 5b into Table 5 and Table 6, respectively.

·         Pages 14-15, lines 532-534: I believe this sentence better fits in the introduction (it could be used at the end of the section, see also the comment above).

·         Page 18, lines 684-694: Although it is not a mandatory requirement, i suggest to do not present the results as a bullet list.  

Author Response

Reviewer 1:

First, thank you for the very thorough reading of the manuscript and the positive review.

• In the affiliation sections the main author presents two emails ([email protected] and [email protected]). Considering the two emails are very similar, I am wondering if one of them is the results of a typo.
• UPDATED
•  
• Page 2, lines 49-51: the authors mention 7 Science papers in which the presence/characterization of hematite blueberries is discussed. However, only 6 of these papers are presented in the reference list. Please add the missing one.
• DONE - Note this required to change the paper numbering (+1) for all papers previously numbered 17-33 to 18-34, and a large number of changes to in text citations.
•  
• Page 2, line 75: “This extra constraint is effectively narrows”. I believe the word “is” can be removed from the sentence.
• DONE
•  
• Page 2, line 76: “weight percentages too high values”, I believe the word “too” should be replaced by “to”.
• DONE
•  
• Page 2, lines 81-92: I would suggest replacing the bullet structure of this section by a regular paragraph describing the novelty of the applied data-analysis approach and the purpose of the overall study.
• The bullet list provides a brief factual summary of what is in the paper. This is always useful and polite to give to the reader. In accordance with the reviewers comments I have added the following paragraph after the bullet list:

• The use of the spaces of filtering distributions and searching mass-balance analysis is novel. These are both described in detail. The use of these novel methods, in combination with the constraint on the content of SiO₂ in Martian hematite blueberries [12], provides results which point to minimum likely hematite content in Martian blueberries around 80 wt% (while more likely hematite content is higher). This minimum is much higher than the only other published minimum (i.e. 24 wt%) [19] on this hematite content. Introducing the new methods and constraining this minimum of hematite content to higher levels than 24 wt% are the main objectives of this paper.

•  
• Page 3, lines 95-96: the sentence is not clear, please rephrase.
• REPHRASED
•  
• Page 12, line 466 (and below): I suggest changing Table 5a and Table 5b into Table 5 and Table 6, respectively.
• I would like the table numbering kept as-is. Both tables refer to Jensen-Shannon distances, so they are naturally linked.
•  
• Pages 14-15, lines 532-534: I believe this sentence better fits in the introduction (it could be used at the end of the section, see also the comment above).
• I am confused by this comment. Perhaps the reviewer is referring to lines 432-434 rather than lines 532-534. The sentence covering lines 532-534 includes details that are only bought into the paper well after the introduction. So this sentence could not be understood if it were placed in the introduction.  A similar sentence to the one on lines 432-434 appears in the Abstract. This position (in the abstract) seems more appropriate to me, since it covers a result that is readily understood. Introductions should cover introductory material, rather than results.
•  
• Page 18, lines 684-694: Although it is not a mandatory requirement, i suggest to do not present the results as a bullet list.
• FINE (They were not presented as a bullet list.)

Reviewer 2 Report

The grey hematite spherules, blueberries on Mars are interesting target on Mars which have been deeply studies by various researchers. The exact composition of these blueberries remains to be explored due to its tiny size that individual spherules for APXS and Mossbauer instrument have not been done. This study gives further composition constraints for them based on search mass-balance demixing method. The author makes efforts on the methodology to get a sound result. I think the paper is well presented and can be accepted.  I only have one comment on the significant digits of the Tables 4, 8, 9. How many digits should be kept for the elemental abundance?  I think four digits should be too many. Please explain and consider the accuracy of the data.

Author Response

First, thank you to the reviewer for their care, effort, and positive review.

The changes the reviewer suggested to the number of digits in three tables have been made.