Geochemistry, Chronology and Tectonic Implications of the Hadayang Schists in the Northern Great Xing’an Range, Northeast China

Round 1

Reviewer 1 Report

Please see my comments attached as pdf

Comments for author File: Comments.pdf

Dear Editor,

Minor changes/mistakes needed in the MS- I have indicated some of them in the text however not all.

Altug Hasozbek

Author Response

Dear Editors and Reviewer:

Thank you for your letter and for the reviewer’s comments concerning our manuscript entitled “Geochemistry and chronology of the Hadayang schists in the northern Great Xing’an Range, NE China: Impliations for the amalgamation history of Xing’an and Songnen blocks” (ID: minerals- 2583694). Those comments are 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 corrections which we hope meet with approval. The main corrections in the paper and the responds to the reviewer’s comments are as flowing:

1. It is said in Lines 8 “The term schist can be referred to any sedimentary, magmatic and/or metamorphic rocks which have been through P and T conditions with texture change. I am not sure in this case, to use the term schist is correct. It can easily be assigned as meta-volcanics or etc.”

Response: Thank you for pointing this out. The rocks studied in this paper have a typical schistose structure and a high content of schistose minerals, so it is identified as schist in this work.

2. Lines 13 “Schist ages respresent detrital package?”

Response: Thank you for pointing this out. The protolith restoration study shows that the protolith of the schists should be intermediate-basic volcanic rocks, so the zircon U-Pb age obtained in this paper represents the crystallization age of the volcanic rocks

3. Lines 84 “the samples are from the melange???”

  Response: Thank you for pointing this out. Yes, the samples are from the melange.

4. Lines 84 “What is that supposed to mean. There is almost 1 km of dcutile shear belt and low T metamorphism where you can not see any effects on zircons?”

Response: Thank you for pointing this out. Zircons from the schist samples are mainly euhedral and elongate, meanwhile, they are characterized by straight rhythmic stripes (Figure 6) and relatively high Th/U ratios (0.49-1.38, Table 2), which is characteristic of magmatic zircons. Therefore, we believe that ductile shear and low T metamorphism have no obvious effects on zircon.

5. Lines 84 “I had to come back here after reading the tectonic part of the MS. The geology of the region is not clear from this map- THe melange boundary, i assume it is intruded by the granites and directly covered by the Quaternary...There is such a huge time difference between the melange and the cover units. There is no other cover units? Eroded or ? ”

  Response: Thank you for pointing this out. In our field study, the melange was initially covered by the Quaternary，but was later revealed by artificial excavation. Therefore, there is a huge time difference between the melange and the cover units.

6. Lines 99 “According to the paper (I could only read the abstract-it is in Chinese) of Fu Jun yu et al 2015 (referred here 62), the tectonic melange geology is available and detailed. It is important to define the tectonic melange in terms of geology, however especially where the focus of this MS is missing here. According to this paper, this schists are the matrix of the melange. The melange formed in a subduction-collision environment- If so, based on the matrix information of the melange, the age discussion is questionable.”

  Response: Thank you for pointing this out. Melanomics can form in different tectonic environments, such as convergent plate margins, passive continental margins, continental rifts, and intracontinental compressive deformation zones (Silver et al., 1980; Raymond et al., 1984; Festa et al., 2010, 2012). The Hadaite complex mentioned in this paper lacks ophiolite and other components, and there is not enough evidence to show that it was formed in subduction collision environment.

Silver E A, Beutner E C. Mélanges. Geology, 1980, 8: 32–34. DOI:10.1130/0091-7613(1980)8<32:M>2.0.CO;2.

Raymond L A. Classification of mélanges. Geological Society of America Special Paper, 1984, 198: 7–20. DOI:10.1130/SPE198.

Festa A, Pini G A, Dilek Y, et al. Mélanges and mélange-forming processes:a historical overview and new concepts. International Geology Review, 2010, 52: 1040–1105. DOI:10.1080/00206810903557704.

Festa A, Dilek Y, Pini G A, et al. Mechanisms and processes of stratal disruption and mixing in the development of mélanges and broken formations:redefining and classifying mélanges. Tectonophysics, 2012, 568/569: 7–24. DOI:10.1016/j.tecto.2012.05.021.

7. Lines 125 “This page is blank?”

  Response: Thank you for pointing this out. This is a typographical error and has been corrected.

8. Lines 186 “Most of the zircons seem like broken. Based on the scale provided here the zircons are big. It is unlikely to have such big zircons in a mafic rocks. And the fact the formation of the schist if the source is unique can easily represent a similar ages”

  Response: Thank you for pointing this out. It is unlikely to have such big zircons in a mafic rock. After checking the CL image of zircon, the scale in Fig. 6 is wrong, which has been modified. Zircon fragmentation may be caused by the selection process.

9. Lines 263-266 “This is the one of the most important fact that the authors need to provide in this paper. Even though it is low T metamorphism, a further understanding of the metamorphism needs to be addressed by related diagrams”

Response: Thank you for pointing this out. In order to better elucidate the influence of metamorphism on rocks, this paper quotes the literature to describe it. Modified here as “After rock metamorphism, high field strength elements (HFSE), such as REE, Y, Th, U, Zr, Hf, Ti, Nb and Ta, etc., tend to exhibit inert-migration characteristics without significant migration [89], so the characteristics of HFSE can better reflect the protolith characteris-tics of metamorphic rocks.”

[89] Pearce, J and Norry, M. Petrogenetic implications of Ti, Zr, Y, and Nb variations in volcanic rocks. Contributions to Mineralogy and Petrology. 1979, 69, 33–47. https://doi.org/10.1007/BF00375192.

10. Lines 367-370 “To conclude this, the whole geology, stratigraphic section needs to be discussed. It is only based on the metamorphic volcanic rocks petrology, the geological assumption should be added with all tectono units of the melange...”

  Response: Thank you for pointing this out. The results of this paper indicate that the XB should have been in the stage of intracontinental extension during the Late Devonian - Early Carboniferous, but it seems inappropriate to limit the time limit for amalgamating XB and SB. The purpose of this paper is to provide a more detailed understanding of the evolution history of XB and SB in the late Paleozoic, so the conclusion of this paper is revised.

11. Writing errors in the lines 10 and 431.

Response: Thank you for pointing this out. The above errors have been modified, and the modification have been colored in red, see the article for details.

Kind regards，

Fuchao Na

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscripts needs minor revision, mainly improvement of English text

Comments for author File: Comments.pdf

The manuscripts needs minor revision, mainly improvement of English text

Author Response

Dear Editors and Reviewer:

Thank you for your letter and for the reviewer’s comments concerning our manuscript entitled “Geochemistry and chronology of the Hadayang schists in the northern Great Xing’an Range, NE China: Impliations for the amalgamation history of Xing’an and Songnen blocks” (ID: minerals- 2583694). Those comments are 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 corrections which we hope meet with approval. The main corrections in the paper and the responds to the reviewer’s comments are as flowing:

1. It is said in Lines 52 “In which sense? chemical, physical, ...?? Please explain better”

Response: Thank you for pointing this out. We have modified here as “the geochemistry is less affected by late transformation”

2. Lines 57 “better: to reveal or at revealing”

Response: Thank you for pointing this out. We have modified here as “This study will provide a more detailed understanding of the evolution history of XB and SB in the late Paleozoic”

3. Lines 72 “What do you mean bu scholars???? other authors??”

Response: Thank you for pointing this out. The expression here is not clear, we have modified here as “In recent years, a series of Neoarchean–Paleoproterozoic magmatic rocksand metamorphic rock series have been identified in the Ulanhot–Longjiang area,”

4. Lines 76 “is this correct???. Do you mean alternating deposits in the succession???”

  Response: Thank you for pointing this out. This expression is incorrect, wo have modified here as “the Early Paleozoic–Lower Permian marine and continental alternative deposition”

5. Lines 206-207 “are these values sufficiently reliable??. metamorphism,a s well as hidrothermal alteration and diagenesis cause changes in these highly mobile elements”

Response: Thank you for pointing this out. Considering that metamorphism, hydrothermal alteration, and diagenesis can cause changes in these highly mobile elements, the discussion of major elements is omitted here.

6. Lines 231 “again the use of this word to indicate new studies, new authors!!”

  Response: Thank you for pointing this out. The expression here is not clear, we have modified here as “Although the magmatic activity in this period was relatively weak in the region [77], in recent years, Late Devonian - Early Carboniferous magmatic rocks have been succes-sively identified in XB, such as Yakeshi-Huolongmen area, Handagai area, Nenjiang area and Zhalantun-Zhalaite area”

7. Lines 246 “what do you mean by scale? please, explain this better”

Response: Thank you for pointing this out. The expression here is not clear, we have modified here as “In summary, a magmatic activity occurred on the XB during the Late Devonian - Early Carboniferous period,”

8. Lines 259 “I doubt these values have not changed compared to the original compositions!!”

Response: Thank you for pointing this out. Considering that metamorphism, hydrothermal alteration, and diagenesis can cause changes in these highly mobile elements, the discussion of major elements is omitted here.

9. Lines 314 “Better to say something like: A lot of progress has been made in the study of ......”

Response: Thank you for pointing this out. We have modified here as “A lot of progress has been made in the study of Late Devonian-Early Carboniferous magmatic rocks in XB”.

10. Lines 323 “Are these diagram types proper or come from previous studies?. If so, the original references to them should be mentioned here”

  Response: Thank you for pointing this out. The original references of Fig. 12 are added.

11. Writing errors in the lines 57, 64, 65, 67, 68, 83, 89, 100, 101, 229, 237, 242, 244, 255, 281,318,372,375,376,379 and 384.

  Response: Thank you for pointing this out. The above errors have been modified, and the modification have been colored in red, see the article for details.

Kind regards，

Fuchao Na

Author Response File: Author Response.pdf

Reviewer 3 Report

The paper needs extensive revision, firstly by adding a petrology part promised in the title. The investigated rocks have to be described in detail because otherwise it is difficult to find out what are the results pertaining to. The connection with SB and XB amalgamating before the Silurian is not compellingly supported, all the more that the geotectonic interpretations rely only on data from the literature, without including the results obtained in the study. Specific comments are listed below:

r2 The text contains by far less petrology than promised.

r11 please change „which protolith are” to make sense logically and grammatically

r11-12 Insert commas, hyphens or something in composed rock names.

r23 think, not link?

r24 should have been

r53 rather derivation than inversion

r57 No way to reveal the history of the Xing’an and Songnen blocks during the Paleozoic from 2 samples taken from an insufficiently described tectonic melange near Hadayang

r75 Abbreviation EXB not explained.

r79 Is XHB actually XHS? – or another undefined thing?

r86-87 The Huolongmen and Morgenhe Formations do not appear in Fig. 2

r96-97 „there is also a Hadayang tectonic mélange belt developed” a remark is not enough, at least a general description should be given

r101 what massive structure?

r105, r110 It is not clear what is meant by „the remaining phenocrysts”

r100-110 It is unclear why the samples are designated as epidote etc. - schist and chlorite, epidote etc. - schists since the dominant mineral is in fact biotite, appearing even more abundant in Fig. 3 than the figures reported

r123 High LOI reflect the content of hydrous minerals, by itself it is not providing any indication of the intimated degree of alteration

r135 The source of the diagrams should be mentioned

r138 The source of the reference data should be given

r156 the mentioned Na2O/K2O ratio is not resulting from the total alkalies content, but from the analytical values

r165-167 Bad adjective/adverb choices, predicate missing.

r173 Something more precise and illustrative than „straight rythmic stripes” would be needed.

r174 high Th/U „which is characteristic of magmatic zircons” needs citation.

r178-179 Is it implied that the ages represent metamorphic ages? – at least this is what „The two ages are interpreted as the crystallization age of the epidote biotite albite schist and chlorite epidote biotite albite schist, respectively.” suggests.

r190 TDM1 and TDM2 should be defined in text.

r197 The insets in Fig. 7 look like weighted average plots, not probability plots.

r203 protolith restoration is unfortunately not possible, I think it is about identification

r200 Abbreviations should be explained

r208-209 „the content of Cr, Ni, Ti and Co is high” – as compared to what? Cr, Ni, Co are actually lower than MORB values (Gale et al., 2013, https://doi.org/10.1029/2012GC004334) and TiO₂ is in the range.

r220 The source of the diagrams should be mentioned

r279-280 now Cr, Ni, and Co are low after being assessed as high in r208-209

r310 The plots in Fig. 11 look more like sample grouping than correlations

r354 Source and abbreviations for Fig. 13 should be mentioned

r398 „con-centration” - remove hyphen created in the editing process

r431-432 Phrase “As the carrier gas, helim was used to transport the ablated sample are sol mixed with Argon from the laser-ablation cell to the MC-ICP-MS torch by a mixing chamber.” hardly comprehensible.

Extensive editing necessary for clarity.

Author Response

Dear Editors and Reviewer:

Thank you for your letter and for the reviewer’s comments concerning our manuscript entitled “Geochemistry and chronology of the Hadayang schists in the northern Great Xing’an Range, NE China: Impliations for the amalgamation history of Xing’an and Songnen blocks” (ID: minerals- 2583694). Those comments are 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 corrections which we hope meet with approval. The main corrections in the paper and the responds to the reviewer’s comments are as flowing:

1.The connection with SB and XB amalgamating before the Silurian is not compellingly supported, all the more that the geotectonic interpretations rely only on data from the literature, without including the results obtained in the study.

Response: Thank you for pointing this out. We agree with this comment. The results of this paper indicate that the XB should have been in the stage of intracontinental extension during the Late Devonian - Early Carboniferous, but it seems inappropriate to limit the time limit for amalgamating XB and SB. The purpose of this paper is to provide a more detailed understanding of the evolution history of XB and SB in the late Paleozoic, so the conclusion of this paper is revised.

2. r2 The text contains by far less petrology than promised.

Response: Thank you for pointing this out. The study of petrology is not the focus of this article, so the petrology in the title has been removed to make the title clearer.

3. r11 please change „which protolith are” to make sense logically and grammatically.

Response: Thank you for pointing this out. Modifications have been made here, please see details in the text.

4. r11-12 Insert commas, hyphens or something in composed rock names.

Response: Thank you for pointing this out. We've inserted hyphens in combined rock names, please see details in the text.

5. r23 think, not link?

 Response: Thank you for pointing this out. The spelling mistake has been corrected, please see details in the text.

6. r24 should have been

Response: Thank you for pointing this out. The mistake has been corrected, please see details in the text.

7. r53 rather derivation than inversion

Response: Thank you for pointing this out. Modifications have been made here, please see details in the text.

8. r57 No way to reveal the history of the Xing’an and Songnen blocks during the Paleozoic from 2 samples taken from an insufficiently described tectonic melange near Hadayang

Response: Thank you for pointing this out. Based on the research results in this paper, the tectonic evolution of Xing 'an Block and Songnen Block in the late Paleozoic period cannot be revealed, so this paper is revised to " This study will provide a more detailed understanding of the evolution history of XB and SB in the late Paleozoic ".

9. Abbreviation EXB not explained.

Response: Thank you for pointing this out. We have supplemented the explanation of the abbreviation EXB, please see details in the text.

10. r79 Is XHB actually XHS? – or another undefined thing?

Response: Thank you for pointing this out. There is a spelling mistake. XHB is actually XHS

11. r86-87 The Huolongmen and Morgenhe Formations do not appear in Fig. 2

Response: Thank you for pointing this out.The Huolongmen Formation and the Morganhe Formation are added in Fig. 2.

12. r96-97 „there is also a Hadayang tectonic mélange belt developed” a remark is not enough, at least a general description should be given.

Response: Thank you for pointing this out. The general description of the Hadayang melange is added, please see details in the text.

13. r101 what massive structure?

Response: Thank you for pointing this out. This is an error in writing, the correct is schistose structure.

14. r105, r110 It is not clear what is meant by „the remaining phenocrysts”

Response: Thank you for pointing this out. The correct is crystalloblasts.

15. r100-110 It is unclear why the samples are designated as epidote etc. - schist and chlorite, epidote etc. - schists since the dominant mineral is in fact biotite, appearing even more abundant in Fig. 3 than the figures reported

Response: Thank you for pointing this out. Sample G1631-1, shows porphyroblastic, lepidoblastic texture and schistose structure, The mineral assemblage consists of albite (～27%), biotite (～30%), chlorite (～8%), epidote (～20%), quartz (～8%) and opaque mineral (～7%). Sample G1631-4 has porphyroblastic, lepidoblastic texture and schistose structure, consisting of biotite (～15%), chlorite (～8%), epidote (～12%), albite (～40%) and quartz (～25%). According to the above characteristics and rock naming principles, sample G1631-1 is named epidote-biotite-albite schist and sample G1631-4 is named biotite-albite schist.

16. r123 High LOI reflect the content of hydrous minerals, by itself it is not providing any indication of the intimated degree of alteration

Response: Thank you for pointing this out. High LOI cannot provide any indication of the degree of alteration, therefore this description is deleted here.

17. r135 The source of the diagrams should be mentioned

Response: Thank you for pointing this out. The source of the Fig. 4 is added, please see details in the text.

18. r138 The source of the reference data should be given

Response: Thank you for pointing this out. The source of the reference data is added, please see details in the text.

19. r156 the mentioned Na₂O/K₂O ratio is not resulting from the total alkalies content, but from the analytical values

Response: Thank you for pointing this out. The mentioned Na₂O/K₂O ratio is not resulting from the total alkalies content, but from the analytical values, we have corrected the logical error.

20. r165-167 Bad adjective/adverb choices, predicate missing.

Response: Thank you for pointing this out. The syntax error has been corrected, please see details in the text.

21. r173 Something more precise and illustrative than „straight rythmic stripes” would be needed.

Response: Thank you for pointing this out. A description of the characteristics of zircon are added here, please see details in the text.

22. r174 high Th/U „which is characteristic of magmatic zircons” needs citation.

Response: Thank you for pointing this out. The citations are added here, please see details in the text.

23. r178-179 Is it implied that the ages represent metamorphic ages? – at least this is what „The two ages are interpreted as the crystallization age of the epidote biotite albite schist and chlorite epidote biotite albite schist, respectively.” suggests.

Response: Thank you for pointing this out. Zircons from the two samples are mainly euhedral and elongate, minewhile, they are characterized by straight rhythmic stripes or typical oscillatory zoning in CL images with high Th/U ratios (0.49-1.38), which is characteristic of magmatic zircons (Rubatto and Gebauer, 2000). Therefore, we believe that the two ages are interpreted as the crystallization age of the epidote-biotite-albite schist and biotite-albite schist, respectively.

24. r190 TDM1 and TDM2 should be defined in text.

Response: Thank you for pointing this out. We have provided explanations for T_DM1 and T_DM2, please see details in the text.

25. The insets in Fig. 7 look like weighted average plots, not probability plots.

Response: Thank you for pointing this out. The insets in Fig. 7 are weighted average plots, and we have corrected this error.

26. r203 protolith restoration is unfortunately not possible, I think it is about identification

Response: Thank you for pointing this out. Protolith restoration is a difficult problem in the study of metamorphic rocks. In this work, protolith discrimination diagram, petrology, petrography and geochemical analysis are used to attempts to restore the protolith of Hadayang schists.

27. r200 Abbreviations should be explained

Response: Thank you for pointing this out. The explanation of abbreviations for Fig. 8 is added, please see details in the text.

28. r208-209 „the content of Cr, Ni, Ti and Co is high” – as compared to what? Cr, Ni, Co are actually lower than MORB values (Gale et al., 2013, https://doi.org/10.1029/2012GC004334) and TiO₂is in the range.

Response: Thank you for pointing this out. The content of Cr, Ni, Ti, and Co is actually lower than the MORB values, which is not sufficient as a basis for debate. We have corrected this description error, please see details in the text.

29. r220 The source of the diagrams should be mentioned

Response: Thank you for pointing this out. The source of the Fig. 9 is added, please see details in the text.

30. r279-280 now Cr, Ni, and Co are low after being assessed as high in r208-209

Response: Thank you for pointing this out. The content of Cr, Ni, Ti, and Co is actually lower than the MORB values, the preceding paragraph has been revised.

31. r310 The plots in Fig. 11 look more like sample grouping than correlations

Response: Thank you for pointing this out. As shown in Fig. 11, The negative correlation between Mg# and CaO, FeO^T, while the fact that Mg# is positively correlated with Cr, Ni, SiO₂ and Na₂O indicates olivine and clinopyroxene frac-tionation,

32. r354 Source and abbreviations for Fig. 13 should be mentioned

Response: Thank you for pointing this out. The Source and abbreviations for Fig. 13 are added, please see details in the text.

33. r398 „con-centration” - remove hyphen created in the editing process

Response: Thank you for pointing this out. The hyphens created in the editing process have been removed, please see details in the text.

34. r431-432 Phrase “As the carrier gas, helium was used to transport the ablated sample are sol mixed with Argon from the laser-ablation cell to the MC-ICP-MS torch by a mixing chamber.” hardly comprehensible.

Response: Thank you for pointing this out. Revise the phrase to “Helium was used as the carrier gas to transport ablated material from the laser-ablation cell after which it was mixed with Ar prior to entering the ICP-MS torch”

Kind regards，

Fuchao Na

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Minor point addressed to the editor. 

No additional editing needed 

Author Response

Dear Editors and Reviewer:

Thank you for your letter and for the reviewer’s comments concerning our manuscript entitled “Geochemistry and chronology of the Hadayang schists in the northern Great Xing’an Range, NE China: implications for the amalgamation history of Xing’an and Songnen blocks” (ID: minerals- 2583694).

Kind regards，

Fuchao Na

Author Response File: Author Response.pdf

Reviewer 3 Report

Thank you for properly addressing my previous comments. There are still relatively few minor adjustments to be done, namely:

r 3 implications

r 214-215 though the images in r 224 are not very clear, the zonation shows also other patterns than oscillatory zonation, for instance sector zoning, also consistent with a magmatic precursor

r219-220 still not clear, it should be stressed that the zircon age corresponds to the age of the magmatic protolith of the schists

r345 in order to more clearly express the idea, the phrase should start with “Although” or a “yet” should be added after the first comma.

r382 asthenosphere and lithosphere are common nouns and should not be capitalized.

r 401 underwent

r 605 it is Le Maitre R. W.

Mostly OK.

Author Response

Dear Editors and Reviewer:

Thank you for your letter and for the reviewer’s comments concerning our manuscript entitled “Geochemistry and chronology of the Hadayang schists in the northern Great Xing’an Range, NE China: implications for the amalgamation history of Xing’an and Songnen blocks” (ID: minerals- 2583694). Those comments are 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 corrections which we hope meet with approval. The main corrections in the paper and the responds to the reviewer’s comments are as flowing:

1. r2 implications

Response: Thank you for pointing this out. The mistake has been corrected, please see details in the text.

2. r 214-215 though the images in r 224 are not very clear, the zonation shows also other patterns than oscillatory zonation, for instance sector zoning, also consistent with a magmatic precursor

Response: Thank you for pointing this out. According to our re-observation of CL images of zircons, some zircons have sector zoning characteristics, such as the fourth zircon in Figure 6a. A description of the characteristics of zircons are added here, please see details in the text.

3. r219-220 still not clear, it should be stressed that the zircon age corresponds to the age of the magmatic protolith of the schists

Response: Thank you for pointing this out. In order to make the expression clearer here, it is modified as follows: The two ages are interpreted as the crystallization age of the magmatic protolith of the two schists, respectively.

4. r345 in order to more clearly express the idea, the phrase should start with “Although” or a “yet” should be added after the first comma.

Response: Thank you for pointing this out. Modifications have been made here, please see details in the text.

5. r382 asthenosphere and lithosphere are common nouns and should not be capitalized.

Response: Thank you for pointing this out. Modifications have been made here, please see details in the text.

6. r 401 underwent

Response: Thank you for pointing this out. Modification has been made here, please see details in the text.

7. r 605 it is Le Maitre R. W.

Response: Thank you for pointing this out. Modification has been made here, please see details in the text.

Kind regards，

Fuchao Na

Author Response File: Author Response.pdf