Mesoproterozoic (ca. 1.3 Ga) A-Type Granites on the Northern Margin of the North China Craton: Response to Break-Up of the Columbia Supercontinent

Round 1

Reviewer 1 Report (Previous Reviewer 1)

Comments and Suggestions for Authors

Dear authors,

 

I am pleased that you took my comments serious as you present high quality data for an important geological event in the North China Craton. Spelling, grammar and style have improved very much and the manuscript has become readable and understandable.

 

I therefore recommend publication after fixing some minor, but important issues listed below.

 

Kind regards

 

Pages 1 and 2 mention the Khondalite Belt and Central Orogenic Belt of the NCC, but these are not shown on Figure 1. Please include these in the diagram.

Page 8: replace “A/nk” with “A/NK”.

Page 8 and elsewhere in the text: Just a comment: the abbreviation REE for “rare earth elements” is generally seen as a so-called plurale tantum (a noun that appears only in the plural form), which is logical as the REE comprise more than one element. So, “REEs” would be a double plural and “REE” suffices.

Page 11: “The granites of the present study are not alkali A-type granites.”  Not alkaline granites?  This must be a typo: the samples plot in the alkaline granite (A-type granite) fields of Figure 9.  

Figure 1: what do the abbreviations ZT, TH, DF, WT, FP, HF, XH, NH, C, TNCO, IMSE, JLJB mean?  These could be explained in the caption, together with the other abbreviations so the figure does not look so cluttered.

 

Figure 2: please re-arrange the sample numbers and ages: they obviously overlap and are unreadable!  Why are there two different symbols for sample location in the map and legend?

Figure 3: please replace “microscopic photographs” with “photomicrographs”.

Figure 8: which Lu/Hf ratio was used to plot the crustal evolution lines? Perhaps 0.01, as for average felsic crust? Please include in diagram or caption.

Figure 9: check spaces between words in “A,I&S.A,I&S type granite;FG.Differentiated”.

Figure 10: “parital melts” should be “parental melts”.

 

END

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report (Previous Reviewer 3)

Comments and Suggestions for Authors

This is a greatly improved MS and the English expression almost flawless. I recommend publication subject to a cleanup of errors in the use of Mesoproterozoic in the opening pages of the MS when in fact some of the events described are instead of older Paleoproterozoic age. The boundary between the Paleo and Mesoproterozoic is placed at 1.6 Ga. Once these issues are addressed, the MS should be in a form suitable for publication. The errors are highlighted on the attached pdf

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear authors,

I am of the opinion that your manuscript „Mesoproterozoic (~1.3 Ga) A-type Granite on the Northern  Margin of the North China Craton: Response to Breakup of the 3 Columbia Supercontinent“ is not ready for publication in Minerals and recommend major revision.

In principle, the topic is suited for Minerals as the data, results and interpretations are of good quality. At some stage, I will be happy to see this study published. However, grammar, writing style and geological terminology are absolutely not up to the standard of an international, English language peer-reviewed journal. Seven authors can do a lot better here, even if English is not their first language.

I have emended the text up to the Discussion to demonstrate the extent of the problem and suggest that you seriously consult someone well versed in scientific English and who is able to assist you in this respect. Large parts are phrased clumsily and geological terms such as phenocryst, myrmekite etc. are not used; instead we get “banded”, “striated” and other undefined, vague or unsuitable terms. Please consult a geological dictionary. In contrast, the methods paragraphs are well written and clear.

Furthermore,

·         The description of the general geology of the study area is too  general. Here I’d expect a concise but meaningful summary of the geological history of the study area from old to young, citing published ages (if available). This should offer a reference frame for the granites dated in this study.

·         The aim of this study is not clear: why focus on these particular granite intrusions? Are the age results new and unexpected? Do they offer a new perspective on the Mesozoic evolution of this part of the North China Craton? Is this of international interest? As it stands, your study reads as a “look what we found” story; it needs to be put on a firmer footing.

·         The text can be rendered more readable by summarising sample petrology in one paragraph and offer detailed petrographic descriptions in an electronic supplement. This will free up space that can be used to address more interesting issues. You the correct petrographic terms and tighten up the descriptions. 

·         Please avoid terms such as “Grade I units” that have no meaning outside the Chinese geological community, or explain them.

·         Zircon ages: only two samples yielding ages of 1279 and 1276 Ma overlap within 2-sigma analytical uncertainty, but sample 2021032 is older than these two (1288 Ma). So, the ages seem to indicate two distinct intrusion event separated in time by, say, 5-10 Ma, or thereabouts. Please take a more critical approach to the dating results. 

·         Figure 2 is too complex as there is too much irrelevant information here. The Quaternary sedimentary cover can be presented in one colour. The lettering of the different granitoid phases should be removed from the map and the legend; the colours should suffice. The many formation names in the legend are not very informative as only of local importance, and are perhaps better replaced with short lithological characterisations (e.g. “sand- and siltstones”, “shallow marine limestones” etc.).

·         Figure 4: the sample numbers in red are very difficult to read and should be changed to white, or to black lettering on a white background.

 ·         Figure 5, Concordia diagrams: several spots do not overlap Condordia, so why did you include these discordant ages in the age calculation for samples 54 and 32?

Additional comments on smaller issues can be found in the pop-ups in the annotated PDF.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

see comments above

Author Response

Dear Professor,

Thank you for the comments on the manuscript of the reviewers and yourself. We have revised our paper entitled “Mesoproterozoic (~1.3 Ga) A-type granite on the northern margin of the North China Craton: response to breakup of the Columbia supercontinent”, carefully taking into account the comments and suggestions in the reviews. All reviews were supportive and constructive. Our responses for the referee’s comments are listed as follows.

Reviewer 1 comments

1. 1. The description of the general geology of the study area is too Here I’d expect a concise but meaningful summary of the geological history of the study area from old to young, citing published ages (if available). This should offer a reference frame for the granites dated in this study.

Reply: Thank you for your constructive suggestions. In the preface to this revision, the geological history of the study area from ancient times to the present was added and the literature published in the area was cited.

2. 2.The aim of this study is not clear: why focus on these particular granite intrusions? Are the age results new and unexpected? Do they offer a new perspective on the Mesozoic evolution of this part of the North China Craton? Is this of international interest? As it stands, your study reads as a “look what we found” story; it needs to be put on a firmer footing.

Reply: Thank you for your constructive suggestions. The North China Craton (NCC) is considered a crucial component of the Columbia supercontinent, with the Paleoproterozoic Concite Belt (~1.95 Ga) and the Central Orogenic Belt (~1.85 Ga) responding to the convergence process of the Columbia supercontinent [10,11]. . However, due to the lack of reliable isotope data on Mesoproterozoic magmatism and tectonism, significant discrepancies remain among researchers about how the NCC was involved in the rifting of the Columbia supercontinent. Mesoproterozoic (~1.3 Ga) magmatism in the North China Craton (NCC) was characterized by diabase sills, while contemporary granitic magmatism was relatively rare, limiting our understanding of the evolution of the NCC during this period. The Mesoproterozoic rock mass was newly identified in this area as part of a 1:50,000 scale regional geological survey. By combining geochronological, geochemical data and regional geological features, it is concluded that the Mesoproterozoic porphyritic granites formed from the northern edge of the NCC from intra-plate tectonic settings during continental extension and rifting, reflecting the NCC's response to the final rifting event of the NCC represent the supercontinent Columbia.

3. The text can be rendered more readable by summarising sample petrology in one paragraph and offer detailed petrographic descriptions in an electronic supplement. This will free up space that can be used to address more interesting issues. You the correct petrographic terms and tighten up the descriptions. 

Reply: Thank you for your constructive suggestions. In the revised version, a concise summary of the sample petrology has been included in one paragraph, while the detailed petrographic descriptions have been appended in an electronic supplement. We have also ensured the use of accurate petrographic terms and tightened up the descriptions.

4. Please avoid terms such as “Grade I units” that have no meaning outside the Chinese geological community, or explain them.

Reply: Thank you for your valuable advice. In this revised manuscript, terms like “Grade I units”, which are specific to the Chinese geological context, have been omitted and replaced with more internationally recognized terminology. Additionally, any such terms that remain have been appropriately explained to ensure clarity for the international readership.

5. Zircon ages: only two samples yielding ages of 1279 and 1276 Ma overlap within 2-sigma analytical uncertainty, but sample 2021032 is older than these two (1288 Ma). So, the ages seem to indicate two distinct intrusion event separated in time by, say, 5-10 Ma, or thereabouts. Please take a more critical approach to the dating results. 

Reply: Thank you for your constructive suggestions. We recalculated the U-Pb ages of the samples. The U-Pb age for sample U-Pb2020054 is between 1270 ± 14 and 1285 ± 13 Ma. The weighted average is 1282.20 ± 3.30 Ma (n=12, MSWD=0.008). The U-Pb age for sample U-Pb2020055 varies between 1273 ± 12 and 1284 ± 13 Ma, with a weighted average of 1278.60 ± 6.10 Ma (n=17, MSWD=0.061). The U-Pb age for sample U-Pb2021032 ranges from 1285 ± 12 to 1294 ± 15 Ma, with a weighted average of 1285.40 ± 2.60 Ma (n=16, MSWD=0.100). The crystallization age of U-Pb zircon shows that the porphyry granites in the study area belong to the Mesoproterozoic magmatic activity and have the same tectonic background. That's why they will be discussed together this time.

6. 6. Figure 2 is too complex as there is too much irrelevant information here. The Quaternary sedimentary cover can be presented in one colour. The lettering of the different granitoid phases should be removed from the map and the legend; the colours should suffice. The many formation names in the legend are not very informative as only of local importance, and are perhaps better replaced with short lithological characterisations (e.g. “sand- and siltstones”, “shallow marine limestones” etc.).

Reply: Your comments are constructive and helpful. In this revision, the Quaternary sediment cover is represented by color in Figure 2. Maps and legends are deleted, the names and codenames of various granites are retained for simplicity. The stratigraphic names in the legend are deleted and the lithological features are briefly described. The names Xiaoyingtu, Chahan and 1488 Highland Intrusion are used in the legend and illustration.

7. Figure 4: the sample numbers in red are very difficult to read and should be changed to white, or to black lettering on a white background.

Reply: In this revision, sample numbers have been changed to black letters on a white background as necessary. In this revision, sample numbers have been changed to black letters on a white background as necessary. 

8. Figure 5, Concordia diagrams: several spots do not overlap Condordia, so why did you include these discordant ages in the age calculation for samples 54 and 32?

Reply: In this revision, the Concordia charts for samples U-Pb2020054 and U-Pb2021032 have been recompiled. The non-overlapping points have been excluded, and their ages have been recalculated accordingly. Additionally, the relevant contents of Figure 5 have been modified to reflect these changes.

9. You noted in the PDF note that“laser beam diameter?”

Reply: Thanks for your constructive suggestions. We have added a note stating that “the test laser beam diameter is 50μm, the laser energy density is 3.5J/cm², the frequency is 8Hz, and the stripping/ablation process is applied. The corrosion time is 40s, and the denudation aerosol is fed into the mass spectrometer using helium gas.”

10. You noted in the PDF note that“X and Y should be replaced with N and E.”

Reply: Thank you for your valuable suggestions. This time, it has been changed to: “In this study, three granitic samples were selected for zircon U-Pb dating: U-Pb2020054 (porphyritic biotite syenite; E: 114°15′22″, N: 41°47′09″), U-Pb2020055 (porphyritic biotite syenite; E: 114°13′59″, N: 41°46′30″), and U-Pb2021032 (porphyritic biotite monzonitic granite; E: 114°14′01″, N: 41°48′02″). All of these samples were fresh and unaltered.”

11. You noted in the PDF note that“Figure 7: what do the grey patterns mean? Areb the analysed granites compared with other granites? Which are these?”

Reply: Thanks for your constructive suggestions. This revision includes a legend for Figure 7, clarifying that the gray fields represent literature data and indicating the source of these literature data.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Interesting data but why? You need to explain the relevance of your data, why you chose a particular suite of samples and how it is relevant to the wider question you are seeking to answer.

Comments on the Quality of English Language

Generally fine but after I read the manuscript I still didn't really understand what the authors were trying to say.

Author Response

1. Dear Professor,

   Thank you for the comments on the manuscript of the reviewers and yourself. We have revised our paper entitled “Mesoproterozoic (~1.3 Ga) A-type granite on the northern margin of the North China Craton: response to breakup of the Columbia supercontinent”, carefully taking into account the comments and suggestions in the reviews. All reviews were supportive and constructive. Our responses for the referee’s comments are listed as follows.

    

   Reviewer 2 comments

   1. Interesting data but why? You need to explain the relevance of your data, why you chose a particular suite of samples and how it is relevant to the wider question you are seeking to answer.

   Reply: Thanks for your constructive suggestions. The North China Craton (NCC) is considered to be a crucial component of the Columbia supercontinent. Within this, the Palaeoproterozoic Khondalite Belt (~1.95 Ga) and the Central Orogenic Belt (~1.85 Ga) responded to the convergence process of the Columbia supercontinent. Nevertheless, due to the lack of reliable isotopic data concerning Mesoproterozoic magmatism and tectonism, considerable discrepancies persist among researchers regarding how the NCC participated in the rifting of the Columbia supercontinent. Mesoproterozoic (~1.3 Ga) magmatism in the North China Craton (NCC) was characterized by diabase sills, while contemporary granitic magmatism was relatively rare, limiting our understanding of the NCC’s evolution during this period. The Mesoproterozoic rock mass was newly identified in the process of a 1:50000 regional geological survey in this area. Therefore, based on detailed petrology, petrography, whole-rock geochemistry, isotope chronology, and Hf isotope studies, this paper attempts to carry out in-depth research on the giant porphyritic granites in the Huade-Kangbao area of Inner Mongolia, in the middle part of the northern margin of the North China Craton. They are identified as acidic magmatic activities related to extension-cracking in the northern margin of the North China Craton during the period of 1.3-1.2 Ga, representing the response of the Columbia supercontinent rifting in the northern margin of the North China Craton.

   2. Comments on the Quality of English Language Generally fine but after I read the manuscript I still didn't really understand what the authors were trying to say.

   Reply: Thanks for your constructive comments. In this paper, the petrochemistry, zircon U-Pb chronology, and Hf isotope analysis of the Mesoproterozoic granites in the northern margin of the North China Craton are studied, and the relationship between the Mesoproterozoic granites in the northern margin of the North China Craton and the rifting of the Columbia supercontinent is expounded. The author is deeply aware that there are prominent problems in English expression. After this revision, we invited professionals with good English to check the full text.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This MS requires some serious editing and rewriting. Quite apart from deficiencies in the English and repeated use of made-up terms not in the geological dictionary, sections of the text were difficult if not impossible to follow -e.g. petrographic descriptions and the reference to Triassic intrusions that would appear to have no bearing on the stated aims of the paper (granite petrogenesis during Mesoproterozoic Columbia breakup). Other problems include the freshness of samples for which geochemistry is presented as the petrographic descriptions repeatedly refer to K-alteration and/or metasomatism. Accordingly, can a reader be assured that the analysed samples were fresh. And just which samples were dated or geochemically analysed? Did the latter include the Triassic rocks or were only Mesoproterozoic samples used - there needs to be more clarity about this in the relevant sections. The abstract would further suggest that a single A-type granite was the focus of the study when in fact a number of granites were examined and analysed. I have pointed out this and other various problems with the MS in the attached annotated pdf. This can be passed on to the authors. Thus, all up, I recommend that the MS be returned to the authors for major revision.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

See the attached pdf for highlighted problems with the English. Particularly disconcerting was the inappropriate use of the singular over plural when describing the granites. The abstract implies that the study is focused on a single A-type granite when in fact samples were drawn from more than one intrusion. What bearing do the Triassic granites have on the aims of the study - were they also analysed and plotted, and if so this needs to be clarified

Author Response

1. This MS requires some serious editing and rewriting. Quite apart from deficiencies in the English and repeated use of made-up terms not in the geological dictionary, sections of the text were difficult if not impossible to follow -e.g. petrographic descriptions and the reference to Triassic intrusions that would appear to have no bearing on the stated aims of the paper (granite petrogenesis during Mesoproterozoic Columbia breakup). Other problems include the freshness of samples for which geochemistry is presented as the petrographic descriptions repeatedly refer to K-alteration and/or metasomatism. Accordingly, can a reader be assured that the analysed samples were fresh. And just which samples were dated or geochemically analysed? Did the latter include the Triassic rocks or were only Mesoproterozoic samples used - there needs to be more clarity about this in the relevant sections. The abstract would further suggest that a single A-type granite was the focus of the study when in fact a number of granites were examined and analysed. I have pointed out this and other various problems with the MS in the attached annotated pdf. This can be passed on to the authors. Thus, all up, I recommend that the MS be returned to the authors for major revision.

Reply: Thanks for your constructive suggestions. The author carried out this research based on a 1:50,000 regional geological survey. Based on the petrochemistry, zircon U-Pb chronology, and Hf isotope analysis of the Mesoproterozoic Xiaoyingtu, Chahancun, and 1488 highland intrusion in the study area, the petrogenesis of the granite during the Mesoproterozoic Columbia rifting is described in this paper. This revision clarifies the specific content of this study in the abstract and body, and makes item-by-item revisions according to the issues you pointed out in the body.

2. Comments on the Quality of English Language. See the attached pdf for highlighted problems with the English. Particularly disconcerting was the inappropriate use of the singular over plural when describing the granites. The abstract implies that the study is focused on a single A-type granite when in fact samples were drawn from more than one intrusion. What bearing do the Triassic granites have on the aims of the study - were they also analysed and plotted, and if so this needs to be clarified.

Reply: Thank you for your valuable suggestions. By referring to the attached pdf, the author has deeply realized that there are prominent problems in English expression. After revising the article according to your comments, we invited professionals with good English to check the article.

3. You noted in the PDF note that “the use of a single sample to determine the genesis of a much larger granite suite is surely unwise. How can a reader be sure that your sample of this suite is truly representative of the granite suite as a whole?

Reply: Your comments are constructive and helpful. Based on the 1:50,000 regional geological survey, a systematic field survey of Mesoproterozoic intrusions in the area was carried out in this study. Three U-Pb dating samples, nine whole-rock geochemical samples, and one zircon Hf isotope sample were taken.

4. You noted in the PDF note that “Is this the same granite referred to above? It is not clear. And if brecciated how can you be sure that its composition has not changed (your high K20 etc) or been altered during brecciation - see earlier point about choice of a representative sample. Or is this a typographic error and the word should be :megacrystic.”

Reply: I'm terribly sorry, this is a spelling mistake on my part. I have modified “megabreccia granite” to “porphyritic granites”.

5. You noted in the PDF note that “what does this mean? the NCC may have some bearing on ideas regarding the rifting and breakup of Columbia but it did not play a role.”and“ditto - what or who is an early scholar? Do you mean “Some researchers have previously proposed....”?”.

Reply: Thanks for your constructive comments. The above problems are not clearly expressed by the author and have been rephrased in this revision.

6. You noted in the PDF note that “Why does this have to be extensional in origin? It seems odd to include an alteration process in the same sentence as magmatic intrusion”.

Reply: Thanks for your constructive comments. Shao et al. (2002) suggested that there was extensive alkaline metasomatism in the northern margin of the North China Craton during the period of 1.3-1.2Ga, which can be regarded as important evidence for large-scale crust-mantle interactions. During this stage, there was also the intrusion of basaltic sills, but the scale was not as significant as that of the first stage.

7. You noted in the PDF note that “why insert this phrase in respect of this magmatic event and not the others? Is this a means of differentiating this event from other rift-related events?”.

Reply: Thanks for your constructive comments. Typical anorogenic rock assemblages, including anorthosite complexes, rapakivi granites, A-type granites, and alkaline rocks, were exposed in the North China Craton between 1.72 and 1.62 Ga. These rocks are primarily distributed along the Xiong'er and Yanliao rifts, representing the magmatic activity associated with the continued rifting process triggered by mantle plumes.

8. You noted in the PDF note that “what does plagioclase-striated assemblage mean? And how come peridotite - an ultrabasic or ultramafic rock- is part of the assmblage? Is this a typographical error?”.

Reply: I'm terribly sorry, this is a spelling mistake of mine.This modification has changed it to “anorthosite-mangerite-charnockite-rapakivi granites assemblage”.

9. You noted in the PDF note that “why not say your sample is from the area in question?”.

Reply: Thanks for your constructive comments. The sills are scattered in an area of over 600 km in length and 200 km in width (1.2 ×105 km²) and compose a Mesoproterozoic large igneous province (LIP; Zhang et al., 2018).

10. You noted in the PDF note that “Grade 1, 2, 3?? What does this mean or refer to? This is a very unusual notation to adopt. And how can they be delineated by single faults??”.

Reply: I'm grateful for your constructive opinions. In this revision, terms such as "Grade I units", which have no meaning outside the Chinese geological community, have been deleted and rephrased.

 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Dear authors,

I see that you have accepted my emendations that I made up to the Discussion, but have not improved the English after that, which frankl annoyed me.

Thus, please correct the language of the complete manuscript and ask someone with a better grasp of English to help you out. I have made further changes up to line 381 to show further examples.

 

A few sentences need to be rephrased as they are unclear or self-contradictory (see notes in annotated PDF).

For this reason I will this time recommend major revisions. 

Kind regards

 

Comments for author File: Comments.pdf

Comments on the Quality of English Language

see remarks above

Author Response

Please see the attached file. Thank you.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Thank you, your revisions are appropriate. Please check the manuscript carefully. I note the misspelling of isotope in line 51 but there may well be other mistakes.

Author Response

Please see the attached file. Thank you.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Despite some improvement to the English in parts of the text, other sections of the MS are still no easier to understand and require serious revision and/or rewriting. Specific problems are highlighted in green on the attached pdf. The petrographic descriptions in particular need to be improved to ensure consistency between the text and figures. Similarly, the discussion on granite petrogenesis could be improved and more thought given to the possibility that your A-type granites were derived through the melting of juvenile crust rather than metasedimentary rocks; this does not rule out crustal contamination by the granite melts. To see how this might be done, you could read a paper by compatriots of yours who recently published a 2024 paper on A-type granites of the same age in North China (Jim et al in GSA Bulletin). Papers by Bonin, Condie and Frost et al have also written widely on A-type granites as your reference list shows but drew quite different interpretations to yours. It might pay to re-read their papers and conclusions.  

Comments for author File: Comments.pdf

Comments on the Quality of English Language

See attached pdf. 

Author Response

Please see the attached file. Thank you.

Author Response File: Author Response.pdf