Copper Sulfide Remobilization and Mineralization during Paleoproterozoic Retrograde Metamorphism in the Tongkuangyu Copper Deposit, North China Craton
Round 1
Reviewer 1 Report
Review of Revised manuscript “Copper sulfide remobilization and mineralization during Paleoproterozoic retrograde metamorphism in the Tongkuangyu Cu deposit, North China Craton”,
By Liu et al.
Comments
This article reports on results from a variety of approaches that were used to study the origin of metamorphosed copper deposits within the North china craton. The work is detailed and I would like to see it published after some minor-to-moderate revisions have been done – mostly editorial. A few minor-to-moderate points are noted here and they are also highlighted on the accompanying PDF file. Only lines on the actual PDF are referred to here for the authors to correct either the minor editorial work or where the wording is not clear.
Specific points to address are explained here:
Line number
1 – insert comma
2 – specify “petrographic”
3 – include error on age; and also the age at which metamorphism occurred
13 – insert “the”
23 – editing needed as the writing is not clear here
46 – include error on the age
62 – delete comma and insert “is” before “a”
65 – replace “as” with “to be”
75 – replace “covered” with “overlain”
92 – start sentence with full word, not abbreviation
100-101 – not clear, edit the highlighted part of the sentence
109-110 – delete the sentence – it’s not needed
Figure 3 caption – correct as indicated
200 - Change to V-SMOW
244-245 – belongs to Materials and Methods section
247 – replace “vigorously” with “well”
251 – change “is” to “are”
252 – should be “relations” not “relation”
204 – change “comparing” to “compared”
266-267 – this is discussion and should be moved to that section.
270 – same as on line 204
272 – this needs editing, and a period in there as well.
279-280 same as on 266-267
283 – change “studied” to “also analyzed for”
291 - change “high” to “higher”
303 – same as on line 92
309 – change “content” to “contents”
311 – change “featured” to “characterized”
314 – change “is” to “was’
317-318 – not clear, should there be +/- 14 to the temperature value? Rectify this. Within 1 what?
326 – delete “in”
362 – i. something IS missing here;
ii. fluid should be subscript;
iii. fix the “per mil” SYMBOL from here downwards.
377- change “suggest” to “suggesting”
379-380 – not a complete sentence, fix this.
383 – i. make “fluid” subscript;
ii. change “comparing” to “compared”
Table 4 - font too small
Table 5 – fix per mil symbol
422-424 – explain further the interpretation in this sentence; why the Pb isotope ratio would be missing?
455 – change “comparing” to “compared”
457 change “are” to “were”
461 – change “base” to “based’
478 – insert “a”
481 – insert “to be”
485 – not clear – edit this part
486 – insert “that”
489 – include a reference number here in place of “?”
491 – replace “to” with “with”
492 – change “signature” to “signatures”
500 - insert “been”
Comments for author File: 
Comments.pdf
Author Response
Dear reviewer,
Thanks for kindly reviewing this manuscript. Please see the attached pdf for our responses to your comments.
Kind regards,
Xuan Liu
Author Response File: Author Response.pdf
Reviewer 2 Report
Review of ms by Xuan Liu et al. on “Copper sulfide remobilization and 27/6/19 mineralization…Tongkuangyu Cu deposit, North China Craton”.
General comments
This interpretation repeats a common weakness: how to explain the sequence of events which leads to mineralization which has been metamorphosed. As usual the explanations include and invite confusion. Early in section 6.4, “we propose that, at Ca 2.2 Ga, initial stratabound copper sulfides…” and “At ca. 1.9Ga… the generated fluids might be responsible for mineralization during retrograde metamorphism…” “A potential source of fluid might be metamorphic fluids released from deeper basement rocks.” I.e., little certainty re the origins and results of possible ore-forming fluids.
The research proposes an explanation for (mainly) copper-iron sulfide mineralization in strongly metamorphosed terrain, with an emphasis on textures and multiple chemical, isotopic and other analyses. Ultimately, it presents an metamor(phogen)ic model (section 6.4) which unfortunately resorts to generalized concepts which advance our knowledge and understanding of metamorphosed mineralization surprisingly little. Even the expression “metamorphogenic model”, the leading phrase of section 6.4, is unfortunately used in its usual ambiguous sense – which part of the model is metamorphic, why is “the model” said to be metamorphic when portions are pre-metamorphic (and possibly post-metamorphic), etc?
The paper speaks of redox-sensitive mineral associations: e.g., hematite and biotite. Does it seriously expect these two minerals to be stable associates? The paper does not respect redox stabilities: mutual stabilities and mutual exclusions.
The redeeming value is in the analyses, which one day may prove very useful. And deserve publication; if necessary, independent of the genetic modeling attempted in this paper.
The paragenetic diagram (Fig. 4) is very elementary. Without discussing each mineral’s “lozenge”, it is obvious that little careful thought has gone into the construction of this diagram.
The authors should subdivide lengthy paragraphs into new paragraphs.
The paper is basically readable, but the English is poorly written. An anglophile should have given the ms a serious review before submission.
Specific comments
Numerous comments may be found on the returned pdfs (apologies for returning 2 copies – I began on one computer and finished on a second, without means to merge the two).
The numerous edits on the abstract alone are indicative of the editing that is needed throughout the remainder of the text. Please have the entire text revised by a competent anglo.
Comments for author File: Comments.pdf
Author Response
Dear reviewer,
Thanks for kindly reviewing this manuscript. Please see the attached pdf for our responses to your comments.
Kind regards,
Xuan Liu
Author Response File: Author Response.pdf
Reviewer 3 Report
The paper was clearly composed in general, some points listed below need to be corrected or clarified only.
* Figure 1: The abbreviated name of "Hu-Bi" (Huyiau-Bizigou) deposits should be replaced with the full name. This abbreviation is introduced in row 99 only.
* Row 83: "crenulation cleavage (S2) overprinted on S2" - on S1, obviously.
* Row 108: "stratiform orebodies" - The term stratiform implies the syngenetic origin of the host rock and the ore. If the paper concludes that this is not the case (and anyway, this origin was not accepted generally as well), 'stratabound orebodies' would be the appropriate description.
* Figure 2: Part (c) does not show any "locations for observing and sampling". Better leave out this part of the caption. On the other hand, the sketch would be more effective with hatching (like the other 3 parts) instead of letter codes.
* Figure 3f: "no sign of metamorphic influence" - The authors may mean no influence of the ductile deformation (like row 136 says, referring to that picture), or rather no overprint. Bn (bornite) is missing from the list of the abbreviations below.
* Figure 4: "bonite" is bornite, misspelled?
* Row 189: "a focused electron beam of 5 m" - 5 microns, μm, probably.
* Row 272: "rel By contrast" - What's this?
* Figure 6: Is the last sentence the explanation for part (d)? Anyway, the referred publications refers this diagram further to Sangster (1990).
* Row 291: "sulfides of the Zhongtiao Mountain are high than those of the upper crust" - Something is missing here, what is higher in these sulfides?
* Row 296: "Those occur as alignments together with peak metamorphic minerals" - Do the authors mean, those occur co-oriented with peak metamorphic minerals?
* Rows 297-303: biotite codes like "Bt IBS" are later finished with lower index typography, Bt IBS. Here it should be typed in that form, too.
* Figure 8d: the form of this diagram is not exactly correct in the pdf, please redesign it!
* Row 324: "HM" is MH on the referred diagram.
* Figure 9: Are the points of diagram (a) individual point measurements (possibly some of these obtained on the same crystal grain), or do they represent grains (e.g. by averaging such series of point measurements like shown on (b))?
* Row 362: Verb is missing, "Dfluid" should look like in the next row. Per-mille signs (from this point on in several cases) do not appear correctly in my pdf text.
* Row 398: "38Ar/36Ar" - 38Ar/36Ar
* Row 461: "Base on" - Based on
* Row 489: "[? ]" - missing reference?
* Row 508 and caption of Figure 13: "stratabounded" - stratabound
* Section without numbering of the rows: "Due to a lack of large heat source and structural forces, most of the ore materials were precipitated within the locally weak zones, e.g., foliations along with cooling and decompression." - What do the authors mean by "structural forces"? Stress generated by tectonics? Foliations are penetrative planar fabric elements and not zones. Did the authors mean shear zones, possibly?
* Section without numbering of the rows: "the ore-hosting terrane may have entered into the brittle zones" - There is no such thing as brittle zone; brittle deformation became more likely with exhumation and unloading.
Author Response
Dear reviewer,
Thanks for kindly reviewing this manuscript. Please see the attached pdf for our responses to your comments.
Kind regards,
Xuan Liu
Author Response File: Author Response.pdf
