Petrogenetic Constraints of Early Cenozoic Mafic Rocks in the Southwest Songliao Basin, NE China: Implications for the Genesis of Sandstone-Hosted Qianjiadian Uranium Deposits

Round 1

Reviewer 1 Report

This is a relatively straightforward and rather well written paper dealing with Early Cenozoic mafic rocks and their relations with the Qianjiadian uranium deposit.The authors provide new isotopic ages, isotope geochemical data and data on major and trace elements. The authors suggest a more or less reasonable model of the genesis of the rocks under consideration based on standard geochemical reconstructions. According to speculations of the authors, these data favor an idea that tectonic inversion of the Songliao Basin during the Cenozoic may have played a significant role in formation of sandstone-type uranium deposits. From my point of view, this tectonic inversion is shown in a vague way which can clearly be seen in Figure 15. In addition, explanations of this model in text are too short. However, if the authors revise Figure 15 and make it more understandable (see my notes in an attached pdf-file), there is no need in editing the text. Revision of Figure 15 is the only serious note.

As to figures, use the same symbols for alkali and tholeiitic basalts in all of figures. It will make reading and understanding figures simpler and better.

To my opinion, the authors sometimes use a wrong style in citing, as if this style is not accepted in Minerals.

At last, English is understandable, but it MUST be checked by a English-speaking geologist. I did not understand in several places what the authors meant. Though English is not my native language, I have dared to suggest corrections in some cases. Again, the text must be checked by an English-speaking person.

Comments for author File: Comments.pdf

Author Response

Response to Reviewer 1 Comments

 

 

Point 1: From my point of view, this tectonic inversion is shown in a vague way which can clearly be seen in Figure 15. In addition, explanations of this model in text are too short. However, if the authors revise Figure 15 and make it more understandable (see my notes in an attached pdf-file), there is no need in editing the text. Revision of Figure 15 is the only serious note.

Response 1: Fig 15 has been revised.

 

Point 2: As to figures, use the same symbols for alkali and tholeiitic basalts in all of figures. It will make reading and understanding figures simpler and better.

Response 2: Revised as suggested, see Figs 6, 7, 8, 9, 12, 13, and 14.

 

 

Point 3: To my opinion, the authors sometimes use a wrong style in citing, as if this style is not accepted in Minerals.

Response 3: We have revised the wrong citation format throughout the manuscript, see attachment named Revised Manuscript with Track Changes.

 

Point 4: At last, English is understandable, but it MUST be checked by a English-speaking geologist. I did not understand in several places what the authors meant. Though English is not my native language, I have dared to suggest corrections in some cases. Again, the text must be checked by an English-speaking person.

Response 4: English has been polished by an English-speaking geologist. See attachment named Revised Manuscript with Track Changes.

 

 

Point 5: Line 1, Title. Petrogenetic constraints of Early Cenozoic mafic rocks in THE southwest Songliao Basin, NE... 


 

Response 5: Revised as suggested, see revised manuscript with track changes.

 

Point 6: Lines 29-30, ...origin that underwent enrichments in... Perhaps, origin includes enrichment.

 

Response 6: Revised, see revised manuscript with track changes.

 

Point 7: Line 30, subduction-derived components? There can be basalt-derived components, slab-derived components, and so on. What you mean?

 

Response 7: Slab-derived components, such as carbonate sediment was proposed.

 

Point 8: Lines 48–49, The tectonic evolution... as the key factors... Inconsistency: singular vs. plural. 


 

Response 8: Singular key factor was suggested.

 

Point 9: Line 49, [01–6]? Perhaps, [1-6]

 

Response 9: Revised.

 

Point 10: Line 52, ...emplaced during extension and uranium deposits? Perhaps, during extension and uranium depositon.

 

Response 10: Revised, see revised manuscript with track changes.

 

Point 11: Line 70, ...presented in [33].... 


 

Response 11: Revise as suggested, the similar modification about citation format throughout the manuscript see attachment named Revised Manuscript with Track Changes.

 

Point 12: Line 77, ...location of THE Songliao...

 

Response 12: Revised.

 

Point 13: Line 82, dill? Perhaps, drill? It would be better "stratigraphic or lithological column"

 

Response 13: Revised as suggested.

 

Point 14: Lines 107–108, ...combined with previous studies on low-temperature thermochronologic data...? Perhaps, ...combined with previous low-temperature thermochronologic data...

 

Response 14: Revised as suggested.

 

Point 15: Lines 114–116. Swap two sentences in these lines.

 

Response 15: Revised as suggested.

 

Point 16: Line 120, ...were deposited IN a syn-rifting tectonic setting.

 

Response 16: Revised.

 

Point 17: Line 133–134, Based on crystalline degree? Perhaps, Based on crystal or grain sizes...

 

Response 17: Revised.

 

Point 18: Lines 135–136, Inconsistency: MEDIUM- TO COARSE- grained rocks are MAINLY composed of FINE-grained rocks.

 

Response 18: Revised, "fine grained” was deleted.

 

Point 19: Line 192, ...{sampleS BLS12-1...

 

Response 19: Revised.

 

Point 20: Fig. 6b, Replace "Data from Cheng et al., 2018" with "Tholeiitic basaltic rocks from [37]"; replace "Data from Xu et al., 2012" with "Alkaline basalts from [46]". The numeric style is used, and the use of 2018a and 2018b in the reference list is redundant. By the way, symbols for data from [37] and [46] are badly distinguishable; it would be better to have them solid (pink and green or something similar).

 

Response 20: Revised, see Fig 6b and references [21] and [37].

 

Point 21: Fig. 6c, symbol grey circle is not deciphered.

 

Response 21: Revised, see Fig 6c.

 

Point 22: Fig. 6c, what does a short line in the centre of the potassium field mean?

 

Response 22: Revised, the short line in the centre of the potassium field was deleted.

 

Point 23: Fig. 6. I recommend arranging Legend at the bottom of the entire figure rather than within panel "b" (it is funny that these sympols are lacking in this panel).

 

Response 23: Revised as suggested, see Fig 6.

 

Point 24: Lines 229–230, Sentence "In general, Ni and Co contents INCREASE ARE..." is not understandable. What do you mean? In general, the increase of Ni and Co contents is positively correlated with the increase of MgO contents in AB and TB groups?

 

Response 24: Revised as suggested.

 

Point 25: Fig. 8b, replace "Alkali basalt from Xu et al., 2012" with "Alkali basalt from [46]" Fig. 8d, replace "Tholeiitic basalt from Cheng et al., 2018" with "Tholeiitic basalt from [37]"

 

Response 25: Revised as suggested, see Fig 8.

 

Point 26: Fig. 9a, replace "Alkali basalts from Xu et al., 2012" with "Alkali basalt from [46]" and replace "Tholeiitic basalts from Cheng et al., 2018" with "Tholeiitic basalt from [37]"

 

Response 26: Revised as suggested, see Fig 9.

 

Point 27: Lines 278–279, "The olivine exhibits subhedral to euhedral shapes (or contours)..." (rocks can have subhedral and euhedral textures rather than minerals).

 

Response 27: Revised, “granular in texture” was suggested.

 

Point 28: Sentence in lines 278–282 must be edited. In particular, the second part of this long sentence (...the olivine xenocrysts of the peridotite xenoliths entrained from the shuangliao basalts [62], indicating magmatic phenocrysts, differing from fragmented mantle-derived xenocrysts.) is badly written.

 

Response 28: Edited, see revised manuscript with track changes.

 

Point 29: Fig. 10a and b, I would recommend incorporating mineral abbreviations into the photos. Sure, it is clear that the central crystals are olivine but what about the surrounding minerals?

 

Response 29: Mineral abbreviations have been incorporated into the photos.

 

Point 30: Line 317, ...(Figure 5d) suggests that a crustal contamination occurred...

 

Response 30: Revised.

 

Point 31: Line 321, "and TB group."

 

Response 31: Revised.

 

Point 32: Fig. 12a, replace "Alkali basalt from Xu et al., 2012" with "Alkali basalt from [46]" and replace "Tholeiitic basalt from Cheng et al., 2018" with "Tholeiitic basalt from [37]".

 

Response 32: Revised as suggested, see Fig 12.

 

Point 33: Lines 338–339, "a relatively depleted asthenospheric generation (?)". Perphaps, you mean a relatively depleted asthenospheric source, is not it?

 

Response 33: Yes, see revised manuscript with track changes.

 

Point 34: Lines 346–347, the following part of text needs to be edited: "(those low Ce/Pb sample may reflect fluid mobile elements Pb was affected by post magmatic processes)". I can only guess what you mean.

 

Response 34: Revised.

 

Point 35: Line 359, (including those from Japan island arc) — I recommend the following name: (including those from the Japanese island arc system).

 

Response 35: Revised as suggested.

 

Point 36: Lines 389–392. As I could have understand you mean that "The AB group displays major and trace element compositions different from those of the TB group...". Furthermore, the rest of this sentence also needs editing.

 

Response 36: Edited as suggested.

 

Point 37: Lines 402, ...the AB group HAS...

 

Response 37: Revised

 

Point 38: Lines 402–403, ...while most SAMPLES...

 

Response 38: Revised

 

Point 39: Line 422, ...A similar mantle source...

 

Response 39: Revised.

 

Point 40: Line 433, replace the Chinese hieroglyphs with English text.

 

Response 40: Revised.

 

Point 41: Fig. 15. However, the lithospheric thinning is NOT SHOWN in this figure. The structure of the tectosphere in panel (a) is identical to that in panel (b), no change occurred from 50 Ma to 40 Ma ago. But this thinning MUST be shown because it is important for the main results of this study. Using arrows, you must show extension in panel (a) and the consequent uplift in panel (b). Furthermore, you must shown how the increasing body of a slab beneath the asthenosphere sole resulted in the tectonic uplift. Two more notes to Fig.15. (1) Lithosphere is a rigid, rocky outer layer of the Earth, consisting of the crust and the solid outermost layer of the upper mantle. In other words, lithosphere consists of the crust and lithospheric mantle that composes the solid outermost layer of the upper mantle. It is this layer that is named "lithosphere" in Fig. 15a and b, i.e. lithosphere occurs beneath the crust. It is a glaring mistake. (2) Panel (c) shows tectonic inversion stating ca. 40 Ma ago. Extension occurred before this event. But exactly what tectonic process was happening during this inversion? You say that it was a new episode of tectonic uplift. You must indicate inversion from extension to tectonic uplift in panel (c). Name "inversion" written in panel (c) means nothing, you should name a concrete tectonic event (uplift).

 

Response 41: Revised, the lithospheric thinning has been in Fig 15b. Extension in panel (a) and the consequent uplift in panel (b) have been shown with arrows. Lithosphere has been replaced with Lithospheric mantle Fig 15a and b. Tectonic inversion has been replaced with tectonic uplift in Fig 15c.

 

Point 42: Line 496, ...In the Hangjingqi area basalts were emplaced at 126.2 ± 0.4 Ma...

 

Response 42: Revised.

 

Point 43: Line 498, Miocene tectonic uplift (not tectonics uplift!) [105], which IS similar...

Response 43: Revised.

 

Point 44: Conclusions. Abstract says that the following scenario is proposed for the study area:"(i) Eocene (~50–40 Ma) lithospheric thinning and crustal extension during which mafic rocks intruded the host sandstones of the Qianjiadian deposit, (ii) a tectonic inversion from extension to tectonic uplift attributed to the subduction of the Pacific Plate occurred at ~40 Ma, and (iii) Oligo–Miocene (~40–10 Ma) tectonic uplift, which is temporally associated with U mineralization." Actually, these items belong to the main results of this study (along with isotope ages and origin of melts parental for alkali and tholeiitic basalts). However, conclusions say about these items in a vague way. Again, you must say definitely that inversion occurred from some concrete tectonic process to other, and the latter represents reducing environment that plays an important role in the uranium mineralization.

 

Response 44: Revised, see the conclusion part.

 

Author Response File: Author Response.docx

Reviewer 2 Report

Dear Authors,

I attached all my comments in the main text . They are mostly technical. Please, check again all citations. A lot of them are not formatted for the Minerals journal. The whole investigation convinced me for the final conclusions. However, me as a mineralogista a feel some lack of mineralogy in the paper. You have focused mostly on Zr data, Ol chemistry, but the whole background is very limited. Can you include at least one more figure dedicated to the mineralogy? Like one BSE fig with the assotiated minerals?

Comments for author File: Comments.pdf

Author Response

Response to Reviewer 2 Comments

 

Point 1: I attached all my comments in the main text. They are mostly technical.

Response 1: Revised as suggested, see revised manuscript with track changes.

 

 

Point 2: Please, check again all citations. A lot of them are not formatted for the Minerals journal.

The whole investigation convinced me for the final conclusions.

Response 2: We have revised the wrong citation format throughout the manuscript, see attachment named Revised Manuscript with Track Changes.

 

Point 3: However, me as a mineralogista a feel some lack of mineralogy in the paper. You have focused mostly on Zr data, Ol chemistry, but the whole background is very limited. Can you include at least one more figure dedicated to the mineralogy? Like one BSE fig with the assotiated minerals?

Response 3: The BSE image showing mineral associations has been added in Fig 3d.

 

Point 4: Line 143, Please add more description to this figure. Commentary on fig 3b-d is needed.


 

Response 4: Revised as suggested, see revised manuscript with track changes.

 

Point 5: Lines 178-181, this part should be in supplementary materials. The authors need to add a few more details about the EMPA like signal(s) used, spectrometers conditions, and standard name for each element.

 

Response 5: Added, see revised manuscript with track changes.

 

Point 6: Fig 10, the main aim for the figure is to focus on olivine crystals. From petrotrological point of view it is important to describe assoctiation. The authors do not have to do it in details, but they can indicate associated minerals with the olivine on fig. 10 a and b.

 

Response 6: Revised as suggested, mineral abbreviations have been added in Fig 10 a and b.

 

Point 7: Fig 10, t%? what does it means? 


 

Response 7: Revised, see Fig 10 c and d, Fo=100*Mg/(Mg+Fe+Mn).

 

Point 8: Figure 8. Wrong way of citation, change it.

 

Response 8: Revise as suggested, the similar modification about citation format throughout the manuscript see attachment named Revised Manuscript with Track Changes.

 

 

Author Response File: Author Response.docx

Reviewer 3 Report

The work proposed by the Authors deals with an in-depth petrological study of the Eocene mafic rocks in the Songliao Basin, NE China, aimed at providing useful data to understand the tectonic evolution of the basin and to understand the role of the magmatic rocks in the genesis of uranium ores occurring in the basin.  While I found the methodological scheme of the work well organized -  in particular the analytical methods are appropriate to develop in detail the petrological aspects of the studied magmatic rocks- and I appreciated both the exposition of data and the discussion regarding the geological and tectonic implications of the petrological study,  I must say that the objectives of the work are only partially achieved as regards the mineralizing phenomena, which appear poorly documented and developed in a rather speculative manner in the discussion. Despite references to existing literature, basic data on ores and host rocks (mineralogy, petrography, geochemistry, type and extent of the alteration zones, etc.) are lacking, and I found the paragraph on "petrography" of sandstones totally inconsistent. Given the structure of the work, I do not expect extreme detail on this part, but at least some essential data that could provide to better frame the role played by magmatic rocks and their alteration halos in mineralizing phenomena, to integrate the two parts of the work together, and to give substance to the final discussion on this point.  These considerations associated with the lack of an important Figure cited in the text (Figure 7!) lead me to suggest a Major Revision for the paper. English is good, apart from small typos in the text and figures. See the attached text for my further observations and suggestions.

Comments for author File: Comments.pdf

Author Response

Response to Reviewer 3 Comments

 

Point 1: The work proposed by the Authors deals with an in-depth petrological study of the Eocene mafic rocks in the Songliao Basin, NE China, aimed at providing useful data to understand the tectonic evolution of the basin and to understand the role of the magmatic rocks in the genesis of uranium ores occurring in the basin.  While I found the methodological scheme of the work well organized -  in particular the analytical methods are appropriate to develop in detail the petrological aspects of the studied magmatic rocks- and I appreciated both the exposition of data and the discussion regarding the geological and tectonic implications of the petrological study,  I must say that the objectives of the work are only partially achieved as regards the mineralizing phenomena, which appear poorly documented and developed in a rather speculative manner in the discussion. Despite references to existing literature, basic data on ores and host rocks (mineralogy, petrography, geochemistry, type and extent of the alteration zones, etc.) are lacking, and I found the paragraph on "petrography" of sandstones totally inconsistent. Given the structure of the work, I do not expect extreme detail on this part, but at least some essential data that could provide to better frame the role played by magmatic rocks and their alteration halos in mineralizing phenomena, to integrate the two parts of the work together, and to give substance to the final discussion on this point.  These considerations associated with the lack of an important Figure cited in the text (Figure 7!) lead me to suggest a Major Revision for the paper. English is good, apart from small typos in the text and figures. See the attached text for my further observations and suggestions.

Response 1: Thank you for your positive comment. We have revised the inconsistent paragraph and changed Title 4.5 with “Characteristics of the host-sandstones and secondary alteration related to mafic intrusions”. In addition, some geochemical data from samples of the green zone has been added to reveal effects of basic intrusions on U mineralization. The missing Figure 7 also has been added in the text. For details, see part 4.5 in the revised manuscript with track changes.

 

Point 2: Line 13, #3, I suppose... 


 

Response 2: Revised, see revised manuscript with track changes.

 

Point 3: Lines 42, Songliao.

 

Response 3: Revised.

 

Point 4: Line 131, crosscut

 

Response 4: Revised.

 

Point 5: Lines 132-133. I think that in spite of the quote of Bonnetti et al., some more data on this point are required in the work to properly develop the discussion on uranium mineralization: e.g., what's the mineral composition and size (extension) of the alteration halos around the mafic bodies?

 

Response 5: Added, the mineral composition of the green alteration include newly precipitated chlorite, epidote and carbonate.

 

Point 6: Line 248, IMPORTANT: I think that the Figure 7 is missing!

 

Response 6: Added.

 

Point 7: Line 293, basaltic.

 

Response 7: Revised.

 

Point 8: Line 296. Absolutely no petrography here, this title MUST be changed. 


 

Response 8: Changed as suggested, see new title 4.5 Sandstone alteration related to the mafic intrusions.

 

Point 9: Lines 297-306. See also my note above. Apart from some general consideration on macroscopic scale ("green" alteration, bleaching of oxidated sediments) and a reference to the work of Bonnetti et al (2017), compositional information about sandstones and alteration halos in sandstones are here totally lacking. If you want to discuss the genesis of the uranium mineralization it's essential to provide some detail about the spatial (extension) and compositional features (mineralogy, geochemistry, petrography) of these.

 

Response 9: Revised, detail about the spatial and compositional features of these Yaojia Formation sandstone have been added. See revised manuscript with track changes.

 

Point 10: Figure 11, array, source.

 

Response 10: Revised, see new Fig 11.

 

Point 11: Line 321, HB? TB, I guess....

 

Response 11: Revised as suggested.

 

Point 12: Lines 323–329. The Figure 7 is missing in the text!

 

Response 12: Added.

 

Point 13: Line 351, different.

 

Response 13: Revised.

 

Point 14: Lines 358–361. This sentence is badly expressed and definitely cryptic... please rewrite!

 

Response 14: Revised.

 

Point 15: Line 392, sources.

 

Response 15: Revised.

 

Point 16: Line 413, TB group, I guess...

 

Response 16: Revised.

 

Point 17: Line 423, may suggest: " have controlled"?

 

Response 17: Revised.

 

Point 18: Line 433, Translate to English, please..

 

Response 18: Revised.

 

Point 19: Fig. 15a and b, Basin, Stagnant. Fig. 15c, Integral.

 

Response 19: Revised, see new Fig 15.

 

Point 20: Line 433, proposed?

 

Response 20: Revised.

 

Point 21: Line 459, Bacterial Sulfate Reduction - perhaps it's better here to report the acronym in full

 

Response 21: BSR has already existed in line 65, bacterial sulphate reduction (BSR).

 

Point 22: Line 459, organic

 

Response 22: Revised.

 

Point 23: Lines 470–472. I think that these concepts deserve more attention, and should be expanded: what kind of alteration in mafic rocks?

 

Response 23: Revised, the alteration in mafic rocks is mainly carbonation.

 

Point 24: Lines 278–279, I agree with you in principle, but I think that this part of the discussion should be supported by petrographic evidences in the previous parts of the text. Only here we have some details on alteration minerals in sandstones! moreover, why do not define the "green alteration" as a form of propylitic alteration?

 

Response 24: Revised, see title 2. Geological setting, the "green alteration" is mainly newly precipitated chlorite, epidote and carbonate in sandstone, which differ from the propylitic alteration.

 

Point 25: Line 500, important

 

Response 25: Revised.

 

 

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

Thank you for having responded to each point: I think the paper is improved in every problematic issue I found in my previous revision.