Comparative Study on Thermodynamic and Geochemical Characteristics between Cemented and Clotted Parts of Thrombolite
Round 1
Reviewer 1 Report
From 1975 according to Web data, it is pubished more 170 works on thrombolites. The formation of thrombolite minerals is observed in Archean and in other geolodgical epochs, and on all continents. These processes are happening simultaneosly as abiotic both biotic with formation of general composite thrombolites minerals. In this paper it was studied peculiarities of the microscopic components of thrombolites, which have been also studied particularly in other works (Han Y, 2020). Besides in 2020, it has been published paper by Han, Zuozhen; Zhuang, Dingxiang; Zhao, Hui at al "Comparative study on thermal behaviors between micrites and thrombolites using thermogravimetric analysis" JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY Vol.139, Issue 2. pp.1229-1242, and editorial paper by V.V. Gurzhiy on Mineralogica Crystallography, Crystals, 2020, Vol.10, 805. So, D. Zhuang with coauthors can be take into account above mentioned publications. The certain defect of this D. Zhuang paper is concluded in a weak english of the paper introduction. Here it is needed also more exactly position the reference square brakets. The main work result consist in the Zhuang Dingxiang and others discovering of different 13C content in biotic and abiotic, or cemented and clotted parts of mineral.
Author Response
Response to Reviewer 1 Comments
Comments and Suggestions for Authors: From 1975 according to Web data, it is pubished more 170 works on thrombolites. The formation of thrombolite minerals is observed in Archean and in other geolodgical epochs, and on all continents. These processes are happening simultaneosly as abiotic both biotic with formation of general composite thrombolites minerals. In this paper it was studied peculiarities of the microscopic components of thrombolites, which have been also studied particularly in other works (Han Y, 2020). Besides in 2020, it has been published paper by Han, Zuozhen; Zhuang, Dingxiang; Zhao, Hui at al "Comparative study on thermal behaviors between micrites and thrombolites using thermogravimetric analysis" JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY Vol.139, Issue 2. pp.1229-1242, and editorial paper by V.V. Gurzhiy on Mineralogica Crystallography, Crystals, 2020, Vol.10, 805. So, D. Zhuang with coauthors can be take into account above mentioned publications. The certain defect of this D. Zhuang paper is concluded in a weak english of the paper introduction. Here it is needed also more exactly position the reference square brakets. The main work result consist in the Zhuang Dingxiang and others discovering of different 13C content in biotic and abiotic, or cemented and clotted parts of mineral.
Point 1: From 1975 according to Web data, it is pubished more 170 works on thrombolites. The formation of thrombolite minerals is observed in Archean and in other geolodgical epochs, and on all continents. These processes are happening simultaneosly as abiotic both biotic with formation of general composite thrombolites minerals. In this paper it was studied peculiarities of the microscopic components of thrombolites, which have been also studied particularly in other works (Han Y, 2020). Besides in 2020, it has been published paper by Han, Zuozhen; Zhuang, Dingxiang; Zhao, Hui at al "Comparative study on thermal behaviors between micrites and thrombolites using thermogravimetric analysis" JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY Vol.139, Issue 2. pp.1229-1242, and editorial paper by V.V. Gurzhiy on Mineralogica Crystallography, Crystals, 2020, Vol.10, 805. So, D. Zhuang with coauthors can be take into account above mentioned publications.
Response 1: Thank you very much for your invaluable guidance and comments on our manuscript. Those comments are all valuable and very helpful for revising and improving our manuscript, and also have an important guiding significance to our researches. I have taken into account above mentioned publications and revised our manuscript according these publications. All changes made in the manuscript have been marked in red.
Point 2: The certain defect of this D. Zhuang paper is concluded in a weak english of the paper introduction. Here it is needed also more exactly position the reference square brakets.
Response 2: Thank you very much for your great suggestion! We have revised the manuscript carefully again and again. In addition, we have also acquired assistances from one native English speaker to further improve the manuscript quality, hoping the new manuscript will meet Journal’s standard, and all the changes were marked in red. In addition, we also find more exactly position for the reference square brakets. The reviewer's invaluable guidance will benefit us in the future research work. Thank you very much for your wonderful guidance.
Point 3: The main work result consist in the Zhuang Dingxiang and others discovering of different 13C content in biotic and abiotic, or cemented and clotted parts of mineral.
Response 3: Thank you very much for your review and patient work. In this paper, the stable carbon isotope results show that, compared with the chemical precipitated sparry calcite in the cemented part, the clotted part contains more microorganisms, which can absorb more 12C through photosynthesis and results in more 13C in the clotted part. Therefore, the carbon isotope δ13C value is higher. After careful modification, we feel the quality of our article has been greatly improved. Thank you again!
Please see the attachment
Author Response File: 
Author Response.docx
Reviewer 2 Report
Materials and Methods
- The size of particles affects the crystallinity of phases in the sample. What is the size of particles from cemented and clotted parts analyzed by XRD diffraction ? (Lines 109-118)
- The impurities from sample can be amorphous phases. It is necessary another characterization technique such as X-Ray fluorescence to determine chemical composition of the sample.
Results and discussions
- Explain in detail why the mass losses of cemented and clotted parts are different to the mass loss obtained by CaCO3 total decomposition (equation 16). Is partial the CaCO3 decomposition? (Lines 228-230)
- What properties mainly affect enthalpy change of cemented and clotted parts? (Lines 249-254)
- Explain in detail why activation energy values of the cemented and clotted parts are differents. (Lines 282-287)
Author Response
Response to Reviewer 2 Comments
Comments and Suggestions for Authors:
Materials and Methods
Point 1: The size of particles affects the crystallinity of phases in the sample. What is the size of particles from cemented and clotted parts analyzed by XRD diffraction ? (Lines 109-118).
Response 1: Thank you very much for your invaluable guidance and comments on our manuscript.
After being ground, the cemented and clotted parts were uniformly passed through a 200-mesh sieve. The content has been added at page 3 from line 114-115 marked in red.
Thanks again!
Point 2: The impurities from sample can be amorphous phases. It is necessary another characterization technique such as X-Ray fluorescence to determine chemical composition of the sample.
Response 2: Thank you very much for your invaluable guidance and comments.
The elemental compositions of cemented and clotted parts were carefully analyzed by EDS (Figures 4a and 4b). The elemental compositions of cemented and clotted parts were C, O, Ca, Al and Pt. Al element came from the stage supporting the sample, and Pt element was caused by spraying gold during sample preparation. The C, O and Ca came from CaCO3. Therefore, the chemical composition of the cemented and clotted parts were the same, and the mineral compositions were also the same combined with XRD analysis. The content has been added at page 7 from line 217-222 marked in red.
In addition, cemented and clotted parts were cleaned with NaClO before thermogravimetric analysis, and the organic matter has been removed. Therefore, only CaCO3. decomposes when the temperature reaches 900 K. Thank you very much for your wonderful review.
Results and discussions
Point 3: Explain in detail why the mass losses of cemented and clotted parts are different to the mass loss obtained by CaCO3 total decomposition (equation 16). Is partial the CaCO3 decomposition? (Lines 228-230).
Response 3: Thank you very much for your careful review and patient work.
The clotted part of thrombolite contains more microorganisms and was generally considered to be the biotic mineral. The cemented part of thrombolite contains less microorganisms and was generally considered to be the abiotic mineral. Under the action of more microorganisms, the crystallinity of calcite in clotted part was higher. Therefore, only a part of calcite decomposes and the final mass loss of clotted part was lower than cemented part under the same temperature conditions. The content has been added at page 8 from line 255-260 marked in red.
Thanks again!
Point 4: What properties mainly affect enthalpy change of cemented and clotted parts? (Lines 249-254).
Response 4: Thank you very much for your careful review and patient work.
The crystallinity mainly affects the enthalpy change of the cemented and clotted parts. The sample with higher crystallinity needs to absorb more heat from the external environment to decompose the minerals (calcite) during thermal decomposition. The crystallinity of clotted part was higher, so its enthalpy change was also larger than cemented part.
Thank you again!
Point 5: Explain in detail why activation energy values of the cemented and clotted parts are differents. (Lines 282-287).
Response 5: Thank you very much for your review and patient work.
The activation energy of clotted part was clearly higher than cemented part, which mainly caused by microbial activities affected the formation of cemented part and the crystallinity of minerals (calcite), and ultimately lead to different thermal characteristics, that is higher thermal stability and activation energy.
After careful modification, we feel the quality of our article has been greatly improved. Thank you again!
Please see the attachment
Author Response File: Author Response.docx
Reviewer 3 Report
The paper by Zhuang and Guo sounds interesting and the topic of thrombolite research is in the frontline of carbonate sedimentology. However, this paper is not fit in the journal Crystals. Firstly, because it is a multidisciplinary approach dealing with calcite minerals in thrombolites, so it is more a petrography/sedimentology paper. Secondly, I have not found any relevant information regarding the crystallography of the mentioned calcite minerals. The appropriate description of the XRD and thermal analysis methods are missing. The crystallinity index and special crystallographic information are missing. Even within completely crystalline materials, the crystallinity can vary, for example, because of different crystalline regions in various orientations as well as crystal defects, and, furthermore, if there are amorphous or nanocrystalline phases in the sample. I do not find any information regarding this! Thirdly, some part of this paper is already published by Han, Z., Zhuang, D., Zhao, H. et al. Comparative study on thermal behaviors between micrites and thrombolites using thermogravimetric analysis. J Therm Anal Calorim 139, 1229–1242 (2020). https://doi.org/10.1007/s10973-019-08559-0
Sorry to say, but I cannot support the publication of this MS in 'Crystals'.
Author Response
Response to Reviewer 3 Comments
Comments and Suggestions for Authors: The paper by Zhuang and Guo sounds interesting and the topic of thrombolite research is in the frontline of carbonate sedimentology. However, this paper is not fit in the journal Crystals. Firstly, because it is a multidisciplinary approach dealing with calcite minerals in thrombolites, so it is more a petrography/sedimentology paper. Secondly, I have not found any relevant information regarding the crystallography of the mentioned calcite minerals. The appropriate description of the XRD and thermal analysis methods are missing. The crystallinity index and special crystallographic information are missing. Even within completely crystalline materials, the crystallinity can vary, for example, because of different crystalline regions in various orientations as well as crystal defects, and, furthermore, if there are amorphous or nanocrystalline phases in the sample. I do not find any information regarding this! Thirdly, some part of this paper is already published by Han, Z., Zhuang, D., Zhao, H. et al. Comparative study on thermal behaviors between micrites and thrombolites using thermogravimetric analysis. J Therm Anal Calorim 139, 1229–1242 (2020). https://doi.org/10.1007/s10973-019-08559-0.
Point 1: The paper by Zhuang and Guo sounds interesting and the topic of thrombolite research is in the frontline of carbonate sedimentology. However, this paper is not fit in the journal Crystals. Firstly, because it is a multidisciplinary approach dealing with calcite minerals in thrombolites, so it is more a petrography/sedimentology paper. Secondly, I have not found any relevant information regarding the crystallography of the mentioned calcite minerals. The appropriate description of the XRD and thermal analysis methods are missing. The crystallinity index and special crystallographic information are missing.
Response 1: Thank you very much for your careful review and patient work.
The cell density and cell volume were used to show the crystallinity index and special crystallographic information of the mentioned calcite minerals. We have added results of the changes in cell density and cell volume of different thrombolites numbered from ZX-5, ZX-7, ZX-9, ZX-11, ZX-13, ZX-15, ZX-17, which were shown in Figure 3a and 3b. The cell densities of cemented parts were 2.688, 2.686, 2.684, 2.687, 2.691, 2.679 and 2.690. However, the cell densities of clotted parts range from 2.701 to 2.716, which were higher than those of the cemented parts (Figure 3a). In addition, Figure 3b shows that the cell volumes of the cemented parts were 371.95, 371.15, 371.28, 370.98, 371.23 and 370.89. However, for the clotted parts, the cell volumes range from 368.58 to 369.54, indicating that the cell volumes were lower than cemented parts. In this study, clotted part exhibits a higher cell density and smaller cell volume because of its higher crystallinity.
The content has been added at page 7 from line 203-213 marked in red.
Moreover, the content of appropriate description of the XRD methods were added at page 3 from line 111-121. “Different thrombolites were cut into small cube samples with a rock cutter, cleaned 3 to 4 times with an ultrasonic cleaning machine, and then polished. Then, the fresh surface of cemented and clotted parts blow-dried with an ultra-quiet air compressor. Finally, a small amount of powder was drilled from the fresh surface by an electric engraving machine for subsequent test. After being ground, the cemented and clotted parts were uniformly passed through a 200-mesh sieve. An appropriate amount of mineral powder was taken out and tested by X-ray diffraction technique (XRD) to analyze the mineral components of cemented and clotted parts. The sample was spread on the groove of the slide that has been cleaned with absolute ethanol and dried in advance. During the measurement, the sample is placed in the sample tank without moving. Experimental conditions were set as the scanning angle is 10° to 90°, the step size is 0.02, and the scanning speed is 5° min-1.”
The content of appropriate description of the thermal analysis methods were added at page 4 from line 125-136. “The effects of temperature changes and different heating rates on the mass loss, heat flow and phase transition of the sample were analysed by thermal analysis. In the process of heating or cooling, different samples have different heat loss and heat flow changes. According to this feature, the composition and structure of different samples can be analyzed and distinguished at different temperature rates (5, 10, 20, and 30 K min-1) from 323.15 to 1273.15K. Recently, there are mainly three qualitative performance methods called TG, DTG and DSC, and a quantitative calculation method called thermal analysis kinetics for comprehensive thermal analysis. After being ground, the cemented and clotted parts were uniformly passed through a 200-mesh sieve. In each experiment, the mass of the sample was 8 mg and all experimental procedures were repeated three times to ensure the accuracy of the results. Finally, all TG, DTG and DSC data were plotted by Origin Lab 9.0 software (Origin-Lab Corporation, USA) to analyze the relationship between heat loss, heat flow changes and temperature.”
Thank you again!
Point 2: Even within completely crystalline materials, the crystallinity can vary, for example, because of different crystalline regions in various orientations as well as crystal defects, and, furthermore, if there are amorphous or nanocrystalline phases in the sample. I do not find any information regarding this!
Response 2: Thank you very much for your invaluable guidance and comments.
The elemental compositions of cemented and clotted parts were carefully analyzed by EDS (Figures 4a and 4b). The elemental compositions of cemented and clotted parts were C, O, Ca, Al and Pt. Al element came from the stage supporting the sample, and Pt element was caused by spraying gold during sample preparation. The C, O and Ca came from CaCO3. Therefore, the chemical composition of the cemented and clotted parts were the same, and the mineral compositions were also the same combined with XRD analysis. The content has been added at page 7 from line 217-222 marked in red.
In addition, cemented and clotted parts were cleaned with NaClO before thermogravimetric analysis, and the organic matter has been removed. Therefore, only CaCO3. decomposes when the temperature reaches 900 K.
Thank you very much for your wonderful review.
Point 3: Thirdly, some part of this paper is already published by Han, Z., Zhuang, D., Zhao, H. et al. Comparative study on thermal behaviors between micrites and thrombolites using thermogravimetric analysis. J Therm Anal Calorim 139, 1229–1242 (2020). https://doi.org/10.1007/s10973-019-08559-0.
Response 3: Thank you very much for your review and patient work.
The paper published by Han, Z., Zhuang, D., Zhao, H. et al. “Comparative study on thermal behaviors between micrites and thrombolites using thermogravimetric analysis” was mainly studies the difference in the crystallinity and thermal stability of two different rocks of thrombolite and micrite. However, this article mainly studies the differences in the crystallinity, thermal stability and stable carbon isotope characteristics between different precipitation area (cemented and clotted part) in the same thrombolite.
The results of previous article shows that crystallinity and activation energy of thrombolites were clearly higher than those of micrites, which provide theoretical reference for the identification of abiotic and biotic limestones in geological history records. This article further proves that the crystallinity and activation energy of cemented part (abiotic mineral) was higher than clotted part (biotic mineral) in the same thrombolite, which provide theoretical reference for the identification of abiotic and biotic minerals.
After careful modification, we feel the quality of our article has been greatly improved. Thank you again!
Please see the attachment
Author Response File: Author Response.docx
Round 2
Reviewer 2 Report
The manuscript can be considered for publication.
Author Response
Response to Reviewer 2 Comments
Comments and Suggestions for Authors:
The manuscript can be considered for publication.
Response: Thank you very much for your invaluable guidance and comments on our manuscript “Comparative study on thermodynamic and geochemical characteristics between cemented and clotted parts of thrombolite” (No. crystals-963127). Those comments are all valuable and very helpful for revising and improving our manuscript, and also have an important guiding significance to our researches. Thanks for the reviewer’s excellent guidance.
Please see the attachment
Author Response File: Author Response.docx
Reviewer 3 Report
It is nice to notice that the manuscript has been improved. The authors have done good work addressing my previous remarks. Additional results, explanations, and interpretations have been added as well. However, there are still several unresolved or questionable issues in the revised version of the manuscript.
1.) The appropriate description of the equipment used for the research is still missing! What kind of XRD?, is it Cu-Kα radiation? (? kV, ? mA). Mineralogists are interested in this too! What kind of thermal analyzer instruments were used? The EDS instrument is an XRF or what? If the authors think that is not relevant, then please cite a previous research paper where the methods were described in more detail.
2.) Figure 1: the term "dolomite" is more for mineral, the rock type is dolostone.
3.) Line 136: Popescu method not "Popscu"
4.) 200-mesh sieve: if you are talking about "200 mesh aperture lab standard test sieve" please indicate the SI scale which is 75 µm.
5.) Line 172: "ground to 75 µm-size grains" not 200 meshes
6.) Have the authors used standards (in-house or NBS 18) for the carbon stable isotope measurements? If yes, please indicate, if not, then the results are questionable.
Therefore I advise a (moderate/minor) revision, but probably the revision satisfactory to the editor should be enough.
Author Response
Response to Reviewer 3 Comments
Comments and Suggestions for Authors: It is nice to notice that the manuscript has been improved. The authors have done good work addressing my previous remarks. Additional results, explanations, and interpretations have been added as well. However, there are still several unresolved or questionable issues in the revised version of the manuscript.
Point 1: The appropriate description of the equipment used for the research is still missing! What kind of XRD?, is it Cu-Kα radiation? (? kV, ? mA). Mineralogists are interested in this too! What kind of thermal analyzer instruments were used? The EDS instrument is an XRF or what? If the authors think that is not relevant, then please cite a previous research paper where the methods were described in more detail.
Response 1: Thank you very much for your careful review and patient work.
An appropriate amount of mineral powder was taken out and tested by XRD (D/Max/2500PC, Neo Confucianism of Japanese Company, Japan) with Cu-Ka radiation to analyze the mineral components of cemented and clotted parts. Experimental conditions were set as the scanning angle is 10° to 90°, the step size is 0.02, and the scanning speed is 5° min-1 at page 3 from line 115-121 marked in red.
In addition, the composition and structure of different samples can be analyzed and distinguished by the thermal analyzer (TGA/DSC1/1600LF, METTLER TOLEDOCo., Switzerland) at different temperature rates (5, 10, 20, and 30 K min-1) from 323.15 to 1273.15K at page 4 from line 127-130 marked in red.
Moreover, The EDS instrument is not an XRF, EDS instrument was mainly used to analyze the elemental composition and chemical composition of minerals. The relevant references where the methods were described in more detail have been added in our manuscript at page 3 from line 122-123 marked in red.
Thank you again!
Point 2: Figure 1: the term "dolomite" is more for mineral, the rock type is dolostone.
Response 2: Thank you very much for your invaluable guidance and comments.
The term "dolomite" in Figure 1 has been replaced by dolostone
Thank you very much for your wonderful review.
Point 3: Line 136: Popescu method not "Popscu"
Response 3: Thank you very much for your review and patient work.
The “Popscu” in our manuscript has been changed into “Popescu method”.
Thank you very much for your wonderful review.
Point 4: 200-mesh sieve: if you are talking about "200 mesh aperture lab standard test sieve" please indicate the SI scale which is 75 µm.
Response 4: Thank you very much for your invaluable guidance and comments.
We have indicated the SI scale which is 75 µm, when talking about “200 mesh aperture lab standard test sieve” in our manuscript at page 3 from line 114-115 marked in red.
Thank you very much for your wonderful review.
Point 5: Line 172: "ground to 75 µm-size grains" not 200 meshes
Response 5: Thank you very much for your invaluable guidance and comments.
The expression of “200 meshes” has been changed into “ground to 75 µm-size grains” in our manuscript at page 6 from line 176-177 marked in red.
Thank you very much for your wonderful review.
Point 6: Have the authors used standards (in-house or NBS 18) for the carbon stable isotope measurements? If yes, please indicate, if not, then the results are questionable.
Response 6: Thank you very much for your invaluable guidance and comments.
We have used standards (NBS 18) for the carbon stable isotope measurements and indicated in our manuscript at page 6 from line 186-187 marked in red.
After careful modification, we feel the quality of our article has been greatly improved. Thanks for the reviewer’s excellent guidance. Thanks again!
Author Response File: Author Response.docx
