Petrographic and Geochemical Inferences for Genesis of Terra Rossa: A Case Study from the Apulian Karst (Southern Italy)

Round 1

Reviewer 1 Report

Comments for Authors:

1.- Abstract: It is not clear what the fundamental objective of this work is, what is to be found out and for what purpose. It is recommended that the authors briefly mention more specifically the methods used in this research.

A short paragraph should be added at the end of the abstract indicating in which field of research or industry these results could be applied.

2.- Introduction: the introduction is very poor, it does not reflect in detail the progress made by other authors; nor is there a critical appraisal of existing results.

The paragraph between lines 27 to 36 should be deleted as it is purely conceptual, which is not correct in the Introduction.

It is recommended that the authors rewrite the introduction and introduce more references.

3.- Figure 1. It appears that the authors attempt to represent the location of the study area by rectangles with very strong black borders in Figures 1a and 1b. Please indicate what these areas are in the symbology at the bottom of these figures.

The maps used in Figures 1a and 1c do not have the geographical orientation symbol (North). Please add.

4.- The map used in Figure 2b has serious errors: first, the symbol for orientation (North) is missing. Secondly, the blue line indicating the cross section profile has no letters at its extremes; e.g. A-Aˈ; I-Iˈ, NE-SW... Please redraw.

5.- Subsection 4.1. "Field observations and sampling" is too long. Authors are advised to simplify the information.

6.- Section 5 "Discussion": The discussion made by the authors is very general and short, and does not seem to refer to the specific results obtained in this work. It is recommended that the authors base the discussion on the results and compare them with those of other authors. Please rewrite.

On the other hand, in this Section "bauxites" is mentioned for the first time and not in the rest of the paper... Why is the word "bauxites" not added in the keywords...?

Author Response

My colleagues and I would like to thank the Reviewers for their helpful constructive comments.

Reviewer 1

1.- Abstract: It is not clear what the fundamental objective of this work is, what is to be found out and for what purpose.It is recommended that the authors briefly mention more specifically the methods used in this research.A short paragraph should be added at the end of the abstract indicating in which field of research or industry these results could be applied.

Reply: 1.-Abstract: The fundamental objective of the work has been clarified and the used methods have been specified.

A short final paragraph has been added at the end of the abstract indicating the field of research these results could be applied.

2.- Introduction: the introduction is very poor, it does not reflect in detail the progress made by other authors; nor is there a critical appraisal of existing results. The paragraph between lines 27 to 36 should be deleted as it is purely conceptual, which is not correct in the Introduction. It is recommended that the authors rewrite the introduction and introduce more references.

Reply: Following the reviewer's indications, the “Introduction” has been strongly implemented by a critical appraisal of existing results, also adding further appropriate bibliographic references.

3.- Figure 1. It appears that the authors attempt to represent the location of the study area by rectangles with very strong black borders in Figures 1a and 1b. Please indicate what these areas are in the symbology at the bottom of these figures.The maps used in Figures 1a and 1c do not have the geographical orientation symbol (North). Please add.

Reply: As shown in Figure 1a, the thick closed line encloses the area in Figure 1b. As shown in Figure 1b, the rectangle with thick perimeter encloses the area in Figure 1c. As shown in Figure 1c, the study area is indicated by the filled red star. To please the Reviewer 1, we have now added these specifications (however, pleonastic in our opinion) in the caption of Figure 1.

The map used in Figure 1a shows meridians and parallels, regularly oriented N–S and W–E, respectively. To please the Reviewer 1, we have now added the North symbol on the map. The Reviewer 1 didn’t notice that the North symbol was already indicated in Figure 1c.

4.- The map used in Figure 2b has serious errors: first, the symbol for orientation (North) is missing. Secondly, the blue line indicating the cross section profile has no letters at its extremes; e.g. A-Aˈ; I-Iˈ, NE-SW... Please redraw.

Reply: As already clearly specified in the caption, the Figure 2b is the geological map of the “study area”, and the adjacent Figure 2a is the satellite image of the same “study area”, the latter including in North indication. To please the Reviewer 1, we have now added the North symbol on the map (however, unnecessary in our opinion).

The Reviewer 1 didn’t notice that the cross section was already oriented by the indications of SW and NE. Moreover, he didn’t notice that we are dealing with only one cross section, therefore, it’s our opinion that the letters at the tips of its trace unnecessary. However we have now added the letters A and A’.    

5.- Subsection 4.1. "Field observations and sampling" is too long. Authors are advised to simplify the information.

Reply: It’s our opinion that all the information described in this subsection are necessary. Moreover, it seems objective to us that about half a page cannot be considered “too long”.

6.- Section 5 "Discussion": The discussion made by the authors is very general and short, and does not seem to refer to the specific results obtained in this work. It is recommended that the authors base the discussion on the results and compare them with those of other authors. Please rewrite.

On the other hand, in this Section "bauxites" is mentioned for the first time and not in the rest of the paper... Why is the word "bauxites" not added in the keywords...?

Reply: The discussion was partially rewrite and reorganized. The results obtained in the present work are extensively discussed and compared with those of the literature.

The word “bauxite” in the previous version of the manuscript was present exclusively in the “Geological setting” and in a sub-paragraph of the “Discussion”. In the current version a broader argumentation about residual deposits is well proposed in the “Introduction”. The comparison between chemical features of terra rossa and bauxiti is now developed during most of the text. As a result, the keywords have also been updated and made more specific.

Further notes:

• Figures 2-3 have been slightly modified following the suggestions of the reviewer 1.
• Figure 6 has been replaced as there was present a small error in a reported EDS spectrum.
• With the aim of refining the English of the manuscript, it was re-read by a native speaker Colleague.

The following papers have been added in the references and in the main text:

Muhs, D. R.; Budahn, J.; Avila, A.; Skipp, G.; Freeman, J.; Patterson, D. The role of African dust in the formation of Quater-nary soils on Mallorca, Spain and implications for the genesis of Red Mediterranean soils. Quaternary Science Reviews 2010, 29(19-20), 2518-2543.

Yu, W.; Oggiano, G.; Mongelli, G.; Zhou, J.; Buccione, R.; Xu, L.; Mameli , P.; Du, Y. U-Pb detrital zircon ages and Hf isotope from Sardinia and Adria Cretaceous bauxite (Italy): constraints on the Alpine Tethys paleogeography and tectonic evolution. Ore Geology Reviews 2022, 105272.

Moresi, M.; Mongelli, G. The relation between the terra rossa and the carbonate-free residue of the underlying limestones and dolostones in Apulia, Italy. Clay minerals 1988, 23(4), 439-446.

Vingiani, S.; Di Iorio, E.; Colombo, C.; Terribile, F. Integrated study of red Mediterranean soils from southern Italy. Catena, 2018, 168, 129-140.

Spalluto, L.; Pieri, P.; Sabato, L.; Tropeano, M. Nuovi dati stratigrafici e cartografici delle unità quaternarie del Foglio 438" BARI"(Puglia-Italia meridionale). Alpine and Mediterranean Quaternary 2010, 23(1), 3-14.

Allocca, V.; Celico, F.; Celico, P.; De Vita, P.; Fabbrocino, S.; Mattia, C.; ... & Tranfaglia, G. Carta idrogeologica dell’Italia meridionale. Istituto Poligrafico e Zecca dello Stato, 2007

Özyurt, M.; Kırmacı, M. Z.; Al-Aasm, I.; Hollis, C.; Taslı, K.; Kandemir, R. REE characteristics of Lower Cretaceous Limestone Succession in Gümüşhane, NE Turkey: implications for Ocean Paleoredox conditions and diagenetic alteration. Minerals 2020, 10(8), 683.

Best regards

Reviewer 2 Report

Dear authors,

thank you for this well-written manuscript, easy to read. I highlighted in yellow in the attached file the few typos or grammatical errors I could detect. My only specific comment is about the role of the terrace marine deposits that appears to be key in your model of terra rossa formation (figure 10). I suggest you provide some more details about this geological formation, supporting your model: mineralogical content, hydrogeological properties favorable to infiltration and reaction front. A word of the hydrogeological setting during the formation of the terra rossa would also be useful (e.g., vadose zone flow?)

Comments for author File: Comments.pdf

Author Response

My colleagues and I would like to thank the Reviewers for their helpful constructive comments.

Reviewer 2

Dear authors, thank you for this well-written manuscript, easy to read. I highlighted in yellow in the attached file the few typos or grammatical errors I could detect. My only specific comment is about the role of the terrace marine deposits that appears to be key in your model of terra rossa formation (figure 10). I suggest you provide some more details about this geological formation, supporting your model: mineralogical content, hydrogeological properties favorable to infiltration and reaction front. A word of the hydrogeological setting during the formation of the terra rossa would also be useful (e.g., vadose zone flow?)

Reply: More details about Quaternary terraced marine deposits (mineralogical content, hydrogeological properties favorable to infiltration, grain size) have been furnished in the present version of the manuscript.

Information about the hydrogeological setting during the formation of the terra rossa has been also provided.

Further notes:

• Figures 2-3 have been slightly modified following the suggestions of the reviewer 1.
• Figure 6 has been replaced as there was present a small error in a reported EDS spectrum.
• With the aim of refining the English of the manuscript, it was re-read by a native speaker Colleague.

Best regards

The following papers have been added in the references and in the main text:

Muhs, D. R.; Budahn, J.; Avila, A.; Skipp, G.; Freeman, J.; Patterson, D. The role of African dust in the formation of Quater-nary soils on Mallorca, Spain and implications for the genesis of Red Mediterranean soils. Quaternary Science Reviews 2010, 29(19-20), 2518-2543.

Yu, W.; Oggiano, G.; Mongelli, G.; Zhou, J.; Buccione, R.; Xu, L.; Mameli , P.; Du, Y. U-Pb detrital zircon ages and Hf isotope from Sardinia and Adria Cretaceous bauxite (Italy): constraints on the Alpine Tethys paleogeography and tectonic evolution. Ore Geology Reviews 2022, 105272.

Moresi, M.; Mongelli, G. The relation between the terra rossa and the carbonate-free residue of the underlying limestones and dolostones in Apulia, Italy. Clay minerals 1988, 23(4), 439-446.

Vingiani, S.; Di Iorio, E.; Colombo, C.; Terribile, F. Integrated study of red Mediterranean soils from southern Italy. Catena, 2018, 168, 129-140.

Spalluto, L.; Pieri, P.; Sabato, L.; Tropeano, M. Nuovi dati stratigrafici e cartografici delle unità quaternarie del Foglio 438" BARI"(Puglia-Italia meridionale). Alpine and Mediterranean Quaternary 2010, 23(1), 3-14.

Allocca, V.; Celico, F.; Celico, P.; De Vita, P.; Fabbrocino, S.; Mattia, C.; ... & Tranfaglia, G. Carta idrogeologica dell’Italia meridionale. Istituto Poligrafico e Zecca dello Stato, 2007

Özyurt, M.; Kırmacı, M. Z.; Al-Aasm, I.; Hollis, C.; Taslı, K.; Kandemir, R. REE characteristics of Lower Cretaceous Limestone Succession in Gümüşhane, NE Turkey: implications for Ocean Paleoredox conditions and diagenetic alteration. Minerals 2020, 10(8), 683.

Round 2

Reviewer 1 Report

The authors have addressed all the Reviewer's questions and recommendations.

This paper is recommended for approval in its present form.

Author Response

We thank you for your constructive criticism which has helped to significantly improve the manuscript.

The punctual answers to the review process 1 had already been indicated in the dedicated section.

Best regards

Francesca Micheletti