Microstructure, Chemistry and Mineralogy Approach for the Diagnostics of Metallic Finds of the Tomba della Biga (Adria, Italy)

Round 1

Reviewer 1 Report

Dear Editor and authors, 

This is an interesting study and the authors have collected a  dataset using a well established methodology. The paper is generally well written and structured. Below i reported some remarks

Abstract 

Lines 30-32: you mention that it is proposed chemistry in the methodology. Microanalyses obtained by EDS are referred as chemistry. Actually this is mineral microanalysis. I suggest to change the term. The same goes to line 57. 

Results

In the section of  micro-Raman analysis there is  no reference prove the presence of these minerals. Please add the relevant references. 

Conclusions

You cannot refer that the research was based on geochemical approach, becaus geochemical analyses are missing. So i suggest to rewrite the sentence in lines 606-607. 

Lines 620-622. You mention the oxidation state of iron. It is the first time you talk about the iron oxidation. How do you observe that was high? Please explain. 

Kind regards!

Author Response

Abstract. Lines 30-32: you mention that it is proposed chemistry in the methodology. Microanalyses obtained by EDS are referred as chemistry. Actually this is mineral microanalysis. I suggest to change the term. The same goes to line 57. 

We thank the Reviewer’s suggestion, and we have modified the abstract and the Introduction.

Results. In the section of  micro-Raman analysis there is  no reference prove the presence of these minerals. Please add the relevant references. 

We thank the Reviewer’s suggestion, and we have added more references.

Conclusions. You cannot refer that the research was based on geochemical approach, becaus geochemical analyses are missing. So i suggest to rewrite the sentence in lines 606-607. Lines 620-622. You mention the oxidation state of iron. It is the first time you talk about the iron oxidation. How do you observe that was high? Please explain. 

We thank the Reviewer’s suggestion, and we have modified the sentence.

Reviewer 2 Report

Dear authors

Many thanks for your efforts on treating a so interesting topic, near to Archeology or Chemistry in Archeological systems.

It is very clear described and it is possible to appreciate every difficulty in to the issue

Many thanks

Author Response

All authors thank the Reviewer for his / her replay.

Reviewer 3 Report

I found your article very interesting, especially because of the detailed descriptions of the samples, the locations and parts from which they were taken and the detailed analyses performed.
I have no comments, just a suggestion: if you can, please elaborate more on the Discussions part or merge it with the Results and create a single Results and discussion section. I say this because the Conclusions seem to contain more information and even more comments than the Discussion section itself.

Author Response

We agree with the Reviewer, and we have add the Discussion into the Results

Reviewer 4 Report

 Comments to the manuscript “Microstructure, chemistry, and mineralogy approach for the diagnostics of metallic finds of the Tomba della Biga (Adria, Italy) submitted by 

Elena Marrocchino, Chiara Telloli, Sara Finotti, Alberta Facchi, Negar Eftekhari and Caterina De Vito to Applied Sciences

Paper contains very interesting results of detail analysis of numerous artefacts from Adria in Italy. I suggest significant changes in the organization of the text. The present version is based on presentation of analytical results ordered according to the method used. In effect description of the same sample appears several times in the text. I suggest to give successively complex descriptions of samples based on all methods applied.

Results of chemical analysis are presented in form of contents of oxides. Results were obtained using EDS analysis. Results can be presented as content of elements (in wt% or atomic %) or as content of oxides (in wt% or moles). Presentation in form of oxides results often in questionable conclusions. For example the composition of alloy composed of Cu and Sn is presented as a mixture of CuO and SnO. |Additionally in effect the content of oxygen is related to the stoichiometry of oxides not to measured value. I suggest to change method of presentation of results of chemical analysis.

Numerous detail comments are listed below.

I suggest verification of English language.

 

Detail comments:

Lines 19-20: „The samples were analyzed using Optical Reflected Light Microscopy (ORLM)” and lines 72-73: “All the metallic samples were observed under optical transmitted light polarized microscopy“. There is a contradiction in these sentences. What kind of microscopy was used? Both?

Line 74: ” These techniques are generally used to characterize mineralogical phases….”. I suggest “mineral phases” instead of “mineralogical phases”

Lines 168-169: “The 10x and 50x microscope objectives were employed to focus the laser beam onto the samples …”. I suggest “were used”.

Line 179: “The accelerating voltage can work from 0.2 to 30 kV”. I suggest to inform readers about parameters used during your study.

Lines 185-186: “For SEM examinations, a piece not metalized of each fragment was firmed on an SEM stub utilizing double-sided conductive adhesive tape”. “not metalized” means “not coated with metallic conductive layer”?

Line 219: ” Sample 1 (Fig. 3a) appears shiny due to the restoration”. I cannot see any shiny fragment on Fig. 3a.

Line 224: “increase in the nucleation of crystals with a very fine size probably”. It is not possible to observe nucleation with naked eye and also using stereoscopic microscope.

Lines 245-246: ” The size of the granules was probably influenced by the high cooling rate…”. Cooling rate during or after production of an alloy? The fragment is unclear for me.

Line 280: “Optical transmitted light polarized observations both on iron and bronze samples”. I suggest “polarized light” (not “polarized observations”).

Lines 282-283: “The primary characters are due to the heterogeneity composition of the metal alloy and to the presence of heterogeneously distributed transition elements”. “heterogeneity in the composition”? “Heterogenous composition”?  Please define “transition elements”?

Lines 285-288: “Some of these siderophile elements are present as sulfides. Furthermore, the presence of silicates (such as olivine, amphibole, anhydrous and hydrated aluminosilicates) with different abundances infers a slag-like appearance of the alloy”. I cannot find identification of these minerals in your study. Is it taken from other publications? Is it slag or alloy? Alloy containing silicate minerals?

Line 328: “The spectra obtained are a random measurement at one point”. What means “random measurement”? Numerous spectra in one point?

Line 333: “Three different macro-areas are selected to be analyzed using SEM”. I suggest the change: “SEM-EDS”. SEM is a device for imaging. SEM-EDS – means SEM equipped with energy dispersive spectrometer (EDS). SEM-EDS can be used for chemical microanalysis but SEM only for imaging.

Line 335-336: “The chemical composition of this sample reveals a high Fe-content, ranging from 93.49 and 81.54 (Table 2).” In Table 2 content of Fe2O3 is presented.

Line 339-340: “Regarding K₂O, Cl, CuO and SO₂ the concentrations are close to the detection limit of the instrument…”. Please add detection limits of the instrument.

Lines 250-351: “This sample is characterized by two large areas, i.e., the surface that seems unaltered and the excavated area containing some spherules (Fig. 6).” I cannot see spherules on Fig. 6. Please indicated them with arrow or change the description.

Line 357: “Lead and Sn are not detected.” Please use either symbols or names of chemical elements (in whole text).

Figures 7, 8, 9: Figures captions are very short. It would be interesting for the reader to know what phases are presented of SEM images. I suggest to add labels on images (e.g. Fig. 9; image 19 – description of darker and brighter field).

Table 2. Perhaps the explanation of the “n.d.” is missing. If “n.d.” stands for “non determined” what is the meaning of value “0.0” in the table (e.g. for K₂O). It was a measured value, potassium was not determined, is it below detection limit?

Lines 412-413: “area: around the copper-colored accumulation”. “Copper-colored” means colour of metallic copper or colour of secondary Cu-minerals (malachite, azurite).

Line 413-414: “The morphology appears not porous and without fractures, resulting completely different from the other two samples previously described”. It is better to describe visible features. You inform readers what is missing (“not porous”, without fractures”).

Line 416-417: “The most abundant oxide is CuO which varies from 20.59 to 94.53 (Table 3), depending on the analyzed areas. Tin oxide is also present with quite high values (from 1.73 up to 55.02)”. You present results of chemical analyses in contents of oxides. It is a traditional method used in Earth sciences but in description of this material it is not justified. Bronze is an alloy containing Cu and Sn (but not a mixture of oxides). Your description suggests that the alloy contains also oxygen.

Line 419: “Iron oxide was less present”. Perhaps “lower concentration”? Is it possible to be “more present” or “less present”?

Lines 434-435: “Copper is the major oxide, ranging from 26.42 to 93.94.” Copper is not an oxide! Is the value in wt%?

Line 458: “Zinc oxide was not detected”. EDS is a method for measurement of the content of elements (not oxides).

Figure 14. Please inform the readers what crystals are presented of SEM images. Perhaps based on chemical composition you can identify them.

Line 522: “restored area with the resin”. What means “restored area”?

Line 528: “goethite (Fe+3O(OH)”. Please correct the formula.

Figure 15. You present Raman spectra and identification. Please indicate which peaks correspond to given mineral.

Line 611: “The concentration of the transition elements (in trace) in the Fe alloy is very low”. What means “transition elements”?

 

 

Author Response

Comments to the manuscript “Microstructure, chemistry, and mineralogy approach for the diagnostics of metallic finds of the Tomba della Biga (Adria, Italy) submitted by 

Elena Marrocchino, Chiara Telloli, Sara Finotti, Alberta Facchi, Negar Eftekhari and Caterina De Vito to Applied Sciences

Paper contains very interesting results of detail analysis of numerous artefacts from Adria in Italy. I suggest significant changes in the organization of the text. The present version is based on presentation of analytical results ordered according to the method used. In effect description of the same sample appears several times in the text. I suggest to give successively complex descriptions of samples based on all methods applied.

            We thank the Reviewer for his / her suggestion, and we have modified table 1.

Results of chemical analysis are presented in form of contents of oxides. Results were obtained using EDS analysis. Results can be presented as content of elements (in wt% or atomic %) or as content of oxides (in wt% or moles). Presentation in form of oxides results often in questionable conclusions. For example the composition of alloy composed of Cu and Sn is presented as a mixture of CuO and SnO. |Additionally in effect the content of oxygen is related to the stoichiometry of oxides not to measured value. I suggest to change method of presentation of results of chemical analysis.

            We thank the Reviewer for his / her suggestion, and we have modified the table and the text.

Numerous detail comments are listed below.

I suggest verification of English language.

 

Detail comments:

Lines 19-20: „The samples were analyzed using Optical Reflected Light Microscopy (ORLM)” and lines 72-73: “All the metallic samples were observed under optical transmitted light polarized microscopy“. There is a contradiction in these sentences. What kind of microscopy was used? Both?

            We completely agree with the Reviewer, it was a misunderstanding. We have corrected the sentence.

Line 74: ” These techniques are generally used to characterize mineralogical phases….”. I suggest “mineral phases” instead of “mineralogical phases”

            We agree with the Reviewer, and we have modified the word.

Lines 168-169: “The 10x and 50x microscope objectives were employed to focus the laser beam onto the samples …”. I suggest “were used”.

            We thank the Reviewer for his / her suggestion, and we have modified the sentence.

Line 179: “The accelerating voltage can work from 0.2 to 30 kV”. I suggest to inform readers about parameters used during your study.

            We thank the Reviewer for his / her suggestion, and we have added more information.

Lines 185-186: “For SEM examinations, a piece not metalized of each fragment was firmed on an SEM stub utilizing double-sided conductive adhesive tape”. “not metalized” means “not coated with metallic conductive layer”?

            We thank the Reviewer for his / her suggestion, and we have modified the sentence.

Line 219: ” Sample 1 (Fig. 3a) appears shiny due to the restoration”. I cannot see any shiny fragment on Fig. 3a.

            We agree with the Reviewer, and we have modified the sentence.

Line 224: “increase in the nucleation of crystals with a very fine size probably”. It is not possible to observe nucleation with naked eye and also using stereoscopic microscope.

            We agree with the Reviewer, and we have modified the sentence.

Lines 245-246: ” The size of the granules was probably influenced by the high cooling rate…”. Cooling rate during or after production of an alloy? The fragment is unclear for me.

            We thank the Reviewer for his / her suggestion, and we have added more information.

Line 280: “Optical transmitted light polarized observations both on iron and bronze samples”. I suggest “polarized light” (not “polarized observations”).

            We thank the Reviewer for his / her suggestion, and we have modified the sentence.

Lines 282-283: “The primary characters are due to the heterogeneity composition of the metal alloy and to the presence of heterogeneously distributed transition elements”. “heterogeneity in the composition”? “Heterogenous composition”?  Please define “transition elements”?

            We thank the Reviewer’s suggestion, and we have modified the sentence.

Lines 285-288: “Some of these siderophile elements are present as sulfides. Furthermore, the presence of silicates (such as olivine, amphibole, anhydrous and hydrated aluminosilicates) with different abundances infers a slag-like appearance of the alloy”. I cannot find identification of these minerals in your study. Is it taken from other publications? Is it slag or alloy? Alloy containing silicate minerals?

            We agree with the Reviewer, it was a misunderstanding and we have modified and delete part of the sentence.

Line 328: “The spectra obtained are a random measurement at one point”. What means “random measurement”? Numerous spectra in one point?

            We thank the Reviewer for his / her suggestion, and we have modified the sentence.

Line 333: “Three different macro-areas are selected to be analyzed using SEM”. I suggest the change: “SEM-EDS”. SEM is a device for imaging. SEM-EDS – means SEM equipped with energy dispersive spectrometer (EDS). SEM-EDS can be used for chemical microanalysis but SEM only for imaging.

            We agree with the Reviewer, and we have modified the word.

Line 335-336: “The chemical composition of this sample reveals a high Fe-content, ranging from 93.49 and 81.54 (Table 2).” In Table 2 content of Fe2O3 is presented.

            We agree with the Reviewer, and we have modified the sentence.

Line 339-340: “Regarding K₂O, Cl, CuO and SO₂ the concentrations are close to the detection limit of the instrument…”. Please add detection limits of the instrument.

            We agree with the Reviewer, and we have added this information in the Material and Method section.

Lines 250-351: “This sample is characterized by two large areas, i.e., the surface that seems unaltered and the excavated area containing some spherules (Fig. 6).” I cannot see spherules on Fig. 6. Please indicated them with arrow or change the description.

            We thank the Reviewer for his / her suggestion, and we have modified the sentence.

Line 357: “Lead and Sn are not detected.” Please use either symbols or names of chemical elements (in whole text).

            We agree with the Reviewer, and we have modified the entire text.

Figures 7, 8, 9: Figures captions are very short. It would be interesting for the reader to know what phases are presented of SEM images. I suggest to add labels on images (e.g. Fig. 9; image 19 – description of darker and brighter field).

            We thank the Reviewer for his / her suggestion, and we have modified the caption of Figure 7, 8 and 9 and also of figure 14.

Table 2. Perhaps the explanation of the “n.d.” is missing. If “n.d.” stands for “non determined” what is the meaning of value “0.0” in the table (e.g. for K₂O). It was a measured value, potassium was not determined, is it below detection limit?

            We agree with the Reviewer, and we have modified the table and more information in the caption.

Lines 412-413: “area: around the copper-colored accumulation”. “Copper-colored” means colour of metallic copper or colour of secondary Cu-minerals (malachite, azurite).

            We thank the Reviewer for his / her suggestion, and we have modified the sentence.

Line 413-414: “The morphology appears not porous and without fractures, resulting completely different from the other two samples previously described”. It is better to describe visible features. You inform readers what is missing (“not porous”, without fractures”).

            We thank the Reviewer for his / her suggestion, and we have modified the sentence.

Line 416-417: “The most abundant oxide is CuO which varies from 20.59 to 94.53 (Table 3), depending on the analyzed areas. Tin oxide is also present with quite high values (from 1.73 up to 55.02)”. You present results of chemical analyses in contents of oxides. It is a traditional method used in Earth sciences but in description of this material it is not justified. Bronze is an alloy containing Cu and Sn (but not a mixture of oxides). Your description suggests that the alloy contains also oxygen.

            We thank the Reviewer for his / her suggestion, and we have modified the table and the text.

Line 419: “Iron oxide was less present”. Perhaps “lower concentration”? Is it possible to be “more present” or “less present”?

            We agree with the Reviewer, and we have modified the sentence.

Lines 434-435: “Copper is the major oxide, ranging from 26.42 to 93.94.” Copper is not an oxide! Is the value in wt%?

            We thank the Reviewer for his / her suggestion, and we have modified the sentence.

Line 458: “Zinc oxide was not detected”. EDS is a method for measurement of the content of elements (not oxides).

            We thank the Reviewer, and we have corrected the text.

Figure 14. Please inform the readers what crystals are presented of SEM images. Perhaps based on chemical composition you can identify them.

            We thank the Reviewer, and we have better explained in the text.

Line 522: “restored area with the resin”. What means “restored area”?

            We thank the Reviewer, and we have better explained in the text.

Line 528: “goethite (Fe+3O(OH)”. Please correct the formula.

            We agree with the Reviewer, and we have corrected the formula

Figure 15. You present Raman spectra and identification. Please indicate which peaks correspond to given mineral.

            We thank the Reviewer for his / her suggestion, and we have modified all the spectra of Figure 15.

Line 611: “The concentration of the transition elements (in trace) in the Fe alloy is very low”. What means “transition elements”?

            We thank the Reviewer, and we have better explained in the text.