New Geological Evidence of the 1755 Lisbon Tsunami from the Rock of Gibraltar (Southern Iberian Peninsula)

Round 1

Reviewer 1 Report

See the attachment including minor comments.

Comments for author File: Comments.pdf

Author Response

 

NOTE: All these changes have been included.

 

- Line 42: lack of the former bracket, should be corrected as Mw (~8.5. 

- Line 99 and 102: “calculated” should be replaced to “analyzed”.

- Line 104: HNO3 should be corrected HNO3.

- Line 117: BH should be as GB.

- Line 117: No information of F1 in Fig.2. Is it Fig.1 instead of Fig.2?

- Line 137: should add the word of Fig.1 for referring F4 in the manuscript.

- Line 141: as same as above, should add the word of Fig.1 for referring F5 I the manuscript.

- Figure 3: should add the mark of F1 to F5 facies on figure since it is difficult for the readers to identify where is the position. Facies have been included.

- Line 180: No figure of Fig.5 in the manuscript. Should be deleted the description for the sentences from line 179 to line 182.

- Line 190: Not Table 3 but Table 2.

 

 

 

Reviewer 2 Report

The manuscript “Did the 1755 Lisbon tsunami invade the Mediterranean Sea?: new mineralogical and geochemical evidence from the Rock of 3 Gibraltar (southern Iberian Peninsula)” provides a set of compositional features for sediments collected from a core at the western limit of the Mediterranean Sea. Compositional data were selected in order to identify a possible sedimentary record of tsunamis and the core is located in a strategic place between the Atlantic and Mediterranean. The research was performed in a way that is likely capable of identifying sediments associated with the 1755 tsunami, including data for stratigraphic assignments. Results and interpretations are convincing. Although I am not native of an English-speaking country, in general, I found it easy to follow.

Some issues, however should be addressed before acceptance in Minerals. Namely:

- Historical documents are used in the paleogeographic interpretations, but the manuscript does not include any copy of old maps or palaeographic sketches. I suggest adding some images depicting former coastal morphologies. These maps/sketches will help to validate the statement that the present research reports for the 1^st time a record of the 1755 tsunami in the Mediterranean. Anyway, it depends on what you call the Mediterranean. I do not know the morphology of the lagoon and evolving areas by 1755, but, apparently, the lagoon where the core was drilled is in the western side of Gibraltar, still facing the Atlantic.

- Before the description of sampling from the core, is necessary to explain how the core was obtained (method, recovery rate, and whatever may disrupt the stratigraphic succession)

- A few requests for mineralogy: Intensity factors were applied to peak area or peak height? Quantifications were performed for which minerals? Although one decimal place could be too much when doing the semi-quantitative mineral estimations by XRD, two places are used to indicate mineral proportions.

- Regarding geochemistry, analytical errors or some information of quality control should be provided. Table 1 doesn't show it (as stated in L. 103). An additional point: authors considered the possibility of As being an indicator of marine influence?

- And for grain-size distributions, I think too much attention is dedicated to kurtosis, since its sedimentological meaning is not that clear. Because kurtosis and sorting tend to correlate negatively, sorting should be enough. By the way, kurtosis is a statistical parameter as standard deviation, while sorting is a property used in sedimentary analysis that is established according to standard deviation. Two different things.

Some more specific points below:

1. 25: Change “(…) to differentiate a tsunamiite from the transport (…)”. A deposit or sedimentary unit can be differentiated from other deposits, not from the process of transporting sediment from distinct settings. Processes and deposits must not be treated as if they were the same thing
2. 30: anthropic instead anthropice
3. 53. Rephrase “main aim is infer the main paleoenvironmental”
4. 56-57: Rephrase. Maybe, instead of transit, border, transition, limit…
5. 58-61: Two succeeding phrases starting by “this rock” is not elegant
6. 64: Natural instead of nature
7. 64-67: Old (historical) maps should be interpreted cautiously. Sometimes the morphological features are exaggerated or simply passed unattended. There can also be the risk that the map is substantially older than the surveys. Again, I suggest adding a copy of the relevant part of the map.
8. 118-119: Not sure if matrix is the right term here.
9. 126-127: Suggest simplifying. E.g., rip-up clasts derived from F1 and F2 are frequent in the lower 3-5cm"
10. 158-159: Rephrase
11. 208-212: Suggest merging iii and iv. Presence of a marine taxon is not that relevant in a coastal succession
12. 216-218: Suggest merging iii and iv. Presence of a marine taxon is not that relevant in a coastal succession
13. 239: “e.g.” not necessary
14. 263: Rephrase “sandy layer from the action of the 1755 Lisbon tsunami”

Figure 1: Although only 5 samples are represented, I think the graphic would be better with line graphics for these 3-4 parameters. In addition, letters could be more uniform, some are big, others difficult to read

I hope that this assessment will help to improve the research.

Author Response

The manuscript “Did the 1755 Lisbon tsunami invade the Mediterranean Sea?: new mineralogical and geochemical evidence from the Rock of 3 Gibraltar (southern Iberian Peninsula)” provides a set of compositional features for sediments collected from a core at the western limit of the Mediterranean Sea. Compositional data were selected in order to identify a possible sedimentary record of tsunamis and the core is located in a strategic place between the Atlantic and Mediterranean. The research was performed in a way that is likely capable of identifying sediments associated with the 1755 tsunami, including data for stratigraphic assignments. Results and interpretations are convincing. Although I am not native of an English-speaking country, in general, I found it easy to follow.

Some issues, however should be addressed before acceptance in Minerals. Namely:

- Historical documents are used in the paleogeographic interpretations, but the manuscript does not include any copy of old maps or palaeographic sketches. I suggest adding some images depicting former coastal morphologies. These maps/sketches will help to validate the statement that the present research reports for the 1^st time a record of the 1755 tsunami in the Mediterranean. Anyway, it depends on what you call the Mediterranean. I do not know the morphology of the lagoon and evolving areas by 1755, but, apparently, the lagoon where the core was drilled is in the western side of Gibraltar, still facing the Atlantic.

Note. An old map has been included (see new Figure 1, C).

- Before the description of sampling from the core, is necessary to explain how the core was obtained (method, recovery rate, and whatever may disrupt the stratigraphic succession).

Note: New data have been included (see 3.1. Sampling).

- A few requests for mineralogy: Intensity factors were applied to peak area or peak height? Quantifications were performed for which minerals? Although one decimal place could be too much when doing the semi-quantitative mineral estimations by XRD, two places are used to indicate mineral proportions.

Note: Intensity factors were applied to peak height. Quantifications were performed por all minerals.

- Regarding geochemistry, analytical errors or some information of quality control should be provided. Table 1 doesn't show it (as stated in L. 103). An additional point: authors considered the possibility of As being an indicator of marine influence?

Note: Analitical errors are included in Table 1 (second line).

- And for grain-size distributions, I think too much attention is dedicated to kurtosis, since its sedimentological meaning is not that clear. Because kurtosis and sorting tend to correlate negatively, sorting should be enough. By the way, kurtosis is a statistical parameter as standard deviation, while sorting is a property used in sedimentary analysis that is established according to standard deviation. Two different things

Note: Kurtosis has been removed from the new manuscript and Figure 2.

Some more specific points below:

1. 25: Change “(…) to differentiate a tsunamiite from the transport (…)”. A deposit or sedimentary unit can be differentiated from other deposits, not from the process of transporting sediment from distinct settings. Processes and deposits must not be treated as if they were the same thing

Note: This phrase has been deleted.

1. 30: anthropic instead anthropice

Note: Changed.

1. 53. Rephrase “main aim is infer the main paleoenvironmental”

Note: This phrase has been changed.

1. 56-57: Rephrase. Maybe, instead of transit, border, transition, limit…

Note: Changed.

1. 58-61: Two succeeding phrases starting by “this rock” is not elegant

Note: The second sentence has been changed.

1. 64: Natural instead of nature

Note: Changed.

1. 64-67: Old (historical) maps should be interpreted cautiously. Sometimes the morphological features are exaggerated or simply passed unattended. There can also be the risk that the map is substantially older than the surveys. Again, I suggest adding a copy of the relevant part of the map.ç

Note: Figure 1 includes an old map (1799) with the location of the Inundation lagoon.

1. 118-119: Not sure if matrix is the right term here.

Note: Matrix is an usual sedimentological term in geology.

1. 126-127: Suggest simplifying. E.g., rip-up clasts derived from F1 and F2 are frequent in the lower 3-5cm"

Note: Changed.

1. 158-159: Rephrase

Note: This sentence has been changed.

1. 208-212: Suggest merging iii and iv. Presence of a marine taxon is not that relevant in a coastal succession
2. 216-218: Suggest merging iii and iv. Presence of a marine taxon is not that relevant in a coastal succession

Note: These two features have been joined.

1. 239: “e.g.” not necessary

Note: Deleted.

1. 263: Rephrase “sandy layer from the action of the 1755 Lisbon tsunami”

Note: This sentence has been changed.

Figure 1: Although only 5 samples are represented, I think the graphic would be better with line graphics for these 3-4 parameters. In addition, letters could be more uniform, some are big, others difficult to read

Note: This figure has been changed.

I hope that this assessment will help to improve the research.

Reviewer 3 Report

The manuscript submitted by Ruiz et al., titled by Did the 1755 Lisbon tsunami invade the Mediterranean Sea?: new mineralogical and geochemical evidence from the Rock of Gibraltar (southern Iberian Peninsula), presented the results of facies, mineralogy, geochemistry and dating of the samples from the core GB. It indicated the evidence of the tsunami invading the western Mediterranean.

Actually, I can see that the tsunami did affect the Mediterranean Sea from the previous evidence in the manuscript, even though the influence decreased rapidly east of the Gibraltar Strait. The study just presented the evidence of mineralogy and geochemistry from one sediment core, in order to confirm the influence of the tsunami. It is not easy for the reader to understand the real scientific meaning of the manuscript just from the content of the backboard. I suggest that the author can supplement some contents to tell the readers the objective of the manuscript.

The main works of the research were the mineralogical and geochemical analysis of the samples from the core GB, but the manuscript did not present the data related these analyses. In the “3. Materials and methods”, the authors mentioned twelve samples from the core GB were analyzed in the study. Such small quantity of the data from the samples maybe not supports the linear correlation analysis of the mineralogy and geochemistry.

In addition, the authors pointed that the results of the XRD analysis are semi-quantitative, so it is a problem to take linear correlation analysis using these data.

The aging data are important, but I wonder why the manuscript just select two samples to conduct radiocarbon dating and both of them are located in the bottom of the core.

There are some mistaken including some spelling and punctuation marks, like “Line 60”, “Line 117”, “Line 244”, “Line 257”.

Author Response

The manuscript submitted by Ruiz et al., titled by Did the 1755 Lisbon tsunami invade the Mediterranean Sea?: new mineralogical and geochemical evidence from the Rock of Gibraltar (southern Iberian Peninsula), presented the results of facies, mineralogy, geochemistry and dating of the samples from the core GB. It indicated the evidence of the tsunami invading the western Mediterranean.

Actually, I can see that the tsunami did affect the Mediterranean Sea from the previous evidence in the manuscript, even though the influence decreased rapidly east of the Gibraltar Strait. The study just presented the evidence of mineralogy and geochemistry from one sediment core, in order to confirm the influence of the tsunami.

It is not easy for the reader to understand the real scientific meaning of the manuscript just from the content of the backboard. I suggest that the author can supplement some contents to tell the readers the objective of the manuscript. The main works of the research were the mineralogical and geochemical analysis of the samples from the core GB, but the manuscript did not present the data related these analyses. In the “3. Materials and methods”, the authors mentioned twelve samples from the core GB were analyzed in the study. Such small quantity of the data from the samples maybe not supports the linear correlation analysis of the mineralogy and geochemistry.

Note:

1. A previous analysis detect five sedimentary facies, clearly differentiated based on their color, texture or paleontological content.
2. With this geological base, representative samples of each one of them were selected for their subsequent analysis (mineralogy and geochemistry).
3. The results obtained support this differentiation and they are key both for the palaeoenvironmental reconstruction and for the distinction of the tsunamiite. As can be seen, most of the samples are close to the limit between F2 and F3 and detect the changes produced by the tsunamiite deposition.
4. It is true that the number of samples is low, but they are representative of the facies and the linear correlation provides trends that are contrasted with other geological analyzes.

 

In addition, the authors pointed that the results of the XRD analysis are semi-quantitative, so it is a problem to take linear correlation analysis using these data.

Note. See point 4

 

The aging data are important, but I wonder why the manuscript just select two samples to conduct radiocarbon dating and both of them are located in the bottom of the core.

Note: There are truly four ages: i) 300 cm depth (~; ii) 215 cm depth; iii) 180 cm depth (grenade fragments: 1779-1781); iv) uppermost filling (F5), deposited after 1945.

 

There are some mistaken including some spelling and punctuation marks, like “Line 60”, “Line 117”, “Line 244”, “Line 257”.

Note. Some changed have been made.

Reviewer 4 Report

The article presents the results of the study of lithology, mineralogy and geochemistry of sedimentary rocks of core samples extracted from lagoon in Gibraltar (South of Iberian Peninsula). The mineral composition and geochemical features of these samples were investigated by means of modern mineralogical and geochemical methods. Methods of mathematical statistics (correlation and cluster analysis) were used in the processing of results obta[ned. The interpretations of data obtained from the tests seem to have been done well, also the article is well compiled and illustrated. The data obtained may be valuable for understanding the main paleoenvironmental changes and to detect possible sedimentary facies associated with the Lisbon tsunami of 1755. So, the paper adds valuable new information and can recommend for publication in Minerals but with some corrections which relate to the Figures, their quality should be improved. 

The abbreviations must be deciphered at the first mention in the text. In addition, the text should be carefully checked by a technical editor and proofreader (see below).     Line 23: geoqchemical= geochemical Lines 120:  46-52%= wt % ? Lines 121:   22-24% = wt % ? Line 122: kurtosis increases (2.38 to 3.03) upward= should be explained. Line  128:  >20 % weight=>20 wt %. Line   146-148: wt %? Line   151: k-feldspar = K-feldspar Line   170: Tab. 1= Table 1 Line   174: μg/kg = ppm ? Line   180: Fig. 5B = Fig. 4B Line   189-190: cal kyr = age in kiloyears? should be explained. Line   190: a sedimentation rate of ~0.65 = should be explained. Line   190: Table 3= Table 2.

Author Response

The article presents the results of the study of lithology, mineralogy and geochemistry of sedimentary rocks of core samples extracted from lagoon in Gibraltar (South of Iberian Peninsula). The mineral composition and geochemical features of these samples were investigated by means of modern mineralogical and geochemical methods. Methods of mathematical statistics (correlation and cluster analysis) were used in the processing of results obta[ned. The interpretations of data obtained from the tests seem to have been done well, also the article is well compiled and illustrated. The data obtained may be valuable for understanding the main paleoenvironmental changes and to detect possible sedimentary facies associated with the Lisbon tsunami of 1755. So, the paper adds valuable new information and can recommend for publication in Minerals but with some corrections which relate to the Figures, their quality should be improved.

Note: New data have been added to Figures 1, 2 and 3.. 

The abbreviations must be deciphered at the first mention in the text. In addition, the text should be carefully checked by a technical editor and proofreader (see below).    

Line 23: geoqchemical= geochemical

Note: Changed.

Lines 120:  46-52%= wt % ?

Note: Changed.

Lines 121:   22-24% = wt % ?

Note: Changed.

Line 122: kurtosis increases (2.38 to 3.03) upward= should be explained.

Note: Kurtosis has been deleted (see Reviewer-1.

Line  128:  >20 % weight=>20 wt %.

Note: Changed.

Line   146-148: wt %?

Note: Changed.

Line   151: k-feldspar = K-feldspar

Note: Changed.

Line   170: Tab. 1= Table 1

Note: Changed.

Line   174: μg/kg = ppm ?

Note: Yes. It is the same unit of measure.

Line   180: Fig. 5B = Fig. 4B

Note: Changed.

Line   189-190: cal kyr = age in kiloyears? should be explained.

Note: Yes. A note has been included (see 4.4).

Line   190: a sedimentation rate of ~0.65 = should be explained.

Note: A new sentence has been added.

 Line   190: Table 3= Table 2.

Note: Changed.

Submission Date

19 October 2021

 

 

 

Round 2

Reviewer 2 Report

Before acceptance, authors should consider a few points.

In my previous evaluation of the manuscript I mentioned that old “maps/sketches will help to validate the statement that the present research reports for the 1st time a record of the 1755 tsunami in the Mediterranean”. The authors added a map to Fig. 1, which makes the work much clearer. Because this map shows that the Inundation lagoon is facing the Atlantic, in my opinion the final phrase of the Discussion section (lines 269-271) can be misleading. But then again, it depends on what we call the Mediterranean.

Regarding my previous comment for lines 118-119 know matrix is a common term in geological description. It usually refers to the fine-grained ground-mass that evolves coarser grains. I never saw it applied to a silt-sand component in peat deposits.

In the revised version, it is mentioned that changed Fig. 2, with grain-size data, was changed. But the only difference I can see is that kurtosis was removed. The grain-size parameters are still presented as tables instead of lines, which would be much easier to read.

Author Response

REVIEWER-2

In my previous evaluation of the manuscript I mentioned that old “maps/sketches will help to validate the statement that the present research reports for the 1st time a record of the 1755 tsunami in the Mediterranean”. The authors added a map to Fig. 1, which makes the work much clearer. Because this map shows that the Inundation lagoon is facing the Atlantic, in my opinion the final phrase of the Discussion section (lines 269-271) can be misleading. But then again, it depends on what we call the Mediterranean.

Note: To prevent any doubt about the Atlantic or Mediterranean location of Gibraltar, all references to the first evidence in the Mediterranean have been changed to the first evidence in Gibraltar.

Regarding my previous comment for lines 118-119 know matrix is a common term in geological description. It usually refers to the fine-grained ground-mass that evolves coarser grains. I never saw it applied to a silt-sand component in peat deposits.

Note: This phrase has been changed.

In the revised version, it is mentioned that changed Fig. 2, with grain-size data, was changed. But the only difference I can see is that kurtosis was removed. The grain-size parameters are still presented as tables instead of lines, which would be much easier to read.

Note: Grain-size parameters have been removed from Fig. 2 and a new table has been included (new Table 1).

Reviewer 3 Report

The authors made some change in the revised manuscript, including some mistakes in the spelling. Actually, the responses  from the authors did not fully match my concerns. I cannot  understand the objective fo the manuscript form the current contents of the manuscript. In addition, the quality and quantity of the some data like XRD, cannot support the results. So I think the manuscript is not suitable  for publication in the Minerals.

Author Response

The authors made some change in the revised manuscript, including some mistakes in the spelling. Actually, the responses  from the authors did not fully match my concerns. I cannot  understand the objective fo the manuscript form the current contents of the manuscript. In addition, the quality and quantity of the some data like XRD, cannot support the results. So I think the manuscript is not suitable  for publication in the Minerals.

Note 1. The first revision of our manuscript included numerous changes according to the reviewer's instructions.

Note 2. Objetives have been specified more adequately (see final paragraph of 1. Introduction.

Note 3. XRD: quality. We have applied a standard procedure applied in other mineralogical studies of coastal sediments (e.g. Vidinha et al., 2007; Sivasamandy y Ramesh, 2015).

 Vidihna, J.M.; Rocha, F.; Andrade, C.; Gomez, C.; Freitas, C. Clay Minerals – A Mineralogical Tool to Distinguish Beach from Dune Sediments. J. Coast. Res. 2007, S150, 216-220.

Sivasamandy, R.; Ramesh, R. Clay  Mineralogy  of   Surface Sediments of Kolakkudi Lake, Musiri Taluk, Tiruchirapalli District.Tamil Nadu, India. Int. J. Res. 2015, 2, 646-657.

Note 4. XRD: quantity. We agree with the reviewer that the number of samples (9) is limited. However, they were carefully selected to be representative of the observed sedimentary facies, as well as to be able to detect changes between pre-tsunamigenic and tsunamigenic facies.

Note 5. These new references have been added.