Chronology of Coastal Alluvial Deposits in The Ria de Coruña (NW Spain) Linked to the Upper Pleistocene Sea Level Regression
Round 1
Reviewer 1 Report
I carefully read the manuscript "Chronology for Alluvial Deposits in the Atlantic Coast of the 2 Ria de Coruña (NW Spain) Linked to the Upper Pleistocene Sea 3 Level Regression" in which the authors discuss the OSL dating of quartz grains obtained from alluvial deposits of the Miño River in order to establish an absolute chronology of their deposition.
The manuscript is well structured giving a good description of the site of interest and the aim of the project. Then, they are discussing the origin, the nature of the samples, their pre-treatment prior to dating and provide a detailed statistical treatment of the results, thus correcting previous misinterpretations by concluding that these deposits are dated to the Upper Pleistocene.
The conclusions drawn are coherent and they are supported by the listed citations. In addition, all figures and tables provided are appropriate and they properly show the data.
For all the aforementioned reasons, I recommend this manuscript to be accepted in its present form.
Author Response
Thank you very much for the Reviewer's comments.
Reviewer 2 Report
Dear Editor, I have finished evaluating Chamorro et al. manuscript submitted to applied science. So, based on the general picture of the manuscript, I got two different impressions from the manuscript. – The first is positive and refers to the materials, methods, results, and discussion presentation. These sections were well constructed and well written, and the possible problems with the method limitations were also explored and discussed regarding the climatic context and the relative sea level oscillations. So if this part is well presented as a final paper should be, the introduction and study area are far below the quality of the other sections. I have marked several minor written problems in the pdf that I will not list here, see the file attached. Based on my evaluation, I would recommend major revisions, focusing on enhancing the introduction and study area section.
The introduction is poorly presented in a single paragraph minor than the abstract. Tell us the motivation and the context of the problem; please enhance this section; this will enhance the audience of the final article.
The study area section is also poorly presented. There is no significant context or geological explanation regarding the study area, and I do not believe that you explored the context of your study area in a seven lines paragraph. I should point out that there isn’t a problem with a short and objective text; however, the text must contain the necessary information.
Line 56 – In the manuscript, the authors indicate that - For this work we have sampled sand lenses (Fig.2) of the best-preserved levels at heights between +2 m and +60 m above present sea-level (apsl), some of them located very close to the coastline (Fig.1).
However, they point in figure 1 that Sample 3 is at 100 m.
Figure 3 – I suggest adding the plot of all samples.
The OSL signals of all the studied samples are dim – How it affects the data reliability?
The authors point to two different basements – one schist and another granitic – are there any methodological implications regarding their mineralogical differences? The authors present their geophysical difference regarding the radiometric gamma map; on the other hand, focusing on grain size and mineralogy, are there implications of the results?
Regarding the discussion – The authors correlated their studied deposits with near deposits (N of Portugal). I suggest adding some information regarding other worldwide deposits to enhance the impact of the manuscript and reinforce your conclusions concerning the sea level influence, which in my opinion, is well constructed and substantiated.
Best regards,
Comments for author File: 
Comments.pdf
Author Response
- I have marked several minor written problems in the pdf that I will not list here, see the file attached. Based on my evaluation, I would recommend major revisions, focusing on enhancing the introduction and study area section.
REPLY: Many thanks for the comments of Reviewer 2. These issues have been corrected.
- The introduction is poorly presented in a single paragraph minor than the abstract. Tell us the motivation and the context of the problem; please enhance this section; this will enhance the audience of the final article.
REPLY: Many thanks for the suggestions of Reviewer 2. Section 1 of the Introduction has been modified to include the problem of the chronology of these coastal alluvial deposits, their importance and the main objective of the work.
- The study area section is also poorly presented. There is no significant context or geological explanation regarding the study area, and I do not believe that you explored the context of your study area in a seven lines paragraph. I should point out that there isn’t a problem with a short and objective text; however, the text must contain the necessary information.
REPLY: Many thanks for the suggestions of Reviewer 2.
Section 2 has been modified by adding more information on the geology of the area.
- Line 56 – In the manuscript, the authors indicate that - For this work we have sampled sand lenses (Fig.2) of the best-preserved levels at heights between +2 m and +60 m above present sea-level (apsl), some of them located very close to the coastline (Fig.1). However, they point in figure 1 that Sample 3 is at 100 m.
REPLY: Thanks for the comments of Reviewer 2. The absolute elevation refers to the height with respect to the current shoreline (current sea level), being different from the relative elevation calculated with respect to the main palaeochannel. The relative heights are shown in Figure 1 caption.
- Figure 3 – I suggest adding the plot of all samples.
REPLY: Many thanks for the suggestions of Reviewer 2. As recommended by Reviewer 2, the radial plots of samples Mero-4, 5 and 8 have been added.
- The OSL signals of all the studied samples are dim – How it affects the data reliability?
REPLY: Many thanks for the comments of Reviewer 2. The sections on results and discussion have been expanded to explain how the dim OSL signal affects the reliability of the data (Lines 182-185 and 297-300).
- The authors point to two different basements – one schist and another granitic – are there any methodological implications regarding their mineralogical differences? The authors present their geophysical difference regarding the radiometric gamma map; on the other hand, focusing on grain size and mineralogy, are there implications of the results?
REPLY: Many thanks for the comments of Reviewer 2. No major differences are observed between the OSL signal in the two lithologies, as would be expected from the radiation maps - although the data of these radiation maps have been obtained at 50 cm from the ground, while we measure inside the core hole. These aspects have been expanded in the text - Lines 172-175).
The text comments and explains that no significant alluvial deposits are developed in the granitic area (in fact, only one deposit has been found), as the main difference between the two lithologies, although the area draining the basin is mostly metasediments. Regarding the dating technique, the estimated DR is not much higher, as would be expected based on other local work we have done in granitic areas. However, it is not possible to go much further in these aspects as we are dealing with only one sample: MERO-8. The OSL signal of this MERO-8 sample is somewhat more intense, but not much more, an aspect that we have also observed in other local works with similar materials (Arce-Chamorro and Vidal-Romaní, 2022 [2]).
- Regarding the discussion – The authors correlated their studied deposits with near deposits (N of Portugal). I suggest adding some information regarding other worldwide deposits to enhance the impact of the manuscript and reinforce your conclusions concerning the sea level influence, which in my opinion, is well constructed and substantiated.
REPLY: Many thanks for the comments of Reviewer 2.
The coastal deposits of northern Portugal are mentioned in the text because it is a relatively similar area to the one analysed in the present work. Both belong to a distensive plate border (separation from the Atlantic), unlike the Cantabrian area (N Spain) (compressional border: collision and/or subduction of the European and Iberian plates). Southern Spain is affected by other types of processes (African plate). These aspects are mentioned in the Introduction: Lines 31-37. It should also be noted that the Ria de Coruña, as the rest of Galician Rias, are very particular formations in this region, aspects which are included in the Study Area (Lines 61-63). In this sense, it does not seem convenient to correlate these results with other areas of the world without knowing in detail tectonic or geomorphological aspects.
Reviewer 3 Report
The paper by Are-Chamorro et al. presente the OSL dating results of samples extracted from sedimentary sequences of alluvial deposits in Northern Spain. The paper is well structured and the results interesting, especially for those involved in studies related to the investigated area. Furthermore I feel that the paper is interesting for the methodological issues which are presented and discussed as related to a large scattering of the data. This discussion surely makes the ms interesting also for a wider audience. I think that the paper is suitable for the publication in its current form.
Author Response
Thank you very much for the Reviewer's comments.
Round 2
Reviewer 2 Report
Dear Editor,
After revising the revised manuscript, I believe that the main points were fixed or explained. Based on this, I recommend accepting the manuscript in its present form.
Best regards,
