Responses to the Comments of the Reviewers Last interglacial sea-level proxies in the Korean Peninsula

Firstly, we greatly thank Drs. Colin V. Murray-Wallace, Craig Sloss, Dan Muhs, and Anonymous Referee for deep insights and constructive review with helpful comments. We have done our best to revise the manuscript according to their corrections and comments. The original comments from the reviewers are in italics, our responses are in standard font, and modifications on the revised manuscript are shown in blue text.

Response: The reviewers are correct that there are some sea-level indicators (SLI) and terrestrial limiting records (TL) reaching over +5 m. Specifically, we have 3 SLI at Wando-Sinji 3 (WALIS LUM ID #464: +6.1 m), and Sacheon-Daepodong (WALIS LUM ID #460: +6 m; #461: +6 m) in the western and southern areas (Table 3 and Figs. 2 and 7). We also have the lowest TL of Haenam-Ijin-ri 3 (WALIS LUM ID #467: +5.4 m) and the lowest SLI of Wando-Sinji 1 (WALIS LUM ID #462: +2.8 m) in the western areas. In the eastern area, we didn't consider LIG sea-level elevation data because of neotectonic uplift since MIS 5e. To address this comment, we changed the text to suggest MIS 5e sea levels lie between +3 and +6 m in the revised manuscript, strictly based on the SLI and TL data, discarding our previous intuitive height of 2 to 5 m. As follows in Abstract section: "~ LIG sea-level records on the west coast of the Korean Peninsula are found at heights of between +3 and +6 m and include marine and terrestrial elevation-limiting records as well as true sea-level indicators." As follows in Concluding remarks section: "~ LIG sea levels appear to be well constrained to between +3 and +6 m by marine limiting records, sea-level indicators, and terrestrial limiting records along the west coast of the Korean Peninsula ~." Response: We used an inverted triangle legend for the terrestrial-limit site. The following sentences were added in the caption of Figure 2: Red circles represent sea-level indicator locations based on OSL ages with exception of the Pohang-Masan-ri area which has an additional paleomagnetic-based age. An inverted triangle shows the location of a terrestrial-limiting point. Age data can be found in Table 3. Bathymetric contour inveral is in meters.
In Figure 7, the following sentence was added in the figure caption: A red circle represents the location of sea-level indicator while blue triangles and brown inverted triangles represent marine-limiting and terrestrial-limiting site locations, respectively. Age data can be found in Table 3. Bathymetric contour interval is in meters. The subsite names of sample sites were added in the revised Figure 2, which accords to those in Table 3 and the open-access spreadsheet (Ryang and Simms, 2021).  Table 3 or anywhere in the article.

Figure 3
Response: We corrected Geumgok-ri 1105 GG to Geumgok-ri 1 and 2 in Figure 3, which accords in the subsite name in Table 3   Response: A sentence was added in the figure caption as follows: Two ages in red indicate LIG ages (WALIS LUM ID #449 and #450 in Table 3).

Line 221 and 222
Line 221 and 222: The abbreviation SWSH and db show up first time. I suggest describe the full name in the text (e.g. line 234) even though the authors have referred Table 1 in line 203.
Response: The sentence was rewritten as follows: where Ul represents the upper limit of the modern analog landform's elevation, Ll represents the lower limit of the modern analog landform's elevation, SWSH represents storm wave swash height, and db represents the breaking depth. Each of these values was obtained from local sources (Table 1). In addition, the sentence in Line 219 was rewritten as it follows: Where E represents the elevation of the sea-level indicator, RWL represents the reference water level, and δRSL accounts for the uncertainties in the paleo RSL (Rovere et al., 2016).

Line 283
Line 283: I suggest to refer Table 3 when mentioning subsites. I cannot find those subsites on Figure 2. Is it possible to put all subsite names on figures?
Response: We put all subsite names in Table 3 on Figures 2 and 7 as a set of the site and subsite names such as Gangneung-Saemokee, Uljin-Hujeong, and Sacheon-Daepo-dong.   (2) We changed 'West' and 'East' to 'Seaward' and 'Landward', respectively.
(4) A sentence was added in the figure caption as follows: Ages in red indicate LIG ages (WALIS LUM ID #470 to #491 in Table 3).

Line 621
Line 621: Based on Table 3 and Figure 15, some terrestrial limit records and sea level indicators reach elevations of over +5 m. How do authors determine the LIG sea levels are between +2 and +5 m?
Response: Same responses for '2.1 One scientific issue' in the upper Main discussion and comments. Response: In Korea, many people have the same surnames such as Choi, Lee, Yoon, and Kim. Our paper has about 30 first authors who have the same surname in our references. Korean readers, as well as international readers, will confuse cited authors while reading the manuscript if given name initials are not provided. Therefore, we prefer including given name initials to help distinguish authors (and sources) in the case where multiple references contain the same surname. Response: We inserted the following sentence in Line 148 on the revised manuscript: However, due to inadequate descriptions of the sampled materials and age dating techniques within the original papers, the two ages were not included in our dataset shown in Table 3 or in the open-access spreadsheet (Ryang and Simms, 2021). Although S.G. Choi (1993;1996) insisted that the fluvial terrace fills with LIG ages correspond to the shoreline angles of nearby marine terraces, he did not present any scientific evidence for such in his papers. Thus, we include his contribution only as historically published data. This work presented the first two numerical LIG ages for coastal areas of the Korean Peninsula, but the ages were not included in Table 3 or in the open-access spreadsheet (Ryang and Simms, 2021). This is why we did not introduce the amino acid racemization method in the 3.3 Dating techniques section. You could refer to 4.2.13 section.

Commented [Line 185]: any faunal elements?
Response: Unfortunately, faunal elements were not described and studied in the original paper. The text below is from a reviewer (Dr Dan Muhs; United States Geological Survey) who has made valuable comments which will enhance the submission. In addition, I will attach a marked up copy of the original manuscript annotated by Dr Muhs. I should be grateful if you can address all the comments. It is a very interesting manuscript and by addressing all the comments, the work will be enhanced in terms of general clarity. I agree that a key point relates to the caption for Figure 6.
My main criticism, and it is an important one I think, is in the caption to Figure 6. I have never encountered a situation in the field that looks like the one figured there and which their equations (1) and (2) are based on. That point needs to be addressed.
Other than that, most of the other comments, though numerous, are pretty minor, and should be able to be fixed fairly easily, I should think.
Response: We cordially appreciate the comments by Drs. Colin V. Murray-Wallace and Dan Muhs. They meticulously reviewed our manuscript and provided insightful and helpful comments. Their main criticism on the caption of Figure 6 is right. We had an error in drawing the schematic diagram, so Figure 6 was redrawn as follows adding draped aeolian sands and nonmarine deposits over the marine deposits and paleo wave-cut platform. You could refer to 4.2.11 section. The followings are in response to their comments in sequence.   Figure 1) and use BLUE (whether one shade or more) for the ocean.

Commented [MDR8]: I do not see the "palaeo-beach pebble gravel" unit in either section. For the NQ t1
terrace, what is the yellow unit?
Response: We found that marks of the paleo-beach pebble gravel were covered by the green and blue shades in the columnar sections when it was modified. We corrected it. For the NQt1 terrace, a sentence was added in the figure caption as follows: Sites YH09 and YH10 in the NQt1 terrace (yellow) were dated to 0.09±0.01 ka and 0.

Commented [MDR9]: say either "aeolian sand" [deposits] or "dunes" [landforms], but not both. Same comment for the next sentence.
Response: The word 'dunes' was deleted in the two sentences.

Commented [MDR11]: A major concern here (and this applies to equations (1) and (2), which you discuss later. As you show here, the "Paleo Seacliff Onlap Elevation" is indeed a maximum-limiting elevation for the shoreline angle elevation, complemented by the minimum-limiting platform elevation. However, I have never seen a situation in the field that looks like this. What you have shown here is what appears to be a marine deposit of
ONE age draped over wave-cut platforms of TWO ages, including the paleo-sea cliff itself. In 40 years of studying marine terraces on three continents and many islands, I have never encountered such a situation. Now, it is very common for NON-marine deposits to be draped over two or more platforms and the intervening paleo-sea cliff, but not this. What is usually found, however, is a paleo-sea cliff back a platform, and the maximum-limiting elevation is the lowest exposed bedrock elevation on that paleo-sea cliff. That measurement, plus the elevation of the lower wave-cut platform will indeed bracket the elevation of the shoreline angle if it is not exposed.
Response: Thank you so much for your kind and detailed comments. Your comments on the overlying deposits are right. We had an error in drawing the schematic diagram, so Figure 6 was redrawn adding draped aeolian sands and nonmarine deposits over the marine deposits and paleo wave-cut platform. In our study area, unfortunately, the paleo-sea cliff back a platform was rarely exposed due to a gradual topographic slope. However, seismic profiles on land showed a subsurface paleo-sea cliff, not exposed on the surface ( Response: Although S.G. Choi (1993;1996) insisted that the fluvial terrace fills with LIG ages correspond to the shoreline angles of nearby marine terraces, he did not present any scientific evidence of the correspondence in his papers. Thus, we include his contribution only as historically published data. This work presented the first two numerical LIG ages for coastal areas of the Korean Peninsula, but the ages were not included in our dataset of Table 3 and the open-access spreadsheet (Ryang and Simms, 2021). A sentence was added as follows: However, due to inadequate descriptions of the sampled materials and age dating techniques within the original papers, the two ages were not included in our dataset shown in Table 3 or in the open-access spreadsheet (Ryang and Simms, 2021). You could refer to 3.2 section. 4.2.14 Commented [MDR14]: Please don't use the phrase "age dating", which is redundant.
Response: We corrected the phrase.

Commented [MDR15]:
Here, and throughout the manuscript, please delete all occurrences of the phrase "absolute age" and instead please use the term "numerical age", which is preferred by geochronologists.
Response: We changed the phrase "absolute age" to "numerical age" throughout the revised manuscript.  For equations (1) and (2), please see the comment made in the caption for Figure   6. This is a MAJOR issue.
Response: You could refer to 4.2.11 section for Figure 6 Response: We inserted 'error range' of ± 1σ SE or ± 2σ SE into the last column of age uncertainty of Table 3, and the corresponding error range was written in each cell of the age uncertainty. We also inserted the following sentence at the end of 3.3.1. Optically stimulated luminescence subsection: the error range had ± 1σ SE or ± 2σ SE according to measurement methods.

Commented [MDR21]:
Here, and in the previous paragraphs, why do you say this? Obviously, there has been uplift…some readers are going to be confused by this discussion and assume you really think that sea level during the LIG was actually this high.
Response: We rewrote these sentences in terms of the SA elevation in subsites of Gangneung-Anin, Donghae-Eadal-dong, Pohang-Yonghan-2, Pohang-Masan-ri, and Gyeongju-Jinri. Table 2 and Figure 14 were also revised. Response: Unfortunately, no paleontological descriptions and studies are using the shell beds in the original paper. and Table 4: We estimated rates of tectonic uplift of the marine terraces along the east coast of the Korean Peninsula using Eq. (12) and the five shoreline angle elevations listed in Table 2.
Uplift Rates (m/ka) = where SA represents the elevation of the shoreline angles and MHHW represents the mean higher high water at the subsites. The ages of the deposits associated with each of the SA can be found in  (Table 4). The error ranges were calculated based on both the range of SA elevations and the age uncertainty (Table 4). The uplift rates for the northern and southern regions of the east coast are sufficiently different as to suggest differential uplift across the region (Table 4; Fig. 2). Response: To address this comment, we revised Table 2 and Figure 14 in terms of the SA elevations as follows.
We also rewrote the related sentences in subsites of Gangneung-Anin, Donghae-Eadal-dong, Pohang-Yonghan-2, Pohang-Masan-ri, and Gyeongju-Jinri. Response: The section title of LIG sea-level fluctuation means fine-scale sea-level fluctuations during LIG, which shares the common section title in many papers of the WALIS special issue. We think our data in the Korean Peninsula are too coarse to constrain fine-scale fluctuations in LIG sea levels.