Change in Sediment Provenance on the Inner Slope of the Chukchi Rise and Their Paleoenvironmental Implications
Round 1
Reviewer 1 Report
The present manuscript by Hyo Jin Koo and colleagues provides a very interesting continuous provenance study spanning the MIS 5 to the Holocene with a relatively well-resolved view on Last Glacial Maximum changes. The manuscript is well written, and rather straightforward to follow, with discriminant plot that attract interest of the reader. However, the present study would greatly benefit from a stronger framing of the novelty and implications before being accepted for publication. Further details are given below supporting this general comment + specific comments/questions are given directly in the pdf file attached.
The introduction is very succinct, and could be better framed with respect to the existing literature. I feel that Authors do not properly address research aims, challenges/gaps, and/or the novelty of the present study. E.g. “In this study, we aim to determine sediment provenances and transport mechanisms using bulk mineralogy and isotope multi-proxy and to reconstruct paleoenvironmental changes in the inner slope of the Chukchi Rise.” Why this choice of Chukchi Rise? Why is it important to reconstruct paleoenvironmental changes, what changes are targeted? Bulk and isotopic composition of sediments is a widely used technique for provenance, which makes the present study another site-specific example of what has been done before. I clearly miss the interest of the present study, its novelty. This is also illustrated in Figure 1 with the “other typical reference cores (PC04; 03M03)” located closeby; is the aim to constrain interpretation of the two other records? Is there a difference in the approach associated to these three records? This needs to be developed further through the introduction to attract the readership. This is relatively well done lines 234-243 of the discussion, but comes a bit late in my opinion.
The terminology of Ice-rafted Debris (IRD), widely accepted as >250um particles, is not used coherently through the manuscript and not fully data-supported. Cf. Figure 2: IRD>63µm, IRD>154µm. What does this interpretation refer to?
The core correlation is doubtful to me, which drives the entire interpretation and discussion about the MIS characteristics. In the absence of proper dating of the core ARA09C-St03, I strongly advice figures 4 and 5 to be discussed Unit-based rather than MISperiod-based. With this comment, I do not intend to question the provenance results, but I am not at ease with the strong conclusions about past circulation vs climate derived for the sole correlation between three selected cores that present drastically different sediment accumulation rates. At minima, a more soft writing should be preferred that could mix the use of conditional tense and soft adverbs such as ‘likely’, ‘potententially’, ‘might’…
E.g. Line 274: “The lowest εNd values of Unit 7 in the late MIS 5 supports the sediment supply from the Canadian Archipelago.” Is there additional evidence from other cores of the Arctic Ocean that would show increased sediment supply from the Canadian Archipelago and thus support an interpretation of Unit 7 = MIS 5?
As such, the section 4.3 would greatly benefit from an introductory sentence such as:
‘Within the limits of our correlation-based dating model, we intend to discuss the implications of changes in sediment provenance with respect to changes in the Arctic paleoenvironment.’ There, and only there should follow the discussion about potential MIS periods. All sentences are turned in the way that everything is granted, which should not be the case.
Finally, there is never mention about the wish to validate these findings by properly dating this core, which is –to me- prejudicial to the acceptance of this study for publication in its present form.
Comments for author File: 
Comments.pdf
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Overall, the article is organized logically, but the following two points should be considered to improve the manuscript, at least.
At first, the present manuscript includes problems on presentation of data. Figures, Tables, and main text, include simple but serious mistakes that authors should have found and corrected before the submission to scientific journals.
Secondary, the most important result of the present study is that authors have divided a core sample into eight units of three cycles based on detailed observation of sediment samples. However, definitions of units or cycles are not clear. Some units contain multiple layers, and a criteria for setting a boundary of 1st/2nd cycles and that of 2nd/3rd cycles seem to be different. Making the definition and the criteria clear, and then describe characteristics of each unit or cycle.
Hope additional comments in an attachment file could help to improve the manuscript.
Comments for author File: Comments.pdf
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
I feel that this new version of the manuscript has been properly revised accounting all my general and specific comments. Thus, I support this manuscript -in its present form- for consideration as publication in the MDPI Journal Applied Sciences.I am particularly satisfied with the addition lines 81-97, which clearly strengthens the interest of the present record from core ARA09C-St03 through this study.
Remark: Supplementary material is not yet accessible in www.mdpi.com
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Author Response
Thanks again for your constructive reports with helpful comments and suggestions.
Reviewer 2 Report
I found that the present version of manuscript has been sufficiently improved, and could be recommended to accept for publication in the journal, after the following, minor corrections.
Line 177; Should be "Fe-oxide"
Line 207; You have noted "the dotted lines represent the boundaries of separated units", then draw the lines for all of the boundaries, even if you want to emphasize the different boundaries in upper panels from those in lower panels (e.g., unit 2/3 and unit 3/4 for upper and lower panels).
Line 231, 233, and 250; Not only for "B1", but also for "B2" and "B3". So, should be "The surficial brown layer B1", "The surficial brown layer B2", and "brown layers B2 and B3".
Author Response
We have modified and improved the manuscript according to your suggestion.
Thanks again for the constructive report with careful comments and suggestions.
Line 177; Should be "Fe-oxide"
ANSWER. We corrected the typing mistake.
Line 207; You have noted "the dotted lines represent the boundaries of separated units", then draw the lines for all of the boundaries, even if you want to emphasize the different boundaries in upper panels from those in lower panels (e.g., unit 2/3 and unit 3/4 for upper and lower panels).
ANSWER. We modified Figure 3. All boundaries of units were represented by dotted lines.
Line 231, 233, and 250; Not only for "B1", but also for "B2" and "B3". So, should be "The surficial brown layer B1", "The surficial brown layer B2", and "brown layers B2 and B3".
ANSWER. We modified as mentioned.
