Review of ESSD essd-2021-126

A standardized database of Last interglacial (MIS 5e) sea-level indicators in Southeast Asia by Maxwell et al.

This Is an interesting dataset that screened and reviewed 14 studies on LIG sea-level indicators in Southeast Asia. After screening the authors report 43 unique RSL proxies that are predominantly coral reef terraces along with data point from a tidal notch. The sites are collated against 134 dated samples from U-series dating and some Electron Spin Resonance (ESR) dating from older studies.

The work is publishable and provides a good summary of the dataset and some implicationS for future work.

I have one primary criticism of the work and that relates to the discussion or lack thereof regarding tectonics. The authors go to great lengths to describe the tectonics of the region in the first part of the paper and this is a great start. They are indeed correct inferring that almost all data from Southeast Asia will be subject to tectonic contamination and they summarise this nicely at the start.

The authors then say very little about tectonics when they start presenting the datasets and plotting the data. This is shame because if one was to assume a LIG global sea level high of somewhere between 5-10 metres (there are many to choose from) and transpose that to their figures then the influence of tectonics since the LIG may be somewhat constrained in terms of average uplift rates. They could then compare that to modern uplift rates in the same systems.  

Minor comments include a few areas of awkward wording and some inclusions which seem superfluous.

Examples include;

Line 36 – Despite our …. (suggest rewording this sentence)

Line 80 – vague statement. Please clarify and reword

Line 435 – I am not sure I see the point of mentioning the Holocene database in section 7.3? If it is as a template for further studies maybe make that explicit.

This paper presents a compilation of SE-Asian relative sea-level indicators from Marine Isotope Stage (MIS) 5e, and some from MIS 5a and 5c. Following a brief introduction, the authors give some background on SE-Asian tectonics, sea-level markers and technical details of the compilation, before going into more details on the specific sites compiled. The paper ends with some general discussion points and future research directions.

I think the paper is well written, and the authors have done a thorough job in systematically and consistently compiling all the data, which was undoubtedly a big effort. This will surely serve as a useful basis for researchers working on Quaternary sea-level in the region (including myself). As with any data-focused paper, it is understandably very descriptive, but nonetheless I would enjoy a little more scientific insights/depth. The future research directions would be the easiest section to insert some creativity, but is very generic; it seems to suggest we need more data from more suitable samples with better descriptions, as could apply anywhere. From a (seismo-)tectonic perspective, I think it would be interesting to investigate how these RSL estimates link with fault slip rates and earthquake activity, and from a geodynamic perspective it would be interesting to understand where the 5e shorelines are in the W half of your study area. According to Sarr et al., 2019, https://doi.org/10.1130/G45629.1) the Sunda Shelf is subsiding, and RSL markers should thus be looked for below present-day sea-level. These are just some suggestions, but in general I think the paper is in a good state to be published, with only some minor remarks for the authors’ consideration.

Minor comments:

Abstract: I think it’s useful to mention as well you have included some MIS 5a and 5c RSL estimates.

Line 33: 14 what? Publications?

Line 36: change to “Despite our work mostly being aimed”

Line 37: change to “also inserted”

Literature overview: I think it’s good to mention here that the Sunda Shelf is largely subsiding (Sarr et al. and references therein, see above), which directly explains the absence of RSL markers in a large part of the map.

Line 72: change to “has resulted”

Line 159: “reflects sea-level stillstands” sounds vague to me. How about “is proportional to the duration of sea-level stillstands?”

Line 170: change to “as 20%”

Line 235: I would change tectonics (very generic) to “active tectonic”

Line 450: Not sure if there is a standard format, but to me it makes more sense to address Future research directions (scientific) before the Data availability (technical details)

Line 451: change to “reveals”

Line 452: change “done” with “obtained”

Line 454: remove “made”

In the data table: small typo throughout when writing “Chutcharavan adn Dutton”