Characteristics of Lake Sediment from Southwestern Mongolia and Comparison with Meteorological Data

Round 1

Reviewer 1 Report

The article titled “Characteristics of lake sediment from southwestern Mongolia and comparison with meteorological data” presents the impact of a climatic factor on lake sedimentation. The paper is interesting and may interest a wide range of scientists, especially those who are interested in climatic and environmental changes during the Holocene. Nevertheless, I have some comments that could add value to the article.

1. Reorganize the article structure. In the Methods chapter, the descriptions are long. It is necessary to divide this chapter into subsections on subsequent analyzes.
2. The main objection is the lack of description of the drilling sediments. Are they laminated or massive? We know nothing about the structure of these sediments. This feature is key in geological research, on its basis it is possible to recreate the past environmental conditions. In this case, despite the fact that a lot of analyzes are performed, there is no correlation with the depths and characteristics of the sediments, and thus their use in geological research.
3. Separate the results from the interpretation e.g. 354-355.

4. The particle size distribution analysis has been described very imprecisely. Please complete and describe this analysis in more detail in the Methods section.
5. In table 3, mark the data that are statistically significant. This table will be easier to read.
6. In chapter 4.1. Meteorological data, I suggest presenting the meteorological data in a table, this will improve the readability of the article.
7. In Fig. 1E one drilling in the Boontsagaan Lake is marked and in Table 1 two. Please explain that.
8. When discussing 3. Wind input, please specify which fractions in lake sediments are the result of aeolian processes? How did the wind influence the parameters, e.g. grain size distribution, e.g. in the winter season, when the lakes were frozen?
9. The factors influencing sedimentation in lakes did not take into account, for example, the topography, and especially the slope of the slopes, which may be of great importance during rainfall and material supply to lakes. An example is the Authors' statement that when the water level is lower, coarser fractions are accumulated on the shore (lines 447-448), which is obvious.
10. Lack of correlation with the results of works examining similar parameters.
11. Title of chapter 5.2. Temperature increase and lake level and vegetation changes have nothing to do with the content. The authors cite much more factors influencing the sedimentation conditions in the lake and the mineral composition than just the temperature. Please change the title to a more adequate one, e.g. Impact of climate factors on the lake level fluctuation.

    Overall, in my opinion, the manuscript needs more work to be more robust and publishable by Geosciences.

    I recommend that this work be accepted for publication in Geosciences but after major revisions are made.

Author Response

Thank you for giving us the opportunity to submit a revised draft of the manuscript “Characteristics of lake sediment from southwestern Mongolia and comparison with meteorological data” for publication in Geosciences.

 

We appreciate the time and effort that all the reviewers dedicated to providing feedback on our manuscript and are grateful for the insightful comments for valuable improvements of our paper. We have carefully addressed all the comments and the paper is revised accordingly. The corresponding changes and refinements made in the revised paper are summarized in our response below, all modifications in the manuscript are marked by "track changing" function. Newly added references are highlighted with yellow.

 

Here are our responses to comments.

 

Comment 1: Reorganize the article structure. In the Methods chapter, the descriptions are long. It is necessary to divide this chapter into subsections on subsequent analyzes.

Response: We appreciate the reviewer`s suggestion. The "Method" chapter is already divided into four subsections.  We prefer to stick to the present form.

 

Comment 2: The main objection is the lack of description of the drilling sediments. Are they laminated or massive? We know nothing about the structure of these sediments. This feature is key in geological research, on its basis it is possible to recreate the past environmental conditions. In this case, despite the fact that a lot of analyzes are performed, there is no correlation with the depths and characteristics of the sediments, and thus their use in geological research.

Response: Thank you very much for your comments. We agree the importance of sediment observation. However, the collect sediment cores are very soft and easy to flow away if we tried to cut the core to observe it. We pushed up the core sediment during the core cutting, and were unable to observe the sedimentary structure. This is why we have done many analyses to know the sediment characteristics.

 

Comment 3: Separate the results from the interpretation e.g., 354-355.

Response: Thank you for pointing this out. However, we believe [line 354-355: The highest fluctuation in organic matter is observed at the upper part of the core, and it corresponds to the evaporation event in 2005–2010 (Yang et al. 2012)] is the observed fact and we prefer the sentence stay there.

 

Comment 4: The particle size distribution analysis has been described very imprecisely. Please complete and describe this analysis in more detail in the Methods section.

Response: We appreciate the reviewer`s suggestion. However, in the case of our study, we have listed the sample preparation procedure and analytical instrument, and we believe the readers understand how the measurement has done.

 

Comment 5: In table 3, mark the data that are statistically significant. This table will be easier to read.

Response: We thank the reviewer for the careful check. We have changed and, used the bold font for high values.

 

Comment 6: In chapter 4.1. Meteorological data, I suggest presenting the meteorological data in a table, this will improve the readability of the article.

Response: We appreciate the reviewer`s suggestion. Basically, all numerical figures are easily understood in Figure 2 except for average value. We added average value in meteorological data in Figure 2 to improve the readability.

 

Comment 7: In Fig. 1E one drilling in the Boontsagaan Lake is marked and in Table 1 two. Please explain that.

Response: We thank the reviewer for the careful check. We checked and modified the figure 1E and added one coring cite.

 

Comment 8: When discussing 3. Wind input, please specify which fractions in lake sediments are the result of aeolian processes? How did the wind influence the parameters, e.g. grain size distribution, e.g. in the winter season, when the lakes were frozen?

Response: Thank you for pointing this out.

All lakes freeze in winter. Based on the correlation between data, we know wind strength is the main factor affecting the grain size, especially in the Boontsagaan lake (Table 3). Boontsagaan Lake is large and deep compared to others, and its freezing period is a little shorter based on fieldwork (recognition after ~2015). Here, the aeolian input can be a significant sediment source near its central part where the sediment core was collected. Lehmkuhl et al. (2018) reflected that near Boontsagaan lake, active barchans formed due to the local existence of strong west-northwest winds. Therefore, aeolian input could have originated from these active dunes. In dry conditions, a wind-eroded material is directly supplied to the lakes. It is a crucial source of particulate material due to strong winds and sparse vegetation cover. As a future work, we will analyse these surrounding wind blown sediment and study how we can identify the aeolian input in lake sediment.

 

Comment 9: The factors influencing sedimentation in lakes did not take into account, for example, the topography, and especially the slope of the slopes, which may be of great importance during rainfall and material supply to lakes. An example is the Authors' statement that when the water level is lower, coarser fractions are accumulated on the shore (lines 447-448), which is obvious.

Response: We agree with the reviewer that the evidence when the water level is lower, coarser fractions  accumulated on the shore may play a role in coase ssediment fraction. We add one sentence to pull attention on this possibility.

 

Comment 10: Lack of correlation with the results of works examining similar parameters.

Response: Thank you for your friendly reminder. We agree with the reviewer that less correlation between meteorological data and sediment characteristics in the case of Orog lake. We assume this is due to our less precise age-model for Orog lake, and we exclude the Orog results from our interpretation .

 

Comment 11: Title of chapter 5.2. Temperature increase and lake level and vegetation changes have nothing to do with the content. The authors cite much more factors influencing the sedimentation conditions in the lake and the mineral composition than just the temperature. Please change the title to a more adequate one, e.g. Impact of climate factors on the lake level fluctuation. Overall, in my opinion, the manuscript needs more work to be more robust and publishable by Geosciences.

Response: Thank you for your nice suggestion. We revised accordingly.

Reviewer 2 Report

Like all formations on Earth, lakes are born, live and die. Their depth and appearance change, which strongly depends on the relief of the basin, on the flowing and flowing rivers and streams, lake precipitation, vegetation and climate.

The manuscript of Uyangaa Udaanjargal and co-authors is devoted to the study of the influence of climate on the processes of sedimentogenesis in the salt lakes of southwestern Mongolia. The authors analyzed the composition of lake sediments in the cores and compared the data obtained with meteorological information.

The article is well structured, characterized by a logical presentation of the material, figures and tables are appropriate.

However, there are the following comments to the manuscript:

1. The abstract should be shortened.
2. In a review of previous studies (Introduction) there are no necessary, in our opinion, references to the articles of Egorov, 1993 (Egorov, A.N. Mongolian salt lakes - some features of their geography, thermal patterns, chemistry and biology. Hydrobiologia 1993, 267, 13-21, doi:10.1007/bf00018788.) and Williams, 1991 (Williams, W.D. Chinese and Mongolian saline lakes - a limnological overview. Hydrobiologia 1991, 210, 39-66, doi:10.1007/bf00014322).
3. Figure 1C does not show the delta of the Tuin River, so it seems that there is no river flow into the lake.
4. In our opinion, it is necessary to show in Figures 1 (D-F) the position of the mouths of rivers flowing into lakes.
5. Section 2 presents very sparingly information about the geological structure and geomorphology of the region. It seems to us that it is worthwhile to provide more data about the composition of rocks in this region, using, for example, information from the article Nottebaum et al., 2021 (Nottebaum, V.; Stauch, G.; van der Wal, J.L.N.; Zander, A.; Schlutz, F.; Shumilovskikh, L.; Reicherter, K.; Batkhishig, O.; Lehmkuhl, F. Late Quaternary landscape evolution and paleoenvironmental implications from multiple geomorphic dryland systems, Orog Nuur Basin, Mongolia. Earth Surface Processes and Landforms, doi:10.1002/esp.5247).
6. I would like to attract the attention of the authors to the detailed description of fault tectonics and earthquakes for this region, presented in van der Wal et al., 2021 (van der Wal, J.L.N.; Nottebaum, V.C.; Stauch, G.; Binnie, S.A.; Batkhishig, O.; Lehmkuhl, F.; Reicherter, K. Geomorphological Evidence of Active Faulting in Low Seismicity Regions-Examples From the Valley of Gobi Lakes, Southern Mongolia. Frontiers in Earth Science 2021, 8, doi:10.3389/feart.2020.589814.), which may be useful in interpreting the results obtained.

Author Response

Thank you for giving us the opportunity to submit a revised draft of the manuscript “Characteristics of lake sediment from southwestern Mongolia and comparison with meteorological data” for publication in Geosciences.

 

We appreciate the time and effort that all the reviewers dedicated to providing feedback on our manuscript and are grateful for the insightful comments for valuable improvements of our paper. We have carefully addressed all the comments and the paper is revised accordingly. The corresponding changes and refinements made in the revised paper are summarized in our response below, all modifications in the manuscript are marked by "track changing" function. Newly added references are highlighted with yellow.

 

Here are our responses to comments.

 

Comment 1: The abstract should be shortened.

Response: We thank the reviewer for the suggestion. We deleted the first paragraph to shorten the abstract. Small changes are also given to include necessary information.

 

Comment 2: In a review of previous studies (Introduction) there are no necessary, in our opinion, references to the articles of Egorov, 1993 (Egorov, A.N. Mongolian salt lakes - some features of their geography, thermal patterns, chemistry and biology. Hydrobiologia 1993, 267, 13-21, doi:10.1007/bf00018788.) and Williams, 1991 (Williams, W.D. Chinese and Mongolian saline lakes - a limnological overview. Hydrobiologia 1991, 210, 39-66, doi:10.1007/bf00014322).

Response: Thank you for your careful review. We revised accordingly.

 

Comment 3: Figure 1C does not show the delta of the Tuin River, so it seems that there is no river flow into the lake.

Response: Thank you for your careful review. We checked and modified the figure.

 

 

Comment 4: In our opinion, it is necessary to show in Figures 1 (DF) the position of the mouths of rivers flowing into lakes.

Response: Thank you for your nice reminder. We revised accordingly.

 

Comment 5: Section 2 presents very sparingly information about the geological structure and geomorphology of the region. It seems to us that it is worthwhile to provide more data about the composition of rocks in this region, using, for example, information from the article Nottebaum et al., 2021 (Nottebaum, V.; Stauch, G.; van der Wal, J.L.N.; Zander, A.; Schlutz, F.; Shumilovskikh, L.; Reicherter, K.; Batkhishig, O.; Lehmkuhl, F. Late Quaternary landscape evolution and paleoenvironmental implications from multiple geomorphic dryland systems, Orog Nuur Basin, Mongolia. Earth Surface Processes and Landforms, doi:10.1002/esp.5247).

Response: Thank you very much for your comments that helped us improve this manuscript. We added a few sentences to introduce paleoenvironmental study in Orog Nuur Basin and cited their contribution.

 

Comment 6: I would like to attract the attention of the authors to the detailed description of fault tectonics and earthquakes for this region, presented in van der Wal et al., 2021 (van der Wal, J.L.N.; Nottebaum, V.C.; Stauch, G.; Binnie, S.A.; Batkhishig, O.; Lehmkuhl, F.; Reicherter, K. Geomorphological Evidence of Active Faulting in Low Seismicity Regions-Examples From the Valley of Gobi Lakes, Southern Mongolia. Frontiers in Earth Science 2021, 8, doi:10.3389/feart.2020.589814.), which may be useful in interpreting the results obtained.

Response: We greatly appreciate the reviewer’s suggestion. According to the comment, we read the mentioned article and cited it in the "site description" chapter. However, we did not cite this paper in our discussion because the  all meteorological data are after the 1957s (the last known big earthquake occurred this time).

Reviewer 3 Report

This manuscript concerns a research paper on lake sediments which are used as a proxy to relate the long-term fluctuations of environmental conditions with sedimentation rates. The research herein presented is certainly within the scope of the Geosciences.

The manuscript is well written and clear. I leave the authors with a list of short comments.

Comments

1. Figure 2 - C. The vertical axis should read Wind (m/s).
2. Figure 2. Meteorological measurements are prone to several errors and it is difficult to believe that those errors remained stable over several decades, 1950-2014. Is there any error estimation in the measurements?. A more detailed analysis of the dataset accuracy is necessary when you want to compare measurements acquired during different decades: men, equipment, financial inputs and methods change.
3. Comparison between sediment characteristics and meteorological data is carried out on the basis of a principal component analysis. This analysis can help to identify source areas, weathering processes and sediment characteristics. Nonetheless, the authors should also acknowledge that Fourier-type and wavelet analysis can help in the identification of the dominant time-bands and ultimately, in the identification of temporal patterns within the meteorological and sediment time-series (see e.g. [1] and related references). This could complement the future work for the authors.

Bibliography

[1] Long-term time-scale bonds between discharge regime and catchment specific landscape traits in the Spanish Pyrenees. C. Juez, E. Nadal-Romero. Environmental Research, 2020.

Author Response

Thank you for giving us the opportunity to submit a revised draft of the manuscript “Characteristics of lake sediment from southwestern Mongolia and comparison with meteorological data” for publication in Geosciences.

 

We appreciate the time and effort that all the reviewers dedicated to providing feedback on our manuscript and are grateful for the insightful comments for valuable improvements of our paper. We have carefully addressed all the comments and the paper is revised accordingly. The corresponding changes and refinements made in the revised paper are summarized in our response below, all modifications in the manuscript are marked by "track changing" function. Newly added references are highlighted with yellow.

 

Here are our responses to comments.

 

Comment 1: Figure 2 - C. The vertical axis should read Wind (m/s).

Response: We thank the reviewer for the careful check. We have modified it accordingly.

 

Comment 2: Figure 2. Meteorological measurements are prone to several errors and it is difficult to believe that those errors remained stable over several decades, 1950- 2014. Is there any error estimation in the measurements?. A more detailed analysis of the dataset accuracy is necessary when you want to compare measurements acquired during different decades: men, equipment, financial inputs and methods change.

Response: We agree with the reviewer that meteorological measurements are prone to several errors at local station data. Unfortunately, information on the actual measurement system is not accessible.  In this study area, eight stations exist and we checked all dataset  and chose four stations based on the data continuity.

 

Comment 3: Comparison between sediment characteristics and meteorological data is carried out on the basis of a principal component analysis. This analysis can help to identify source areas, weathering processes and sediment characteristics. Nonetheless, the authors should also acknowledge that Fourier-type and wavelet analysis can help in the identification of the dominant time-bands and ultimately, in the identification of temporal patterns within the meteorological and sediment time-series (see e.g. [1] and related references). This could complement the future work for the authors.

Bibliography [1] Long-term time-scale bonds between discharge regime and catchment specific landscape traits in the Spanish Pyrenees. C. Juez, E. Nadal-Romero. Environmental Research, 2020.

Response: We greatly appreciate the reviewer’s suggestions. We have checked article and Fourier-type and wavelet analysis. We would consider this method in the future work.

Round 2

Reviewer 1 Report

Thank you for your thorough analysis of the reviews. I am satisfied with the answer, I understand that in the case of the drilled sediments it was not possible to describe the sediment structure. On line 478, please replace "slop flow" with, for example, overland flow or sheet flow.