Sediment history mirrors Pleistocene aridification in the Gobi Desert (Ejina Basin, NW China)

Schwamborn, Georg; Hartmann, Kai; Wünnemann, Bernd; Rösler, Wolfgang; Wefer-Roehl, Annette; Pross, Jörg; Schlöffel, Marlen; Kobe, Franziska; Tarasov, Pavel E.; Berke, Melissa A.; Diekmann, Bernhard

doi:https://doi.org/10.5194/se-11-1375-2020

Articles | Volume 11, issue 4

https://doi.org/10.5194/se-11-1375-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/se-11-1375-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 11, issue 4

Research article

|

23 Jul 2020

Research article |

| 23 Jul 2020

Sediment history mirrors Pleistocene aridification in the Gobi Desert (Ejina Basin, NW China)

Georg Schwamborn, Kai Hartmann, Bernd Wünnemann, Wolfgang Rösler, Annette Wefer-Roehl, Jörg Pross, Marlen Schlöffel, Franziska Kobe, Pavel E. Tarasov, Melissa A. Berke, and Bernhard Diekmann

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Final revised paper (published on 23 Jul 2020)
Preprint (discussion started on 04 Nov 2019)

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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RC1: 'Sediment history mirrors Pleistocene aridification in the Gobi Desert (Ejina Basin, NW China)', Attila Ciner, 18 Nov 2019
- AC2: 'response to RC1 and RC2, to SC1 and SC2', Georg Schwamborn, 14 Jan 2020
- AC3: 'response to RC1 and RC2, to SC1 and SC2', Georg Schwamborn, 14 Jan 2020
SC1: 'a few suggestions', Isla Castaneda, 02 Dec 2019
SC2: 'Suggestion for manuscript improvement', Christian Leipe, 03 Dec 2019
RC2: 'Review of Schwamborn et al Ejina Basin paper', Anonymous Referee #2, 09 Dec 2019
- AC2: 'response to RC1 and RC2, to SC1 and SC2', Georg Schwamborn, 14 Jan 2020
- AC3: 'response to RC1 and RC2, to SC1 and SC2', Georg Schwamborn, 14 Jan 2020
AC1: 'Response to all', Georg Schwamborn, 09 Dec 2019

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

AR by Georg Schwamborn on behalf of the Authors (30 Jan 2020)

ED: Referee Nomination & Report Request started (04 Feb 2020) by Marc Oliva

RR by Anonymous Referee #3 (11 Feb 2020)

Suggestions for revision or reasons for rejection

Review on the manuscript “Sediment history mirrors Pleistocene aridification in the Gobi Desert (Ejina Basin, NW China)”, by Schwamborn et al., journal “Solid Earth”.

General comments.
This is a very interesting work dealing with the interactions between the tectonic and climate dynamics through the study of the sediments of a 200-long core extracted from the Ejina Basin in northwestern China. The manuscript is well written and presents a good state of the art / related literature revision. The methods are considered appropriate, well chosen and explained with high detail and wealthy data. The results are considered good, and thoroughly descripted and explained. And finally, the discussion presents a good interpretation of them, integrating them with the related literature and reaching valuable conclusions for a better understanding of the palaeogeography and palaeoenvironments of the region. The scientific quality is considered very good for the journal, and for the results themselves, and honestly, I only have some minor comments to this work, which consider that deserves being published.

Abstract.
Ok, very complete despite their synthetic character, and with many data of interest. It summarizes well the manuscript.

Introduction.
This section includes a comprehensive review on the relevance of the study of sediments in this area in relation to the interactions of the tectonics and climate forcing. An appropriate chronological background of the main tectonic events is included together with the dynamics of the sediment transport and accumulation in the area through the main streams, from the origin in the erosion of the main mountain ranges to the formation of the main alluvial fans. With this information, the aim of the paper is well justified. However, I suggest to move the last paragraph (L78-82) to the results section so that the results do no get ahead so soon in the manuscript.

Study area.
The information given in this section is very complete and gives a nice and accurate overall picture of the study area /region. In the first part, i.e. geographical setting, I suggest to include some data regarding to the specific location with latitude/longitude. Regarding to the climate, the data provide are adequate, but I wonder if the authors could add some information regarding to the synoptic climatology of the summer (i.e. the winter anticyclone is mentioned but no what happens in summer).

L101/102: change the “2” in “km2” to superscript.
L105: idem for “14” in “14C”.
L102: “m/s”, better as “m s-1”. Information about wind direction and seasonal changes susceptible to modify precipitation throughout the year?
L114: please, add a hyphen in “ice free”.
L118-126: this comprehensive information about the vegetation may be summarized considering the nature and aims of this paper.

Methods.
The methods selected by the authors are considered appropriate for the study, and its use is well justified. The explanation of each method includes very detailed information. However, it seems to me that some sub-sections (i.e. methods/techniques) are explained with more detail and data than others (compare e.g. mineralogy subsections with pollen analysis or chronostratigraphy). Thus, a more balanced explanation of the methods is recommended. Moreover, in most of the cases, due to the use of many abbreviations, symbols and technical information, those readers not very familiarized with these techniques/and methods, may “be lost” when reading through this section. The information given is considered appropriate, but in the case of the sub-section 3.9 some results are given (L260-266), and I suggest to re-locate them and move to the ‘Results section’.

L129: what do the authors mean with “maximum distance”? Could they specify it?
L276-277: change the exponent of the power notation and the numbers of the isotopes (mass number in 10Be and 26Al) to superscript.
L278-280: please, correct the units of the production rates to “atoms (g quartz)-1 yr-1”.
L280: “stopped muonic”? Do the authors mean slow muons?
L281: please, format the mass numbers as superscript.
L282: I think that the authors mean an “online calculator” rather than a “tool”. But which tool do the authors refer to? CRONUS? Please, clarify it.
L284-285: please format the length and density units to “cm-2”.
L287: this is a result; thus, please move to the ‘Results’ section.

Results.
The presentation and description of the results is considered good, although possibly, they might be summarized as a slightly shorter extent would benefit the manuscript.

L293: the three units should be mentioned now. Then continue with the description of each one.
L357-359: this is an interpretation, and thus I recommend to move it to the discussion section.
L363, L366, L367: please, change to “cm ka-1”.
L389: this is an interpretation – please, move it to the discussion section.
L421-422: this is an interpretation – please, move it to the discussion section.
L430-431: this is an interpretation – please, move it to the discussion section.
L437-438: this is an interpretation – please, move it to the discussion section.
L439: be careful with the decimal separators – change to point (decimal) instead of comms (thousands million years).
L445-447: this is an interpretation – please, move it to the discussion section.
L450-458: this information may be summarized, and even relocated: either in the ‘Methods’ section or in the ‘Discussion’, due to its usefulness for the interpretation or its relevance itself.

5. Discussion.
The interpretation of the results and their explanation in the context of the related literature is very clear and easy to follow. I only have some minor observations:

L526: which is the symbol at the beginning of the line? A typo? “Chenopodiaceae”: format it in italics.
L556, L557: please, change “/ka” to “ka-1”.
L616-618: this reasoning is really interesting. I wonder if the authors could support this finding on some data of regional atmospheric palaeocirculation.
L627: what is “MTP”: the meaning of this abbreviation has not been presented before.
L629: “CaCO3”: format the “3” as subscript.

6. Conclusions.
The conclusions summarize well the findings of the manuscript and the tectonic/climatic palaeogeographic interactions. Nothing else to add. Ok.

Figures and tables.
I cannot assess their quality as they are not included together with the manuscript, and wasn’t able to see them.

Referee Report: PDF

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RR by Mark Allen (25 Feb 2020)

ED: Publish subject to minor revisions (review by editor) (25 Feb 2020) by Marc Oliva

AR by Georg Schwamborn on behalf of the Authors (28 Feb 2020) Author's response

ED: Publish as is (04 Mar 2020) by Marc Oliva

ED: Publish as is (18 Mar 2020) by Elias Samankassou (Executive editor)

AR by Georg Schwamborn on behalf of the Authors (19 Mar 2020)

Short summary

We use a sediment core from the Gobi Desert (Ejina Basin, NW China) to illustrate the landscape history of the area. During 2.5 million years a sediment package of 223 m thickness has been accumulated. Various sediment types document that the area turned from a playa environment (shallow water environment with multiple flooding events) to an alluvial–fluvial environment after the arrival of the Heihe in the area. The river has been diverted due to tectonics.