Review Reports - Geochemistry of Geothermal Fluids in the Three Rivers Lateral Collision Zone in Northwest Yunnan, China: Relevance for Tectonic Structure and Seismic Activity

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The purposes of the manuscript was to define geochemical signatures and origins of geothermal fluids in the three rivers lateral collision zone, and to analyze the relationships among the deep-source fluid release, tectonic structure and seismic activity.

Unfortunately, the work formulated in this way presents several shortcomings, including:

• The chemical classification does not take into consideration the salinity of the water;

• Binary diagrams with chloride should be added;

• There is no study on the saturation indices of the various mineral phases present in the aquifers;

. The bibliography is incomplete.

For this reason, I believe that the work can only be published after a moderate revision

The comments are in the attached file

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript describes the results of an investigation of the geochemistry of geothermal fluids in the three rivers lateral collision zone in northwest Yunnan, China and their implications in understanding the tectonic structure and seismic activity ofthe regions. Overall, the manuscript is well written and clear. However, it would benefit from careful proof reading. In addition, Table 1 would benefit and provide additional clarity from being organized around fault zones (like the figures), rather than sample numbers.

Calculated circulation depths presented in Tabel 1 are based on estimated temperatures using the quartz geothermometer. However, at temperatures below 180-200 °C, the chalcedony geothermometer is more appropriate. Recalculating the estimated temperatures using this geothermometer (t = 1032/(4.69 - log(SiO₂)) – 273.15) results in a lower estimated maximum temperature (samples 35,52, & 72) of ~130 °C and a shallower estimated circulation depth of 5.7 km and minimum circulation depths of less than 0.5 km. If the quartz geothermometer is to be used, a better rational needs to be provided in the manuscript beyond a reference to a non-English language publication.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The paper presents a large number of chemical and isotopic data on waters and gas discharges. It is a good dataset that also includes numerous isotopic analyses of 3He/4He. However, the paper is poorly written in many parts, starting from the abstract. Introduction and geological framework, in my opinion, deserve a deeper insight from the perspective of the cited bibliography, there is a complete lack of description of the hydrogeological setting, while the methods lack a detailed description (and related bibliography) of gas sampling. Free gases are generally collected from bubbling pools by using a plastic funnel positioned above the gas emergence and connected to pre-evacuated glass thorion-tapped flasks through a silicon tube. A NaOH solution is also added in the flask based on the type of analysis (Giggenbach flask). Here, the authors mention a glass bottle sealed with a rubber plug and adhesive plaster to avoid atmospheric contamination. I remain doubtful about the sampling procedure. The results should be separated from the discussion. The Results section must describe the raw data with no discussion or interpretation. The discussion of the chemical composition of over 70 waters is "summarized" in half a page, in which numerous statements are made without any depth: the geological complexity of the study area is not even considered (volcanic rocks, carbonates, sands, metamorphic rocks are present), nor are cold waters discussed separately from thermal ones, nor the possible presence of one or more aquifers (there is no mention of the hydrogeological setting in paragraph 2). Even minor and trace elements are dismissed in a few lines. The treatment dedicated to geothermometers is also lacking. There is no in-depth analysis of the only interesting sample in Fig. 5 (besides, it's not even clear which sample it refers to), but estimates are made even for cold waters. Regarding the gases, there is no indication in Fig. 1b of where they were sampled. Are they uniformly distributed or localized in specific areas? Since there is a good dataset of He and C isotopic data, I would try to use the d13C-CO2 vs. CO2/3He diagram by Sano and Marty (1995). Frankly, I read the final paragraphs with less attention, I will simply say that the circulation model is deficient as there is no reference to the geology of the study area. These and other comments are available in the attached PDF. In my opinion, this paper cannot be pubblished in the present form.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Remarks from reviewer have been correctly addressed and the paper in my opinion is now acceptable.
Best regards

Author Response

Thank you for your diligent review and valuable feedback. We appreciate your time and efforts in assessing our paper. We are glad to hear that the paper is now deemed acceptable in your opinion.

Your insights and suggestions have significantly contributed to the improvement of our work, and we are grateful for your constructive feedback.

Best regards

Reviewer 3 Report

Comments and Suggestions for Authors

The work has definitely improved, but I still find it difficult to read. The English still needs improvement, as does the overall structure, which needs to be streamlined. There are still several things that don't convince me in the presentation of the data and their interpretation. You will find some comments in the attached PDF