Dear Sebastian and co-authors,

After a careful study of the revised manuscript by an anonymous reviewer, it appears to me that you have not fully exploited the suggestions made to you by the first two reviewers.

While the paper still presents a very interesting data set in excellent form, both with respect to style of writing and quality of illustrations, the following points would have benefitted from a more rigorous effort on your part:

1.
The rheological evolution of the northern and southern sections of the Woodroffe Thrust is still not very well explained. Simply referring to a follow-up paper is not enough. If the shear zones are strain softening, should not the efficiency of the softening mechanism be the main controlling factor determining the ultimate width ? This issue remains unexplained. Why not focus more on the strain softening mechanisms, as suggested? With the key message being that (hydration) reactions control the rheological evolution of a mylonite, the paper would be a clear step forward compared to previous studies by Camacho et al and Bell & Etheridge.

2.
With respect to the CO2 - your answer to the second reviewers question is not satisfying. If the Woodroffe Thrust did not channelize these fluids, how did the fluids get to where they are now? The hypothesis proposed is not very well supported by the CO2 data and requires a better discussion.

3.
You did not properly describe (and justify) the thresholding technique you used, error estimates are missing, methods for the separation of peaks are not explained. Statements such as "sophisticated segmentation tools [...] require careful checking of the output results" do not qualify. The reliability of your results needs to be demonstrated - your "believe" that the results are "quite reliable" is not convincing.


A few minor points:

line 22 - increase in the abundance of fluids
line 26 - difference between fault and shear zones (cf. Ramsay's definition of shear zones)?
line 53 onward - I think this could be pitched better - reads a bit like "just another contribution" and doesn't really grab the reader's attention/interest. Why not emphasize what new data you are adding?
line 377 - For the sake of whose simplicity?
line 447 - This is avoiding the important question as to where these fluids come from and how they travelled.
line 518 - and increasing displacement?
line 535 - Why is this a contradiction?
line 539 - effective viscosity contrast?
line 545 - It's not exactly new that even small amounts of fluid will support strain localization.


I would kindly ask you now to address the 3 remaining points of criticism and to correct the minor points. With these final revisions in place you will be looking forward to a very nice publication.

Thanking you in advance for your efforts,

Renée Heilbronner

Dear Sebastian and co-authors,

Thank you for the final revisions. I accept that you want to save the discussion on the dependence of rheology and microstructure on varying metamorphic conditions and water activity for a forthcoming paper.

Therefore, the paper is now ready to be published.

--- almost ready. There are a few typos you have to take care of and one or two other fixes:

1. Replace "ca." by " approx." in lines 20, 58, 62, 93
2. I suggest you delete "critically" in line 50
3. Delete space before comma in line 56

in Supplementary material:
line 50: replace "spectrum" by "grey scale*
line 52: "minimizes" not "minimalizes"
Figure S3: Please introduce labels (a) and (b). Also, a legend is required for white, grey, black on the left. Rework caption.
Figure S5: it is "element map" not "elemental map"

That's it!

Thank your for submitting to Solid Earth,

all the best from rainy Basel

Renée

Dear authors, please consider the remarks of the Topical Editor, and then your paper is ready for publication. Many thanks for choosing SE !, Charlotte Krawczyk.