Thank you for submitting this revised version and for diligently addressing reviewer comments. As you know, you received two reviews for this manuscript. The first review recommended consideration following major revisions. The second recommended consideration following only minor revisions. Having read the revised version and your responses to the two reviewers, I feel that significant progress was made toward eventual publication. I also feel, however, that additional improvements are required before the manuscript can move on to an accepted status. As such, I will reconsider your manuscript following additional minor revisions.

Please address the following line referenced comments in a revised version of your manuscript. While completing those revisions, I request that you pay particular attention to comments regarding the scope of geochemical interpretations, and one of your preferred models for calcite precipitation in sandstones.

I look forward to seeing a revised version of this work, and I believe it will ultimately make a good contribution to this special issue.

Best,
Randy Williams

15: You only use “structural and diagenetic heterogeneities” twice in the abstract, so I suggest not defining the acronym here for the sake of text clarity. In fact, unless you are up against a space constraint I would personally recommend that you leave acronyms out of the abstract all together, but I will leave that to you to decide.

22: The fact that isotope values are negative does not in itself support a meteoric environment, particularly when the scale of d18O (vpdb vs smow) has not been specified. Suggest just stating interpretation that isotopes support a meteoric fluid source and elaborate later.

38: Texture is a bit vague here. Please specify what is meant in this case.

47: The paper by Williams et al. you are citing was actually published in 2016, not 2017.

50: Please remove the word “different”, it is not necessary.

67: I do not understand the use of “besides” here. Perhaps it should be “in particular” to draw specific attention to calcite of all the cements that can form in DB’s?

68: After much thought, I agree with Reviewer #1 - this statement under emphasizes the advances that have been made in this field. Please be more specific about what aspects remain poorly constrained. I think it would be fair to say that the controls on the origin and distribution of calcite cements remain poorly constrained, both in DB’s or even in undeformed reservoir rocks.

70: Wilson et al. (2003, Geology) would be another appropriate reference for vadose zone effects in DB’s.

80: I think this line needs a bit more specificity. A lot of work has actually looked at and thought about why low-permeability DB’s are selectively cemented by quartz (authors Laubach, Millikin, Williams, Lander, etc). With respect to calcite, I think your statement is true, so maybe that is the specificity that needs added?

83: This opener sentence needs revised for clarity. It is difficult to follow. It is also an important moment to frame your study for the reader.

84: Many would be willing to debate about how novel it is to take a cross-disciplinary approach such as this to look and diagenesis and fluid flow in deformation bands. Stated as generally as it is, many of us have done very similar. If this line is kept, I suggest merging it with the following which is much more specific.

101: This information needs a citation.

116: Please cite this information.

118: Do you really know this value to the second decimal place? Sort of precludes any variability at the outcrop scale.

Figure 1: Please revisit this figure in terms of text size. Some of this is too small to be easily read. As a general rule, the minimum font size that should be used is 8-point.

Figure 2: Same comment as above.

145: Please pluralize “altitude”.

150: To my mind “orientation” encompasses both strike and dip so “dip” here is redundant.

154: Natural light? As in an old microscope that actually reflects sunlight?

156-157: Texture is used twice here in two different contexts. Please specify. The word is a bit ambiguous and is being used a lot in this paragraph.

178: “Prediction uncertainty”?

181-182: Please but the DB orientations in standard azimuthal form here and throughout (i.e. 340 instead of N20W). It is considerably easier to follow and in my opinion is generally the standard for structural work of this type.

183: Suggest deleting “mostly”.

217-218: Concretions/nodules occurring preferentially in coarser-grained horizons is consistent with observations made by Hall et al (2004, J. Sed. Res.) and Davis et al (2006, Sed. Geol.).

Figure 4: What is the red box in panel C?

450-455: Isn’t is also true that you did not observe any crushed or comminuted calcite in the db’s? It seems that would be the most compelling evidence that DB formation preceded calcite cementation?

459: The last sentence does not follow from the previous. You confirmed that cement precipitation postdates db formation based on your observations. The following discussion about why that might be the case (strengthening) is appropriate, but it does not provide any additional confirmation for your original interpretation.

470: Isn’t this sort of a truism in describing them as “db-parallel” nodules?

497: Please change “poral” to simply “pore”.

512: Please just state simply whether you infer that cataclasis increases or decreases tortuosity

528: I think the term would be “transmissivity” and I would argue it is not appropriate for a comparison here because it inherently includes a component of element thickness. Maybe just hydraulic conductivity would be preferable?

527-540: This mechanism needs more discussion. First, whether or not an increase in residence time would lead to increased precipitation depends greatly on the details of the local geochemistry. I would argue that the primary control on calcite precipitation is the degree of supersaturation in the fluid. Is there an inherent reason that a simple increase in residence time would alter supersaturation with respect to calcite? One could actually argue the reverse - an increase in residence time means that for every mol of calcite precipitated we see a corresponding decrease in the degree of supersaturation, and decreasing rates of precipitation. Higher flow rates could more effectively maintain optimal supersaturations - at high flow rates, you are always bringing in a fresh source of supersaturated fluids. Also, this mechanism is not so easily distinguished from that proposed by Whitworth. I understand the title and abstract of that work describe “gouge”, but in reality what they were looking at was pulverized sand. There isn’t really an inherent difference between that and what is typically observed in deformation band faults.

541-545: The citations that showed increase rates of cementation in deformation bands due to surface chemistry effects associated with fracturing are all specific to quartz cements and I think that should be specified. The hypothesis has many problems when applied to calcite cements in sandstones, in part because the cementing phase is distinct from the substrate (grains), and in part because deformation bands that exhibit little to no cataclastic deformation (i.e.. Work by Williams, Mozley, Goodwin, Rawling, etc) often also show preferential cementation. A bit more discussion could be added here covering those points.

575: Please avoid 1-sentence paragraphs.

579-590: With respect, I do not see how any of these factors point necessarily to a meteoric phreatic environment. I have seen literally every one of these features in hydrothermal calcite deposits formed at several kilometers depth, where highly evolved basinal fluids were responsible for cement formation. CL color is a particularly bad metric for making these conclusions. Drusy textures certainly indicate a phreatic environment, but they have nothing to do with whether the fluid was meteoric. The only reliable indicator of meteoric fluids present in this study is the oxygen isotope data, and those data are reasonably compelling. Moreover, the maximum burial depth of these units is 1 km. Why not just focus on those more obvious sources of justification for a meteoric environment?

593-594: The negative nature of the isotope values alone does not support this interpretation. Stable isotope values mean very little without some inference on temperature and therefore inferred fluid compositions. In this case, your maximum burial depths are less than 1 km. This should allow you to assume a reasonable temperature range and calculate potential fluid d18O compositions. Without that, the interpretations related to meteoric environments remain uncertain.

606: I am not sure why you are trying to pile up so much evidence that the system was fluid saturated during cement formation? There is no evidence of vadose cementation (e.g. pendant or meniscus cement geometries, micritic calcites, etc) and plenty of evidence for phreatic (sparry, drusy calcite, poikilotopic textures). Why pull in other considerations which are quite frankly a bit tenuous in their relationship to phreatic environments specifically?

632-645: See comments above regarding what CL and isotopic variations reasonably can and cannot say without additional constraints. The degree to which CL variations are being used to infer fluid chemistry variations here is questionable. Both the CL activator (Mn) and quencher (Fe) are redox and pH dependent to varying degrees. How then do we so directly link CL colors to redox??

680-681: But how would we include such information? What is the spatial distribution of these features? How large are they on average? Perhaps suggest some future research imperatives along these lines?

707-710: See comments above. Fluid “slow down” is not so easily differentiated from the solute sieving hypothesis.

718: See comments above re: interpretation of isotopic results.

Please see attached pdf.

Dear Dr Del Sole,
Thank you once again for your diligence in addressing my criticisms. I have now reviewed your response to those criticisms and the latest revised version of your manuscript. I am satisfied with both, and as such I am recommending publication without further revision. This will make an excellent addition to the special issue, and I look forward to seeing it in print.

Best,
Randy Williams
Topical Editor

Dear authors,
many thanks for this thoroughly revised manuscript. I'm looking forward seeing this version finally published.
With best regards, Lotte Krawczyk.