Editor comments on Roberts et al., ‘LA-ICP-MS U-Pb carbonate geochronology: strategies and progress with examples from fracture-fill calcite’

Overall this paper represents a useful updated review on in-situ carbonate geochronology that will be valuable contribution to the community and particularly those new to the application. It provides a thorough introduction to the method, applications and most importantly the limitations, potential pitfalls and matters of potential concern that any future analyst should be aware of.

The reviewers were largely supportive of this paper, particularly AKC and the authors have mostly addressed the specific corrections proposed by both reviewers and have presented reasonable responses to reviewers. I am mainly satisfied that these corrections have been made with the following exceptions.

There are a few points that the authors have not addressed/ might be worth considering before the manuscript is finalised:

1. Troy Rasbury commented “This manuscript is sort of a funny mix of a review and new datasets… While it is nominally a review of vein dating, it is not a complete review of what is out there.” I very much agree with this opinion and I do not think that the authors have made any corrections to address this criticism. The paper is a mix of review and new data and although a lot of what is presented is very useful, it is not really a review of all previous work, instead is a compilation of all the data reported from the BGS lab. Perhaps the authors could make this clear in the abstract/introduction- or include more examples from the published literature (for instance in figures such as figure 14). Troy also commented “my overall take on the manuscript is that it could be more compactly packaged and could do a better job of reviewing all of the U/Pb dating of vein material- perhaps leaving off discussion of speleothems which is well covered by Woodhead and a laundry list of carbonate characterization techniques that aren’t tied to examples.” Again, I agree with this statement and I do not think that the authors have addressed this- they have made no attempt to make the manuscript any shorter or more compact. I have two suggestions for how you might achieve this:

a. Section 2- Discussion of ID vs in-situ techniques- although this is of course a very important topic for discussion in geochronology much of this discussion has already been covered in other publications focused on geochronology methods. I therefore think this text could be shortened. Figure 2 for instance is very useful and I think if the text could be focused on these carbonate-specific examples would help concentrate the discussion.

b. Section 8- Troy’s comment “The modeling of initial disequilibrium is a very important contribution. Why is it so late in the paper?” I agree with this- I think that this section is an important and relatively novel contribution to the community, however, it is buried at the end of this very long paper and I worry that it will be lost due to this. I think that this would make much more impact if this was taken out and made into its own separate manuscript. You could then extend to include details of how to make the corrections with worked examples. This would help the reader understand how to make the corrections as well as why they are important. It is up to the authors what to do with this section- I realise that you won’t want to make it into a separate manuscript, but I just wanted you to know that I think it would be much more widely read if you did separate it. Perhaps you could consider adding a worked example as a small addition or refer to an example from the literature?

2. Although the methods are clearly presented in the supplementary material, it is not clear whether the primary data for any unpublished examples used by the authors is presented in the Supplementary material? Perhaps the authors could include a data table for any unpublished data?

I have also made a few suggestions on the attached annotated manuscript.

Overall this paper represents a useful updated review on in-situ carbonate geochronology that will be valuable contribution to the community and particularly those new to the application. It provides a thorough introduction to the method, applications and most importantly the limitations, potential pitfalls and matters of potential concern that any future analyst should be aware of.

I am satisfied that the authors have addressed reviewer and editorial comments and have made some useful edits to the text and additions in this new version including updated figures 6 and 7. I am also happy that the authors have now included data in the supplementary material. I am therefore pleased to accept this manuscript for publication. I look forward to reading it in it's final format in the special volume for Carbonate Geochronology. Although I have read through the revised manuscript, I would urge the authors to do a careful final check through to find any final typos or small editorial mistakes.

Dear Nick and colleagues,

I am happy to let you know that your manuscript has now been accepted for publication in Geochronology.

All the best,
Georgina