I have now reviewed the reviewer comments and the author responses. Both reviewers were very positive about this paper and only suggested relatively minor corrections. The authors have made these corrections and I feel they have addressed all reviewer concerns.
I have a few minor comments that the authors can address before they submit the final version of the manuscript.
I look forward to seeing this in ESURF.

I am pleased to accept this submission for publication after careful review (and positive reception) by two reviewers and the Associate Editor. I think this paper will be very important in setting the groundwork for wider application of Be-10 and am excited to see it in e-surf.

I have a few minor notes to add to those from the AE; most of these are typographical. The authors should be easily able to address both sets of these comments before uploading the final version of their manuscript for typesetting. That being said, I do not consider these small edits to be required for accepting the manuscript.

My most substantive suggestion is for the authors to add a sentence (perhaps in the Methods) clarifying whether they modified the sediment preparation procedure to optimize for the small grain size fractions, particularly in the steps involving acid leaching. If possible, the authors might also specify how much mass loss they observed during the HF etching (and whether this was greater for the small 50-100 micron fraction). I think this information may be useful to researchers wanting to replicate the authors' approach, since few prior studies have worked with such small grain sizes.

In addition, I have the following minor editorial remarks:
p3, line 27: replace colon with semicolon followed by "for example"
p3, line 31: remove "the" before "10Be"
p3, line 35: remove "processes"
p4, line 9: better to say "has a small alluvial plain"
p4, line 10: remove comma
p5, line 13: does this mean decanted after a few minutes? presumably the decanting did not itself take a few minutes?
p6, line 28: "but only" (add but)
p7, line 40: OCTOPUS should be in all capital letters for consistency
p8, line 1: change semicolon to comma
p8, line 17: remove comma after Roering et al. (1999) reference
p8, line 25: "although it is situated" (add it is)
p9, line 8: remove "an erosion mechanism enhanced by cold conditions" as this is repeated from the line above
p9, line 18: remove comma after reference
p10, line 3: it, not they
p10, line 9: "fluvial dynamics ... efficiently mix"
Fig 1 caption: map, not maps (last sentence)
Table 1: it may help to clarify in a footnote, or in the Methods section of the text, why there are two different neutron production rates for the different size fractions of each sample, but the same muon rates