Review 1:

•    Does the paper address relevant scientific questions within the scope of CP? Yes

•    Does the paper present novel concepts, ideas, tools, or data? Yes

•    Are substantial conclusions reached? Yes, however the primary goal of establishing a new chronology for the Alto dell’Ortles core, marks a more incremental change in knowledge. Interpretation of the Pb record is not described (instead it is saved for a future manuscript).

•    Are the scientific methods and assumptions valid and clearly outlined? Yes

•    Are the results sufficient to support the interpretations and conclusions? Yes

•    Is the description of experiments and calculations sufficiently complete and precise to allow their reproduction by fellow scientists (traceability of results)? Yes

•    Do the authors give proper credit to related work and clearly indicate their own new/original contribution? Yes

•    Does the title clearly reflect the contents of the paper? Yes

•    Does the abstract provide a concise and complete summary?  Yes

•    Is the overall presentation well structured and clear?  Yes, a few minor typos and grammatical errors throughout.

•    Is the language fluent and precise? Yes

•    Are mathematical formulae, symbols, abbreviations, and units correctly defined and used? Yes

•    Should any parts of the paper (text, formulae, figures, tables) be clarified, reduced, combined, or eliminated? Minor change to figure 1 described below.

•    Are the number and quality of references appropriate? Yes

•    Is the amount and quality of supplementary material appropriate? Yes

We thank Reviewer 1 for the positive evaluation of our manuscript and constructive suggestions.

Specific Comments:

Page 4 Line 22: Were any meltwater samples collected during CFA analysis of the core to test for Pb recovery following leaching to test the theory that different leaching times were the primary driver of the differences between core 1 and core 3?

No additional leaching tests were performed for this specific study. Trace metal concentration differences due to acid leaching are related to method specific acidification of samples prior the analyses. It depends on acid concentration, acidification time (e.g., Uglietti et al., 2014; Rhodes et al., 2011) and, as we demonstrated in Uglietti et al. (2014), also on the chemical/mineralogical characteristics of the sample itself and the study site. According to a previous test with one single ice sample from the same Mt. Ortles ice core (Uglietti et al. 2014), Pb concentration would not seem to be affected by acid leaching time. However, in that study changes were investigated for acidification times between 24 h and 43 days, not covering the short acidification timescale typical of Continuous Flow Analysis (1-2 minutes; Core 3 analyses, this study) and Discrete Analysis (less than one day; Core 1 analyses, this study).

A manuscript of one of our co-authors is currently under review in the Journal of Analytical Atomic Spectrometry (Münster et al., 2025 JAAS), in which these shorter timescales, from minutes to a few hours, were investigated (1.5-250 minutes) for alpine ice core samples. Those results show a 2-to-3-fold increases in the measured Pb concentration over that short time range, which may explain the observed difference in absolute Pb concentration between core 1 and 3, supporting our explanation of a leaching effect on a time scale of a few hours.

In any event, a fundamental point is that acid leaching time does not affect the shape of the Pb records in cores 1 and 3 that are used in our paper for aligning the depths of these two cores. This point is already made in our manuscript where we state: “In any case, different acidification methods do not affect Pb trends and features (maxima, minima, Pb variations) used for wiggle matching.” In the revised manuscript, we will extend the information so far provided in a specific Supplementary Information section according to the text presented above. 

Figure 1. The dotted blue lines across the cores are not described in the figure caption.

Thank you for the notification, the description will be added.

Page 15 Line 4: Using “remarkable” to describe the r value of 0.41 is an overstatement.

Agreed, this will be deleted.

Please see our response in the attached pdf file.