Updated Chronology of the Last Deglaciation in the Făgăraş Mts (Romania)

Point-by-point response to Comments and Suggestions of Reviewer 1

Comments 1: This manuscipt is well organized. However, there are some points could be improved.

Response 1: Thank you for the time and effort you have spent reviewing our study. Thank you for your comments, for which our responses are highlighted in red below.

Comments 2: Could you describe more details about the rocks which you got samples? Such as, does the lithology or weathering affect the dating age?

Response 2: The study area is part of the Suru lithostratigraphic formation composed of paragneiss, micaceous quartzites and intercalations of amphibolites and gneissic amphibolites (Pană, 1990).

Pană, D. (1990) Central and northern Făgăraş – lithological sequences and structure. D. S. Inst. Geol. Geofiz. 74/5: 81-99.

CRE ages did not show any correlation with lithological differences, although we note that the currently available CRE dataset of the central Făgăraş Mts is quite limited.

The first information has been inserted into 3.1 section when sample collection is described, while the lack of relation between lithology and CRE ages are documented in 5. section.

Comments 3: In fig.4, it might be better to campare the Late Glacial situation with the near area like Alps or the other mountains, then we could get more information about the paleoenvironment changes.

Response 3: Principally we agree with the suggestion, however the Alps are already quite far from the study site (The distance to the Eastern Alps is >900 km, while to the Western Alps is already >1300 km). Synthetising Late Glacial deglaciation histories from the surrounding ranges of the Alpine-Dinaric region up to 1300 km, or so would make a book (see Palacios et al., 2023 https://doi.org/10.1016/C2021-0-00331-X). We would refrain from such an overinterpretation of the currently available dataset counting only 10 CRE ages (half of which was interpreted as minimum age since they were too young compared to their morphostratigraphic position). However, to not refuse the comment completely we assessed the opportunity to include additional data from surrounding areas and extend the spatial comparison beyond the Southern Carpathians. We selected data from the literature on regional deglaciation chronology where the studied site is not farther than 600 km from the Fagaras Mts and the applied CRE calculation comparable (Lal/Stone scaling, correction for denudation and snow cover) to this study. Four studies met these criteria (beside Retezat which was originally used for comparison). Two ranges are situated in the northern part of the Carpathians Chorna Hora (Rintercknecht et al., 2012 ) and High Tatras (Zasadni et al., 2023 https://doi.org/10.1016/B978-0-323-91899-2.00042-5); and two ranges from the Central Balkan (Macedonia) Jablanica (Ruszkiczay-Rüdiger et al., 2020) and Jakupica (Ruszkiczay-Rüdiger et al., 2022). The glacial stages with the corresponding most probable CRE ages are added to the revised version of Figure 4a.

Another relatively near potential place could be the Rila Mts, situated ~400 km southward from the Fagaras Mts, however only the largest glacier extent have been dated there, and was assigned to LGM (http://dx.doi.org/10.1016/j.quaint.2012.06.027 ) so the Late Glacial situation cannot be integrated in Fig 4.

Comments 4: In the discussion, it is better to discuss more linkage between the global climate change and the local landscape evolution, because they may both control the fluctuation of glaciers in the research period.

Response 4: We agree with this comment. However, we included Greenland ice core record supporting the linkage between large-scale climate change and glaciological mass balance fluctuations in the Fagaras Mts. Beside this we included local/regional paleoclimate records in the discussion because we are convinced that this local/regional climate changes could primarily regulate the glaciological mass balance fluctuations.

However, as a consequence of the changes in response to the previous comment and the comments from Reviewer 3 the discussion has been extended and/or rephrased at a couple of places. Figure 4 has been improved, too.

Point-by-point response to Comments and Suggestions of Reviewer 2

Comments 1: The study presents an extended work on deglaciation chronology for the Southern Carpathians. They present an advanced procedure to recalculate existing ¹⁰Be exposure ages and document 10 new ages. The recalculated and new ages are 2.5 to 12% older than the previously published data. The comparison to Greenland ice core record documents convincing evidences of climate links to regional climate.

The presentation is considerably advanced compared to previous studies, and the recalculation of existing data, including surface denudation, uplift and snow shielding appears essential.

I suggest to publish the manuscript as is, as an essential advancement of South Carpathian deglaciation research.

Response 1: Thank you for the time and effort you have spent reviewing our study. Thank you for the reviewer's words of appreciation and for supporting the publication of our manuscript. We are pleased that he/she thinks well of our work. We ourselves hope that the results will help the advancement of better knowledge and ultimately improved understanding of the deglaciation of the Southern Carpathians.

Point-by-point response to Comments and Suggestions of Reviewer 3

Comments 1: I enjoyed reading this manuscript. I found the work and the results interesting, particularly the calculation of the correction of the ¹⁰Be ages and its application to previous results.

Response 1: Thank you for the time and effort you have spent reviewing our study. Thank you for your comments, for which our responses are highlighted in red below.

Comments 2: In the Materials and Methods, in general, many deglaciation chronology studies have relied on ¹⁴C dating of organics (plant roots, stems) incorporated in morainal deposits. Was this not possible in this field area?

Response 2: According to our best knowledge no organic remains have  been found yet in original (i.e. synsedimentary) stratigraphic position in morainic material in the Fagaras Mts (or in the Southern Carpathians at all) which could be suitable for radiocarbon dating. Anyway, we are pretty sure that radiocarbon age from organics has not been published from the moraine deposits of the southern Carpathians. The first numerical geochronological data for the moraine deposits of the Southern Carpathians have been obtained owing to the application of in situ cosmogenic exposure dating.

Comments 3: Also in this section, please be very clear from the start in the text which samples were collected in this study and which were collected earlier (I realize it is clear in Figure 1, but it would be helpful to have it in the text).

Response 3: Thank you for pointing this out. After careful reading of the original text, we recognized that in the sentence describing the morphostratigraphic situation of F9 sample, which belongs to the sample set of the previous study the citation was lacking. We added a citation to Kuhlemann et al., 2013 (Ref 17) again in this sentence (see line 183).

Comments 4: In Results - lines 273-275. Could the age of the boulder in question be a consequence of displacement by colluvial processes post-glacial retreat?

Response 4: We agree with this comment. Colluvial processes are mentioned beside permafrost degradation in the revised text (see line 275).

Comments 5: Discussion - lines 334-335. Yes, the age of the Younger Dryas (12.9 ka - 11.6 ka) would yield an exposure age of ~12 ka.

Response 5: We agree with this comment. As we see it, no action is needed.

Comments 6: Discussion - lines 351-353. I would have liked an expansion of this point (inherited cosmogenic isotopes). Could you explore this with another two or three sentences?

Response 6:  A sentence was added explaining that CRN inheritance from previous glacial stages may lead to an old bias of the estimated exposure ages. We also explain that in this case the glaciers in the corresponding glacial phase may have been longer, which would be morphologically more similar to the deglaciation pattern described in the Retezat Mts.

Comments 7: Discussion - lines 359-360. This is a very honest concession. Thank you

Response 7 Thank you for this comment. As we see it, no action is needed.

Comments 8: Discussion - lines 366-368. How likely is it that the landforms from these much older glaciations would have survived the more recent advances?.

Response 8: As a logical prerequisite a landform of a relatively larger glacier extent can survive a subsequent glacier advance if the subsequent advance occupied a relatively smaller extent. Landforms from pre-LGM glaciations could be found all around Europe (see Part IV in Palacios et al., 2022 https://doi.org/10.1016/C2020-0-00404-4 ). For instance, MIS6 landforms have been documented in the High Tatras situating c. 540 km NW (Zasadni et al., 2021 https://doi.org/10.1016/j.catena.2021.105704) or in the Durmitor Mts situating c. 520 km SW (Hughes et al., 2011 https://doi.org/10.1016/j.quascirev.2011.08.016) from the Fagaras Mts.

Comments 9: Discussion - line 396. Please provide the age for the GI-1. Onset at 14.7 ka

Response 9: The commented sentence has been rephrased including the currently accepted age of the onset of GI-1.

Comments 10: Discussion - line 434: The Romanian speleothem record at 13 ka - wouldn't this be Younger Dryas?

Response 10 No. The cited study reported a pronounced drop in the oxygen isotope profile (0.6–1‰) from 12.6 to 11.4 ka in two speleothems. It was interpreted as a change to colder climate, approximated better the Younger Dryas, or GS-1 climate event.