Reconstructing dynamics of the Baltic Ice Stream Complex during deglaciation of the Last Scandinavian Ice Sheet

Szuman, Izabela; Kalita, Jakub Z.; Diemont, Christiaan R.; Livingstone, Stephen J.; Clark, Chris D.; Margold, Martin

doi:https://doi.org/10.5194/tc-18-2407-2024

Articles | Volume 18, issue 5

https://doi.org/10.5194/tc-18-2407-2024

© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Special issue:

Icy landscapes of the past (CP/ESSD/ESurf/TC inter-journal...

https://doi.org/10.5194/tc-18-2407-2024

© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 18, issue 5

Research article

|

16 May 2024

Research article |

| 16 May 2024

Reconstructing dynamics of the Baltic Ice Stream Complex during deglaciation of the Last Scandinavian Ice Sheet

Izabela Szuman, Jakub Z. Kalita, Christiaan R. Diemont, Stephen J. Livingstone, Chris D. Clark, and Martin Margold

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Final revised paper (published on 16 May 2024)
Supplement to the final revised paper
Preprint (discussion started on 25 Jul 2023)
Supplement to the preprint

Interactive discussion

Status: closed

CC1:
'Comment on tc-2023-107', Margot Böse, 22 Aug 2023

Dear authors,
you have done a lot of work of integrating morphological results from the Baltic Sea bottom and examples from adjacent areas. But at any case it is necessary to include the results from Rügen Island (Gehrmann and Kenzler c. f. ) as parts of the island have been strongly affected by glacitectonic processes from different directions. The citations you can find in Lüthgens et al. 2020, EGQSJ.
Margot Böse

Citation: https://doi.org/10.5194/tc-2023-107-CC1
- AC1: 'Reply on CC1', Izabela Szuman, 30 Oct 2023
  
  Dear Margot Böse,
  We appreciate your comment on the preprint. Of course we know this paper. In Table 1 we just concentrated on studies that are spatially placed along the Baltic bottom, but we would cite paper by Gehrmann and Hardig 2018 in the following sentence : L398 “Ice marginal signatures in the southern sector often comprise overprinted lobes arising from oscillations and readvances of ice margins (Figs 6, 9B) along with switching of flow orientations and changing lobe positions during overall retreat (cf. e.g., Pedersen 2000; Kjær et al., 2003; Gehrmann & Hardig 2018)”
  Once again thank you very much for your kind reminder.
  Best regards,
  Izabela Szuman-Kalita
  Jakub Kalita
  Christiaan Diemont
  Stephen Livingstone
  Chris Clarke
  Martin Margold
  
  Citation: https://doi.org/10.5194/tc-2023-107-AC1
CC2:
'Comment on tc-2023-107', Sarah Greenwood, 06 Sep 2023

Exploitation of newly available terrain datasets in the Baltic region is undoubtedly welcome, since the offshore sector was both dynamically important to the last ice sheet and highly under-researched. However, we identify a number of concerning problems with the work presented here, notably the quality and rigour of the landform mapping.
Please find details in the attached pdf. We comment only on internal issues in the manuscript. We do not discuss interpretations guided by any data not available to these authors, only what is presented as figures or text in the manuscript.
Sarah Greenwood, Carl Regnéll, Richard Gyllencreutz, Karol Tylmann

Citation: https://doi.org/10.5194/tc-2023-107-CC2
- AC2: 'Reply on CC2', Izabela Szuman, 30 Oct 2023
  
  Dear Sarah Greenwood et al.
  Please find details in the attached pdf.
  
  Best regards,
  Izabela Szuman et al.
  
  Citation: https://doi.org/10.5194/tc-2023-107-AC2
RC1:
'Comment on tc-2023-107', Anonymous Referee #1, 13 Sep 2023

I think the scientific quality (rigour) falls between fair and good. Fair because evidence for some of the presented results are not convincing enough or alternative explanations not considered.

Citation: https://doi.org/10.5194/tc-2023-107-RC1
- AC3: 'Reply on RC1', Izabela Szuman, 30 Oct 2023
  
  Dear Reviewer,
  Please find details in the attached pdf.
  
  Best regards,
  Izabela Szuman et al.
  
  Citation: https://doi.org/10.5194/tc-2023-107-AC3
RC2:
'Comment on tc-2023-107', Anonymous Referee #2, 21 Sep 2023

General comments:

This study is ambitious and the specific topic is highly relevant for the glacial dynamical development

of the Fennoscandian ice sheet.
The manuscript is of a suitable length and its structure is proper, making it easy to crasp. However, I

agree with the comments of the anonymous referee and interactive comments by Greenwood et al.

The mapping procedure quality issues (misinterpretations), lack of use of geological maps and the

need for re-evaluation of some interpretations cause a need for major revisions.

Specific comments: (in order to minimize duplication, I will mainly comment only those points not

mentioned by Greenwood et al. or Anonymous referee)
L25 (Abstract): “…broad changes in ice flow geometry, ranging from SE-NW to N-S and then to NWSE.”

<> Ice flow direction replacing ice flow geometry? And maybe with description of the flow

areas, for example: SE-NW in the western (SW of Malmö) area.
L139_L146: terminology to be clarified: The unconsolidated sediments versus sedimentary rocks.

Also it is unclear what is meant with “soft sediments”
L150: Elevation data => Bathymetric data?
L205: Soft sediment => unconsolidated sediment?

Technical corrections:

L77: “…from the south…”=> from towards the south
L134 and L138: “…north-western Baltic…” and “…SE Baltic…” => north-western Baltic main basin and

SE Baltic main basin?
Figure3B and 3D: conglometare => conglomerate (Is there a better word, for example bathymetric

data type margin etc.?)
L429: could passed => could have passed

Citation: https://doi.org/10.5194/tc-2023-107-RC2
- AC4: 'Reply on RC2', Izabela Szuman, 30 Oct 2023
  
  Dear Reviewer,
  Please find details in the attached pdf.
  
  Best regards,
  Izabela Szuman et al.
  
  Citation: https://doi.org/10.5194/tc-2023-107-AC4

Peer review completion

AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload

ED: Reconsider after major revisions (further review by editor and referees) (13 Dec 2023) by Irina Rogozhina

AR by Izabela Szuman on behalf of the Authors (28 Jan 2024) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (31 Jan 2024) by Irina Rogozhina

RR by Anonymous Referee #1 (08 Feb 2024)

Suggestions for revision or reasons for rejection

General comments:
The manuscript is now better written, easier to follow and more concise. The title is also better now. I still think that it is a bit difficult to filter the role of uncertain observations on maps but on the other hand I consider this point to be minor, not really affecting the outcomes or conclusions made. The main concerns I have raised earlier have been adequately noticed and answered. The fact that there has been simultaneous mapping within a part of the study area by Greenwood et al. 2024 does not seem to create marked contradictions but rather they work well together to improve our understanding of glacial dynamics and their role in future modelling approaches. Some minor specific comments and technical corrections are presented below.
Specific comments:
L34-35: Using the word amplitude in this context (Fig 1D) sounds odd to me (meaning relative height)
L77: Zeise, 1889; after Stephan, 2001) <> wrong reference style? - should be Zeise, 1989 after Stephan, 2001)
Table 1: Referencess > References
L95+L108: reference to Greenwood et al. should be 2024 (ok in the reference list)
L138 v L139: terms glaciofluvial and glacifluvial are both used (also later in the manuscript), please prefer glaciofluvial.
Fig. 5B: I still don´t recognize these as ribbed moraines (see also Greenwood et al 2024) but this is a minor interpretative point in the wider context of the study)
Fig. 4: “Light and dark grey indicate onshore and offshore areas respectively” <> should be so that light grey are offshore (the deepest water)?
L275 (Fig. 5G): “This overlapping arrangement, seen here, is not common across the study area.” <> good point here – I think this Landsort Deep is a fascinating and enigmatic feature and the overwhelming presence of interpreted glacial lineations (also in Greenwood et al 2024) raises questions about their origin.
L317: > can be inferred
L345: Ice-marginal meltwater channels in the study are … (remove: in the study)
L404 Discussion: reference to work by Greenwood et al 2024 fits nicely here (but note the wrong year in the text reference)
L525-527: We confirm this … but also identify a Swedish ice source … <> I think the authors should refer here also to the findings by Greenwood et al. 2024
L566-568: Same here – reference to Greenwood et al 2024 needed or write differently to avoid using the reference in conclusions

Referee Report: PDF

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ED: Publish subject to minor revisions (review by editor) (21 Feb 2024) by Irina Rogozhina

AR by Izabela Szuman on behalf of the Authors (28 Feb 2024) Author's response Author's tracked changes Manuscript

ED: Publish subject to technical corrections (22 Mar 2024) by Irina Rogozhina

AR by Izabela Szuman on behalf of the Authors (27 Mar 2024) Author's response Manuscript

Short summary

A Baltic-wide glacial landform-based map is presented, filling in a geographical gap in the record that has been speculated about by palaeoglaciologists for over a century. Here we used newly available bathymetric data and provide landform evidence of corridors of fast ice flow that we interpret as ice streams. Where previous ice-sheet-scale investigations inferred a single ice source, our mapping identifies flow and ice margin geometries from both Swedish and Bothnian sources.