Pleistocene glacial history of the New Zealand subantarctic islands

Rainsley, Eleanor; Turney, Chris S. M.; Golledge, Nicholas R.; Wilmshurst, Janet M.; McGlone, Matt S.; Hogg, Alan G.; Li, Bo; Thomas, Zoë A.; Roberts, Richard; Jones, Richard T.; Palmer, Jonathan G.; Flett, Verity; de Wet, Gregory; Hutchinson, David K.; Lipson, Mathew J.; Fenwick, Pavla; Hines, Ben R.; Binetti, Umberto; Fogwill, Christopher J.

doi:https://doi.org/10.5194/cp-15-423-2019

Articles | Volume 15, issue 2

https://doi.org/10.5194/cp-15-423-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/cp-15-423-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 15, issue 2

Research article

| Highlight paper

|

14 Mar 2019

Research article | Highlight paper |

| 14 Mar 2019

Pleistocene glacial history of the New Zealand subantarctic islands

Eleanor Rainsley, Chris S. M. Turney, Nicholas R. Golledge, Janet M. Wilmshurst, Matt S. McGlone, Alan G. Hogg, Bo Li, Zoë A. Thomas, Richard Roberts, Richard T. Jones, Jonathan G. Palmer, Verity Flett, Gregory de Wet, David K. Hutchinson, Mathew J. Lipson, Pavla Fenwick, Ben R. Hines, Umberto Binetti, and Christopher J. Fogwill

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Final revised paper (published on 14 Mar 2019)
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Preprint (discussion started on 25 May 2018)
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Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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RC1: 'Pleistocene glacial history of the New Zealand subantarctic islands', Anonymous Referee #1, 25 Jun 2018
- AC1: 'Response to Reviewer 1', Eleanor Rainsley, 08 Sep 2018
RC2: 'Pleistocene glacial history of the New Zealand subantarctic islands', Anonymous Referee #2, 09 Aug 2018
- AC2: 'Response to Reviewer 2', Eleanor Rainsley, 08 Sep 2018

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

ED: Reconsider after major revisions (11 Sep 2018) by Denis-Didier Rousseau

AR by Eleanor Rainsley on behalf of the Authors (23 Oct 2018) Author's response

ED: Referee Nomination & Report Request started (24 Oct 2018) by Denis-Didier Rousseau

RR by Anonymous Referee #2 (20 Nov 2018)

RR by Anonymous Referee #1 (22 Nov 2018)

Suggestions for revision or reasons for rejection

This paper « Pleistocene glacial history of the New Zealand subantarctic islands » by E. Rainsley et al. presents new data, from the subantarctic Islands Auckland and Campbell, and a flowline modelling of a large U-shaped valley if the Campbell Island. The multi proxies linked to a flowline glacier modelling is very interesting. The authors did improve the paper taking into account previous remarks.
The results concerning the flowline simulations implying a large seasonal temperature amplitude during the last glacial maximum are interesting, reconcile the different geomorphologic and vegetation data from these Subantarctic islands and highlights the importance of the seasonal amplitude. However there are still a few incoherencies or non discuss aspect for the methodology and discussion:
-Why do the authors used the SST reconstruction by Hayward et al. for ODP 594 and not the higher resolution record from the same site: core MD97-2120 by Pahnke et al.? Furthermore in fig. 9 they plot the Pahnke et al. temperature record instead of the Hayward et al. record they used for part of the flowline model runs. In the same figure they could also show the Hayward temperature record over the last 500ka indicating local temperature changes for stage 10 and 12.
I would appreciate that the authors indicate why they choose to run the model over the last glacial cycle and not the last 4 cycles: computing time? Problems to reconstitute the bed topography back in time?
The data indicate a glaciation with an larger extent than the LGM one that the authors assume to occur around 68ka. They do not discuss the fact that it could be the maximum extent during stage 6 or stage 8. I think a few lines at least are necessary to rule out these possibilities.

A number of typo errors are to be corrected, a few of them are listed below.
2.1 Line 26 : Peninsula n missing
3.2 line 25 suppress “is”
4.1 line 15 “separate” + correct end of line
p20 Line 21 “formation”
Fig 7 What are the two yellow at ~55 et 63kans?
Fig. 9 “Basal peat age range” interval is not placed correctly on the figure. . The ACR is not marked as a strong SST decrease in the SST records they present nor in other SST records of the Southern Ocean from the Subantarctic zone, opposite to what the authors says. SST temperature records are different than EDC isotopic record, they indicate temperature closer to Holocene ones before the ACR and indicate a small decrease or on only a plateau in the warming for the ACR.

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ED: Publish subject to minor revisions (review by editor) (22 Nov 2018) by Denis-Didier Rousseau

AR by Eleanor Rainsley on behalf of the Authors (14 Dec 2018) Author's response Manuscript

ED: Publish subject to technical corrections (17 Dec 2018) by Denis-Didier Rousseau

AR by Eleanor Rainsley on behalf of the Authors (19 Dec 2018) Author's response Manuscript

Short summary

The New Zealand subantarctic islands, in the Pacific sector of the Southern Ocean, provide valuable records of past environmental change. We find that the Auckland Islands hosted a small ice cap around 384 000 years ago, but that there was little glaciation during the Last Glacial Maximum, around 21 000 years ago, in contrast to mainland New Zealand. This shows that the climate here is susceptible to changes in regional factors such as sea-ice expanse and the position of ocean fronts.