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Research Article

The early rise and late demise of New Zealand’s last glacial maximum

Henrik Rother, David Fink, James Shulmeister, Charles Mifsud, Michael Evans, and Jeremy Pugh
  1. aInstitute for Geography and Geology, University of Greifswald, 17489 Greifswald, Germany;
  2. bAustralian Nuclear Science and Technology Organisation, Menai, NSW 2234, Australia;
  3. cSchool of Geography, Planning and Environmental Management, The University of Queensland, St. Lucia Campus, Brisbane, QLD 4072, Australia;
  4. dMoultrie Geology, Banyo, QLD 4014, Australia; and
  5. eDepartment of Geological Sciences, University of Canterbury, Christchurch, New Zealand

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PNAS August 12, 2014 111 (32) 11630-11635; first published July 28, 2014; https://doi.org/10.1073/pnas.1401547111
Henrik Rother
aInstitute for Geography and Geology, University of Greifswald, 17489 Greifswald, Germany;
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  • For correspondence: henrik.rother@gmail.com
David Fink
bAustralian Nuclear Science and Technology Organisation, Menai, NSW 2234, Australia;
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James Shulmeister
cSchool of Geography, Planning and Environmental Management, The University of Queensland, St. Lucia Campus, Brisbane, QLD 4072, Australia;
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Charles Mifsud
bAustralian Nuclear Science and Technology Organisation, Menai, NSW 2234, Australia;
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Michael Evans
dMoultrie Geology, Banyo, QLD 4014, Australia; and
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Jeremy Pugh
eDepartment of Geological Sciences, University of Canterbury, Christchurch, New Zealand
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  1. Edited by Mark H. Thiemens, University of California, San Diego, La Jolla, CA, and approved June 13, 2014 (received for review February 3, 2014)

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Significance

We present here a comprehensive record of glaciation from a New Zealand valley glacier system covering the critical 15,000-y period from the local last glacial maximum (LGM) to near the end of the last ice age. This record from a key site in the midlatitude Southern Hemisphere shows that the largest glacial advance did not coincide with the coldest temperatures during this phase. We also show that the regional post-LGM ice retreat was very gradual, contrary to the rapid ice collapse widely inferred. This demonstrates that glacial records from New Zealand are neither synchronous with nor simply lag or lead Northern Hemisphere ice sheet records, which has important implications for the reconstruction of past interhemispheric climate linkages and mechanisms.

Abstract

Recent debate on records of southern midlatitude glaciation has focused on reconstructing glacier dynamics during the last glacial termination, with different results supporting both in-phase and out-of-phase correlations with Northern Hemisphere glacial signals. A continuing major weakness in this debate is the lack of robust data, particularly from the early and maximum phase of southern midlatitude glaciation (∼30–20 ka), to verify the competing models. Here we present a suite of 58 cosmogenic exposure ages from 17 last-glacial ice limits in the Rangitata Valley of New Zealand, capturing an extensive record of glacial oscillations between 28–16 ka. The sequence shows that the local last glacial maximum in this region occurred shortly before 28 ka, followed by several successively less extensive ice readvances between 26–19 ka. The onset of Termination 1 and the ensuing glacial retreat is preserved in exceptional detail through numerous recessional moraines, indicating that ice retreat between 19–16 ka was very gradual. Extensive valley glaciers survived in the Rangitata catchment until at least 15.8 ka. These findings preclude the previously inferred rapid climate-driven ice retreat in the Southern Alps after the onset of Termination 1. Our record documents an early last glacial maximum, an overall trend of diminishing ice volume in New Zealand between 28–20 ka, and gradual deglaciation until at least 15 ka.

  • surface exposure dating
  • global climate linkages

According to the Milankovitch orbital theory of glaciation, variations in northern high-latitude summer insolation are responsible for glacial–interglacial cycles (1, 2). On this basis, it is commonly assumed that climatic changes in the Northern Hemisphere (NH) constitute the principle forcing mechanism for glaciation in the Southern Hemisphere (SH) (3). However, in recent times, this view has been challenged by studies showing that at least some glacial signals in the SH have no NH correlative or precede events in the NH by up to 1.5 ka (4⇓⇓–7). Although some of these patterns can be explained by an extended bipolar seesaw model, other features, including the decreasing expression of hemispheric antiphasing away from the polar regions, indicate that additional forcing mechanisms must be involved (8).

A compilation of glacial records from the NH indicates that midlatitude ice sheets in North America and northern Eurasia began a major expansion phase between 33–29 ka (9). From this time onward, relative sea level reconstructions indicate a steady increase in global ice volume, until most ice sheets had reached a near-maximum extent by 26.5 ka, followed by 6–7 ky of equilibrium conditions until the onset of final retreat around 20–19 ka (9). For the midlatitude SH, specifically New Zealand (NZ), paleoecologic data (10), supported by dated glaciofluvial aggradation sequences (11), have also suggested an onset of mountain glacier growth around 30–28 ka (12). Contrary to NH ice volume trends, however, recent records from NZ may indicate that maximum glaciation in the Southern Alps occurred before 28 ka, several thousand years before the NH ice maximum (13⇓–15). A second aspect in the debate centers on determining the precise onset of last glacial maximum (LGM) retreat (a period referred to as Termination 1 and dated to ∼19–10 ka) and the mode of this deglaciation (i.e., models of collapse versus slow recession) in NZ. Together, these issues are responsible for ongoing controversy about the evolution of the last glacial-to-interglacial transition in the SH midlatitudes and the relative importance of interhemispheric climate forcing versus regional insolation and/or synoptic forcing of SH glaciation.

Previous Work

NZ represents one of only three areas in the SH midlatitudes that experienced extensive late Quaternary glaciation. During the LGM, valley glaciers 70–100 km in length reached the alpine forelands of the eastern Southern Alps, whereas shorter and steeper glaciers in the western Alps typically terminated into the Tasman Sea. According to cosmogenic exposure ages from Lake Pukaki terminal moraines in the central Southern Alps, it has been suggested that large-scale glacial retreat in NZ commenced at 17.4 ka, representing “the start of the termination of the LGM” (16). This appeared to be virtually indistinguishable from the onset of the final LGM retreat at similar NH and SH midlatitude sites, supporting the idea of a global mechanism responsible for triggering a “near-synchronous” ice retreat at these far-field sites. Conversely, evidence for millennial-scale climate reversals in NZ at the end of Termination 1, during the Antarctic Cold Reversal (14–15 ka) and the Younger Dryas chronozone (11–12 ka), has been interpreted to indicate late-glacial climatic antiphasing with NH events (17, 18).

Compounding these apparently incompatible interpretations of the NZ glacial history using cosmogenic exposure dating is the introduction of a local 10Be reference production rate for the NZ region (19). This new production rate is significantly lower (by 16%) than the statistically weighted mean global production rate obtained from a collection of geographic calibration data sets (20). As a consequence, any intercomparison of glacial chronologies, both relative and absolute, across the globe, as well as from within NZ itself, requires great care to ensure a consistent synthesis of the published data. Specifically, exposure ages from NZ calculated using the global production rate (20) are now considered to underestimate landform ages by anywhere from 1.8–4.5 ky across the period of interest (i.e., 15–30 ka). This draws into question the previously implied synchronicity of the onset of the final LGM retreat in NZ and NH midlatitude sites (16) as the rescaled NZ timing for “glacial collapse” increases (by 2.8 ky) to 20.2 ka. Recent studies by Putnam and colleagues (15, 21) report that at Lake Ohau and the Rakaia Valley in the central Southern Alps, fast retreat from LGM moraines commenced around 17.8 ka, followed by a substantial reduction in overall glacier length (−50%) over a period of ∼1,000 y. A similar rapid post-LGM ice decay has also been proposed for overall glaciation across NZ, with an estimated 60% reduction in glaciated area soon after the onset of the final retreat (12). However, a different view is provided by Shulmeister and colleagues (14), who reconstruct a much lower rate of ice retreat during the same period (10–20% glacier reduction) on the basis of exposure dating of terminal and recessional moraines in the Rakaia Valley (renormalized using the lower local 10Be production rate; see ref. 19).

Despite significant progress in reconstructing NZ glacial dynamics, a common deficiency in the available glacial chronologies is the relatively short-term nature of the investigated moraine sequences. Missing are moraine records spanning the whole sequence from the ice maximum to the subsequent retreat stages pertaining to the whole LGM cold period of 30–15 ka. In NZ, such records are rare: in the western Alps because most major LGM glacier systems were marine terminated, and in the eastern Alps because many cross-valley terminal and retreat moraines were buried during ice retreat in deep proglacial troughs or destroyed by extensive postglacial fluvial processes. Here we present an extended glacial reconstruction from the Rangitata Valley, a major drainage system of the central Southern Alps in which an extensive moraine record survived in a stranded position on the interfluves between the entrenched Rangitata and Rakaia trunk valleys. This allows the assessment of glacier dynamics within a single catchment from the local LGM, through Termination 1, and into the last glacial–interglacial transition.

Study Site and Methods

The targeted moraines are located in the Lake Clearwater and Lake Heron areas of the Rangitata Valley, ∼50 km downstream from the modern glacier margins. At its maximum extent, the Rangitata Glacier comprised two major lobes: a southern ice tongue that followed the trunk Rangitata Valley (Rangitata lobe), and a northern lobe that advanced onto a higher-lying area north of Harper Range (Clearwater lobe). A smaller distributary lobe from the main Rakaia Glacier entered the Lake Heron area from the north via the Prospect Hill saddle (Heron lobe; Fig. 1). Ice marginal landforms consist primarily of lobate laterofrontal dump moraines, lateral moraines, and hummocky terrain that formed during the disintegration of the ice lobes. These landforms are present over a considerable down-valley distance and altitudinal range and have formed the basis for an earlier geomorphic differentiation of five late Pleistocene glacial landform associations (22). Until now, no absolute ages have been available to constrain the timings of these glacial advances in the area.

Fig. 1.
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Fig. 1.

Location of the Rangitata catchment in the South Island, NZ (A), study areas (B), and positions of all sampled moraines and resulting cosmogenic exposure ages (C and D). The shaded relief map (B) shows the topographic context and the ice outlet routes of the major Rangitata and Rakaia glaciers. Inset rectangles denote regions of sampled moraines, with their relative locations detailed for the Lake Clearwater (C) and Lake Heron (D) interfluves. Multiple terminal and lateral moraine sequences span the period from maximum ice extent during the LGM (29–28 ka) to subsequent retreat phases in the Clearwater and Heron areas (19–15 ka). Sites selected for 10Be and 26Al exposure dating are indicated by numbered black circles and comprise from two to five boulders per site. All ages shown are derived from in situ 10Be with associated analytical errors (for 26Al ages, see SI Appendix). Bold ages represent site-weighted mean ages with their standard mean error (ages using scaling schemes calculated via the CRONUS on-line web-calculator are given in SI Appendix, Tables S4 and S5). Five sample ages denoted with an asterisk are interpreted to be outliers (two of these relate to prelocal LGM sites). Sample ages denoted with a b were derived from bedrock.

Covering a valley distance of ∼12 km in-board from terminal ice positions of the Heron and Clearwater lobes, we sampled 56 quartzo-feldspathic sandstone (greywacke) erratics from 17 moraine sites and two ice overridden bedrock surfaces (SI Appendix, Fig. S3). Five samples of this total were rejected as outliers. We calculate exposure ages on the basis of a sea-level high-latitude spallation 10Be production rate for NZ of 3.87 ± 0.08 atoms/gquartz/a (19) and a 26Al production rate of 26.08 ± 0.55 atoms/gquartz/a corresponding to a 26Al/10Be production ratio of 6.727 (20). All exposure ages were calculated using the CRONUS Web-based calculator. Both spallation and muon production rates were then scaled to geographic location and altitude of the individual sample sites, using the scaling methods of T. Dunai (ref. 23; for age results based on other scaling schemes, see SI Appendix).

Results

Of the 73 zero-erosion ages (58 10Be and 15 26Al ages; Fig. 1 and SI Appendix) presented in this study, 48 are from the Clearwater and 25 from the Heron area. Apart from two sites (site 10, site 11 ∼600 m above the valley floor, all in-valley terminal and lateral moraine weighted average ages fall between 27.7 and 15.8 ka, providing one of the most extensive glacial sequences from NZ to track ice extent from the local LGM until well after the onset of the last termination. We bracket this sequence into four distinct periods consistent with an early local LGM ice extent, an initial phase of ice volume reduction followed by stabilization (or readvance) of the ice front at 25 ka, further recession and renewed ice front stabilization (or readvance) at 19 ka, and a gradual final retreat phase from 19 to 15 ka (Fig. 2 and SI Appendix, Fig. S4).

Fig. 2.
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Fig. 2.

Summary of the Rangitata glacial chronology based on 49 10Be exposure ages (excluding three outliers) that characterize four phases of last glacial–interglacial activity (A–D in graph). The width of the bars represents the timing of moraine formation during each glacial phase according to the weighed mean (with standard mean error) for moraines grouped according to valley position, and thus indicating similar ice extent. The y axis denotes relative glacial extent, with 1.0 representing the approximate maximum ice extent during the LGM (total Rangitata glacier length, 65–70 km). Ice recession from the local LGM position commenced at 18.7 ± 0.3 ka. At 15.8 ka, the Rangitata glacier terminated ∼11 km up-valley from the first inbound recessional moraines, indicating the survival of more than 80% of the overall glacier length (and nearly 70% of the full LGM glacier length) through to 15.8 ka.

Two ice-overridden hills in the Heron Basin yield mean site ages of 27.7 ± 0.5 ka (site 12) and 27.6 ± 0.8 ka (site 13). On the basis of the required ice thickness to overflow these sites (site-13 surface ∼230 m above valley floor), we infer that during its maximum extent, the Heron ice lobe coalesced with the glacier tongue occupying the Clearwater area. The cumulative weighted mean age for site 12, and site 13, representing the minimum local LGM age, is 27.7 ± 0.4 ka (n = 6, SI Appendix, Fig. S4A). After the initiation of ice retreat from this local LGM ice position, the two lobes separated again, with an independent terminal moraine position established in the Heron area soon thereafter at 27.6 ± 0.8 ka (site 14). Evidence for a comparable down-valley ice extent is also indicated by an elevated lateral moraine NW of Lake Heron, giving an age of 25.0 ± 0.6 ka (site 17; SI Appendix, Fig. S4A), suggesting only minor changes in ice volume during this time. Interestingly, the next up-valley moraines (site 15, site 16), located no further than 3–4 km from the ∼27.6 ka ice position (site 14), yield significantly younger site ages of 19.0 ± 0.4 ka (site 15) and 18.6 ± 0.3 ka (site 16).

Ice recession from these younger moraine positions and through Termination 1 is preserved on the Clearwater interfluve, where nine moraine sites were investigated. Two Clearwater moraines (site 1, 18.7 ± 0.7 ka, and site 8, 18.5 ± 0.4 ka) and the two Heron moraines at site 15 (19.0 ± 0.4 ka) and site 16 (18.6 ± 0.3 ka) clearly show that a stable ice front was established by ∼19 ka in both areas (site 1, site 8, site 15, and site 16; weighted mean age, 18.7 ± 0.2 ka; n = 17). During the next 3–4 ky, ice recession from these positions was gradual, with the ice front moving at most 8–10 km up-valley, leaving several nested clusters of closely spaced moraines. The largest of these recessional moraine clusters (site 2, site 3, and site 4) is located southeast of Spider Lakes, yielding overlapping ages of 17.0 ± 0.6 ka (site 2), 16.6 ± 0.5 ka (site 3), and 17.9 ± 0.6 ka (site 4), with a weighted mean age of this moraine group of 17.1 ka ± 0.3 (n = 10, one reject; SI Appendix, Fig. S4C). Coeval retreat of the main Rangitata Valley glacier during this time is observed at site 9 (17.2 ± 0.4 ka). The final stages of retreat from the Clearwater area are preserved through three moraines ∼8 km upstream (site 6, 16.8 ± 0.4 ka; site 7, 15.8 ± 0.4 ka; site 5, 15.8 ± 0.3 ka), with a weighted mean age of 16.1 ± 0.2 (n = 11, one reject; SI Appendix, Fig. S4D).

Collectively, the moraines show a broad up-valley decrease in age consistent with a retreating ice margin, which was punctuated by repeated ice still stands. Ice thickness reduction within the ∼12 ky of retreat from the local LGM limit to our youngest moraine at about 16 ka amounts to 400–500 m. The oldest ages were obtained from six glacial boulders from two sites in the Dogs Hill Range (∼600 m above valley floor; Fig. 1C), yielding individual boulder ages of 113.2 ± 4.0, 104.5 ± 3.5, and 84.6 ± 2.5 ka (site 11) from the higher surface and 54.6 ± 3.4, 48.6 ± 1.9, and 31.4 ± 1.1 ka (site 10) from the lower of these surfaces. Despite their broad age range, these erratics clearly relate to previous, larger-scale glacier advances in the central Southern Alps. Removing the youngest boulder age from each site, their weighted mean site ages (site 11, 108.3 ± 2.4 ka; site 10, 50.1 ± 1.7 ka) fall into the last glacial cycle. A more robust interpretation of the ages requires a reliable measure of long-term surface weathering of greywacke rock. An upper limit estimate of greywacke erosion rate of 1–2 mm/ky would yield site-11 erosion-corrected exposure ages between 141–114 ka and site-10 ages between 53–32 ka, which are effectively coeval with glaciation during late marine isotope stage (MIS) 6/MIS-5 and MIS-3, respectively. We report erosion-uncorrected ages but note that in some cases, thin quartz veins were found to be ∼5 mm proud of the sampled surface (SI Appendix, Fig. S3D), giving a minimum erosion rate of ∼0.3 mm/ky. This is almost identical to the amount of postemplacement erosion on greywacke surfaces reported from NZ by Kaplan and colleagues (17). Assuming a much higher erosion rate of 1–2 mm/ky, the ages would increase by 2–4% (i.e., ca. 300 y at 15-ka and 1 ky at 30-ka exposure), showing that within these limits, the uncertainties resulting from potential surface erosion would have no effect on our main conclusions.

Discussion and Conclusion

Our detailed chronology of the Rangitata glacial system establishes four distinct phases of the LGM and last deglaciation in NZ (Fig. 2): a maximum local LGM ice extent reached shortly before 28 ka (phase A), an initial phase of ice volume reduction followed by stabilization or readvance of the ice until 25 ka (phase B), further ice volume reduction after 25 ka and renewed stabilization of the ice at 18.7 ka at moraine positions only a few kilometers (∼3–4 km) distant from the local LGM limit (phase C), and a gradual and final glacier retreat commencing shortly after 18.7 ka (and lasting to about 15.8 ka), producing numerous closely spaced recessional moraines representing the regional onset of Termination 1 (phase D). Coeval with this last phase, Antarctic ice core records indicate cessation of severe cold conditions that had persisted for the previous 10 ky and commencement at 18–19 ka of continuous warming proxied via increasing δ18O and a synchronous rise in atmospheric CO2 (24⇓–26).

The exposure age results show that recession of the Rangitata Glacier from the innermost LGM moraine (site 1) commenced at about 18.7 ± 0.7 ka, which is similar, although slightly earlier, than the 17.8 ± 0.2 ka onset of major LGM retreat found by Putnam and colleagues (21) in the nearby Rakaia Valley. There, dating of recessional moraines points to extensive local deglaciation between 17.8–15.6 ka, interpreted to coincide with Heinrich Stadial 1 in the North Atlantic (21). Considering the time evolution of the presented Clearwater–Heron glacial sequence, we also document recession during this time, but significantly, we find no evidence for a rapid pace of deglaciation in NZ (12). In contrast, we see that retreat of the Rangitata Glacier between 18.7–15.8 ka was very gradual, with ∼70–80% of the local LGM glacier length surviving until 15.8 ka. This outcome differs markedly from other NZ deglaciation studies, specifically from Lake Pukaki (16), Lake Ohau (15), and the Rakaia Valley (21), which all report recession or collapse of major ice tongues over tens of kilometers during a short period. However, we note that in these areas, the expression of rapid local ice retreat was heavily influenced by the formation of large and deep proglacial lakes during deglaciation (27, 28). These proglacial lakes established heat advection and wave impact as significant additional mechanisms of ice loss, probably leading to locally enhanced rates of ice recession. This mode of post-LGM retreat was a common feature of glacier systems across the Southern Alps, as evidenced by widespread glaciolacustrine deposits, particularly in the Eastern Alps, that have been documented by numerous glacial workers (e.g., refs. 29⇓⇓⇓⇓⇓–35). Within this type of retreat setting (i.e., early transition to lake-terminated glaciers after the onset of retreat), ice-loss dynamics frequently decouple from climatic influences, implying that these glacier systems may not present reliable indicators for inferring overall regional deglaciation trends and/or reconstructing climatic signals.

In this context, we suggest that the Rangitata record offers a distinct advantage because this glacier retreated predominately via a grounded glacier margin with little to no influence from lake calving on ice retreat dynamics. Our results indicate that the Rangitata Glacier reached its largest LGM ice extent about 28 ka ago and maintained these glacial limits until 25 ka, with only a minor reduction in ice volume during this time. This timing corresponds well with the first major LGM cooling event (28.8–25.4 ka), as defined by the composite NZ climate event stratigraphy (36), and is also broadly contemporaneous with glacial maxima recorded at other midlatitude Southern Hemisphere sites (37⇓–39) and the onset of major cooling observed in the Talos Dome and European project for ice coring in Antarctica-Dome C ice cores of Antarctica (24, 40, 41). However, we note that within the NZ pollen-based climate stratigraphy, the largest Rangitata ice advance occurred near the transition from mild interstadial conditions [New Zealand climate event (NZce)-11 phase ∼30–28.8 ka: pollen flora 81–95% trees and shrubs] to a progressively cooler climate (NZce-10 phase 28.8–25.5 ka: pollen flora 49–71% trees and shrubs). Compared with the last glacial coldest period in NZ (NZce-6 dated to 21.7–18.3 ka; ref. 36), we infer that the ice maximum coincided with less-severe but probably moister climatic conditions.

Recent records from both hemispheres have emphasized that similar to many continental alpine glaciers, various parts of the major ice sheets in Eurasia and Antarctica were not in synchrony with the global LGM (42). More important, although most sectors of the largest ice sheet, the Laurentide Ice Sheet, along with the Cordilleran Ice Sheet, and the southeast sector of the Scandinavian Ice Sheet appear to have reached their maximum extent synchronous with the global LGM (43, 44). We find that contrary to these NH trends, in which where ice sheets expanded strongly between 29–26 ka (9) and then remained at near-maximum limits until the end of the LGM (19–18 ka), our findings show that in NZ each ice advance subsequent to the 28-ka maximum was less extensive, suggesting an overall trend of diminishing regional glaciation in NZ between 28–20 ka.

The available terrestrial and marine evidence from the NZ region, supported by regional paleoclimatic modeling (45), indicates that the persistence of relatively high levels of precipitation against a background of moderate cooling during the early LGM (∼30–28 ka) are responsible for generating the largest LGM ice advance in NZ; conversely, the subsequent less-extensive ice advances reflect a trend of decreasing precipitation that limited glaciation during the remainder of the LGM in NZ, despite intensifying cooling. Although global ice volume remained stable or even slightly increased between 26–20 ka, glacier systems in NZ were in slow but continuous retreat. The pattern is repeated at ∼19 ka, when our record shows a region-wide hiatus in warming or ice-stillstand that is coeval with the onset of major retreat in the NH. This implies an overall scenario in which increasing NH summer insolation initiates the slow retreat of NH ice sheets (from 20 ka onward), whereas Antarctic ice extent remains stable at this time. It is now also evident that the Southern Ocean plays an important role in the further demise of global ice volume by invoking major changes in oceanic CO2 discharge. Once CO2 levels rise sharply (from 18 ka onward), Antarctic temperatures increase synchronously (26), triggering the onset of retreat in Antarctica and the midlatitude SH (NZ).

Acknowledgments

Cosmogenic surface exposure dating was funded by Australian Institute of Nuclear Science and Engineering Grant 05/219 (Australian Nuclear Science and Technology Organisation) and the Australian Nuclear Science and Technology Organisation’s Cosmogenic Climate Archives of the Southern Hemisphere Project 0203v.

Footnotes

  • ↵1To whom correspondence should be addressed. Email: henrik.rother{at}gmail.com.
  • ↵2Deceased February 2012.

  • Author contributions: H.R. and J.S. designed research; H.R., M.E., and J.P. performed research; D.F. and C.M. contributed new reagents/analytic tools; H.R. and D.F. analyzed data; and H.R., D.F., and J.S. wrote the paper.

  • The authors declare no conflict of interest.

  • This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1401547111/-/DCSupplemental.

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Structure of the LGM in New Zealand
Henrik Rother, David Fink, James Shulmeister, Charles Mifsud, Michael Evans, Jeremy Pugh
Proceedings of the National Academy of Sciences Aug 2014, 111 (32) 11630-11635; DOI: 10.1073/pnas.1401547111

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Structure of the LGM in New Zealand
Henrik Rother, David Fink, James Shulmeister, Charles Mifsud, Michael Evans, Jeremy Pugh
Proceedings of the National Academy of Sciences Aug 2014, 111 (32) 11630-11635; DOI: 10.1073/pnas.1401547111
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