Downwearing rates obtained from tectonically active coasts provide evidence of rapid rock breakdown following coseismic uplift. These measurements help solve puzzles about 'missing' marine terraces and have implications for accurate reconstruction of past sea levels, earthquakes and rock coast evolution. However, very few detailed erosion datasets exist for uplifted shore platforms, making it uncertain if erosion records from one coast can be extrapolated to other regions with similar tectonic, geologic, or geomorphic characteristics. Here we present new downwearing rates from an inter-tidal mudstone shore platform at Kahutara Point, M & amacr;hia Peninsula, New Zealand that was uplifted likely by similar to 3 m within the last 300 years. Downwearing rates were measured over 49 months/4.05 years using the Micro-Erosion Meter (MEM) and Structure-from-Motion photogrammetry: the mean annual downwearing rate was 1.08 mm yr(-1), while the total erosion at individual MEM stations ranged from 0.44 to 14.37 mm (equivalent to mean downwearing rates of 0.11 to 3.54 mm yr(-1)). Orthophotographs of the eroded rock surfaces indicate the combined role of marine processes (waves and tides), sub-aerial weathering processes, salt weathering and biological activity in the erosion of the mudstone platform surface. The downwearing rates from Kahutara Point, M & amacr;hia Peninsula are statistically similar to previously published downwearing rates (1.23 mm yr(-1)) from mudstone platforms at Kaik & omacr;ura Peninsula, New Zealand, that were obtained prior to the 2016 Kaik & omacr;ura earthquake, but are significantly different from perturbed post-uplift downwearing rates (2.25 mm yr(-1)) obtained from the same MEM stations following coseismic uplift of similar to 1 m. This work provides valuable data to support comparison of the development of shore platforms and marine terraces at Kaik & omacr;ura and M & amacr;hia at different stages of their tectonic evolution.

The Antarctic environment is amongst the coldest and driest environments on Earth. The ultraxerous soils in the McMurdo Dry Valleys support exclusively microbial communities, however, 15 million years ago, a tundra ecosystem analogous to present-day southern Greenland occupied this region. The occurrence of ancient soil organic carbon combined with low accumulation of contemporary material makes it challenging to differentiate between ancient and modern organic processes. Here, we explore the additions of modern organic carbon, and the preservation and degradation of organics and lipid biomarkers, in a 1.4 m mid-Miocene age (similar to 14.5-14.3 Ma) permafrost soil column from Friis Hills. The total organic carbon is low throughout the soils (<1 wt %). The near-surface (upper 35 cm) dry permafrost has lower C:N ratios, higher delta C-13(org) values, higher proportion of branched fatty acids with an iso and anteiso configuration relative to n-fatty acids, lower phytol abundance and higher contributions of low-molecular weight homologues of n-alkanes, than the underlying icy permafrost, indicating higher contributions from bacteria-derived organic matter. Conversely, the icy permafrost contains higher molecular weight n-alkanes, n-fatty acids and n-alkanols, along with phytosterols (e.g. sitosterol and stigmasterol) and phytol (and its derivatives pristane and phytane) that are indicative of the contributions and preservation of higher-level plants. This implies that legacy mid-Miocene age carbon in the near-surface soils (ca. 35 cm) has been prone to microbial organic matter degradation during times when the permafrost thawed, likely during relatively warm intervals through the late Neogene (similar to 6.0 Ma) and sporadically during the Holocene (<1 %), when ground summer temperatures were >=+2 degrees C (based on branched glycerol dialkyl glycerol tetraether (brGDGT) temperature reconstructions). Conversely, lipid biomarkers found deeper in the permafrost have been preserved for millions of years. These results suggest that ancient organics preserved in permafrost could underpin significant ecological changes in the McMurdo Dry Valleys under the current warming climate.

Luminescence is a powerful dating technique that is increasingly being used as a new tool to investigate surface processes. In the past decade, it has been used successfully for instance to estimate virtual sediment velocity in rivers, sediment storage time in floodplains, and to trace sediment sources (McGuire & Rhodes, 2015; Gray et al., 2018; Sawakuchi et al., 2018; Guyez et al., 2022; Guyez et al., 2023). As part of ongoing development, here we quantify sediment transport and catchment-wide erosion rates in natural systems using luminescence. For this purpose, single-grain post infrared-infrared (pIRIR) equivalent doses of felspars from modern floodplain deposits were measured in several catchments in the Southern Alps of New Zealand and compared to catchment-wide erosion rates derived from 10Be cosmogenic nuclide concentrations measured in fluvial quartz grains. The fraction of grains that were well-bleached before their burial in the modern floodplain was calculated, as well as the fraction of grains with a saturated luminescence signal. Signal distribution was characterised using the central age model. Our findings indicate that the luminescence signal is characterized by few well-bleached grains and lots of grains with a high luminescence signal where erosion rates are high. On the other hand, in catchments with lower erosion rates, bleaching appears to be more pervasive, resulting in an overall lower luminescence signal. Therefore, we hypothesize that bleaching efficiency is related to erosion rates. To test the relationship between luminescence, bleaching, erosion, and transport processes, we include the luminescence signal of individual grains in a landscape evolution model that already takes into account the concentration of cosmogenic nuclides (Carretier et al., 2023). By tracking both signals in an evolving stream basin, the model helps better understanding the relationship between erosion and luminescence signal, on longer time scales. Single-grain pIRIR equivalent holds promise as a new method for measuring erosion and sediment transport.

Cosmogenic radionuclides (CRNs) have been proposed as a tool for tracking landslide sediment, yet interpreting the in-situ Be-10 signal through time with respect to the post-seismic sediment cascade has proved challenging in the few examples where it has been applied. To determine how useful the Be-10 concentration is in providing insights into the fluvial response of co-seismic sediment delivery, we measured the Be-10 concentration in multiple grain sizes in two catchments in New Zealand affected by the 2016 Kaikoura earthquake. A 6-year post earthquake time series of Be-10 measurements was compared to a sediment budget produced by differencing lidar surveys over the same study period. Results showed that the Be-10 concentrations in the sand fraction are controlled by the post-seismic hillslope delivery, whereas the Be-10 concentrations in the coarser grains respond to the total volume of landslide material in the active channel. Faster Be-10 dilution and recovery of the sand fraction indicates that the transport rate of the sediment pulse is highly dependent on grain size. The residence of the fine-grained sediment is estimated to be within a decade of the earthquake, although it may take several centuries to evacuate the entirety of the landslide pulse. We observe different magnitudes of Be-10 dilution between two study catchments, which is attributable to a difference in connected landslide volume from hillslopes. We also demonstrate that the dilution factor has little relationship to conventional landslide metrics on a global scale. Our analysis suggests that the magnitude of dilution is controlled through a complex relationship between the connected landslide volume, the degree of sediment mixing and the delivery and evacuation time of landslide sediment. Additionally, if coarse sediment is primarily sourced through mass-wasting events, measuring just the sand Be-10 concentration will bias the catchment-averaged erosion rate.

I present the first dataset of Late Quaternary glacial maximum extent and deglaciation along with quantitative paleoclimate reconstructions from the Ahuriri River valley, Southern Alps, New Zealand. The new constraints based on geomorphological mapping and sixty-six cosmogenic 10Be surface exposure ages offer the opportunity to test hypotheses about the climate system, to better understand the processes that drove ice retreat and readvance during the Last Glacial Maximum and the subsequent glacial termination. Reconstructions of past glacier geometries indicate that the local ELA was depressed by ~880 m and climate was 5±1 °C colder than present (1981–2010) at 19.8±0.3 ka, while ELA was depressed by ~770 m and climate was 4.4±0.9 °C colder at 16.7±0.3 ka. Subsequent estimations suggest ELA elevations at 14.5±0.3 ka, 13.6±0.3 ka, and 12.6±0.2 ka were ≤700 m, ≤630 m, and ~360 m lower than today. This equates to air temperatures of ≤3.9 °C, ≤3.5 °C, and 2.3±0.7 °C colder than today, assuming no changes in past precipitation. The small amount of warming estimated in this study between 19.8±0.3 and 16.7±0.3 ka differs somewhat from glacial reconstructions in other major valleys in the Southern Alps, specifically from Rakaia River valley. Robust constraints of glacier changes in the Ahuriri valley between 14.5±0.3 and 12.6±0.2 ka confirm that an early glacier readvance occurred in New Zealand at this time, which has been previously recognised with only limited evidence. The reconstructed ELA suggests that the coldest part of the Late Glacial reversal occurred at 14.5±0.3 ka.

In March, 2019, a trackway of seven footprints was found at a riverbank outcrop of Maniototo Conglomerate Formation in the Kyeburn River, Central Otago, South Island, New Zealand. In this study, we describe this first known occurrence of moa (Dinornithiformes) footprints to be found and recovered in Te Waipounamu/South Island. Footprints of the trackway were ∼46 mm deep, 272–300 mm wide and 260–294 mm in length. An associated separate footprint was 448 mm wide and 285 mm long. Cosmogenic nuclide dating of adjacent overlying beds from the same formation establishes a mean minimum age of burial age for the tracks of 3.57 Ma (+1.62/−1.18 Ma) with a mode of 2.9 Ma, which we interpret to be Late Pliocene, with a conservative age range of Pliocene to Early Pleistocene. The trackway maker is identified as a moa from the Emeidae family, probably from the genus Pachyornis, with a mean mass of 84.61 kg that was travelling at a speed of 2.61 kmh−1. The single adjacent footprint was made by an individual from the family Dinornithidae, most likely from the genus Dinornis with an estimated mass of 158 kg. These moa footprints represent the second earliest fossil record of moa.

The last glacial termination was characterised by millennial-scale episodes of warming and cooling that appear offset between the hemispheres. It has been proposed that this bi-polar seesaw is the result of climate system feedbacks. A key debate, which remains unresolved, concerns the relative roles of the atmosphere and oceans in transmitting these climate responses between the hemispheres. In this study we present quantitative climate proxy data to show that air temperatures in New Zealand, as recorded by mountain glaciers, tracked millennial-scale warming and cooling of local surface temperatures of the adjacent Tasman Sea throughout the last glacial termination. Both realms were dominated by warming between 18 ka and 12 ka, interrupted by a multi-centennial to millennial-scale cooling event centred on 14 ka, coincident with the Antarctic Cold Reversal. Reconciling our climate proxy evidence with a transient climate model simulation of the glacial termination, we find that the timing and amplitude of temperature changes are consistent with changing Atlantic meridional overturning circulation (AMOC). The southwest Pacific region displays a particularly sensitive response to AMOC intensity changes, despite its far-field situation from the North Atlantic. This sensitivity represents the combined impact of fast-acting oceanic teleconnections and regional atmosphere-ocean response associated with changes to the southern westerly winds. Our findings highlight that recent hypotheses promoting the role of southern westerlies as a critical component of deglaciation may be complementary to, rather than competitive with, the bipolar seesaw paradigm.

BACKGROUND: Firefighting is recognised as a physically demanding occupation involving exposure to hazardous environments and activities. An aging workforce combined with the age-related decline in physical fitness may result in increased future workers’ compensation expenditure for fire service organisations. OBJECTIVE: The objective of this research was to investigate the costs associated with musculoskeletal sprain and strain injury and the impacts of age and injury location on Workers’ Compensation claims submitted by professional urban firefighters. METHODS: Claim rates, direct costs, and days lost were extracted from a professional Fire Service organisation’s workers’ compensation claim database for financial years between 2011 to 2018. RESULTS: The mean cost per claim increased with age, with a mean claim cost of the 60–70-year-old group over 10 times more than the 20–29-year-old group. The mean days lost per claim were also higher for claims submitted by firefighters aged over 50. CONCLUSIONS: Older firefighters miss more workdays when injured and are associated with increased claims costs, particularly those in the 60–70-year group. With an aging workforce, Fire Service organisations must implement appropriate management and prevention strategies to reduce the potential risks associated with an aging workforce.

Oblique terrestrial laser scanning (TLS) enables topographic change detection at scales (10- 1 -100 cm) that are appropriate for coastal cliff erosion monitoring. Despite this, published applications of TLS on cliff are limited to a small number of sites around the world. Here we report new TLS point cloud datasets from 9 years of monitoring (2014-2023) at Rothesay Bay within the Hauraki Gulf, New Zealand, which has relatively low wave energy and a meso-tidal range. The 120 m-length scan area includes cliffs of 10-30 m height, formed of horizontally bedded soft sedimentary flysch rock. The cliffs are fronted by an 140 m wide near-horizontal shore platform that terminates in an abrupt seaward edge. Previous research at this site has estimated long-term cliff erosion rates within a range of 1.4 +/- 0.1 to 14.3 +/- 0.1 mm/year on the basis of measured shore platform width, assuming that the shore platform has widened over time over 6000 years of stable Holocene sea level, and that the seaward edge of the shore platform has not retreated. Volumetric cliff-face erosion rates were detected through 17 scans over a 9-year window (2014-2023), including intensive monthly TLS scanning between July 2021 and July 2022. Results show that the average cliff recession rate over the past decade has been 41 +/- 2 mm/ year, and monthly scans show a range in erosion rates of 30 to 288 mm/year. The cliff recession rate detected with TLS is 3 to 30 times higher than erosion rates derived based on the shore platform width. If erosion had been constant at this rate over approximately 6000 years, a total cliff retreat of >245 m would be expected, whereas the contemporary shore platform is only 140 m wide. We discuss two possible hypotheses for the confounding width of the modern shore platform: 1) that modern cliff retreat rates are faster than past erosion rates; 2) that the seaward edge of the shore platform does not reliably demarcate Holocene cliff recession. We present new bathymetric survey mapping seaward of the shore platform edge that reveals multiple rocky features that are distinguished by steep slope breaks and planar surfaces. Understanding the evolution of the intertidal shore platforms during the Holocene era may necessitate new insights on how cliffs formed toward the end of the last marine transgression. This could potentially be investigated through the study of subtidal marine bathymetry.

AbstractA linear relationship between rates of physical erosion and chemical weathering is apparent in slowly eroding landscapes. Whether the relationship remains linear in rapidly eroding landscapes is less clear. Field‐based research into this relationship between erosion and weathering rates has largely been conducted in temperate climates with granitic bedrock. In tropical settings, the contribution of chemical mass loss to total denudation may approach, or even exceed, that of erosion. We report 10Be‐in‐quartz cosmogenic radionuclide and soil chemistry data from the Suckling‐Dayman Metamorphic Core Complex (SDMCC) in Papua New Guinea. Despite being exhumed at cm‐per‐year rates, its lower‐plate domed and striated morphology suggests minimal denudation, which is confirmed by our 10Be‐in‐quartz data (0.02–0.18 mm/yr). We suggest that rolling hinge‐style back‐rotation of the SDMCC's lower plate and the combination of a tropical climate and highly weatherable metabasalt bedrock have played a fundamental role in preserving the tectonic topography of this remarkable metamorphic core complex.

Abstract Redshaw, AS, Carrick-Ranson, G, Bennett, H, Norton, KI, and Walker, A. Effect of aging on movement quality in Australian urban firefighters. J Strength Cond Res 37(11): e601–e608, 2023—Adequate levels of movement quality (MQ) are required to safely perform occupational tasks in physically demanding and hazardous professions such as firefighting. Although it is well established that MQ deteriorates with age in population studies, there is conflicting evidence in older tactical populations. This study sought to examine the relationship between age and MQ in Australian urban firefighters. The impact of physical activity, injury history, and body mass index on MQ were also explored. The MQ of 324 professional Australian urban firefighters was assessed using MovementSCREEN MQ assessment tool. Scores of whole-body MQ ranged from 35.3 to 82.6 (0–100 scale), with a mean score of 59.2 ± 10.0. There was a moderate, negative association between MQ and age (r = −0.500; p ≤ 0.001), with those older than 50 years of age having significantly lower scores of MQ than their younger counterparts (p ≤ 0.001). Secondary analysis found that higher body mass index (r = −0.285; p ≤ 0.001), lower habitual physical activity levels (r = 0.165; p ≤ 0.003), and the presence of any musculoskeletal injury in the previous 12 months (p = 0.016) had significant negative effects on composite MQ. Firefighters older than 50, obese, and engaging in low levels of physical activity should be considered a high priority for functional strength training interventions to maintain adequate MQ throughout their careers.

&lt;p&gt;The Southern Alps / K&amp;#257; Tiritiri o te Moana in Aotearoa New Zealand have attracted scientists to study the interactions between climate and tectonics for decades. It has long been argued that tectonic uplift of this orogen is approximately balanced by erosion. The prevailing westerly airflow at the latitudes of the Southern Alps has created a strong orographic effect with precipitation decreasing sharply across the orogen&amp;#8217;s main divide. The signature of this orographic effect is apparent in erosion rates that decrease from west to east, and from the dominant types of erosional processes that operate on either side of the orogen&amp;#8217;s main divide. Most studies quantifying erosion over geologic timescales have focussed on the wetter&amp;#8212;but areally significantly smaller&amp;#8212;side of the orogen. Here, we seek to quantify the Pliocene&amp;#8211;Recent erosion history of the Southern Alps&amp;#8217; much larger and drier eastern side using cosmogenic radionuclides (&lt;sup&gt;10&lt;/sup&gt;Be and &lt;sup&gt;26&lt;/sup&gt;Al), tracer techniques (U&amp;#8211;Pb) and a grain size analysis on fluvial deposits in the Canterbury region that record concomitant erosion of this mountain range. Cosmogenic radionuclides provide a powerful tool to constrain catchment-scale erosion rates on timescales of 100&amp;#8211;100,000 years, which is the temporal range at which tectonic and climatic forcings overlap and meso-scale stratigraphic architecture is created, thereby offering critical insights into the dynamics between tectonics, climate, and surface processes. Detrital grain U&amp;#8211;Pb analysis of the fluvial deposits will be used to establish the sediment&amp;#8217;s provenance, while a grain size analysis of the river sediments will provide insights into associated past stream dynamics. With this multi-method study, we seek to constrain both spatial patterns and catchment-scale rates of erosion of the eastern Southern Alps, as well as their changes through time and see if erosion has been affected by major climatic shifts during the Pliocene and Pleistocene epochs. Finally, this research will provide a benchmark for assessments of anthropogenically influenced erosion of the eastern Southern Alps. Preliminary results from &lt;sup&gt;10&lt;/sup&gt;Be and &lt;sup&gt;26&lt;/sup&gt;Al analyses and dating of fluvial terraces will be presented.&lt;/p&gt;

Landslide deposits preserved in the geological record afford opportunities to better inform hillslope and seismic hazard and risk models, particularly in regions where observational records are short. In the Southern Alps of New Zealand, small coseismic landslides are frequent, but the geological record preserves several instances of more substantial (> 1 km 3 ) but infrequent mass failures. With an estimated volume of 27 km 3 , the giant Green Lake Landslide represents one of the largest subaerial landslides on Earth. Previous work has suggested this deep-seated mass movement was most likely triggered by high-intensity seismic shaking, but that local structural weakness and/or glacial debuttressing may help to explain the anomalously large failure volume. Resolving the potential contribution of the latter is important given predictions concerning alpine deglaciation in the coming decades to centuries. Key to resolution are secure chronologies of landslide emplacement and past glacier change. Here we present in situ cosmogenic 10 Be exposure ages from the Green Lake Landslide that suggest an emplacement age of 15.5 ± 0.7 ka. Recent work shows that glacial retreat in the region was underway by 19 ka, indicating that the Green Lake Landslide was emplaced 3–4 kyr after the onset of glacier retreat. Given the geometry of the former confining valley glacier, we expect that the deglaciation-landslide age gap is closer to the upper end of this estimate. If correct, this conclusion places greater weight on the roles of local geological structure and/or a great earthquake as factors contributing to the exceptionally large volume of this event.

Continental-scale ice sheets have covered Antarctica since an interval of global cooling near the Eocene–Oligocene boundary around 33.9 million years ago (Ma). However, the sequence of events that led to the emergence of the persistent ice sheet in modern East Antarctica remains disputed. The transition to permanent polar aridity in high elevations of East Antarctica is critical to our understanding of the threshold response of glacial systems in Antarctica to changes in surface temperature at lower elevations. Here we constrain the onset of the polar aridity—which was probably necessary for regional ice-sheet stability—by assessing meteoric beryllium-10 profiles in mid-Miocene and late Quaternary soils at three sites situated 1,200–1,800 metres above sea level in the McMurdo Dry Valleys. Interpreting these profiles as indicators of water infiltration, we find that meteoric beryllium-10 entered mid-Miocene soils as late as the late Miocene. Reconstructions based on palaeo-active-layer thickness and known thresholds of meteoric beryllium-10 mobility suggest late Miocene summer temperatures of 7–10 °C with annual precipitation >10 mm. Therefore, the high elevations have probably been under a hyper-arid polar climate since the late Miocene (~6 Ma) and not the middle Miocene (13.8–12.5 Ma) as indicated by some previous reconstructions. Together, our findings indicate that high elevations of the McMurdo Dry Valleys probably experienced warm and wet climatic intervals from ~14.0 to 6.0 Ma, which reconciles observations of coastal warmth and reduced ice in the Ross Embayment. This finding also suggests that the McMurdo Dry Valleys may be more susceptible to climate change than anticipated.

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Documenting and quantifying sediment transport in natural system, especially over millennial timescale, is still challenging. Among potential new approaches, recent development has shown that luminescence signal could be used to estimate transport parameters in rivers such as virtual velocity of sediments, storage time or sediment sources (McGuire & Rhodes, 2015; Gray et al., 2018; Gray et al., 2019; Sawakuchi et al., 2018; Guyez et al., 2022).In this study, we focus on the factors controlling post-infrared feldspar luminescence signals (pIRIR) of modern fluvial sediments in upstream areas. The objective is to examine whether pIRIR equivalent dose distributions relate to landscape erosion rates and associated sediment fluxes. To test this hypothesis, we studied catchments in the Southern Alps of New Zealand (SANZ), one of the world’s most active mountain ranges, with extremely high rates of exhumation and erosion.For eight catchments of the SANZ, we compared the single-grain pIRIR equivalent dose distributions from modern fluvial sediments with catchment-wide erosion rates obtained using measurements of 10Be cosmogenic nuclide concentration in modern fluvial quartz grains. The latter approach is widely used to quantify catchment-wide erosion rates on millennial time scales.Using the cosmogenic methods, we found catchment-wide erosion rates ranging from 0.2 to 4.0 mm/yr. The rates increased along the mountain range from South-West to North-East, confirming results by Larsen et al. (2014), and may reflect a tectonic uplift gradient related to northward segmentation of the Alpine fault. In addition, erosion rates on the Western side were higher than the Eastern side, which we attribute to the climatic gradient of the SANZ, related to orographic effect.We measured single-grain pIRIR equivalent dose (De) distributions at the outlet of each catchment. We calculated (1) the fraction of grains whose luminescence signal is saturated (Bonnet et al., 2019; Guyez et al., 2022), (2) the fraction of well-bleached grains. We also characterized the De distribution using (3) the central age model (CAM; Galbraith et al., 1999) and (4) the bootstrapped minimum age model (BS-MAM; Cunningham & Wallinga, 2012). We found a relationship between those four proxies and erosion rates obtained from 10Be, as well as with suspended sediment yield (Adams, 1980; Hicks et al., 2011) and channel steepness index.Our study shows that single grain pIRIR equivalent dose distributions reflect erosion and sediment fluxes of a catchment. This new property could be further developed with the perspective to use this proxy as a new independent tool to quantify erosion and transport processes in a wide range of fluvial settings on time scales shorter than cosmogenic methods.

ABSTRACT Glacial landscapes preserve records of past climate change. Investigating the glacier–climate system over the Late Quaternary provides information about past climate change and context for present‐day glacier response to climate warming. Using 28 beryllium‐10 ( 10 Be) surface exposure dates and snowline reconstructions, we present glacier fluctuations and climate changes for the Antarctic Cold Reversal in the Ahuriri River catchment, Southern Alps of New Zealand (44°7′50″S, 169°38′29″E). Prominent terminal and lateral moraine features from the upper right tributary of the Ahuriri River valley have exposure ages of 14.5 ± 0.3, 13.6 ± 0.3 and 12.6 ± 0.2 ka, suggesting retreat of the glacier during the Antarctic Cold Reversal. Maximum elevation of lateral moraines (MELM) and accumulation area ratio (AAR) suggest snowline elevations at these ages were ≤700, ≤630 and ~360 m lower than today, respectively. This equates to air temperatures ≤3.9, ≤3.5 and 2.3 ± 0.7 °C lower than today (1981–2010), assuming no changes in past precipitation. Ice‐sculpted bedrock surfaces bound by a lateral moraine at nearby Canyon Creek have an age of 13.1 ± 0.3 ka, indicating the moraine correlates with those in the Ahuriri upper right tributary. MELM and AAR reconstructions from the Canyon Creek suggest that snowline elevations at 14.5–13.6 ka were ≤500 or ~380 m lower than today, corresponding to air temperatures ≤2.8 or 2.4 ± 0.7 °C lower than the present‐day (1981–2010). Our results provide insight into the structure of the Antarctic Cold Reversal in the Southern Alps, showing that the largest glacier advance occurred at the start of this interval at c . 14.5 ± 0.3 ka and was followed by gradual retreat. We hypothesize that the early cooling and glacier readvance in New Zealand at the onset of the Antarctic Cold Reversal were triggered by a latitudinal shift of the Southern Hemisphere westerly wind belt.

IMPORTANCE Concussions are common in sports. Return-to-play protocols can be enhanced by objective biometrics. OBJECTIVE To characterize temporal changes of headpulse, a digital biometric, in athletes with sports-related concussion; to explore the association of unstructured physical activity with headpulse changes. DESIGN, SETTING, AND PARTICIPANTS This cohort study included headpulse measurements from players in the highest level of amateur Australian Rules Football in South Australia. Analysis included feasibility and validation phases, with the feasibility cohort recruited between August 5, 2021, and September 10, 2021, and the validation cohort recruited between May 5, 2022, and September 3, 2022. Data were analyzed October 2022 through January 2023. INTERVENTIONS Cranial accelerometry detected micromovements of the head following cardiac contraction (what we have described as "headpulse"). Headpulse was serially recorded for 1 month in concussed individuals. MAIN OUTCOMES AND MEASURES Headpulse waveforms underwent frequency transformation analysis per prespecified algorithm. Result Z scores were calculated. Headpulse Z scores exceeding 2 (2 SDs from control means) met an abnormality threshold. Headpulse sensitivity, timing, and duration of change were determined. RESULTS A total of 59 control and 43 concussed individuals (44 total concussions; 1 control also concussed, 1 concussed individual injured twice) provided headpulse measurements. The feasibility cohort (all male) included 17 control (median [IQR] age, 23 [19-28] years) and 15 concussed individuals (median [IQR] age, 21 [19-23] years). The validation cohort included 25 female (median [IQR] age, 21 [20-22] years) and 17 male (median [IQR] age, 26 [23-29] years) control individuals, and 8 female (median [IQR] age, 28 [20-31] years) and 20 male (median [IQR] age, 21 [19-23] years) concussed individuals. Headpulse reached abnormality threshold in 26 of 32 concussed individuals (81%; 9% on day 0, 50% by day 2, 90% by day 14). Headpulse alterations lasted 14 days longer than symptoms and were exacerbated by return-to-play or unsupervised physical activity. CONCLUSIONS AND RELEVANCE In this study of 101 amateur Australian Rules Football athletes, the digital headpulse biometric was evaluated in 44 sports-related concussions. Compared with controls, new headpulse changes occurred after concussion; this objective metric may complement return-to-play protocols.

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