Understanding the spatio-temporal dynamics of suspended sediment source activation is essential for effective ecological management, risk assessment, and infrastructure planning. Provenance analysis, which traces sediment origins, plays a crucial role in these applications, but is often based on costly fingerprinting methods. In this study, we validate a time- and cost-effective fingerprinting approach based on X-ray diffraction (XRD) data. We implement and compare two non-linear inversion schemes (steepest descent and Quasi-Newtonian) applied to binned XRD data and spatial information on potential source areas, in order to invert detrital mineralogical data into erosion rate maps while quantifying posterior uncertainty and error propagation. Forward-inverse tests with synthetic data demonstrate consistent convergence of the posterior solution and reveal the influence of geological complexity, tracer selection, and signal blending on inversion performance. The application to real-world datasets from the Gornergletscher catchment further validates the practical utility and robustness of the model.

Abstract. The electron spin resonance (ESR) of quartz can be used as a low temperature thermochronometric system, however, to date no field validation of the approach has been made. Here we explore the ESR signals of quartz from six samples from the MIZ1 borehole (Tono, Japan). Previous studies have shown that this low-relief region underwent Quaternary exhumation at rates of <0.2 mm yr-1. We investigate whether quartz ESR signals can resolve such low rates of exhumation, or whether the samples are in thermal equilibrium with ambient borehole temperature. ESR thermochronometry requires that both sample-specific signal saturation and thermal decay are constrained in the laboratory, which makes measurements highly time-consuming. To overcome this, the development of a standardised growth curve (SGC) was explored, which allowed more rapid constraint of the trapped-charge concentrations of each of the samples. Thermal kinetic parameters were determined using an isothermal decay experiment for each individual sample and except for sample MIZ1-08, it was possible to fit all the isothermal decay data together to yield a single set of kinetic parameters that successfully described the dataset. The ESR thermochronometry results show that the MIZ1 samples are in thermal equilibrium for the Al-centre, and that Monte-Carlo inversion of the ESR data yields present-day borehole temperature within 1σ uncertainties for all samples except the lowest temperature sample. In contrast, inversion of the different Ti-centre options (A, B, D) yields temperatures 15–20 °C above contemporary borehole temperature, indicating rock cooling equivalent to a total exhumation of ~1 km over the same period. The cause of this discrepancy is unclear but may relate to sub-linearity of Ti-centre dose response, that led to underestimation of the trapped-charge concentration and hence an overestimation of borehole temperature. Our results validate ESR-thermochronometry of the Al-centre and show that an SGC and common thermal kinetic parameters may be used to expediate sample measurements, however ESR-thermochronometric data from the Ti-centre should be used cautiously until further validation data are available.

Central Nepal is a key natural laboratory for investigating crustal kinematics, exhumation, and thermochronometric records within a critically tapered orogenic wedge. In the High Himalayas, thermochronologic data record remarkably young cooling ages and rapid late Cenozoic exhumation rates, yet the kinematics driving these patterns remain actively debated. Most models aiming to explain the physiographic transition across the Himalayan range propose either predominantly in-sequence deformation focussed on the Main Himalayan Thrust (MHT), with underplating and the growth of a Lesser Himalayan duplex, or significant out-of-sequence (OOS) faulting in the Main Central Thrust (MCT) zone. Existing thermochronometric datasets allow for both end-member interpretations, highlighting the non-uniqueness of steady-state kinematic models based on traditional thermochronometers alone.We address this issue by adding trapped-charge thermochronometers (luminescence and ESR thermochronometry), which, owing to their extremely low effective closure temperatures, are uniquely sensitive to

Glacial erosion and sediment evacuation are key in shaping polar and mountain landscapes and influencing downstream ecological and social systems. The glacier dynamics and hydrology responsible for these processes are closely linked to hydrological and climatic (hydro-climatic) conditions. Recent studies indicate that sediment export and glacier erosion respond strongly to hydro-climatic variations across millennia to individual events lasting hours to weeks. (a) Sedimentary records and numerical ice flow models indicate increased erosion during glacier retreat following climate warming. (b) Rising equilibrium line altitudes due to climate change enhance meltwater access to subglacial sediment, increasing sediment export markedly. (c) Changing meltwater dynamics over hydrological events, particularly daily variations in melt or precipitation events, strongly impact sediment transport capacity. We propose that hydro-climatic changes from millennia to hours, along with the climatic conditions themselves, provide a useful framework for examining glacier erosion. The sensitivity of glacier erosion and sediment export to hydro-climatic conditions likely introduces timescale biases when averaging glacier erosion over long or short periods. Major uncertainties in interactions amongst processes and their relevant timescales underscore the need to better understand climate change impacts on glacierized landscapes. Emerging observational methodologies combined with numerical models may provide new insights into the complex and interacting dynamics controlling glaciers' impact on sediment export. Plain Language Summary Glaciers play a crucial role in shaping many cold landscapes and in influencing ecosystems and communities downstream. How glaciers erode rock and move sediment depends on glacier dynamics and hydraulics, which depend on climate. Yet, recent research shows that glacier erosion and sediment export processes can vary dramatically due to climate change and increased glacier melt, occurring over thousands of years to short-lived events lasting only hours. The trends we identify include processes that create sediment at the base of the glacier, affect sediment access to meltwater, and the hydraulic processes controlling its mobilization. Understanding the evolution of these geomorphic processes under changing climate conditions is key to evaluating the impact of glaciers on landscapes, oceans, ecosystems and societies. However, large uncertainties remain about the interaction of glacier erosion and sediment transport over different periods. New observational techniques and numerical models can help us fill key knowledge gaps and improve our understanding of the impact of climate change on glacierized regions.

Accurate constraint of the trapped charge population is necessary for precise temperature reconstruction using thermoluminescence (TL) palaeothermometry. Here, we assess the performance of existing measurement protocols to accurately determine TL signal growth of K- and Na-feldspar. We compare four different protocols - single aliquot regenerative dose (SAR), multiple aliquot regenerative dose (MAR; signal resetting by both bleaching and annealing), and multiple aliquot additive dose (MAAD). A key challenge in protocol reliability is sensitivity change related to signal reset at the beginning of measurement in regenerative protocols. We identify sensitivity change by comparison of initial slopes of the dose response curves of regenerative and additive protocols. Further, we compare equivalent doses (De) determined using the various protocols to those obtained from a single aliquot regenerative additive dose (SARA) measurement to assess protocol performance. While sensitivity change and the level of protocol performance are strongly dependent on the individual sample and temperature range, strong desensitisation of the feldspar TL signal in the lower temperature range (200-250 degrees C) during SAR and bleached MAR results in De overestimation and leads to the protocols' exclusion from further consideration. Annealed MAR and MAAD on the other hand show approximately equal performance. As the level of saturation is relevant for the reliability of MAAD results, we suggest that this is considered when choosing a measurement protocol, and that the choice of kinetic model for dose response is carefully evaluated.

Reconstructing the transport histories and provenances of glacial sediments and ice-contact deposits (e.g. tills, moraines) in formerly glaciated regions remains a major challenge, particularly at icefield- to ice-sheet scales and over multi-millennial timescales. Yet such reconstructions are central to key questions in Quaternary science, including estimates of past glacial erosion rates and sediment fluxes, the role of subglacial sediment storage in erosion reduction, or the reconstruction of past ice-flow dynamics, ice divides, and transfluences. While numerical modelling can enable one to reproduce past glacial sediment transport via coupling glacier models with particle tracking, this becomes computationally unfeasible over large spatial domains and paleo timescales using traditional computing. As a result, no study to date has simulated glacial sediment transport using large particle numbers (tens of millions) across continental-scale icefields such as the one occupying the European Alps during the Last Glacial Maximum (LGM). Here, we overcome this limitation using the Instructed Glacier Model (IGM), which allows the coupling of 3D Lagrangian particle tracking with high-resolution glacier simulations, both accelerated on Graphics Processing Units (GPU). This unlocks the modelling of ice advection of millions of particles at minimal additional computational cost, allowing simulations of glacial sediment transport across the European Alps over multi-millennial timescales (40-18 ka) and at the unprecedented spatial resolution of 300 m. We achieve similar to 50 & times; faster computation tracking 20 million particles across the Alps using a single GPU instead of 60 CPU threads. In doing so, we produce the first Alps-wide modelling reconstruction of glacial sediment transport during the LGM, using process-based particle seeding schemes to represent both subglacial (e.g. abrasion, plucking) and supraglacial (e.g. rockfall, landslides) sediment sourcing. Results are analysed through complementary "sink-to-source" (deposit provenance) and "source-to-sink" (potential depositional pathways) analyses, enabling us to reconstruct the LGM glacial transport of numerous ice-contact deposits and surface lithologies across the Alps. We find that supraglacially sourced glacial sediments are typically eroded earlier, experience longer glacier residence times, and undergo greater cumulative ice-free exposure than those of subglacial origin, with implications for the interpretation of cosmogenic nuclide inheritance in glacial deposits. Our new coupled glacier-particle modelling framework opens avenues for quantitative model-data comparisons using glacial geomorphology and provides a powerful tool for reconstructing paleo ice dynamics, sediment provenance, and Quaternary glacial landscape evolution.

Understanding past natural climate variations during the Quaternary period is crucial for understanding the ongoing climate change. Glaciation events during the Quaternary have left visible footprints in today's landscape, such as moraines and trimlines, that could be used to reconstruct paleo glacier extent. Reconstructed glacier extent offers great potential to retrieve paleo-climate information during the coldest episodes of the Quaternary by inverting a glacier evolution model. However, current inversion methods are computationally expensive and their forward model relies on simplified physics. Fundamentally, they all assume glaciers are in a stationary state, which is simplistic and fails to capture essential transient features linking climate to glacier response.Here, we develop a new Machine-Learning (ML)-based inversion technique that overcomes the previously-mentioned limitations to reconstruct the glacier equilibrium line altitude (ELA), a proxy for temperature and precipitation, during a glacial maximum from reconstructed glacier extent. Our forward model consists of a deep-learning emulator that learns the physical processes of a glacier from climate forcing to the glacier response. This approach has the advantage of being computationally highly-efficient, as well as allowing for automatic (thanks to the automatic differentiation) inversion of reconstructed glacier extent to retrieve a realistic ELA field that informs us about paleoclimates.When applying our method to the Last Glacial Maximum in the European Alps, our reconstructed ELA fields show a clear separation between the northern and southern Alps, with northern ELAs being considerably lower as shown in Fig 1. Our results are supported by the glacier footprints reconstructed from geomorphological observations in the northern Alps, which suggest the presence of large glacier lobes. In contrast, the glacial lobes in the southern Alps were noticeably smaller.Our method is applicable in any formerly glaciated areas, and therefore has a high potential for paleoclimate reconstruction of the Earth’s coldest episodes.Figure1. The resulting ELA field from inverting the ‘observed’ glacier footprint. There is a visible difference in the climate between the north and the south.

Reconstructing the last glaciation of the European Alpine Ice Field via numerical modelling has been challenged by persistent model-data disagreements, including large overestimations of its former thickness. Here, we tackle this issue by applying the Instructed Glacier Model, a three-dimensional, high-order, and thermo-mechanically coupled model enhanced with physics-informed machine learning. This new approach allows us to produce an ensemble of 100, Alps-wide and 17 thousand-year-long (35-18 ka) simulations at 300 m spatial resolution. Unfeasible with traditional models due to computational costs, our experiment substantially increases model-data agreement in both ice extent and thickness. The model-data offset in ice thickness, for instance, is here reduced by between 200% and 450% relative to previous studies. The results yield implications for more accurately reconstructing former ice velocities, ice temperatures, basal conditions, glacial erosion processes, glacial isostatic adjustment, and climate evolution in the Alps during the Last Glacial Maximum. Furthermore, the switch to GPU-based computations enables us, for the first time, to also couple our Alpine Ice Field model with three-dimensional and time-transgressive ice advection of particles (tens of millions). Here, particles are seeded to mimic both the subglacial (e.g. abrasion, plucking) and supraglacial (e.g. rockfall) origins of glacially-transported sediments. Using our ensemble best-fit simulation, we present the results of tracking the sink-to-source transport trajectories of distinct LGM ice-contact deposits (e.g. terminal moraines), and the LGM source-to-sink transport trajectories of specific surface lithologies, throughout the Alps. We find that modelling the Alps-wide glacial transport of particles also helps us better understand the complex internal ice dynamics of the former Alpine Ice Field, including transfluences and the zipping/unzipping behaviours of different tributary glaciers. More generally, this work demonstrates that physics-informed AI-driven glacier models can overcome the bottleneck of high-resolution continental-scale modelling required to accurately describe complex topographies and ice dynamics.

Abstract. Over the past fifteen years, trapped-charge (T-C) thermochronometry has been established as an ultra-low temperature (<80 °C) thermochronometric system. Its novelty is its ability to resolve rock cooling within the final few km of Earth's surface, as well as rock-surface temperature changes since the Last Glacial Maximum to the present day. Deriving temperature histories from the luminescence signals of feldspar minerals, or the electron spin resonance signals of quartz minerals, requires the modelling of both signal accumulation and signal loss in response to mineral exposure to ionizing radiation and temperature, as well as athermal signal losses for feldspar minerals. Two open-source libraries have been developed in MATLAB that allow different numerical models to be used for this purpose; the first is applicable to the infra-red stimulated luminescence (IRSL) of feldspar minerals (OSLThermo) and the second to the electron spin resonance (ESR) signal of quartz minerals (ESRThermo). These libraries have been made available in GITHUB and this contribution describes their broad structure, the T-C models that have been implemented and their practical use. Codes are available for download on GitHub: https://github.com/GeorginaKing/OSLThermo for luminescence thermochronometry & https://github.com/GeorginaKing/ESRThermo for ESR thermochronometry.

25 thousand years ago, the European Alps were covered by the kilometre-thick Alpine Ice Field. Numerical modelling of this glaciation has been challenged by model-data disagreements, including overestimations of ice thickness. We tackle this issue by applying the Instructed Glacier Model, a three-dimensional model enhanced with physics-informed machine learning. This approach allows us to produce 100 Alps-wide and 17 thousand-year-long simulations at 300 m resolution. Previously unfeasible due to computational costs, our experiment both increases model-data agreement in ice extent and reduces the offset in ice thickness by between 200% and 450% relative to previous studies. Our results have implications for better estimating former ice velocities, ice temperature, basal conditions, erosion processes, and paleoclimate in the Alps. This study demonstrates that physics-informed machine learning can help overcome the bottleneck of high-resolution glacier modelling and better test parameterisations, both of which are required to accurately describe complex topographies and ice dynamics.

The climatic conditions, particularly the sources of precipitation that enabled extensive glacial growth during the Last Glacial Maximum (LGM) in the European Alps, remain poorly constrained. Here, we apply an inversion method to reconstruct equilibrium line altitude (ELA) fields using glacier footprints, such as the moraines deposited by Alpine glaciers during the LGM. By employing a machine-learning emulator trained on outputs from a glacier-evolution model, we predict glacier maximal thickness. The emulator is integrated into a gradient-based inversion scheme to derive ELA fields consistent with LGM footprints. The results show that the reconstructed ELA fields align with those from previous studies, validating the robustness of our approach. Unlike existing inversion methods, our approach is more general and avoids restrictive assumptions. Notably, by incorporating the transient response of glaciers to climate variability (we do not assume steady state), we show that the cold spell period is crucial for interpreting the reconstructed climate patterns-an aspect previously overlooked. Our findings provide new insights into climatic variability during the LGM, particularly concerning the interaction between precipitation patterns and the cold spell period. Furthermore, the computational efficiency of our method makes it applicable to large-scale paleoclimate reconstructions based on glacier footprints.

The Himalayan Main Frontal Thrust (MFT) currently accommodates approximately half, i.e., 12-23 mm/yr, of the convergence between the Indian and Eurasian tectonic plates by uplift and deformation of the Sub -Himalayas. While deformation is well documented at modern and million -year time scales, almost no quantitative data are available that constrain Quaternary time scale deformation rates along and within this key tectonic unit. Filling this knowledge gap is crucial to better understanding tectonics and the seismic cycle in this densely populated Himalayan region. We quantify exhumation rates in the Sub -Himalayas using the recently established luminescence thermochronometry technique over time scales of 105 yr, which documents exhumation over the final few kilometers of Earth's crust. The ultra -low closure temperature of luminescence thermochronometry enables us to resolve thermal histories from the Siwalik Group (Nepal) rocks, which have experienced maximum burial temperatures of similar to 120 degrees C. An extensive set of 33 samples was collected from western Nepal to eastern Bhutan, from which 22 yield exhumation rates of similar to 3-11 mm/yr over the past similar to 200 k.y. We converted these values to minimum cumulative thrust slip rates of similar to 6-22 mm/yr, assuming a thrust dip angle of 30 degrees. Our luminescence thermochronometry results show that the Sub -Himalayan fold -and -thrust belt, particularly the MFT, accommodates at least 62% of Himalayan convergence since at least 200 ka. Our data also show activity of some intraSiwalik thrusts throughout this period, implying that internal deformation of the orogenic wedge and strain partitioning may have occurred.

Previous studies have shown that the low-relief Tono region (Japan) underwent Quaternary exhumation at rates of <1 mm yr-1. Here we explore whether electron spin resonance (ESR) signals of quartz from six samples from the MIZ1 borehole can resolve such low rates of exhumation, or whether the samples are in thermal equilibrium with ambient borehole temperature. ESR thermochronometry requires that both sample-specific signal saturation and thermal decay are constrained in the laboratory, which makes measurements highly time-consuming. To overcome this, the development of a standardised growth curve (SGC) was explored, which allowed more rapid constraint of the trapped-charge concentrations of each of the samples. Thermal kinetic parameters were determined using an isothermal decay experiment for each individual sample and except for sample MIZ1-01, it was possible to fit all the isothermal decay data together to yield a single set of kinetic parameters that successfully described the dataset. Using a single set of kinetic parameters also allows faster measurement. The ESR thermochronometry results show that the MIZ1 samples are not in thermal equilibrium, but rather reflect ongoing exhumation in this region. Exhumation rates determined from the Al-centre are consistent with existing thermochronometric data and indicate total exhumation of 385 ± 220 m over the past 1 Myr. In contrast the different Ti-centre options (A, B, D) yield a total exhumation of ∼1 km over the same period. The cause of this discrepancy is unclear but may relate to sub-linearity of Ti-centre dose response, that lead to underestimation of the trapped-charge concentration and hence an overestimation of exhumation rates. Our results indicate that ESR-thermochronometry can be successfully applied in low-relief zones undergoing exhumation at rates <1 mm yr-1, and that an SGC and common thermal kinetic parameters may be used to expediate sample measurements.

The impact of climate on mountain relief is often questioned, mainly due to the difficulties of measuring surface processes at the timescale of glacial-interglacial cycles. An appropriate setting for studying mountain erosion in response to Quaternary climate change is found in the Tateyama mountains in the Hida mountain range (northern Japanese Alps) due to distinct geomorphological features. The Japanese Alps uplifted within the past similar to 1-3 Myr and experienced multiple glaciations during the late Quaternary. We use ultra-low temperature thermochronometers based on the luminescence of feldspar minerals from 19 rock samples and the electron spin resonance (ESR) of quartz minerals from 8 rock samples, in combination with inverse modelling to derive rock cooling rates and exhumation rate histories at 10(4)-10(6) year timescales from three transects in the Tateyama region. While luminescence signals have already reached their upper dating limit, ESR signals (Al and Ti centres) yielded ESR ages of similar to 0.3-1.1 Ma, implying surface processes active in the Pleistocene. Based on a negative age-elevation relationship, local relief reduction at a cirque-basin scale is identified over the past 1 Myr, whereas a positive age distribution with elevation for samples close to the mountain top does not follow this trend. Inverse modelling reveals rock cooling rates on the order of 20-70 degrees C/Myr, with slightly faster cooling for cirque-floor samples, which equate with erosion rates of 0.5-1 mm/yr that exceed rates from periglacial and slope processes in the same locality. Thus, our data suggest that Quaternary climate change coupled with distinct surface processes modified the slopes of the Tateyama mountains leading to a localised decrease in relief within an individual cirque basin over the second half of the Quaternary.

The transition from slow flow to rapid sliding is a noticeable feature of both ice sheets and outlet glaciers. Most existing models attempting to understand the complex physical transition processes assume an idealized model geometry with a flat bed. These models have shown that the onset of sliding entails basal refreezing, which in turn suppresses sliding. The theoretical difficulties in understanding sliding commencement in these process-based models contrast with the apparent ubiquity of the transition in the field. Here, we hypothesize that the presence of basal topography could resolve the inconsistency between model predictions and field observations. We test our hypothesis by investigating the flow-to-sliding transition in a process-based model of ice flowing over bedrock with significant roughness. We assume that the bed is rigid and that the boundary condition at the bed is no-slip. We incorporate variations in basal topography into an iterative nonlinear Stokes solver for thermo-mechanically coupled ice deformation using the Immersed Boundary Method. This approach permits us to address the basal ice to bedrock transition with high accuracy and to study the impact of the shape of this transition zone. Our results suggest that shear heating in the vicinity of pronounced roughness extends well into the bulk of the ice, leading to a spatially variable viscosity. These spatial variations in topography can therefore significantly impact the overall viscosity distribution in the ice. High shear strain rates localize at the tops of the bedrock topography. Thermo-mechanical feedback lead to the spontaneous formation of internal shear band over time, by connecting the topographic heights. The internal shear zone accommodates the majority of shear deformation, inducing a sliding motion of the upper part of the domain. Our results provide a process-based explanation of recently measured ice deformation data at the West margin of Greenland Ice Sheet (Maier et al. 2019). It is also consistent with the proposed existence of a radio-echo free zone located in the lowest hundreds of meters above bedrock (Drews et al. 2009, Fujita et al. 1999). Maier, Nathan, et al. "Sliding dominates slow-flowing margin regions, Greenland Ice Sheet." Science advances 5.7 (2019): eaaw5406. Drews, Reinhard, et al. "Layer disturbances and the radio-echo free zone in ice sheets." The Cryosphere 3 (2009): 195-203. Fujita, Shuji, et al. "Nature of radio echo layering in the Antarctic ice sheet detected by a two‐frequency experiment." Journal of Geophysical Research: Solid Earth 104.B6 (1999): 13013-13024.

High-relief glacial valleys shape the modern topography of the Southern Patagonian Andes, but their formation remains poorly understood. Two Miocene plutonic complexes in the Andean retroarc, the Fitz Roy (49 degrees S) and Torres del Paine (51 degrees S) massifs, were emplaced between 16.9-16.4 Ma and 12.6-12.4 Ma, respectively. Subduction of oceanic ridge segments initiated ca. 16 Ma at 54 degrees S, leading to northward opening of a slab window with associated mantle upwelling. The onset of major glaciations caused drastic topographic changes since ca. 7 Ma. To constrain the respective contributions of tectonic-mantle dynamics and fluvio-glacial erosion to rock exhumation and landscape evolution, we perform inverse thermal modeling of a new data set of zircon and apatite (U-Th)/He from the two massifs, complemented by apatite 4He/3He data for Torres del Paine. Our results show rapid rock exhumation recorded only in the Fitz Roy massif between 10 and 8 Ma, which we ascribe to local mantle upwelling forcing surface uplift and intensified erosion around 49 degrees S. Both massifs record a pulse of rock exhumation between 7 and 4 Ma, which we interpret as enhanced erosion during the beginning of Patagonian glaciations. After a period of erosional and tectonic quiescence in the Pliocene, increased rock exhumation since 3-2 Ma is interpreted as the result of alpine glacial valley carving promoted by reinforced glacial-interglacial cycles. This study highlights that glacial erosion was the main driver to rock exhumation in the Patagonian retroarc since 7 Ma, but that mantle upwelling might be a driving force to rock exhumation as well. The isotopic system (U-Th)/He in apatite and zircon record the ages in which a rock experiences relatively low temperatures (200-60 degrees C) at shallow crustal depths (6-1 km). We present a new data set of low-temperature thermochronometers for rocks of the Fitz Roy and Torres del Paine mountains in the Southern Patagonian Andes. Fast rock cooling can be forced by intensified surface erosion, and/or tectonic and mantle activity. An episode of fast cooling between 10 and 8 Ma was identified in the Fitz Roy mountains, and mantle upwelling forcing surface uplift, combined with high fluvial erosion may have caused fast rock exhumation. A regional episode of fast rock cooling between 7 and 4 Ma causing 1-3 km of exhumation in the Fitz Roy and Torres del Paine is coincident with the onset of Patagonian glaciations, which would have enhanced erosion and, thus, rock exhumation. An episode of fast rock cooling in the Quaternary is recorded in Torres del Paine rocks, interpreted as enhanced fluvio-glacial erosion during the Plio-Pleistocene climate transition toward faster glacial/interglacial cycles. Therefore, we were able to quantify separately the effects of tectonics and climate changes on rock exhumation, what is usually difficult due to simultaneously occurring processes. Mantle upwelling in Southern Patagonia is the most likely mechanism forcing rock exhumation between 10 and 8 Ma in the Fitz Roy massif Apatite (U-Th)/He data reveal glacial erosion as the main driver to the exhumation of the Fitz Roy and Torres del Paine between 7 and 4 Ma Apatite 4He/3He data reveal intensified fluvio-glacial erosion in Torres del Paine as a result of the Plio-Pleistocene climate transition

The exhumation of bedrock is controlled by the interplay between tectonics, surface pro-cesses, and climate. The highest exhumation rates of centimeters per year are recorded in zones of highly active tectonic convergence such as the Southern Alps of New Zealand or the Himalayan syntaxes, where high rock uplift rates combine with very active surface processes. Using a combination of different thermochronometric systems including trapped-charge ther-mochronometry, we show that such rates also occur in the Hida Mountain Range, Japanese Alps. Our results imply that centimeter per year rates of exhumation are more common than previously thought. Our thermochronometry data allow the development of time series of exhumation rate changes at the time scale of glacial-interglacial cycles, which show a four-fold increase in baseline rates to rates of -10 mm/yr within the past -65 k.y. This increase in exhumation rate is likely explained by knickpoint propagation due to a combination of very high precipitation rates, climatic change, sea-level fall, range-front faulting, and moderate rock uplift. Our data resolve centimeter-scale sub-Quaternary exhumation rate changes, which show that in regions with horizontal convergence, coupling between climate, surface processes, and tectonics can exert a significant and rapid effect on rates of exhumation.

&lt;p&gt;The impact of Quaternary climate change on landscape evolution, and more specifically the timing of incision of the overdeepened Alpine valleys, remains difficult to quantify with existing thermochronometric methods. Thermochronometers are used to determine rates of rock cooling, however most techniques are insensitive to temperature changes &lt;60 &amp;#176;C that occur within the last kms of Earth&amp;#8217;s crust. Recording cooling rates within this temperature range is essential if the impact of glacial-interglacial cycles on rock exhumation is to be resolved.&lt;/p&gt; &lt;p&gt;Electron spin resonance (ESR) thermochronometry applied to quartz minerals has the potential to span this thermal (and temporal) gap. We are developing this method by building upon previous studies (e.g. Scherrer, 1993) with the ultimate aim of constraining the timing of incision of the Rh&amp;#244;ne valley. Preliminary data from the Japanese Alps (King et al., 2020) indicate that ESR thermochronometry could resolve rates of &lt;1 mm/yr over Quaternary timescales.&lt;/p&gt; &lt;p&gt;To determine a rock cooling history using ESR thermochronometry, signal accumulation and signal thermal loss must be robustly determined within the laboratory. We have collected a series of geological samples including rocks from boreholes that have known isothermal histories to investigate the potential of this technique. Our objective is to use the latter rocks to confirm the validity of our laboratory measurements and data-fitting/numerical models. Specifically, we have investigated known-thermal history samples from the MIZ1 borehole (Japan) and the KTB borehole (Germany) as well as samples from Sion in the Western European Alps.&lt;/p&gt; &lt;p&gt;Preliminary data reveal that the ESR dose response and thermal decay of different quartz samples is highly variable. Whereas the Al-centre of some samples exhibits linear dose response to laboratory irradiation up to 15 kGy, the Al-centre of other samples exhibits exponential, or double-exponential growth and saturates at doses of 3-4 kGy. The Ti-centre of most samples is well described by a single saturating exponential function, however samples from the MIZ1 borehole exhibit pronounced sub-linearity in the low-dose response region. Furthermore, whereas for some samples the Al-centre is less thermally stable than the Ti-centre, for other samples the inverse is observed. These observations suggest that a uniform measurement protocol and data-fitting approach may not be appropriate for quartz ESR data.&lt;/p&gt; &lt;p&gt;Inversion of two KTB samples yielded temperatures within uncertainty of borehole temperature, however results for the MIZ1 borehole are more variable and can only recover temperature at best within ~10%. Investigations into the cause of the poor results for the MIZ1 borehole are ongoing (i.e. measurement protocol, data-fitting/numerical model) and will be discussed. Preliminary data from Sion are promising and reveal consistent cooling rates.&lt;/p&gt; &lt;p&gt;&amp;#160;&lt;/p&gt; &lt;p&gt;Scherer, T., Agel, A., and Hafner S. S.: Determination of uplift rates&amp;#160;using ESR investigations of quartz, KTB Rep. 93-2. Kontinentales Tiefbohrprogram der Bundesrepublic Deutschland Nieders&amp;#228;chs. Landesamt Bodenforsch., Hannover, 121&amp;#8211;124, 1993.&lt;/p&gt; &lt;p&gt;King, G.E., Tsukamoto, S., Herman, F., Biswas, R.H., Sueoka, S., Tagami, T. Electron spin resonance (ESR) thermochronometry of the Hida range of the Japanese Alps: validation and future potential.&amp;#160;&lt;em&gt;Geochronology&lt;/em&gt;&amp;#160;2, no. 1 (2020): 1-15.&lt;/p&gt; &lt;p&gt;&amp;#160;&lt;/p&gt; &lt;p&gt;&amp;#160;&lt;/p&gt; &lt;p&gt;&amp;#160;&lt;/p&gt;

We present a method for tracking radio-tagged pebbles and cobbles through subglacial meltwater channels under shallow temperate glaciers. Natural particles tagged with active radio transmitters were injected directly into a large subglacial channel 300 m up-glacier from the terminus of the Glacier d'Otemma, Switzerland. A roving antenna was developed to localise tagged particles planimetrically in subglacial and proglacial channel reaches (350 and 150 m long, respectively) using a probabilistic technique, delivering records of the change in particle location and transport distance over time with uncertainty. The roving antenna had a ±5−15 m planimetric precision, a 75% particle localisation rate and operated at a maximum ice depth of 47 m. Additionally, stationary supraglacial and proglacial antennas continuously monitored the passage of tagged particles through consecutive reaches of the channel, constraining the timing of particle transport events. The proglacial antenna system had a 98.1% detection rate and was operational to 0.89 m water depth during testing. Roving and stationary antenna records were combined to create a transport distance model for each particle, which may be used in conjunction with hydraulic data to investigate the kinematics of particle motion. When applied at scale in future studies, this method may be used to reveal the mechanisms and timescales of coarse sediment export from Alpine glaciers.