Luminescence dating of rock surfaces is an emerging and exciting branch of research in geochronology with great application potential. In principle the technique can be used to date hitherto undatable geological and archaeological materials or geomorphological landscape elements. As such, luminescence-based rock surface dating (RSD) is highly complementary to OSL sediment burial and other Quaternary dating techniques.   

RSD basically comes in two variants: rock surface burial dating (RSbD) and rock surface exposure dating (RSeD), both being highly active and promising geochronological research strands undergoing methodological development, refinement and testing. Meanwhile numerous ways of analyzing RSb and RSe luminescence data exist and different approaches to calculate rock surface ages have been introduced, yet no standardized way of handling RSb or RSe luminescence data has been put forward.

Here we present an open-source software package that is based on the software language Python©. The program enables users to evaluate their rock surface luminescence data via a simple graphical user interface (GUI). The program allows processing of data which originate either from CCD or EMCCD images or from the conventional "drilling and slicing" approach and takes various types of OSL, IRSL and IRPL signals into account. We incorporated all currently available and stat-of-the art bleaching models into the software package and provide the user with maximum degree of flexibility for normalizing luminescence signals. In the case of RSeD different calibration procedure options are implemented. Ultimately, the software allows single as well as multiple exposure and burial ages from rock surfaces to be derived.

How to cite: Meyer, M., Freiesleben, T., and Riedle, T.: The Python time machine – an open source software application for luminescence-based rock surface dating, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22933, https://doi.org/10.5194/egusphere-egu26-22933, 2026.

The geomorphic and sedimentological evolution of the dynamic Satluj River basin is understood through a detailed analysis that combines comprehensive morpho-sedimentary mapping, lithofacies analysis, and optically stimulated luminescence (OSL) dating to evaluate the impact of base-level fluctuations. Although the valley is far from the current coastline, evidences of minor changes in base level caused by climate and sea level processes reach deep into the hinterland is clearly seen in such a dynamic mountain catchment of the Himalaya. These changes majorly control river dynamics, sediment transport, and overall landscape evolution. Frequent landslides, temporary channel damming, lake formation, and large fluvio-lacustrine sedimentary successions direct periods of enhanced sediment input and aggradation. Morphotectonic indices and the presence of seismites in these deposits suggest significant tectonic influence on base-level-driven geomorphic responses.

Optical chronology identifies two major aggradation phases: one from about 30 to 24 ka and another from about 17 to 11 ka. During these phases, more sediment was deposited, less material was transported, and the local base level temporarily rose owing to valley damming. In these periods, the landscape was unstable, resulting in numerous mass-wasting events, the creation of dammed palaeolakes, and the preservation of extensive sedimentary records. Subsequent incision stages form strath terraces, vertically incised gorges, offset channels, and modifications in the shape of Quaternary sediments. This indicates that the base level declined again and tectonic activity resumed.

The observed relationship between aggradation-incision cycles, dammed lakes, and tectonically influenced base-level fluctuations demonstrates how climate-driven base-level modifications can be greatly amplified in dynamic mountain belts. The findings suggest that base-level signals connected to sea-level fluctuations may have an indirect impact on sedimentation and geomorphology over significant distances upstream through complex sediment-routing systems. This study adds new constraints on late Quaternary catchment-scale geomorphic adjustment and improves understanding of how sea-level-induced base-level changes interact with tectonics, landslides, and fluvial processes to shape the Himalayan landscape.

How to cite: Shahrukh, M. and Kumar, A.: Propagation of Base-Level Signals into an Active Himalayan Catchment: Morpho-Sedimentary and OSL Evidence from the Satluj River Valley, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-730, https://doi.org/10.5194/egusphere-egu26-730, 2026.

The deglaciation history of the European Alps is thought to be well established, however, the timing of glacier retreat in the eastern Alps remains poorly constrained. Here, we present the first ¹⁰Be exposure ages from the Klagenfurt Basin (Carinthia, Austria), which was covered by the piedmont lobe of the Drau glacier during the Last Glacial Maximum (LGM). The ¹⁰Be ages were obtained from glacially polished quartz veins between ~530 and ~800 m a.s.l. and range from 17.4±0.6 to 13.5±0.7 ka (mean age: 15.9±1.0 ka). The age data indicate that deglaciation of the Klagenfurt Basin occurred near the end of the Oldest Dryas stadial and are consistent with published ¹⁰Be ages from the flat tops of the ~2000-m-high Nock Mountains farther north (mean age: 15.0±1.2 ka) (Wölfler et al., 2022). Both data sets refute a widely accepted scenario, in which the southeastern Alps were already ice-free by ~19-18 ka (e.g., van Husen, 1997; Reitner, 2007; Ivy-Ochs et al., 2023). Our reassessment of the underlying age constraints for this still prevailing view shows that the respective ¹⁴C ages were obtained from bulk-sediment samples in two postglacial lakes (Lake Längsee: Schmidt et al., 1998, 2002; Lake Jeserzer See: Schmidt et al, 2012). ¹⁴C ages from bulk lake-sediment samples are, however, known to overestimate the true sedimentation age due to a reservoir effect (e.g., Ilyaschuk et al., 2009; Hou et al., 2012). At Lake Längsee, the overestimation of the true sedimentation ages by the ¹⁴C ages is confirmed by a layer of Neapolitan Yellow Tuff, whose age was independently determined by ⁴⁰Ar/³⁹Ar dating at its origin (Deino et al., 2004). Later deglaciation than previously assumed is further supported by two published ¹⁰Be age data sets from the Hohe Tauern mountains, which indicate LGM ice-surface lowering between ~18.6 and ~14.8 ka (Wirsig et al., 2016) and rock-glacier stabilization at ~16-14 ka (Steinemann et al., 2020), respectively. Our interpretations agree with palaeo-precipitation records derived from cave carbonates, which indicate enhanced autumn and winter precipitation during the LGM and until ~17 ka (Spötl et al., 2021; Warken et al., 2024). The combined evidence presented in our study shows that deglaciation of the southeastern Alps occurred at ~16-15 ka and hence later than previously thought.

References

Deino et al., 2004, J. Volcanol. Geotherm. Res., 133, 157–170, doi.org/10.1016/S0377-0273(03)00396-2.

Hou et al., 2012, Quat. Sci. Rev., 48, 67–79, doi.org/10.1016/j.quascirev.2012.06.008.

Ilyaschuk et al., 2009, Quat. Sci. Rev., 28, 1340–1353, doi.org/10.1016/j.quascirev.2009.01.007.

Ivy-Ochs et al., 2023, In: European Glacial Landscapes—The Last Deglaciation, 175–183, doi.org/10.1016/B978-0-323-91899-2.00005-X.

Reitner, 2007, Quat. Int. 164/165, 64–84, doi.org/10.1016/j.quaint.2006.12.016.

Schmidt et al., 1998, Aquat. Sci. 60, 56-88.

Schmidt et al., 2002, Quat. Int., 88, 45–56.

Schmidt et al., 2012, J. Quat. Sci. 27, 40–50. doi.org/10.1002/jqs.1505.

Spötl et al., 2021, Nature Commun. 12, 1839, doi.org/10.1038/s41467-021-22090-7.

Steinemann et al., 2020, Quat. Sci. Rev. 241, 106424, doi.org/10.1016/j.quascirev.2020.106424.

Warken et al., 2024, Comm. Earth Environ. 5, 694, doi.org/10.1038/s43247-024-01876-9.

Wirsig et al., 2016, Quat. Sci. Rev. 143, 37–50, doi.org/10.1016/j.quascirev.2016.05.001.

Wölfler et al., 2022, J. Quat. Sci., 37, 677–687, doi.org/10.1002/jqs.3399.

How to cite: Hampel, A. and Hetzel, R.: Deglaciation of the Klagenfurt Basin (Austria): constraints from 10Be exposure dating and implications for the glacial history of the southeastern Alps, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1613, https://doi.org/10.5194/egusphere-egu26-1613, 2026.

The uplift of the Rhenish Massif is recorded by strath terraces along major rivers, however, absolute age control for the terraces is still scarce, and terrace correlations with Quaternary climate cycles are uncertain and partly contradictory. Along the Rhine, two terrace levels – the Older and Younger Main Terrace (OMT and YMT) – occur above a marked break-in-slope, which separates a steep lower valley from a broad upper valley with gentle slopes. Based on limited paleomagnetic data, an age of 730–800 ka for the YMT was often assumed and used to estimate rock uplift (e.g., Meyer & Stets, 1998). Here, we present the first ¹⁰Be – ²⁶Al isochron-burial ages for the OMT and YMT at two sites: Kasbach-Ohlenberg and Bad Hönningen. At Kasbach-Ohlenberg, the OMT yields a burial age of 1.4–1.6 Ma, while the YMT is dated to 0.7–0.8 Ma. These ages and the small vertical distance of only a few meters between both terraces indicate a prolonged period with little river incision, followed by a phase of more rapid incision and rock uplift. The elevation of the bedrock strath of the YMT above the Rhine (i.e., ~160 m) implies an average uplift rate of ~200 m/Ma during this phase. At Bad Hönningen, the OMT yields a burial age of 1.1-1.4 Ma. This younger age and the higher elevation of the OMT at this site suggest that rock uplift increases toward the internal part of the Rhenish Massif. The temporal coincidence between the onset of uplift and plume-related intraplate volcanism in the Eifel at ~700 ka (e.g., Lippolt et al., 1983) suggests a mantle-driven origin for the uplift. Our ongoing work will result in additional age–elevation data for terrace sites along the Rhine, thus enabling a more detailed reconstruction of the timing, rate, and spatial variability of uplift in the Rhenish Massif.

References
Lippolt, H.J., 1983. Distribution of volcanic activity in space and time. In: Fuchs, K., von Gehlen, K., Mälzer, H., Murawski, H., Semmel, A. (Eds.), Plateau Uplift. Springer, Berlin, pp. 112–120.
Meyer, W., Stets, J., 1998. Junge Tektonik im Rheinischen Schiefergebirge und ihre Quantifizierung. Z. dt. geol. Ges. 149, 359–379. https://doi.org/10.1127/zdgg/149/1998/359.

How to cite: Terraza, M., Wolff, R., Hetzel, R., Ritter, B., Binnie, S., Preuss, J., Hoselmann, C., Weidenfeller, M., and Heinze, S.: Accelerated uplift of the Rhenish Massif (central Europe) since 700–800 ka revealed by isochron-burial dating of strath terraces, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1787, https://doi.org/10.5194/egusphere-egu26-1787, 2026.

In areas of multiple exposure-burial histories the use of two cosmogenic radionuclides (CRN) with different half-lives allows to reveal the disequilibrium between CRN concentrations and provide a better understanding of landscape evolution. This study aims to quantify bedrock denudation rates in the Western Mecsek Mts (southern Pannonian Basin), a low-elevation hilly area that is currently being exhumed from under its loess cover deposited during the Quaternary glaciations. Concentrations of ¹⁰Be and ²⁶Al were measured in samples taken from flat, soil-covered ridge tops and stream sediments from several small river catchments composed of Permian and Triassic sandstones and conglomerates. Low ²⁶Al/¹⁰Be ratios are indicative of unsteadiness caused by significant past burial of the bedrock surfaces. A Monte Carlo (MC) model was developed to reveal the temporal evolution of the loess cover as a function of glacial-interglacial climate, and to determine the true rate of bedrock denudation accounting for both loess-covered periods with shielding and zero erosion as well as phases of exposure and bedrock denudation during periods without loess.

Our model showed that higher-elevation catchments and ridges were exposed for 40 to 85%, while lower-elevation areas were uncovered for less than 30% of time during the last 1 Ma. The modelled time integrated bedrock denudation rates were similar for the ridge crests and basin-averaged samples suggesting a steady relief. However, a well-expressed difference was found between the areas spending most of the time loess covered and the less covered group with mean integrated denudation rates of 5±5 m/Ma and 19±8 m/Ma, respectively. Single nuclide ¹⁰Be denudation rates overestimated the modelled, time-integrated denudation rates by a factor of ~1.5 for the more exposed group and by a factor of ~13 (up to >30) for the mostly covered areas. These rates, especially the latter, are slower than published values for similar climatic, tectonic, and topographic settings. If the simple, single nuclide ¹⁰Be approach was used, these differences would have remained hidden, and the true lowering rate of bedrock would have been overestimated by a factor that increases with the shielding time.

This is the first study quantifying the influence of past loess covers on CRN concentrations in bedrock and to estimate the denudation rates corrected for this shielding. Our findings reveal that the steady-state assumption of the CRN concentrations may also be violated in small, non-glaciated catchments without intermittent sediment storage. Where single-nuclide ¹⁰Be denudation rates are higher than sediment-trap estimates, the shielding effect of past sediment cover (such as loess) could also explain the discrepancy. Accordingly, we recommend the use of the paired ²⁶Al/¹⁰Be approach to test the presumption of cosmogenic nuclide equilibrium not only in large catchments and formerly glaciated areas, but also in settings where past sediment cover may have lasted long enough to lower the CRN ratio.

Funding: PURAM, Mecsekérc Ltd., NKFIH project FK 124807. Sample processing: Cosmogenic Laboratories of Budapest (n=16) and of the University of Edinburgh (n=4); AMS measurements: ASTER, Aix en Provence (n=16) and SUERC, Glasgow (n=4)

How to cite: Ruszkiczay-Rüdiger, Z., Knudsen, M. F., Bauer, M., Telbisz, T., Team, A., and Sebe, K.: Quantification of Quaternary loess cover and integrated denudation rates using cosmogenic nuclide Aluminium-26 and Beryllium-10 disequilibrium (Mecsek Mountains, Pannonian Basin), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2959, https://doi.org/10.5194/egusphere-egu26-2959, 2026.

Over the past decade, several research groups have developed and applied methods for using Infra-Red Stimulated Luminescence (IRSL) from sand-sized grains of alkali feldspar collected from the active channels of different rivers. These methods used either conventional multiple grain IRSL measurements, or single grain IRSL determinations, but all depend on comparisons of results from different sampling locations to reconstruct virtual velocity. In its simplest form, this approach relies on the Ergodic principle as the basis for time-space equivalence of different samples. While this can often represent a successful approach, recent anthropogenic disturbances to fluvial systems may in some cases render this method problematic. For example, where channel engineering or dam construction cuts off or modifies the natural sediment supply, samples collected downstream of these locations may provide signals that are inconsistent with those from upstream.

For this reason, our research team has been developing IRSL approaches to attempt to reconstruct sediment storage times and virtual velocity by inverting measured Multiple Elevated Temperature (MET) IRSL signals from single grains of alkali feldspar. Some grains preserve a record that is shaped by multiple episodes of storage during burial and light exposure during transport; storage causes trapped charge populations responsible for IRSL signals to grow in a predictable manner, while light exposure causes a reduction in each population. Multiple IRSL signals measured at a range of temperatures in the laboratory display different sensitivity to light, resulting in different degrees of “bleaching” (reduction in trapped charge). When a grain is subject to multiple episodes of burial and bleaching, the different IRSL signals move away from being in an equilibrium ratio with each other, allowing us to constrain their past burial and bleaching histories, within some limits. In this presentation, we shall compare results from this novel single grain MET-IRSL inversion approach with conventional IRSL sediment transport approaches, and assess performance from grains subject to laboratory simulations of different burial-bleach cycles. The new technique has great potential to help understand contemporary and past fluvial dynamics and sediment storage, as well as determination of sediment sources and channel erosional processes, and can contribute significantly to applications such as catchment carbon dynamics, or assessing impacts of engineering structures.

How to cite: Rhodes, E. and Spano, T.: Reconstructing virtual velocity and fluvial dynamics using MET-IRSL from single grains of sand, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4552, https://doi.org/10.5194/egusphere-egu26-4552, 2026.

Luminescence ages are powerful agents for tracing past sediment dynamics and deciphering complexities inherent in the evolution of past landscapes. If applied in temporal periods suitable for luminescence-based methods, they provide accurate dating results but with somewhat limited spatial resolution. This is primarily due to the time-consuming nature of luminescence sample preparation and measurement procedures. Luminescence screening methods, for instance, using portable equipment [1] that focuses only on light intensities rather than absorbed dose/dose-rate ratios, provide a convenient shortcut. Assuming a suitable geologically homogeneous environment, they provide initial insights and relative chronologies and can be useful in developing an appropriate sampling strategy for a more detailed study.

However, the hope of delivering, even provisionally, instant chronologies could not yet be satisfied. While our approach similarly cannot offer instant chronologies, we propose here a gradient-boosted decision tree approach [2] to model the complex interactions among physical parameters (e.g., dose rate, water content, sedimentology) and convert luminescence intensity values into the age domain. Our approach uses age-depth relationships of ages and intensities from different profiles, combined with additional features such as geographical information (latitude, longitude, depth below ground surface). We demonstrate that we can satisfactorily and robustly predict pseudo-luminescence ages from signal intensities using only a small training dataset (n = 31). This enables us to considerably enhance the age resolution of luminescence dating chronologies in suitable environments, particularly in those where sedimentary deposits are relatively homogenous.

A limitation of our approach is our reliance on a favourable, homogeneous sampling environment (here, sandy deposits of aeolian origin), which cannot be directly transferred to other geologically more complex settings; however, we are confident that the general approach remains valid and can be adapted on regional scales to increase age resolution.

References

[1] Sanderson, D. C. W. and Murphy, S.: Using simple portable OSL measurements and laboratory characterisation to help understand complex and heterogeneous sediment sequences for luminescence dating, Quaternary Geochronology, 5, 299–305, https://doi.org/10.1016/j.quageo.2009.02.001, 2010.

[2] Chen, T. and Guestrin, C.: XGBoost: A Scalable Tree Boosting System, in: Proceedings of the 22nd ACM SIGKDD International Conference on Knowledge Discovery and Data Mining, New York, NY, USA, 785–794, https://doi.org/10.1145/2939672.2939785, 2016.

How to cite: Kreutzer, S., Heydari, M., Hanson, P. R., Kadereit, A., Mahan, S. A., and Schmidt, C.: A gradient boosted decision tree approach for high-resolution luminescence chronologies, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5323, https://doi.org/10.5194/egusphere-egu26-5323, 2026.

The Thermochronology @ Purdue (T@P) noble gas mass spectrometry facility was established at Purdue University between 2020 and 2023. In this presentation, we will detail the T@P laboratory’s instrument configuration and demonstrate the facility’s capabilities for both helium-based thermochronometry and cosmogenic noble gas geochemistry. The primary instrument in the T@P laboratory is an Isotopx NGX, a multi-collector sector field mass spectrometer with a Nier-type source, which has a custom detector configuration consisting of three discrete dynode electron multipliers, including one fitted with an electrostatic filter, and two Faraday cups with ATONA® amplifiers. The NGX is connected to a custom-built, fully automated, ultra-high vacuum extraction line that includes an activated charcoal cryogenic trap and two getters for gas purification, two manometrically-calibrated gas standards for sensitivity calibration (air and ³He-enriched helium), and a manometrically-calibrated ³He spike for measurements of radiogenic ⁴He by isotope dilution. Gases are extracted by heating samples under vacuum using a diode laser system in a feedback control loop with either a calibrated optical pyrometer (better than ± 10 ºC precision), or a bare, thin-wire thermocouple in contact with the sample (better than ± 3 ºC precision). We will present isotopic analyses made in the T@P laboratory of reference materials for both helium-based thermochronometry (Durango apatite) and cosmogenic noble gas geochemistry (CRONUS-P, CRONUS-A, CREU-1) as well as from example applications in Earth and planetary surface processes.

How to cite: Tremblay, M. M., Guo, H., Dziekonski, E. T., Ickert, R. B., and Blair, D.: Helium-based thermochronometry and cosmogenic noble gas geochemistry in the Thermochronology @ Purdue (T@P) noble gas mass spectrometry facility, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5827, https://doi.org/10.5194/egusphere-egu26-5827, 2026.

Sufficient temperature rise during frictional heating is a key parameter controlling whether luminescence dating of fault gouges can determine the timing of past earthquakes. Regardless, the true temperatures induced in the rock during a co-seismic slip event are often unknown. This significantly hampers the accuracy of luminescence age results from fault gouges. Laboratory-controlled friction experiments can adequately simulate different friction scenarios by modulating normal stress and slip velocity and then recording induced temperatures using thermocouples [1] or an infrared camera [2]. However, monitoring those events in nature is highly impractical for past events.

Systematic luminescence studies on ultraviolet (UV) radiofluorescence (RF) of quartz reported a strong correlation between heating and subsequently recorded UV-RF signaldynamics [3,4].

Here, we explore the potential of UV-RF to shed light on the extent of friction-induced temperature in quartz-bearing host rocks. In our experiments, we tested one sediment quartz sample with a known luminescence characteristic and a polymineral sample from the North Tehran Fault. For one part of each sample, we first recorded a UV-RF temperature profile after heating subsamples in batches from 30 ºC to 575 ºC in increments of 25 ºC. The other (untreated) part was then subjected to frictional heating in the laboratory under a normal stress of 12 MPa and a slip velocity of 5 cm/s using a rotary shear apparatus. During the experiment, the frictional heat was recorded using an infrared camera. We then measured the UV-RF signal and projected the results onto the signal-preheat profile to estimate the (unknown) frictional heat temperature.

Although our study is preliminary at this stage, we could calculate realistic friction-induced temperatures for the quartz sample. In contrast, the UV-RF signals of the polymineral sample will require additional experiments. We will present the experimental design and initial results, and discuss the challenges and the potential of our approach for tracking the temperature levels generated by earthquakes.

References

[1] Kim, J.H., Ree, J.-H., Choi, J.-H., Chauhan, N., Hirose, T., Kitamura, M., 2019. Experimental investigations on dating the last earthquake event using OSL signals of quartz from fault gouges. Tectonophysics 769, 228191. https://doi.org/10.1016/j.tecto.2019.228191

[2] Heydari, M., Kreutzer. S., Hung, C.C., Martin, L., Ghassemi, M.R., Tsukamoto, S., Niemeijer, A., under review, Scientific Reports. Unveiling Earthquakes: Thermoluminescence Signal Resetting of a Natural Polymineral Sample in Laboratory-Produced Fault Gouge

[3] Friedrich, J., Pagonis, V., Chen, R., Kreutzer, S., and Schmidt, C.: Quartz radiofluorescence: a modelling approach, Journal of Luminescence, 186, 318–325, https://doi.org/10.1016/j.jlumin.2017.02.039, 2017a.

[4] Friedrich, J., Fasoli, M., Kreutzer, S., and Schmidt, C.: The basic principles of quartz radiofluorescence dynamics in the UV - analytical, numerical and experimental results, Journal of Luminescence, 192, 940–948, https://doi.org/10.1016/j.jlumin.2017.08.012, 2017b.

How to cite: Heydari, M., Niemeijer, A., and Kreutzer, S.:  Radiofluorescence as a tool to estimate the degree of friction-induced heat caused by co-seismic slip , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5853, https://doi.org/10.5194/egusphere-egu26-5853, 2026.

During the Quaternary period the Fennoscandian ice sheet reached far into Europe on several occasions. Especially the last two ice sheet expansions, the Saalian and Weichselian, left many marks on the Danish land surface and shaped the landscape, leaving behind outwash plains, terminal moraines, tunnel valleys, and other glacial landforms. Although, there is general consensus regarding which ice advances resulted in which landscape features, most correlations have not yet been verified by absolute dating. To improve constraints on the ice cover history of the Danish area, we have carried out ¹⁰Be profiling on several outwash plains across Denmark. These outwash plains have been chosen (i) to constrain the timing of the overall ice margin retreat across Denmark, and (ii) to decipher whether the northern part of the prominent 90-degree landform (the “Main Stationary line”) belongs to the Last Glacial Maximum advance (~20.000 years ago) or a previous ice advance, such as the Kattegat advance (~30.000 years ago). Denmark is located right at the foothills of the Fennoscandian ice sheet, and we expect our results to have strong implications on the understanding of ice sheet dynamics at play during advance-retreat cycles of continental sized ice sheets, as well as to improve the understanding of the glacial history of Northern Europe. At EGU some of the preliminary results from this investigation will be presented.

¹⁰Be profiling is a technique which involves sampling sediment from several depths below the surface at a specific location. Interpretation of the ¹⁰Be concentrations can lead to age estimation of the sampled deposit, since the concentrations will depend on the cosmogenic exposure history of the sediment package. A set of samples from different depths are needed to separate the pre- and post-burial ¹⁰Be nuclide concentrations or to draw attention to ¹⁰Be irregularities throughout the profile indicating asynchronous deposition. The numerical modelling of nuclide concentrations carried out in this study serves as proof of concept and highlights the applicability of the ¹⁰Be profiling approach. Hence, alongside the preliminary results of the study, our novel MATLAB implementations for interpreting ¹⁰Be profiles will also be showcased.

How to cite: Allaart, L., Nørgaard, J., Knudsen, M. F., Andersen, L. T., Nielsen, J. B., and Larsen, N. K.: Dating DK: Cosmogenic 10Be depth profiling of glacial outwash plains in Denmark, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9469, https://doi.org/10.5194/egusphere-egu26-9469, 2026.

Basin-averaged erosion rates derived from cosmogenic nuclide concentrations are one of the most commonly used data for the study of landscape evolution histories across a wide range of tectonic and climatic regimes. Despite recent advances in global nuclide datasets and analytical techniques, methods for converting measured concentrations into denudation rates have progressed little.

Converting cosmogenic nuclide concentrations to denudation rates requires several key assumptions; however, one in particular is more difficult to assess, which is that denudation rates remain spatially and temporally constant over timescales comparable to the nuclide integration period. These assumptions rarely hold in nature, especially in mountain catchments with pronounced knickpoints propagating upstream, complicating the interpretation of a single mean concentration. Previous studies have often only evaluated how mean concentrations are affected when one or more assumptions are violated. However, minerals sampled from complex landscapes likely represent distinctly non-Gaussian populations that cannot be adequately characterized by a single mean value.

We present modelling results of cosmogenic nuclide concentration distributions in catchments experiencing spatially and temporally variable denudation rates under different tectonic and climatic forcings. Analysing concentration distributions rather than mean values alone reveals how assumption violations affect inferred denudation rates. Our model employs a detachment-limited stream power law and calculates nuclide accumulation from multiple production pathways using the Lifton-Sato-Dunai scaling scheme.

Preliminary results indicate that the presence of knickpoints does not significantly compromise the interpretation of cosmogenic nuclide concentrations except in cases with fast knickpoint retreat rates in high-relief catchments. However, we find that even moderate climatic changes (simulated by varying the erodibility constant), can yield significant errors in inferred versus real denudation rates. We propose that simple evaluations of cosmogenic nuclide distributions can enhance the reliability of denudation rate estimates in future applications.

How to cite: Grimm, L., Adams, B. A., and Fox, M.: Understanding key assumptions in cosmogenic nuclide-derived catchment-average denudation rates, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12912, https://doi.org/10.5194/egusphere-egu26-12912, 2026.

Rock glaciers are common permafrost features in mountain landscapes around the globe with a geohazard relevance sourcing large amounts of debris while also acting as aquifers storing large amounts of water, yet their long-term (i.e. centennial to millennial scale) dynamics remain poorly constrained due to limited dating efforts. Short term observations, via GPS, InSAR, UAVSAR, Lidar or feature tracking, show acceleration of flow rates of rock glaciers in all mountain regions.

We use rock glacier RG-2 in the Uinta Mountains (Utah, USA, 3 300 m asl) as a natural laboratory to test and cross-calibrate a novel luminescence-based surface dating technique: optically stimulated luminescence rock surface exposure dating (OSL RSeD). This method exploits the latent OSL or IRSL signals stored in quartz and feldspar bearing rocks and the fact that, in the upper centimeters of rock surfaces, these signals are reset (zeroed) by daylight exposure. By integrating previously CRN-dated quartzite boulders (n = 9) on RG-2 into our analysis, we (i) assess the sensitivity of parameters in the OSL bleaching-with-depth model, (ii) evaluate the model’s underlying assumptions, and (iii) interpret the resulting OSL ages.

Furthermore, we present a standardized, statistically robust workflow to normalize luminescence-depth profiles to saturation based on sequential analysis, suitable for datasets obtained by the 1D-coring-and-slicing- as well as the 2D-EMCCD-approach for various geological and archaeological dating applications.

How to cite: Sperlich, D., Munroe, J., Ramisch, A., and Meyer, M. C.: Cross-Calibration and Sensitivity Analysis of OSL Rock Surface Exposure Dating Using Cosmogenic Nuclide Ages on an Uinta Mountains Rock Glacier (Utah, USA), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14245, https://doi.org/10.5194/egusphere-egu26-14245, 2026.

Over the past few centuries, the natural flow of river water and sediment has been significantly disrupted by human activities, including land‐use change, dam and reservoir construction, and variable precipitation. Sediment accumulation in reservoirs leads to declining storage capacity, reduced water quality, and navigational challenges. While hydraulic models can characterize these issues over annual to decadal timescales, they are less effective for predicting sedimentation trajectories over decades to centuries. At these longer timescales, feedbacks between reservoir sedimentation and upstream erosion and deposition influence delta growth and sediment delivery, complicating the development of long-term sediment management strategies. To address this gap, we developed a workflow for building and calibrating open source, coupled landscape evolution models (LEMs) and delta sedimentation models (DSMs) for real-world watersheds. Here, we present preliminary results from the Chattahoochee River in the southeastern United States. The river is segmented by six major dams, each creating a reservoir and corresponding sub-catchment. We constructed a set of six LEMs using Landlab (one for each sub-catchment) and run them sequentially from upstream to downstream, using the sediment outflux from each model as input for the next. The LEMs are calibrated using cosmogenic ¹⁰Be mean catchment erosion rates, modern land-use data, and sediment trapping calculations. We then evaluated how well each model reproduced watershed sediment fluxes inferred from late 21st century suspended-sediment measurements. The DSMs are constructed using PyDeltaRCM and are driven by output sediment flux and provenance data from the LEMs. Using the pre-reservoir topography as a boundary condition, we validate the models by replicating the post-reservoir delta growth. We then use variable land use and hydraulic forcings in the LEMs to assess different future sedimentation patterns in the deltas. Our workflow can be easily applied to any reservoir with bathymetric data and can help stakeholders understand how upstream human impacts may influence a range of possible sedimentation patterns over the coming decades.

How to cite: Sheehan, C., Behn, M., Snyder, N., Cortese, L., and Dahl, T.: From Free-Flowing to Fragmented: Using Calibrated Models to Assess Impacts of Multiple Dams on Watershed Evolution, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14441, https://doi.org/10.5194/egusphere-egu26-14441, 2026.

Located at an active arc-continent collision zone subject to a tropical climate, the Taiwan mountain belt is characterized by intense tectonic activity, resulting in rapid landscape evolution. In the Western Foothills of southwestern Taiwan, geodetic data reveal rapid surface deformation during periods of low seismicity, where the upper crust is dominated by mudstone lithology. However, mapped active structures do not fully explain the observed sharp deformation gradients and uplift patterns. This discrepancy motivates an evaluation of how strain is accommodated across different timescales and whether the present-day deformation reflects persistent long-term kinematics or transient processes.

Using the ratio of meteoric ¹⁰Be to mineral-weathered ⁹Be measured from five river-sediment samples collected from watersheds with distinct short-term uplift rates, spatial variations in basin-scale denudation rates (D_met) and their relationship to short-term uplift are evaluated. Although meteoric-¹⁰Be-derived denudation rates are particularly suitable for quartz-poor regions such as southwest Taiwan, the method relies on several assumptions that require validation. To assess its applicability, additional samples were collected from watersheds in the Central Range east of the study area, where in situ ¹⁰Be-derived denudation rates (D_insitu) are available.

In the Western Foothills area, D_met successfully captures large-basin denudation (0.77 ± 0.07 mm/yr) as the integrated signal of sub-basin denudation rates (average of 0.74 ± 0.01 mm/yr). Across two regions, D_met values are systematically lower in the Western Foothills than in the Central Range (5.8 - 7.4 mm/yr, with an outlier of 32 mm/yr), reflecting contrasts in lithology, climate setting, and topographic relief. In the Central Range, D_insituvalues (0.2-4.5 mm/yr) differ from D_met, suggesting that potential grain-size differences between the two methods lead to distinct sediment transport behaviors. Nevertheless, D_met remains informative by reproducing basin–sub-basin integration in the Western Foothills and distinguishing denudation regimes between regions.

Within the Western foothills, D_met correlates weakly with uplift rate, slope, and relief. The normalized channel steepness index (k_sn­) shows an unexpectedly weak to negative relationship with D_met. This pattern suggests that meteoric ¹⁰Be-derived denudation rates might not represent short-term surface deformation rates or are integrated over timescales that differ from those represented by geomorphic indices. This likely reflects transient surface adjustments rather than steady-state conditions. In contrast, D_met seems to positively correlate with the extent of barren-land (badland) surfaces developed in weak mudstone formation, suggesting first-order control on basin-averaged meteoric ¹⁰Be inventories. Although badlands have been proposed to be associated with rapid erosion in this region, the correspondence between their development timescale and the integration timescale of meteoric ¹⁰Be derived denudation remains uncertain.

Future work will expand sampling across additional basins spanning a wider range of badland extent and uplift signatures to test the robustness of these relationships and refine the link between short-term deformation and longer-term surface response. Additional analyses will quantify meteoric ¹⁰Be inventories on barren land and vegetated hillslopes to evaluate differences in meteoric ¹⁰Be retention across contrasting hillslope environments, thereby refining the applicability and sensitivity of the methods to hillslope transport processes.

How to cite: Nguyen, N.-T., Siame, L., Le Béon, M., Léanni, L., Pathier, E., and Team, A.: Landscape Response to Rapid Uplift in Southwestern Taiwan: Insights from Denudation Rates Measurement from Cosmogenic 10Be (Meteoric)/9Be Ratios and Morphometric Indices, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15516, https://doi.org/10.5194/egusphere-egu26-15516, 2026.

High-definition digital elevation models (DEMs) from airborne light detection and ranging (LiDAR) are very powerful tools in detecting unknown tectonic-geomorphic features and quantifying cumulative slip from repeated faulting events. The faulted geomorphic features, however, need to be somehow dated to convert the slip to long-term slip rate, and this task still remains as a challenging part of many tectonic geomorphic and paleoseismic studies. The dating is particularly difficult in mountainous and densely vegetated regions, where we are most benefitted from LiDAR DEMs but most often confront challenges in finding datable organic materials in high-energy gravelly deposits. Here we attempted to date left-laterally faulted fluvial terrace surfaces discovered along the Nobi active fault system (NAFS) in the Etsumi Mountains, central Japan, by using a terrestrial cosmogenic nuclide Be-10. In this region, terrace surfaces are covered with thin aeolian loess deposits of <1 m thick, with generally thinner loess cover on younger and lower surfaces. We employed the depth-profile method to simultaneously determine the age and inherited nuclide concentration, incorporating the effect of loess deposition after terrace abandonment. Exploratory pits for depth profiling were excavated at two sites along the NAFS; the Nukumi-Shiratani site on the low terrace surface along the Nukumi fault and the Nogo site on the middle terrace surface along the Neodani fault. Our results show the terrace abandonment ages that are consistent with the generally accepted terrace-formation and incision history modulated by global climate changes (MIS 2 and MIS 4 for the low and middle terrace surfaces, respectively) and also with crypto tephras identified in the loess deposits. In turn, the long-term left-lateral slip rate for the Nukumi fault was first determined whereas that for the Neodani fault proved to be substantially larger than estimates from previous studies.

How to cite: Kaneda, H., Matsushi, Y., Ogura, Y., Ohta, R., and Matsuzaki, H.: Dating faulted terrace surfaces with thin aeolian loess cover by using terrestrial Be-10 depth profiles: an attempt along the Nobi active fault system, central Japan, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16139, https://doi.org/10.5194/egusphere-egu26-16139, 2026.

The observation that topography trends with snowline altitude despite large differences in tectonic uplift in various locations provides the foundation of the glacial buzz-saw hypothesis. However, despite numerous modelling studies, very few quantitative data are available that document the timing or rate of glacial topography formation. Consequently, challenges remain to explain why some localities (e.g. Alaska, southern Andes) seem to escape the glacial buzz-saw. This data gap is driven by the difficulty in constraining rates of glacial erosion over kyr-Myr timescales.

Here, we use a novel thermochronometry technique, based on the Electron Spin Resonance (ESR) of quartz minerals, to constrain the timing of cirque basin formation adjacent to the Rhône valley, Switzerland. The Fully basin, near the town of Sion, sits above the ~1.5 km deep glacial Rhône valley, and is thought to have been incised by ~400 m during the Quaternary. Samples were collected in a transect across the basin, and complement samples previously investigated using ESR-thermochronometry from the Rhône valley (Wen et al., 2024).

Forward modelling using a modified version of Pecube together with the kinetic parameters of existing ESR samples from the area (Wen et al., 2024) shows that ESR-thermochronometry data should be able to constrain the timing of cirque basin incision. This will provide the first dates and rates of glacial buzz-saw activity and will be contrasted with the timing of Rhône valley incision.

How to cite: King, G., Bernard, M., Wen, X., Cox, S., Dave, A., and Schmidt, C.: Putting rates on the buzz-saw? Constraining the timing and rate of cirque valley incision, Rhône valley, Switzerland., EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16746, https://doi.org/10.5194/egusphere-egu26-16746, 2026.

The southern Central Andes forearc preserves extensive low-relief wave-cut platforms and fluvial terraces that record long-term margin uplift, yet the timing and driving mechanisms are still debated. Here we present eleven new in situ ¹⁰Be exposure ages from high fluvial terraces and four ages from a lower terrace, combined with geomorphic analyses across eight adjacent catchments, to reassess the age and tectonic significance of the degradational surfaces (pediplain) present between 29.5 and 32.5°S. Erosion-corrected exposure ages indicate that the high terrace formed during the Early Pleistocene, while a lower terrace records incision at Middle Pleistocene. Longitudinal terrace–channel profiles reveal systematically increasing relief toward the coast that terminates near the surface projection of the 50–60 km slab-depth contour, coincident with the downdip limit of megathrust domain-C earthquakes. This spatial relationship supports a regionally coherent uplift signal produced by the cumulative effect of deep coseismic deformation. In peninsular settings, notably the Altos de Talinay, this long-wavelength signal is overprinted by short-wavelength uplift consistent with localized underplating. Our results demonstrate that the high fluvial terraces and the shore wave-cut platform constitute a single, regionally continuous geomorphic marker recording an Early Pleistocene forearc uplift phase extending from ~16° to 42°S. This orogen-scale emergence implies a subtle but widespread change in subduction dynamics during the last Early Pleistocene, the causes of which are not clearly understood.

How to cite: Gianni, C. R., Ballato, P., Schildgen, T., Gianni, G., Wittmann, H., Melnick, D., and Faccenna, C.: Geomorphic imprint of an Early Pleistocene uplift phase of the Andean forearc and its underlying mechanisms, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22489, https://doi.org/10.5194/egusphere-egu26-22489, 2026.