CL5.3 | Geochronological tools for environmental reconstructions
Geochronological tools for environmental reconstructions
Co-organized by BG2/GM2
Convener: Irka Hajdas | Co-conveners: Gina E. Moseley, Arne Ramisch, Andreas Lang
Posters on site
| Attendance Wed, 17 Apr, 16:15–18:00 (CEST) | Display Wed, 17 Apr, 14:00–18:00
Hall X5
Wed, 16:15
The Quaternary Period (last 2.6 million years) is characterized by frequent and abrupt climate swings that were accompanied by rapid environmental change. Studying these changes requires accurate and precise dating methods that can be effectively applied to environmental archives. A range of different methods or a combination of various dating techniques can be used, depending on the archive, time range, and research question. Varve counting and dendrochronology allow for the construction of high-resolution chronologies, whereas radiometric methods (radiocarbon, cosmogenic in-situ, U-Th) and luminescence dating provide independent anchors for chronologies that span over longer timescales. We particularly welcome contributions that aim to (1) reduce, quantify and express dating uncertainties in any dating method, including high-resolution radiocarbon approaches; (2) use established geochronological methods to answer new questions; (3) use new methods to address longstanding issues, or; (4) combine different chronometric techniques for improved results, including the analysis of chronological datasets with novel methods, e.g. Bayesian age-depth modeling. Applications may aim to understand long-term landscape evolution, quantify rates of geomorphological processes, or provide chronologies for records of climate change and anthropogenic effects on Earth's system.

Posters on site: Wed, 17 Apr, 16:15–18:00 | Hall X5

Display time: Wed, 17 Apr 14:00–Wed, 17 Apr 18:00
Precise dating of the 8.2 kyr event provides evidence for global climate response
Florian Adolphi, Michael Sigl, and Jürg Beer
Xuefeng Wang, Lisheng Wang, Zhibang Ma, Wuhui Duan, and Jule Xiao

Gypsum is a common evaporate mineral in a wide variety of geological settings, especially in arid and semi-arid areas. It often precipitated from the natural brine systems with trace amounts of U and almost no Th, rendering it a potentially valuable U-Th geochronometer. However, U-Th dating of gypsum is often challenging, such as how to quickly and completely digest gypsum into solution, and avoid the re-crystallization of gypsum particles during the digestion and chromatography process. Here we present a rapid and practical method for high-precision U-Th dating of gypsum using the (NH4)2CO3 exchange reaction and double-spike method by MC-ICPMS. Our developed protocol addresses these conventional challenges by using the chemical reaction between calcium sulfate and carbonate, resulting in the (NH4)2SO4 solution and CaCO3 precipitate. Then the CaCO3 could be easily digested by diluted acid. With the solid-liquid separation, Ca2+ and SO42- ions are also effectively separated, minimizing the recrystallization of gypsum. The (NH4)2CO3 median, the gypsum/carbonate molar ratio of 1: 4, and the exchange reaction duration of 1.5 ~ 2 hours are suggested in this protocol. Since there is no gypsum U-Th dating reference materials to validate the accuracy of different approaches and ensure methods are repeatable across laboratories. We also prepared and characterized two natural gypsum U-Th dating reference materials (PXCG-1, PXCG-2) from PiXiao Cave, southwest China. Data from three different laboratories exhibit good agreement with both 238U content, δ234U, 230Th/238U activity ratio, and the 230Th ages. The 230Th ages of PXCG-1, PXCG-2 RMs proposed are 66.97 ± 0.31 ka, 260.82 ± 3.39 ka, respectively.

How to cite: Wang, X., Wang, L., Ma, Z., Duan, W., and Xiao, J.: U-Th dating of gypsum: methodology and reference materials, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6080,, 2024.

Irka Hajdas, Carley Crann, Kristine DeLong, Barbara Fiałkiewicz-Kozieł, Juliana Ivar Do Sul, Jerome Kaiser, Francine M.G. McCarthy, Simon Turner, Allison Stenger, Colin Waters, and Jens Zinke

The unprecedented environmental changes resulting from anthropogenic activities initiated during the Great Acceleration of the mid-20th century can be traced using radiocarbon analysis. The cosmogenic isotope 14C, which is produced in the atmosphere, is well-known as the geochronological tool applied to archives of the last 55 thousand years. However, during the last 200 years, the natural signal of 14C in the atmosphere and connected reservoirs (biosphere, ocean, soils, etc.,) has been perturbed by human activities. Two anthropogenic effects are observed: a decreasing trend observed in 14C concentration of the atmosphere (Suess effect) which has been temporarily reversed by aboveground thermonuclear tests of the 1950/60s.

The excess of the artificially produced 14C (bomb pulse) is a useful time marker for the mid-20th century and the detection of the bomb peak in natural archives has thus been proposed as a tool to locate and date the onset of a proposed new epoch, the Anthropocene [1].

Here we present the results of radiocarbon analysis conducted as a part of the research dedicated to establishing the Global boundary Stratotype Section and Point (GSSP) for the proposed Anthropocene series. The studied sites include corals (Flinders Reef, AU and Flower Garden Banks, USA)[2, 3], peat (Śnieżka peatland, PL)[4], lake sediment (Crawford Lake, CA and Searsville Lake, USA)[5, 6] and marine sediment (East Gotland Basin, Baltic Sea)[7]. The variety of records (different carbon reservoirs) required site and sample-specific treatment prior to analysis and site-specific interpretation of the measured 14C. Nevertheless, the mid-20th century bomb peak was detected at all but one of these sites (Searsville Lake)[6]. In all records, the observed onset of the 14C bomb peak always postdates 1954, the year of the first atmospheric 14C bomb increase. The specific reservoir effects and corrections will be discussed.


The Anthropocene Review, 2023. 10(1):

1.    Waters, C.N., et al. (Eds.), Candidate sites and other reference sections for the Global boundary Stratotype Section and Point of the Anthropocene series.  p. 3-24.

2.    Zinke, J., et al., North Flinders Reef (Coral Sea, Australia) Porites sp. corals as a candidate Global boundary Stratotype Section and Point  for the Anthropocene series.  p. 201-224.

3.    DeLong, K.L., et al., The Flower Garden Banks Siderastrea siderea coral as a candidate Global boundary Stratotype Section and Point  for the Anthropocene series. p. 225-250.

4.    Fiałkiewicz-Kozieł, B., et al., The Śnieżka peatland as a candidate for the Global boundary Stratotype Section and Point  for the Anthropocene series.  p. 288-315.

5.    McCarthy, F.M.G., et al., The varved succession of Crawford Lake, Milton, Ontario, Canada as a candidate Global boundary Stratotype Section and Point for the Anthropocene series.  p. 146-176.

6.    Stegner, M.A., et al., The Searsville Lake Site (California, USA) as a candidate Global boundary Stratotype Section and Point for the Anthropocene Series. p. 116-145.

7.    Kaiser, J., et al., The East Gotland Basin (Baltic Sea) as a candidate Global boundary Stratotype Section and Point for the Anthropocene series. p. 25-48.

How to cite: Hajdas, I., Crann, C., DeLong, K., Fiałkiewicz-Kozieł, B., Ivar Do Sul, J., Kaiser, J., McCarthy, F. M. G., Turner, S., Stenger, A., Waters, C., and Zinke, J.: 14C bomb peak and the onset of the Anthropocene, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10443,, 2024.

Altug Hasözbek, Fernando Jiménez-Barredo, Arash Sharifi, Ali Pourmand, Regina Mertz-Kraus, Michael Weber, Denis Scholz, Stein-Erik Lauritzen, Josep M. Parés, and Silviu Constantin

Recent advancements in MC-ICPMS technology have significantly enhanced the application of U/Th geochronometry in both biogenic and chemically precipitated carbonate rocks of almost middle Pleistocene to upper Holocene. This burgeoning use, particularly in the study of late Pleistocene earth surface processes, underscores the need for standardized reference materials with a broad age spectrum with different uranium and thorium concentrations. Addressing this need, our study evaluates speleothem specimens, Gol-e-Zard Cave Standard (GZS) and Bergen Speleothem Standard (BSS), as potential reference materials.

BSS-2 was processed as a homogenized powder and dissolved aliquot for U-Th dating using MC-ICP-MS analysis. We employed various digestion and ion-resin chromatography separation methods, followed by U-Th dating using MC-ICP-MS at CENIEH, University of Miami, and University of Mainz. The ion chromatography protocols yielded recovery rates ranging from 85% to over 95%. U-series analyses of powdered BSS-2 indicated uncertainties between 0.2-1.5%, attributed to variations in the Beta-factor and the specific U and Th standard bracketing procedures used across laboratories. The dissolved BSS-2 aliquots yield between 1.5-2% of uncertainty. Obtained U-Th ages were 122.8 ± 3.3 ka (University of Miami), 124.5 ± 0.3 ka (University of Mainz), and 123.9 ± 3.2 ka (CENIEH) in the powdered samples. Furthermore, in dissolved samples, the Th-ages vary between 126.9 ± 2.9 to 127.9 ± 3.1 (CENIEH & University of Miami). GZS was prepared as a dissolved standard and the Th-date results obtained from this stalagmite are 3967 ± 0.1 to 3988 ± 0.1 (University of Miami), and 3967 ± 0.1 to 4060 ± 0.4 (CENIEH).

All Th-dates required no correction as activity ratios [230Th/232Th] exceeded 500 and 150 for BSS-2 and GZS, respectively. The consistency of these preliminary results across different laboratories suggest that GZS and BSS-2 are promising reference materials for U-Series analysis of calcium carbonate.

How to cite: Hasözbek, A., Jiménez-Barredo, F., Sharifi, A., Pourmand, A., Mertz-Kraus, R., Weber, M., Scholz, D., Lauritzen, S.-E., M. Parés, J., and Constantin, S.: Assessing Gol-e-Zard Cave (GZS) and Bergen Speleothem Standards (BSS) for U/Th Geochronometry Using MC-ICP-MS, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13250,, 2024.

Arnaud Nicolas, Gesine Mollenhauer, Maylin Malter, Jutta Wollenburg, and Florian Adolphi

In order to correctly determine leads and lags in the climate system and compare different proxy records over long time periods, it is important to build robust chronologies that can provide the temporal foundation for paleoclimate correlations between marine, terrestrial and ice-core records. One of the main challenges for building reliable radiocarbon-based chronologies in the marine realm is to estimate the regional marine radiocarbon reservoir age correction. Estimates of the local marine reservoir effect, ΔR, during the deglaciation can be obtained by 14C-independent dating methods such as synchronization to other well-dated archives. The cosmogenic radionuclide 10Be provides such a synchronization tool. Its atmospheric production rate is globally modulated by changes in the cosmic ray flux caused by changes in solar activity and geomagnetic field strength. The resulting variations in the meteoric fallout of10Be are recorded in sediments and ice cores and can thus be used for their synchronization.

In this study we use for the first time the authigenic 10Be/9Be record of a Laptev Sea sediment core and synchronize it to the 10Be records from absolutely dated ice cores. Based on the resulting absolute chronology, the ΔR  was then estimated for the Laptev Sea during the deglaciation. The deglacial estimate for the benthic ΔR value for the Laptev Sea is 345±60 14C years, corresponding to a marine reservoir age of 864±90 14C years. We discuss the obtained ΔR in comparison to modern ΔR estimates from the literature and its consequences for the age-depth model. Our refined age-depth model can be used as a reference for the Laptev Sea and the wider Siberian regions of the Arctic Ocean.    

How to cite: Nicolas, A., Mollenhauer, G., Malter, M., Wollenburg, J., and Adolphi, F.: Refining the age-depth model of a marine sediment record in the Laptev Sea using Beryllium-10, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17301,, 2024.

Fernando Jimenez, Altug Hasozbek, Mathieu Duval, Josep M. Pares, M. Isabel Sarró-Moreno, Ana I. Barrado-Olmedo, Estefania Conde-Vila, Marta Fernández-Díaz, Jose Manuel Cobo, Martin Perez-Estebanez, and Javier Alonso-Garcia

Keywords: Geochronology, Sediment, Uranium, Thorium, Microwave Digestion, HR-ICP-MS

In Quaternary geochronology, accurately estimating natural radiation exposure is crucial for dating materials using Electron Spin Resonance (ESR) and Optically Stimulated Luminescence (OSL). Traditional methods like gamma and alpha spectrometry, despite their utility, are limited by sample size requirements and time inefficiency, especially in low-radiation contexts. This study explores the efficacy of Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) and Plasma Mass Spectrometry (ICP-MS), including both Quadrupole (ICP-QMS) and High-Resolution (HR-ICP-MS), for analyzing uranium, thorium, and potassium concentrations in sediments.

We compared various acid digestion methods using standard hot-blocks, microwave digestion, and single cell microwave technology on Sediment Reference Materials (NIST BRS 8704, OREAS 24d). Potassium detection was more accurate with ICP-OES (96% precision) than ICP-QMS (80%). In contrast, HR-ICP-MS significantly outperformed ICP-QMS in measuring uranium and thorium (U and Th recoveries of 99% and 94% vs. 83% and 81%, respectively). Moreover, microwave-assisted digestion methods showed slight advantages in uranium and thorium recovery.

Our findings suggest that a four-acid microwave-assisted digestion, combined with potassium measurement via ICP-OES in radial mode and uranium and thorium quantification using HR-ICP-MS, offers the most accurate and time-efficient approach for natural dose determination in sediment dating. This methodology is particularly relevant for cave, river, and stream sediments even with expected low uranium levels.

How to cite: Jimenez, F., Hasozbek, A., Duval, M., Pares, J. M., Sarró-Moreno, M. I., Barrado-Olmedo, A. I., Conde-Vila, E., Fernández-Díaz, M., Cobo, J. M., Perez-Estebanez, M., and Alonso-Garcia, J.: Advancing Quaternary Geochronology: Impact of Sample Preparation and Analytical Techniques on Natural Radioactive Dose Assessment in Stream Sediments, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18258,, 2024.

Konrad Tudyka, Kacper Kłosok, Maksymilian Jedrzejowski, Andrzej Rakowski, Sławomira Pawełczyk, Alicja Ustrzycka, Sebastian Miłosz, and Aleksander Kolarczyk

μGraphiline is an innovative, fully automated graphitization system designed for radiocarbon dating using accelerator mass spectrometry. This system streamlines the conversion of samples into CO2 and subsequently into graphite. The standard configuration of μGraphiline is capable of preparing 24 targets daily, demonstrating its high throughput. It achieves a graphitization efficiency of over 95% for 1 mg graphite targets. μGraphiline also offers additional modules for stepped combustion, ramped pyrolysis, and oxidation, all of which can be operated at user-defined temperatures. Furthermore, its design ensures a low background and reproducibility, significantly enhancing the accuracy and reliability of radiocarbon measurements.


One of the notable advantages of the system is its low maintenance requirements. It operates efficiently without the need for working gasses such as helium (He), argon (Ar), oxygen (O2), explosive hydrogen (H2) or liquid nitrogen, which simplifies its operation and enhances safety. This feature, coupled with its modular design and high efficiency, virtually no cross-contamination between modules and samples makes μGraphiline an advanced solution for radiocarbon dating. Lastly, the system's repeatability and reliability are backed by reference materials measurements from the International Atomic Energy Agency, demonstrating good repeatability. 


This demonstrates μGraphiline's capability to deliver fast, consistent and accurate results, making it a valuable tool for various scientific and research applications.

How to cite: Tudyka, K., Kłosok, K., Jedrzejowski, M., Rakowski, A., Pawełczyk, S., Ustrzycka, A., Miłosz, S., and Kolarczyk, A.: μGraphiline: a high-throughput, low-maintenance, fully automated 14C graphitization system, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18925,, 2024.

Norbert Frank and the DCWC

U-series disequilibrium dating or more specifically 230Th/U - dating of cold-water corals is a major absolute chronological toolbox to study the evolution of coral reefs through time and to determine absolute time scales for climate proxies. Advances in multi-collector inductively coupled ion source mass spectrometry (MC-ICPMS) have continuously improved precision of Th and U isotopic measurements over the past decades thanks the development of new high ohmic resistors for Faraday cups. Consequently, isotopic measurements and absolute precision levels are in epsilon ranges for 234U/238U ratios and in the case of materials older than a few tens of thousands of years also for 230Th/238U ratios. To obtain accurate ages the corals isotope ratios need to evolve as a U series closed system and must be free of initial 230Th and non-carbonate materials. The latter being often traced using the natural most abundant 232Th isotope. Coral diagenesis, bio-erosion, residual ferromanganese coatings, recrystallization, and recoil displacement of U isotopes are known sources of age disturbances and U series open system behavior. Here, I want to advocate, however, that such cold-water corals can be ideal dating objects opening far reaching perspectives of marine climate science and for past ecosystem studies. Based on approx. 1200 coral ages and isotope ratios of reef-forming cold-water corals, which correspond to strict quality criteria, a perfect agreement with theoretical predictions of a closed U series system can be found. The resulting oceanic initial (234U/238U) activity ratio for the past 510 ka varies by at most 6.7 ‰ (2s) surrounding the mean of modern seawater and of all reconstructed values of 146.5 ‰ (HU1 reference material is assumed here to be in secular radioactive equilibrium). Consequently, the 234U/238U ratios may be used for dating of old cold-water corals to expand the dating range to more than 1.2 million years. Moreover, any significant deviation between closed system 234U/238U ages and 230Th/238U ages may be used to detect U series open - system behavior. Based on the combined age determination, more consistent chronologies can be derived for cold-water coral reefs beyond 350 ka and theoretically the quality of this archive has opened a path for absolutely dated marine climate proxy records since the Mid Pleistocene Transition.

How to cite: Frank, N. and the DCWC: 230Th/U and 234U/238U dating of cold-water corals: Approaching the disequilibrium theory, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19089,, 2024.

Magdalena Biernacka and Sebastian Kreutzer

Lyoluminescence (LL) is light emission during the solvation of previously irradiated crystals in the liquid-solid interface (Atari, 1980). Our aim is the breakthrough development of lyoluminescence as a dating tool on halite (here: sodium chloride and potassium chloride) for application in Earth Sciences. The positive correlation between radiation dose and LL light emission makes crystal lattice defects viable natural ionizing radiation dosimeters. With a saturation dose of ~10 kGy (e.g. Atari et al., 1973) for sodium chloride dissolved in pure water and for realistic dose rates of ~4 Gy/ka (e.g., Han et al., 2014), the LL signal from salt minerals potentially may determine an age up to 2.5 Ma.
We hypothesize that LL, naturally observable in salt minerals, will allow dating the last recrystallization event significantly beyond the age limits of conventional luminescence-dating methods. In the past, the potential of halite as a material for optical luminescence dating had been suggested, e.g. Bailey et al., (2000); Zhang et al., (2005). However, LL may offer an additional luminescence-dating tool for routine use in geochronology but targeting the crystallization instead of heat or light exposure event. Moreover, it may enable tapping into different archives and subsurface processes where only the event of the last hydration is of interest.
In our contribution, we present the first basic design of a measurement prototype using 3D printing and preliminary experimental results of salts easily soluble in water.

Atari, N.A., 1980. Lyoluminescence mechanism of gamma and additively coloured alkali halides in pure water. Journal of Luminescence 21, 305–316.
Atari, N.A., Ettinger, K.V., Fremlin, J.H., 1973. Lyoluminescence as a possible basis of radiation dosimetry. Radiation Effects 17, 45–48.
Bailey, R.M., Adamiec, G., Rhodes, E.J., 2000. OSL properties of NaCl relative to dating and dosimetry. Radiation Measurements 32, 717–723.
Han, W., Ma, Z., Lai, Z., Appel, E., Fang, X., Yu, L., 2014. Wind erosion on the north‐eastern Tibetan Plateau: constraints from OSL and U‐Th dating of playa salt crust in the Qaidam Basin. Earth Surf Processes Landf 39, 779–789.
Zhang, J.F., Yan, C., Zhou, L.P., 2005. Feasibility of optical dating using halite. Journal of Luminescence 114, 234–240.

How to cite: Biernacka, M. and Kreutzer, S.: Lyoluminescence: a potential tool for dating evaporites up to the Middle-Pleistocene?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21472,, 2024.