Recent  

We use microCT scanning to improve the quality of ³He exposure ages measured in detrital magnetite. We show that the presence of inclusions can significantly increase the measured amount of ³He and thereby the exposure age. By prescreening magnetite with microCT and analyzing only inclusion-free grains, this problem can be avoided. We also calibrate the cosmogenic ³He production rate in magnetite relative to ¹⁰Be in quartz, which can be used for similar studies in the future.

Artificial intelligence techniques are capable of automatically detecting fission tracks in minerals. The AI-Track-tive software presented here can be used to automatically determine fission track densities for apatite fission track dating studies. Apatite fission track dating is mainly applied to tectonic research on exhumation rates in orogens. Time-consuming manual track counting can be replaced by deep neural networks capable of automatically finding the large majority of tracks.

Luminescence dating requires irradiating the sample in the laboratory. Here, we address some concerns about the reliability of the calibration procedure that have been published recently. We found that the interplay between geometrical parameters such as grain size and aliquot size impacts the calibration value more than previously thought. The results of our study are robust and allow us to recommend an improved calibration procedure in order to enhance the reliability of the calibration value.

Apatite and zircon (U–Th) / He thermochronology is now a mainstream tool to reconstruct Earth's evolution through the history of cooling and exhumation over the first dozen kilometers. The geological implications of these data rely on the precision of measurements of He, U, Th, and Sm contents in crystals. This technical note documents the methods for He thermochronology developed at the GEOPS laboratory, Paris-Saclay University, that allow (U–Th) / He data to be obtained with precision.

Distinguishing between different dolomitization processes is challenging yet critical for resolving some of the issues and ambiguities related to the formation of dolomitic rocks. Accurate U–Pb absolute dating of dolomite by LA-ICP-MS could contribute to a better understanding of the dolomitization process by placing syngenetic, early diagenetic, and/or epigenetic events in the proper geological context.

We generated a synthetic dataset applying published kinetic models and distinct annealing kinetics for the apatite fission track and (U–Th)/He methods using a predetermined thermal history. We then tested how well the true thermal history could be recovered under different data interpretation schemes and geologic constraint assumptions using the Bayesian QTQt software. Our results demonstrate that multikinetic data increase time–temperature resolution and can constrain complex thermal histories.

Our contribution enhances the infrared radiofluorescence dating technique, used to determine the last sunlight exposure of potassium feldspars in a range of about 600 to 600 000 years backwards. We recorded radiofluorescence images of fine sands and processed them with tailored open-source software to obtain ages from single grains. Finally, we tested our new method successfully on two natural sediment samples. Studies in Earth science will benefit from improved age accuracy and new insights.

High-resolution geochronology is one of the key factors to predict volcanic eruptions. To build up a high-resolution geochronological framework, we reported 21 new high-precision eruption ages (⁴⁰Ar / ³⁹Ar) for a ~ 3.3 × 10⁶-year-old volcanic field: Milos (Greece). In combination with geochemical information and eruption volumes from the volcanoes of Milos, the long-lived volcanic history could provide important clues for the prediction of volcanic eruptions.

We carried out thermal annealing experiments between 500 and 1000 °C to determine the closure temperature of radiation-damage annealing in zircon (ZrSiO₄). Our results show that the different Raman bands of zircon respond differently to annealing. The repair is highest for the external rotation Raman band near 356.6 cm⁻¹. The closure temperature estimates range from 250 to 370 °C for different bands. The differences in closure temperatures offer the prospect of multi-T zircon Raman dating.

This paper shows that the current practice of filtering discordant U–Pb data based on the relative difference between the ²⁰⁶Pb/²³⁸U and ²⁰⁷Pb/²⁰⁶Pb ages is just one of several possible approaches to the problem and demonstrably not the best one. An alternative approach is to define discordance in terms of isotopic composition, as a log ratio distance between the measurement and the concordia line. Application to real data indicates that this reduces the positive bias of filtered age spectra.

This paper demonstrates how to model optically stimulated luminescence (OSL) and radiocarbon ages in a Bayesian framework, using a dedicated software tool called BayLum. We show the effect of stratigraphic constraints, of modelling the covariance of ages when the same equipment is used for a series of OSL samples, and of including independent ages on a chronological inference. The improvement in chronological resolution is significant.

To explore the U–Pb geochronometer in fluorite, the spatial distribution of uranium and other substituted elements in natural crystals is investigated using induced fission-track and synchrotron radiation X-ray fluorescence mapping. LA-ICP-MS U–Pb dating on four crystals, which preserve micrometer-scale variations in U concentrations, yields identical ages within analytical uncertainty. Our results show that fluorite U–Pb geochronology has potential for dating distinct crystal growth stages.

We compare two published U–Pb and ⁴⁰Ar / ³⁹Ar geochronologic datasets to produce eruption rate models for the Deccan Traps large igneous province. Applying the same approach to each dataset, the resulting models agree well, but the higher-precision U–Pb dataset results in a more detailed eruption model than the lower-precision ⁴⁰Ar / ³⁹Ar data. We explore sources of geologic uncertainty and reiterate the importance of systematic uncertainties in comparing U–Pb and ⁴⁰Ar / ³⁹Ar datasets.