Recent  

The `Likhall´ zircon bed helps to constrain the timing of increased meteorite bombardment of the Earth, during the Ordovician period. It is important to understand the timing of this meteorite bombardment when attempting to correlate it with biodiversity changes during the Ordovician period. Calibrating a good age for the ´Likhall´ bed is however challenging and benefited in this study from advances in sample preparation.

The mollusc Arctica islandica can survive for hundreds of years and its annual growth captures environmental conditions, so each shell provides a detailed climatic record. Dating is essential for sample selection, but radiocarbon and crossdating are time-consuming and costly. As an alternative, amino acid geochronology was investigated in the three aragonitic layers forming the shells. This study confirms the value of AAG as a method for rangefinder dating Quaternary A. islandica shells.

We demonstrate a machine learning method to estimate the temperature changes of the earth's crust over time. The method respects physical laws and conditions imposed by users. By using observed rock cooling ages as constraints, the method can be used to estimate the tectonic and landscape evolution of the earth. We show the applications of the method using a synthetic rock uplift model in 1D and an evolution model of a real mountain range in 3D.

The work presented here focusses on understanding the nature and lifespan of the Delamerian Orogeny (mountain belt). The results obtained support the hypothesised nature of the long-lived Delamerian Orogeny. The orogen has potential for Cu-Au deposits and the results contribute to the fundamental understanding of the region that will assist in exploring for mineralisation. The aims have been achieved through ⁴⁰Ar/³⁹Ar dating of important structures within the rock units of the orogen.

Radiometric dating methods, involving laser-ablation as sample introduction, require robust calibrations to reference materials with similar ablation properties to the analysed samples. In the case of the Rubidium-Strontium dating method, calibrations are often conducted to a nano-powder with different ablation characteristics than crystalline minerals. We describe the limitations of this approach and recommend an alternative calibration method, involving natural minerals.

We describe a new method of reconstructing the long-term, pre-observational frequency and/or intensity of wildfires in forested landscapes using trace concentrations of the noble gases helium and neon that are formed in soil mineral grains by cosmic-ray bombardment of the Earth's surface.

Developing models that relate stratigraphic position to time are important because they allow the rock record to be understood in terms of absolute time, allowing global comparisons. In this study we developed a novel method for developing these models (called age-depth models) that uses two different types of chronologic information, dated rocks, and records of variations in earths orbit (astrochronology). The resulting models are very precise which can improve understanding of past climates.

Chemical abrasion (CA) is a technique that reduces or eliminates the effects of Pb-loss in zircon U-Pb geochronology. However, CA has yet to be applied to large-n detrital zircon (DZ) analyses. We show that CA does not negatively impact or systematically bias U-Pb dates and improves concordance, precision, and accuracy. When applied to DZ samples prior to laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), CA improves the resolution of DZ age populations.