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It is 50 years since Sieveking et al. published their pioneering research in Nature on the geochemical analysis of artefacts from Neolithic flint mines in southern Britain. In the decades since, geochemical techniques to source stone artefacts have flourished globally, with a renaissance in recent years from new instrumentation, data analysis, and machine learning techniques. Despite the interest over these latter approaches, there has been variation in the quality with which these methods have been applied. Using the case study of flint artefacts and geological samples from England, we present a robust and objective evaluation of three popular techniques, Random Forest, K-Nearest-Neighbour, and Support Vector Machines, and present a pipeline for their appropriate use. When evaluated correctly, the results establish high model classification performance, with Random Forest leading with an average accuracy of 85% (measured through F1 Scores), and with Support Vector Machines following closely. The methodology developed in this paper demonstrates the potential to significantly improve on previous approaches, particularly in removing bias, and providing greater means of evaluation than previously utilised. [ABSTRACT FROM AUTHOR]

The Rosebank field, located in the Faroe-Shetland Basin, contains producible hydrocarbons in intra-basaltic siliciclastic reservoirs. The volcanic-reservoir interface is poorly studied and the geochemical system, as a function of distance from the basalt, is largely unknown. The current paper applies a geochemical model coupling mineral dissolution and precipitation with element diffusion to investigate the geochemical system in time and space from the basalt-sandstone interface. Earlier studies indicate few negative effects on reservoir properties despite the proximity to a reactive volcanic lithology. The causes of this minimal impact have not been studied. The numerical simulations in this study expand on the knowledge demonstrating that precipitation of authigenic phases at the basalt-sandstone interface buffer the formation water solution for key elements, which hamper the transport of solutes and subsequent precipitation of secondary minerals within the reservoir. Saturation index values over the simulated period indicate that precipitation of authigenic phases should not extend beyond the basalt-sandstone interface. This shows that diffusion alone is not enough to reduce the reservoir quality due to increased precipitation of secondary phases. The basalt dissolution rate varies according to the silica concentration. The combined effects on silica concentration by diffusional fluxes, mineral precipitation and dissolution, control the basalt dissolution rate, and there are no differences in the results between high and low basalt reactive surface area. [ABSTRACT FROM AUTHOR]