Abstract In order to investigate the effects of geological setting and the surrounding lithology on coastal sediment samples, four properties were analysed in a series of samples collected from different localities: colour determined by spectrophotometry; particle size distribution determined by laser granulometry; chemical composition determined by ICP-MS (inductively coupled plasma mass spectrometry); and low-field magnetic susceptibility determined using a susceptibility meter. A hierarchical cluster analysis was applied to ascertain the capacity of the different properties for discrimination between samples from the different geological settings. The study reveals that colour analysis only allowed discrimination between different geographical areas; particle size distribution allowed separation between dune and beach samples; chemical composition allowed discrimination between both different geological settings and also between dune and beach sands; and, finally, the combination of magnetic susceptibility with colour and particle size distribution allowed for clear discrimination between geological settings, and between beach and sand dunes. The studied samples are part of a larger and growing collection of data, and a more extensive evaluation will continue to be made for a more definitive assessment of the use of different characteristics for discrimination. So far, the results give confidence that it is meaningful to use these characteristics, especially when examined in combination, to distinguish between different locations.

Abstract Here, we explore the evolution of the coastal stretch between Mira Beach and Quiaios Beach in Portugal to understand how it adapted to climatic oscillations. To accomplish this, we integrate subsurface radar images, and sedimentological and chronological data, of the emerged coastal barrier. Our results show the installation and progradation of a stable barrier anchored to transgressive dunes 400 years ago. This is just the last pulse of barrier growth within a complex approximately 5000 year-long history of shoreline stability/instability. Episodes of inland dune mobility have been related to instabilities in the beach sediment budget driven by enhanced storminess and wave rotation around 4.25 and 1.14 ka ago. Conversely, lagoonal deposits documented in the literature suggest periods of relative barrier stability and growth around 4.3 and 2.7 cal ka BP. Wave and wind climate variability are driven by shifts in one of the major modes of atmospheric circulation in the North Atlantic, the North Atlantic Oscillation (NAO). Episodes of persistent positive mode of the NAO related to barrier growth and enhanced longshore sediment transport; those of persistent negative mode contributed to instabilities in the beach sediment budget and aeolian activity by enhancing storminess, but reduced effective longshore sediment transport.

Abstract Magnetic susceptibility measurement methodology, its reproducibility and accuracy of analysis were tested on soil samples to evaluate its potential use in forensic applications. It was observed that magnetic susceptibility can enable discrimination between soil samples, measured values are reproducible over time and the analysis can be carried out on small samples. However, in order for this method to be used in a forensic soil investigation, it is important to always adopt the same analytical protocol during analysis.

Abstract Coastal erosion impact on low-lying sandy shorelines represents a worldwide problem, which is particularly felt in various segments of the Portuguese coast where this geomorphological type represents 42% of its total length. Beach nourishment is a viable engineering alternative for shore protection and the assessment of offshore sources of beach-fill material is an essential aspect when implementing this mitigation strategy. The CHIMERA project carried out a multidisciplinary inspection on four segments of the west Portuguese coast to assess their potential as offshore borrow areas for beach nourishment. Altogether, these segments covered an area of c . 35 km 2 , at water depths between 20 and 42 m. They were surveyed using multibeam, sub-bottom profiler, ultra-high resolution multichannel seismics and a set of 126 surface samples and 72 vibrocores (with 3 m long each). To comply with the Portuguese legislation, sand types were assessed by granulometric and chemical analyses for evaluating the quality of sediments in terms of contamination. High-resolution magnetic surveys were conducted to find potential archaeological artefacts. The adopted methodology proved to be adequate to quantify and describe the spatial distribution of useful sediment volumes, supporting the ongoing Integrated Coastal Sediment Strategy for mainland Portugal.