Abstract In a cold case investigation of a 1983 homicide, trace amounts of soil were identified on a 10-year-old victim's pyjama top. Swatch samples were cut from the pyjama top, specifically the hem, to determine the provenance of this questioned soil. A comparative study was undertaken of the questioned soil with control soils from the Onkaparinga estuary using morphological observations with the naked eye and scanning electron microscopy (SEM), chemistry, traditional laboratory X-ray diffraction (XRD) and synchrotron µ-XRD. Synchrotron µ-XRD with high-intensity X-rays provided greater sensitivity and resolution than the laboratory XRD source to identify pyrite and clay minerals on the pyjama top. SEM confirmed that these mineral particles are deeply impregnated in gaps between fibres of the fabric, which are likely to have originated under water with force being applied on the pyjama top – implying that the victim was pushed into the mud. This is substantiated by transference shaking experiments, where mineral particles are dominantly located on the surface of the fabric. The questioned soil samples have a moderately strong degree of comparability with the control hypersulphidic subaqueous soils containing pyrite in the Onkaparinga River estuary – providing evidence that the soils have similar origins. The accused was found guilty by a Supreme Court judge of murder.

Abstract The Port Willunga Formation is a cool–water, marine, quartzose, clay–rich, biosiliceous, and calcareous sedimentary succession of Early Oligocene age that accumulated in a series of proximal estuarine paleoenvironments along the eastern side of the St. Vincent Basin, South Australia. Coeval strata in two of the paleo–embayments are interpreted to record deposition during one ~ 3.5 My–long eustatic sea–level fluctuation. Transgressive facies above a ravinement surface comprise quartzose sands (subaqueous marine tidal dunes) that grade upward into fossiliferous floatstones and mudstones (shoreface to shallow basin–floor environments) that accumulated in a protected embayment. Highstand sediments are distinctly cyclic at the meter scale and consist of epifaunal bryozoan–pecten–echinoid clay–rich floatstones that become less fossiliferous but more spiculitic and chert–rich upward in each cycle. Whereas cyclic sediments in one embayment (Willunga) are interpreted to have accumulated on a current–swept, illuminated seafloor, those in the other (Noarlunga) are thought to have been deposited in a lower–energy, sub–photic setting. Cyclicity is interpreted to record the increasing influence of fluvial fresh water in the system during each sea–level fluctuation. Comparison with underlying strata reveals a striking similarity in depositional style and stratigraphic packaging between Late Eocene and Early Oligocene deposits; both are interpreted as paleoestuarine. Differences between the dark, organic–rich, biosiliceous, and low–diversity Eocene highstand deposits and the light, more calcareous, and more diverse Oligocene highstand deposits are interpreted to be due to local depositional controls. An important implication of local controls is that several postulated unconformities in the succession are not due to global eustatic changes but are ravinement surfaces related to estuarine sedimentation dynamics. Such controls, specifically terrestrial climate, hydrodynamic energy, and trophic resource levels were more important in determining sediment composition than eustasy and Southern Ocean cooling. Similar biosiliceous–carbonate sedimentary facies are a recurring feature of cool–water deposition throughout the Phanerozoic.

Abstract Using forensic soil science and forensic geology as trace evidence and searches for burials is the theme of the papers in this Special Publication. The concept and design of this volume was initially established by the International Union of Geological Sciences, Initiative on Forensic Geology, which successfully brought together forensic geologists, forensic soil scientists, police officers and law enforcement agents in the investigation of crimes. In this introductory paper a brief overview is provided of the developments in interdisciplinary knowledge exchange with use of soil and geological materials (known as ‘earth materials’) in the search for burials and the provision of trace evidence. The aim is to provide background information on the role and value of understanding ‘earth materials’ ranging from the landscape scale, to the crime scene through to microscopic scale investigations to support law enforcement agencies in solving criminal, environmental, serious and organized crime, and terrorism. In this connection, recent advances in field and laboratory methods are highlighted. Finally, the 20 papers in the volume are briefly introduced and these include a diversity of global operational case studies that involve collection and analysis of earth material from crime scenes and searches for homicide graves and other buried targets.