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Soil forensics aid in Tasmanian murder case

Citation

Doyle, RB and Bottrill, R, Soil forensics aid in Tasmanian murder case, Proceedings of the Joint Australian and New Zealand Soil Science Conference, 2-7 December 2012, Hobart, Tasmania, pp. 662. ISBN 978-0-646-59142-1 (2012) [Conference Extract]

Abstract

Tasmania has a very diverse range of soil formation environments due to wide variations in geology, landforms, landscape history and climatic setting. Parent materials range from mafic to highly siliceous, with some carbonates; mean annual rainfall from 400 to 3000 mm/year while soil formation periods range from a few thousand to several millions of years. This setting leads to a wide range of soil types with vastly differing mineralogy, chemistry and stratigraphy occurring in relatively close proximity. This diversity can assist in criminal investigations and prosecutions via soil evidence helping to both eliminate and/or locate crime scenes from an investigation or to support presence or absence of incriminating additions or modifications to soil materials. We used X-ray diffraction and a sequence of soil profile descriptions at a crime scene to show earthy lime rich materials found above the murder victim in a deep pit (4 m) were exotic to that environment. The local soil type, in which the victim was located, was a very deep Acidic Red Ferrosol formed from dolerite in the Tasmanian highlands. The subsoils of the soil profiles described adjacent to, upslope and down slope of the murder site had acid reaction (pH < 5.0), were deeply weathered, clay textured and red to dark reddish brown in colour. X-ray diffraction analysis undertaken identified the light coloured, highly alkaline (pH 11.8) lime rich materials as being composed of 90 95% calcium carbonate with traces of calcium hydroxide ("lime"). These properties supported the incompatibility of the "lime" with the soil, showing it to be exotic to the site. This fact helped to link the perpetrators to the crime scene.

Item Details

Item Type:Conference Extract
Research Division:Earth Sciences
Research Group:Physical Geography and Environmental Geoscience
Research Field:Geomorphology and Regolith and Landscape Evolution
Objective Division:Environment
Objective Group:Environmental and Natural Resource Evaluation
Objective Field:Environmental and Natural Resource Evaluation not elsewhere classified
Author:Doyle, RB (Dr Richard Doyle)
ID Code:79391
Year Published:2012
Deposited By:Agricultural Science
Deposited On:2012-09-08
Last Modified:2012-12-18
Downloads:0

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