An Introduction to Forensic Geoscience
By Elisa Bergslien
May 2012, Wiley-Blackwell
Geophysicist and meterologist Alfred Wegener once lamented in the foreword of his “The Origin of Continents and Oceans” that “We are like a judge confronted by a defendant who declines answer, and we must determine the truth from the circumstantial evidence.“; he continues “It is only by combing the information furnished by all the earth sciences that we can hope to determine “truth”…“
It seems that these words can be used also to describe the book “An Introduction to Forensic Geoscience“, published in 2012 and written by hydrogeologist Elisa Bergslien, as she demonstrate in 11 main chapters how methods used in the fields of geology, geography, geomorphology, sedimentology, mineralogy and petrology, palaeontology and biology can be used to collect evidence and help to solve crimes.
Chapter 1 introduces the topic with an overview of the historic development of geology during the 19th century and early use of mud on cloths to connect a suspect with a crime. With the development of advanced methods to identify minerals (for example thin sections and microscopes adapted to use polarized light) earth-sciences became more and more involved in crime scene investigation and merged finally with modern forensic methods to form today’s “Geoforensics“.
The subsequent chapters are dedicated to specific applications of geology-related topics (like minerals, rocks, fossils, but also the landscape and survey methods) in criminology.
Chapter 2 introduces mineralogy and mineral identification. The main text deals with the theory (for example the structure of crystals and definition of a mineral) and provides various flow charts and tables to identify the most common minerals a crime investigator can encounter in his career.
Chapter 3 is similar in structure to the previous chapter, however focusing on rocks, their formation and identification in the field as in samples. In apposite boxes the use of these principles is retold in recent or historic crime cases, like the case when the texture and fossil content of a limestone revealed the thief of an entire cargo of best Scottish Whiskey.
Chapter 4 provides a basic overview for the use of topographic and geologic maps, coordinate systems, map projections and GPS devices, redirecting the student also in the last paragraph to freely available cartographic material or programs in the internet. Modern Geographical Information Systems are mentioned only briefly; however the interested reader is referred to further readings in a list of recommended books and cited papers, which concludes all the main chapters.
Chapter 5 is entirely dedicated to the world of sand (intended as a mixture of both natural mineral grains, but also anthropogenic substances) and how the microscopic examination of it can solve a crime. One of the most surprising use of this method occurred during World War II, when the shape of mineral grains and the content of microfossils found in the sand ballast of balloon bombs landing in the U.S. revealed their provenance from the distant shores of Japan.
Chapter 6 will be particular interesting to material researches, prospectors, jewellers and goldsmiths, as it explains the physical as geological characteristics of most common gem stones and the differences to identify real gems from fake material (like glass, but also modern synthetic materials).
Chapter 7 discusses in great detail the most common kind of geologic evidence: soil and dirt. With the basic knowledge of minerals and rocks acquired in the previous chapters Bergslien introduces soils as complex mixture of unweathered and wheatered geologic educts, emphasizing the structure, origin, characteristics and identification (explaining for example the X-ray Diffraction Spectrometry) of one of the most important component of soils – clay minerals.
Thanks to an exotic type of clay minerals, used in an artificial pond, but not present in the autochthonous soils, in 2000 Janice Dodson was found guilty for murdering her husband during a hunting trip.
Chapter 8 is an intriguing excurse into the use of minerals as pigments in artwork and inks. The most important pigments are presented, including common identification methods, like Raman Spectroscopy and Chromatography, to reveal forgeries which use less valuable or artificial pigments.
Chapter 9 introduces fossils as evidence, both to determine geologic time or a suspect. Most of this chapter is dedicated to systematic palaeontology, especially microorganisms with hard shells, like diatoms, radiolarians and foraminifers. A brief collection of crime cases, involving stolen fossils, concludes this chapter.
Chapter 10 discusses the contributions by geologist to the fields of anthropology and archaeology. Ancient holes or gravesites are often revealed by disturbed or compacted sediments and geological maps can identify regions with easily excavable material, where it is likely that somebody will dig a hole to hide a body or treasure. Finally using geophysical survey methods – like Magnetometry and Ground-penetrating RADAR – archaeologist or the police can almost “look” into the underground.
Chapter 11 deals with one of the main fields of interest of the author, as she discusses the use of hydrogeology to identify the sources of environmental pollution and the enforcement of environmental law. Curiously the analysis of the isotope geochemistry of the water that the famous Iceman once consumed (the signature of the water was preserved in his teeth) helped to clarify the area of origin of the oldest murder victim we today know.
Apart introducing the interested layman to the fascinating applications of geoforensics, “An Introduction to Forensic Geoscience” can also be used by teachers and undergraduate students of earth sciences as resourceful “physical geology” textbook, even if the book addresses the U.S. market, as many cited laws or classification schemes are valid only in the States.
Students or professionals in forensic sciences will profit from an easily accessible text to geological concepts, which emphasizes the strengths – but also the limitations – of geology applied to the prosecution of crimes.
DISCLAIMER: This review is based on a copy of “An Introduction to Forensic Geoscience” kindly provided by the publisher, however I have no affiliation with the publisher or author; the review reflects my personal opinion on the discussed book.
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