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“Life is hard. Then you die.
Chapter 13 Chapter 13 Soil Analysis “Life is hard. Then you die. Then they throw dirt in your face. Then the worms eat you. Be grateful it happens in that order.” —David Gerrold, American science fiction writer Kendall/Hunt
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In Soil Analysis you must:
Chapter 13 In Soil Analysis you must: Identify a soil’s common constituents Determine the origin of a soil sample Interpret a topographic map Understand the concept of spectrophotometry Forensic Soil Convention Kendall/Hunt
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Kendall/Hunt Publishing Company
Chapter 13 Kendall/Hunt Publishing Company Kendall/Hunt
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…and… analyze and present data mathematically using graphs
Chapter 13 …and… analyze and present data mathematically using graphs Why soils can be used as class evidence When soils can be used as circumstantial evidence Kendall/Hunt
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Chapter 13 (Review) Circumstantial evidence: additive collection of facts used to infer a conclusion about something unknown; a theory, supported by a significant quantity of corroborating evidence explained by an expert witness in court. Kendall/Hunt
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Soil is considered Trace evidence that is easily transferred anywhere.
Chapter 13 Soil is considered Trace evidence that is easily transferred anywhere. Physical evidence Class evidence Kendall/Hunt
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Forensic Geology The legal application of earth and soil science
Chapter 13 Forensic Geology The legal application of earth and soil science Characterization of earthen materials that have been transferred between objects or locations and the analysis of possible origin or sources Kendall/Hunt
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Forensic Geologist Tools
Chapter 13 Forensic Geologist Tools Binocular microscopes Petrographic microscopes X-ray diffraction Scanning electron microscopes Microchemical analysis Kendall/Hunt
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Chapter 13 History 1887–1893—Sir Arthur Conan Doyle wrote about scientific ideas and techniques for solving crimes in his Sherlock Holmes books. This included information about soil and its composition which had never actually been used. 1893: Austrian criminal investigator, Hans Gross, wrote that there should be a study of “dust, dirt on shoes and spots on cloth.” He observed, “Dirt on shoes can often tell us more about where the wearer of those shoes had last been than toilsome inquiries.” Kendall/Hunt
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Chapter 13 History continued 1904—Georg Popp, German forensic scientist, presented the 1st example of earth materials used as evidence in a criminal case, the strangulation of Eva Disch. 1910—Edmond Locard, was a forensic geologist, and was most interested in the fact that dust was transferred from the crime scene to the criminal. This helped to establish his principle of transfer. Kendall/Hunt
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Chapter 13 Soil: Naturally deposited materials covering earth’s surface and are capable of supporting plant growth The Earth 75%—oceans, seas and lakes 15%—deserts, polar ice caps and mountains 10%—suitable for agriculture Kendall/Hunt
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Soil Formation Living matter—plants, animals, microorganisms
Chapter 13 Soil Formation Living matter—plants, animals, microorganisms Inorganic materials Climate Parent materials Relief—slope and land form Time Kendall/Hunt
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Chapter 13 Soil Profile Topsoil Subsoil Parent material Kendall/Hunt
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Chapter 13 Composition Sand Silt Clay Organic matter Kendall/Hunt
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Soil Nutrients—macro Nitrogen Phosphorus Potassium Calcium Magnesium
Chapter 13 Soil Nutrients—macro Nitrogen Phosphorus Potassium Calcium Magnesium Sulfur Nutrients—micro Manganese Iron Boron Copper Zinc Molybdenum Chlorine Kendall/Hunt
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Chapter 13 Soil Collection Collection of soil samples depends on the circumstances of the crime. Indoor scenes will differ from outdoor scenes in the type of evidence that can be recovered and the way in which these samples are collected. Kendall/Hunt
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Outdoor evidence in soil…
Chapter 13 Outdoor evidence in soil… Kendall/Hunt Publishing Company Kendall/Hunt
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Chapter 13 Soil Comparisons May establish a relationship or link to the crime, the victim, or the suspect(s) Physical properties—density, magnetism, particle size, mineralogy Chemical properties—pH, trace elements Kendall/Hunt
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Chapter 13 Making an impression… if the shoe fits... Kendall/Hunt
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Probative Value of Soil (ability to prove something)
Chapter 13 Probative Value of Soil (ability to prove something) Types of earth material are virtually unlimited. They have a wide distribution and change over short distances. As a result, the statistical probability of a given sample having properties the same as another is very small Evidential value of soil can be excellent Kendall/Hunt
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Increasing Probative Value
Chapter 13 Increasing Probative Value Rare or unusual minerals Rocks Fossils Manufactured particles Kendall/Hunt
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Minerals More than 2000 have been identified
Chapter 13 Minerals More than 2000 have been identified Twenty or so are commonly found in soils; most soil samples contain only 3 to 5 these minerals Characteristics for identification: size, density, color, luster, fracture, streak, or magnetism Kendall/Hunt
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Rocks Aggregates of minerals Types Formation Natural—like granite
Chapter 13 Rocks Aggregates of minerals Types Natural—like granite Man-made—like concrete Formation Igneous: lava-volcanic Sedimentary: “settled” limestone Metamorphic: formed under pressure: gneiss Kendall/Hunt
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Kendall/Hunt Publishing Company
Chapter 13 Kendall/Hunt Publishing Company Kendall/Hunt
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Kendall/Hunt Publishing Company
Chapter 13 Kendall/Hunt Publishing Company Kendall/Hunt
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Fossils Remains of plants and animals
Chapter 13 Fossils Remains of plants and animals May help geologists to determine the age of rocks Some are scarce and can be used to identify regions or locations Kendall/Hunt
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Palynology The study of pollen and spores Important to know:
Chapter 13 Palynology The study of pollen and spores Important to know: What is produced in a given area The dispersal pattern Variation in size and weight For additional information about palynology visit: Kendall/Hunt
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Trilete spores. Such spores are the earliest evidence of life on land
Chapter 13 Trilete spores. Such spores are the earliest evidence of life on land Kendall/Hunt
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Chapter 13 Pollen on a car Kendall/Hunt
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Forensic Palynology: A person was found hanged in a barn
Chapter 13 Forensic Palynology: A person was found hanged in a barn in what appeared to be a suicide, however, police were suspicious because the hanged person had not been depressed nor had he left a suicide note. There were five people the police believed had a motive to kill the person, and each would directly profit by the victim's death; nevertheless, each suspect had an alibi. Kendall/Hunt
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Chapter 13 A forensic pollen analysis of the rope used to hang the victim contained pollen commonly found on a farm where vegetables were being grown. One of the five suspects owned a small truck-farm and made a living from selling a variety of vegetable crops. Kendall/Hunt
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Chapter 13 Although this single piece of evidence was not enough to convict any suspect, it helped police narrow their suspects to one individual. Through careful surveillance of the primary suspect, the police were able to gather enough evidence to arrest the suspect for the man's murder. Kendall/Hunt
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We are here
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Chapter 13 Soil Evidence Class characteristics—the type of soil may have similar characteristics at the primary and/or secondary crime scene, on the suspect or on the victim Individual characteristics—only if the soil has an unusual or specialized ingredient such as pollen, seeds, vegetation, or fragments. Kendall/Hunt
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Chapter 13 Sand Sand is the term applied to natural particles with a grain diameter between 1/16 mm and 2 mm. Its color and contents are dependent upon the parent rock and surrounding plant and animal life. (The photo on the right shows color differences in sand from six locations around the world.) Kendall/Hunt
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Chapter 13 Sand Characteristics Composition is based on the material of the source; also gives the sand its color Texture is determined by the way the source was transported Shape rounded, squared off or star shaped Grain size large…small Kendall/Hunt
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Chapter 13 Kendall/Hunt
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Sand Types Continental sands—formed from weathered continental rock,
Chapter 13 Sand Types Continental sands—formed from weathered continental rock, usually granite Ocean floor sands—formed from volcanic material, usually basalt Carbonate sands—composed of various forms of calcium carbonate Tufa sands—formed when calcium ions from underground springs precipitate with carbonate ions in the salt water of a salt lake Kendall/Hunt
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Chapter 13 Sand Evidence “In every grain of sand is a story of earth.” —Rachel Carson Class characteristics: the type of sand may have similar characteristics to the primary and/or secondary crime scene, on the suspect or on the victim Individual characteristics: only if the sand has an unusual ingredient or contaminant. Kendall/Hunt
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Chapter 13 Kendall/Hunt
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Chapter 13 Virtual Sand Lab Take a look at other examples on the website from the Geology Department at Pasadena City College. Or look at more sand Kendall/Hunt
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A creature which taxonomically belongs to Family Calcalinidae, Order Foraminiferida, Class Rhizopoda, Phylum Protozoa. Its scientific name is Baclogypsina sphaerulata. It is distributed from Tanegashima Island towards the subtropical and tropical areas. Individual size is around 1mm, its skeleton is with 5~6 processes, making it a real star shape. Locally, the star sands occur abundantly, sometimes they are more than true sand grains in some beaches. In Iriomote Island, it can be found at every beach when we look for it carefully, in particular it is abundant at Hoshizuna Beach.
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Forensic Geology in the News
Chapter 13 Forensic Geology in the News A 9-year-old’s body was found in a wooded area along a river in Lincoln County, South Dakota. A forensic geologist collected soil samples from the fenders of a suspect’s truck and the area where the body was found. Both soils contained grains of a blue mineral that turned out to be gahnite, a rare mineral that had never been reported in South Dakota. As a result, the soil tied the suspect to the crime. Check out other cases at: Kendall/Hunt
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