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C H A P T E R
13
S O I L A N A LY S I S
“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
OBJECTIVES
After reading this chapter, you will understand:
• Why soils are class evidence.
• When soils can be used as circumstantial evidence.
• How to present data mathematically using graphs.
You will be able to:
•
•
•
•
Identify soil’s common constituents.
Relate soil type to the environment.
Interpret a topographic map.
Understand the concept of spectrophotometry and its
applications.
• Use technology and mathematics to improve investigations
and communications.
• Identify questions and concepts that guide scientific
investigations.
• Communicate and defend a scientific argument.
SOIL AS EVIDENCE
Soil can be important physical evidence at a crime scene because it is
everywhere and is easily transferred accidentally. As with other trace
evidence, forensic scientists looking at soil compare samples to
establish a link or relationship; the more characteristics that can be
Body parts of a murder victim, including an ear,
were discovered in a marsh. The rest of the body
could not be found. Grains of sand from the
ear were not endemic to the black mud marsh.
Examination of the sand grains showed salt
crystals, not enough to imply an ocean beach
environment, but perhaps an estuary near the
ocean. The nearest such place to the crime scene
was searched, and the rest of the body recovered.
—abstracted from Forensic Geology
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Individual evidence, like fingerprints, can be
related to a single source, while class evidence
can be associated only with a group of items
that share properties or characteristics.
matched, the greater the probability of common origin. Comparative
analysis uses physical properties such as density, magnetism, and
particle size as well as chemical properties such as pH.
L A B O R AT O R Y A C T I V I T Y
Collecting and Observing Soil
Materials
soil samples
petri dish
magnifying glass or
stereomicroscope
Procedure
Georg Popp was a famous forensic investigator
in the early 20th century. A farmer, who already
had a bad reputation as a poacher, was suspected in a woman’s murder. By a stroke of luck,
the suspect’s wife had cleaned his shoes the day
before the murder, and he had worn them only
one day.
Popp noted several individual layers in the
thick cake of soil on the bottom of the suspect’s
shoes: The first, closest to the sole of the shoe,
contained goose droppings, which littered the
suspect’s farm. The second layer showed many
grains of a red sandstone common to the area of
the crime scene. The third layer had a mixture of
coal, brick dust, and cement fragments, which
were common to ruins where the murderer had
hidden his gun.
The suspect claimed that on the day of the
murder he had walked only in his fields, yet the
distinctive field soil of porphyry, milky quartz,
and mica was absent in the layers on his shoes.
Not only was Popp able to differentiate
between locales, but he also established the
time sequence of visitation.
1. Bring into school 2 to 4 ounces of soil from around your home. The
container should be labeled with your name, the date on which it was
collected, and the specific location (such as by front walk, back flower
garden, and the like).
2. Put your sample in a labeled petri dish.
3. Describe the sample so that it may be compared to others. Record all
observations in your notebook.
4. Observe and describe the soil samples of at least 3 classmates.
Based on observations, can soil samples be individualized enough to be
used as evidence?
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WHAT IS SOIL?
Soil is one of the most common materials in the world. Soil is a
complex mixture of different-sized mineral grains from the
weathering of rock and organic material from the decay of
vegetation and animals. The proportion of sand, silt, clay, and
organic matter determines a soil’s properties. For example, at
one extreme, there is sand, the result of chemical and physical
weathering. At the other end, slow anaerobic decomposition of
vegetative matter forms a dark organic soil, such as that found
in swamps and bogs.
Soil’s composition is different from place to place and is controlled by five important factors: climate, parent material, living
organisms, topography, and time. A sample taken a few meters
deep may be very different from a sample taken above it. This
can also happen when samples are taken a few meters apart;
investigators can sometimes use these differences to conclusively
prove the common origin of two samples.
The forensic definition of soil includes anything mixed in with
the soil, such as bits of glass, cinders, asphalt, paint, metal, concrete, bricks, and the like (human-made disintegration products),
as well as natural products such as vegetation, seeds, animal
matter, spores, and lichens. Often, presence of artifacts makes a
soil sample unique to a particular location and provides a link to
another sample. For example, soil from either side of a galvanized fence usually contains zinc, dirt below an asphalt shingle
roof may show shingle stones, and potting soils often contain
slow-release mineral pills.
Thus, soil can be important physical evidence at a crime
scene; it’s everywhere and is easily transferred (don’t forget
Locard’s principle!). For example, samples of soil or mud can
link a suspect’s car to clothing, shoes, or other instruments used
at a crime scene. As with most forensic physical evidence, comparative tests determine a common origin.
“Observation tells me that you have a little
reddish mould adhering to your instep. Just
opposite the Wigmore Street Office they have
taken up the pavement and thrown up some
earth, which lies in such a way that it is difficult
to avoid treading in it in entering. The earth is of
this peculiar reddish tint which is found, as far as
I know, nowhere else in the neighbourhood.”
—Sherlock Holmes to Dr. Watson,
in Arthur Conan Doyle’s The Sign of Four
A vertical cross-section of soil
shows rather distinct layers
called horizons. Thus soil can
vary both on the surface as
well as with depth.
HORIZONS
A = topsoil, mostly
humus, dark
B = clay, some
humus, iron oxides
C = partially
weathered rock
Bedrock
“When two objects come in contact with each
other, material is transferred. The intensity and
duration of the contact and the nature of the
material determines the extent of the transfer.”
—Edmond Locard (1934)
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L A B O R AT O R Y A C T I V I T Y
A Hit-and-Run Accident
A middle-aged male, later identified as Bud Coreopsis, was found dead on
the shoulder of Route S98, obviously the victim of a hit-and-run accident.
Investigators took samples of soil and fragments of glass from the scene.
Police found two likely suspects who could be placed on the highway at
the estimated time of the accident. The following dried soil samples were
submitted to your crime lab:
A. Soil taken from the clothes of the victim
B. Soil from the accident site
C. Soil scraped from under the right front fender of suspect Blossom
Cowslip’s red Citroen
D. Soil scraped from under the right front fender of suspect Fescue
Snakeroot’s red BMW
E. Soil removed from Coreopsis’s yard
Materials
The word organic refers to substances composed
primarily of hydrocarbons; that is, carbon and
hydrogen. Conversely, inorganic substances
contain a preponderance of elements other than
C and H. In soils that would be Si, O, Mg, Al,
Fe, Ca, K.
glass petri dishes
magnet
universal pH paper
universal pH indicator
weighing paper or boat
graph paper
ruler
test tubes
Spectronic 20 spectrometer
soil samples
set of sieves
density gradient columns
UV light
top-loading balance
oven
stereomicroscopes
magnifying glasses
Procedure
General Appearance
1. Examine each of the soil samples with a magnifying glass or under
the stereomicroscope using reflected and transmitted light. Note the
presence of unusual material or vegetation such as leaves, roots, pine
needles, hair, metal specks, fibers, building materials, trash, or the like.
Such objects can provide valuable clues. Record your observations.
A fluorescent material absorbs light of a shorter
wavelength (often in the ultraviolet) and emits
light of a longer wavelength (often in the visible
part of the spectrum).
2. Direct ultraviolet light on the soil samples. Note what particles, if
any, fluoresce. Certain minerals fluoresce (e.g., fluorite, some calcites,
willemite) as well as many manufactured articles such as fibers and
plastics. Record your observations.
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3. Pass a magnet through the soil samples to collect and identify any
iron objects. Record your observations.
Color
4. The color of a soil is generally related to the presence of particular
minerals or organic matter. For example, red soils tend to have highly
oxidized iron (that is, rust); black soils tend to contain organic matter,
or humus. Wet soil is usually darker than dry soil. The soil must be
dried (usually at 100°C for an hour) before making color comparisons.
Your samples have been dried already. Select a paint color panel that
most closely matches the color of the soil sample. Use it in your report.
Acidity
5. Certain soils may be especially acidic or basic. Those high in limestone
(CaCO3), for example, will be basic. Soils containing sulfides (S⫺2) and
sulfates (SO4⫺2) are usually acidic. Measure the pH by placing a small
amount of sample in a test tube, add about a centimeter of distilled
water, shake, let the mixture settle, note any discoloration of the water,
then add a drop of universal pH indicator. Compare to a color chart,
and record the pH. Sometimes you can identify acidic or basic grains
by pressing wet universal pH paper against the soil. Look for dots of
color under magnification and match to the pH color index. Record
your observations.
There are an estimated 1,100 distinguishable
soil colors. Instead of using paint panels, soil
scientists use a book of color chips called The
Munsell Soil Color Charts to describe the color of
soil samples.
humus: the organic part of soil. Soils
high in humus are dark colored and
usually form either under prairie grasses
or in wet locations, such as bogs and
marshes, where lack of oxygen slows
decomposition of the organic matter.
The acidity of a solution is described by pH,
a number that represents the hydrogen ion
concentration in a solution:
pH = ⫺log[H+]
Particle Size
6. The composition of soil determines not only its color, but also the
range of particle sizes (texture). If the samples come from the same
source, then they should have the same range of particle sizes.
Arrange the set of sieves in order with the largest holes (the
smallest screen number) on the top and the finest screen at the
bottom. Screen numbers of 20, 40, and 100 work well.
Loam is a medium-textured soil of sand, silt, and
clay, as well as organic matter. Loamy soils are
best for gardens. An average soil is 45 percent
minerals, 25 percent water, 25 percent air, and
5 percent organic matter.
Table 1: Grain Size Scale
mm
3.35
2.00
0.850
0.425
0.250
0.150
0.075
0.038
0.002
Sieve series, No.
6
10
20
40
60
100
200
400
Texture
gravel
very coarse
coarse
medium
medium fine
fine
very fine
Stealing saguaro cactus in Arizona and the very
expensive cyclads in California has become a
very lucrative business. Bills of sale are easy to
come by, so the soil on the root systems is the
only physical evidence.
sand
silt
clay
Below 0.1 mm, dimensions can be expressed in
microns or micrometers:
1 mm = 1,000 microns
= 1,000 ␮m
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Soil scientists have identified more than 70,000
kinds of soil in the United States.
7. Weigh between 5 and 10 g of dried sample and add to the top sieve.
Rub your finger over it to break up any large lumps. Put the cover and
bottom base on the set of sieves and shake for a few minutes. Tap the
sides, remove the cover, and weigh the contents of each sieve.
8. What is the best way you can present your data for comparison to the
other samples? Label and save each fraction of soil for later use. See
the accompanying table for typical grain sizes of different types of soil.
Density
Specific gravity is the ratio of the density of a
substance to that of water.
density: mass per unit volume
9. About 400 years ago, Galileo discovered that a ball of wax could be
suspended between a layer of salt water and a layer of fresh water:
Objects seek the level of their density. This principle will be used to
classify compare soil types. The particles making up soils vary in density
as well as in particle size. If two soils are from the same location, they
should contain particles of similar densities. Determine the density
distribution of the particles by adding soil to a tube containing layers of
different-density liquids. Each particle will “float” at an equidensity point
in the column, providing a density profile of the soil sample.
10. Use density gradient columns for this part of the activity. Your teacher
has made these by layering various proportions of xylene (d = 0.88
g/cc) and bromoform (d = 2.89 g/cc).
11. For each soil sample, weigh onto weighing paper or into a weighing
boat 0.1 g of the dried soil fraction that has passed through the 20
mesh screen and remains on the 40 mesh sieve.
Typical soil density profiles
12. Carefully pour it into a labeled density gradient column. Do not jostle
the column. Within hours, the individual particles of the soils will
settle to their density levels. Particle size will have no influence on the
density level, just on how fast they settle. Why?
Quartz (SiO2) is a common constituent of many soils. Pure quartz
is called silica and has a density of 2.65 g/cc, which is very close to
the density of bromoform. Organic matter, on the other hand, has a
density of less than 1.00 g/cc. Where would you expect to find each of
these components in a density column?
13. Draw a soil density profile of all the samples and comment on the
differences.
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Rate of Settling
14. This method measures how rapidly a homogeneous sample of soil
settles in water. The finer and lighter the particles, the longer it will
take them to settle, that is, for the suspension to clear. The amount
of light transmitted through the sample can be measured as a
function of time through the procedure of spectroscopy by using a
spectrophotometer.
spectroscopy: the branch of science
that involves the study of electromagnetic radiation and its interaction with
matter
spectrophotometer: a device for
measuring the interaction of light with
matter
You will use a Spectronic 20 for this experiment. This instrument
measures the amount of a particular wavelength of light absorbed by
or transmitted through a sample. In this case you will measure only the
amount of light transmitted through the sample of soil with time after
dispersing it by shaking it in water. Sand settles faster than silt, and silt
settles faster than clay. See the table on page 297.
Decide how best to do the experiment and to present this type of
data.
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Questions
Probative value is the ability of evidence to prove
something that is relevant to the crime.
1. Whose car killed Bud Coreopsis? What evidence of probative value do
you have? Explain.
2. Do you have enough evidence to convict?
3. What more could be done to tighten the case?
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L A B O R AT O R Y A C T I V I T Y
Where Is Alice Springs?
On Thursday, July 18 at 9:38 AM, the Springdale County Police received a call
from a Mrs. Marshall, who was concerned about the whereabouts of her
friend, Alice Springs. Marshall was to have had lunch with Alice the day
before, but she never showed up. Marshall called Alice’s house, but there
was no answer. That evening, she called again. Mr. Springs curtly told her
that Alice’s mother was ill, so Alice had gone to Florida to visit her. Marshall
felt that it not like Alice just to leave without telling her best friend.
The next morning, Marshall called their hairdresser because she knew
Alice had an early morning appointment. Alice had not appeared and had
not called to cancel. This prompted Marshall to call the police.
The county police had received over the years a number of domestic
violence complaints about Alice and Rusty Springs. Indeed, Alice had
appeared bruised and cut on several occasions. However, charges were
never pressed.
The police stopped by the Springses’ house in Martinsville that evening.
Rusty Springs brusquely repeated that his wife had left Wednesday to visit
her sick mother in Florida, and he didn’t know when she would be back.
On Saturday, July 20 at 11:41 AM, after hours of searching, Detective
Chernozem found Alice’s mother’s phone number in Orlando and called
her. She said that Alice was not there and that she was quite well, thank
you! A call to the county seat produced a search warrant, and that evening
Detective Chernozem and a colleague descended on the Springs home.
A thorough search turned up nothing out of the ordinary. There were
several shotguns (Mr. Springs was a duck hunter), but none had been fired
recently. As they were leaving through the garage, Detective Chernozem
noted a shovel (Figure 1) leaning against the wall next to a pair of black,
knee-high rubber boots. What had caught his attention was a dark,
puddlelike stain on the garage floor emanating from the blade of the
shovel. Looking more closely, he noted a small amount of dark soil under
the foot ridge of the shovel. He asked Rusty, who had been dogging them
ever since they set foot on his property, if he had been digging recently.
Rusty remarked that he had been working in the garden in the backyard.
The detective went out back looking for freshly spaded ground. Finding
none, he nevertheless took a sample of soil from the garden. Back in the
garage, he collected a small amount of dark soil from the back of Rusty’s
pickup truck. On a whim, he peered at the underside of the rear left fender of
the truck and saw a coating of dirt (Figure 2), which he carefully dislodged
with his penknife. It was damp, so it peeled off as a layer. It looked rather like
fudge with a dusting of light brown sugar. He observed the same coatings
above the other tires, but not on Mrs. Springs’s old Cavalier. Rusty testily
denied driving anywhere in the last week other than to work, the bar, and the
grocery store. Detective Cherozem impounded the shovel as they finally
departed.
Consider this episode in light of Alice Springs’s disappearance. Develop a
hypothesis of what could have happened. What are the clues? Should Detective
Chernozem have done more while he had access to Springses’ house?
DNA PAY DIRT
Scientists are investigating soil for genetic
information new to science that may result in a
new antibiotic or other lifesaving medicine. The
resource being tapped into is microbial DNA,
with genetic instructions for microbe-made
chemicals—antibiotics, insecticides, anticancer
drugs, antiparasitic agents, and others—that
now can only be imagined.
“If there are all these different kinds of
bacteria, there must be all kinds of chemicals that
they’re making,” says Jo Handelsman, professor of
plant pathology and a leader of the project aimed
at creating vast libraries of new genetic information from the soil. Indeed, soil microbes, scientists
know, live in close relationships with other
organisms in the same niche, and they almost
certainly depend on the chemicals they make for
everything from defense to communication.
The simple fact that most soil microbes cannot be cultured and studied in the laboratory
has prompted researchers to embark on a quest
to harvest the hidden potential of soil microbes
and the chemicals they make. The promise of
this genetic find is great. The relatively few soil
microbes that can be grown in the lab have
already yielded a host of helpful products,
from critical antibiotics and anticancer drugs to
antifungal compounds and herbicides.
—(University of Wisconsin, Madison)
Figure 1 The shovel
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Fender
Dark soil layer
Lighter soil layer
Figure 2 Dirt encrustation
Detective Chernozem collected five samples:
A. soil from the Springses’ garden
Earthworms digest organic matter, recycle
nutrients, and make the surface soil richer. One
earthworm can digest 36 tons of soil in one year!
Just how big a pile of soil is that?
B. soil from the shovel in the garage
C. soil from the bed of the truck
D1. the thicker, dark layer of soil from under the truck’s fender
D2. the lighter, thin layer coating the dark layer from under the truck’s
fender
Now, using forensic soil analysis techniques, characterize each sample.
What conclusions can you draw from your results? Are your results consistent with your original hypothesis of what may have happened? Are all the
dark soil samples the same?
Suggest a hypothetical reenactment of disposal of the body. Using the
map on page 303 draw up explicit directions so the police know where to
look, and quickly, because the predicted rain may destroy vital clues.
Through your rapid, astute, deductive reasoning, Detective Chernozem
and several colleagues are dispatched to the Mount Horeb swamp road,
where indeed there is an apparent blind spot running from the road to the
creek. The police notice a tire track in the dark muck by the road but no
footprints. After 15 minutes of traversing an area of cattails and saw grass,
they find disturbed soil on a slight rise by an old duck blind. They soon
unearth the body of Alice Springs, wrapped in a wool blanket. They take a
sample of the dark soil, as well as a sample from the dirt road leading into
the area. A plaster cast is made of the tire impression. (Did Detective
Chernozem check the tires of the truck?)
The swamp soil can now be compared to the dark-colored samples from
the Springses’ house that you have already charactarized. The sample from
the dirt road can be compared to the “light brown sugar” coating of the
dark soil from under the fender of Rusty Springs’s truck.
Each crime investigation team should submit a report with diagrams,
maps, and lab data that can be used in the prosecution of Rusty Springs
for the murder of his wife, Alice Springs. Each conclusion must be
supported to withstand any cross-examination by the defense.
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Figure 3 Topographic map of the Martinsville-Mount Horeb area
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Elevation, feet
Figure 4 The Mount Horeb swamp
460
440
420
400
stream
swamp
road
house
road
stream
Figure 5 Possible topographic profile, running SW to NE, near a line of sight; vertical scale
exaggerated
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The Coors Kidnapping
Q CASE
STUDY
Adolph Coors III, chairman of the Coors Brewing Company,
was kidnapped in the winter of 1960. Joseph Corbett, Jr., alias
Walter Osborne, had driven along the dirt road to Coors’s
ranch in the Rocky Mountains of Colorado. At a bridge over
a creek, he stopped Coors on his way to work and forced
him into his yellow Mercury sedan. There apparently was a
struggle, and Coors was fatally wounded.
Osborne’s burned-out car was found eight days later near
a municipal dump on the New Jersey shore. Incredible
detective work by the FBI established Osborne’s identity and
compiled circumstantial evidence through paper trails.
Coors’s body was found about seven months after the
kidnapping at a dump high in the Rockies. A few weeks later,
Osborne was found and arrested; however, he remained
silent. Nevertheless, Osborne had left a record of his travels
on the underside of his car.
Dust and grit from the dirt roads Osborne had traveled were
used to place him in the vicinity of the Coors ranch, the area
of the dump where the body was found, and the dump in
New Jersey. The inner three layers of dirt taken from under
Osborne’s car were compared to 421 samples of soil from
areas of Colorado alone to make a match. Ultimately, the
geological description and the sequence of the dirt layers
were the key evidence in reconstructing the crime and
convicting Osborne (see Figure 6).
Rocky Mountains
Pink feldspar dust
from granite
Coors Ranch area
Light gray quartzose, angular
sands from sandstone, shale
clay, limestone
Near dump where
body found
Pink feldspar dust grading
to coarser and brighter
Atlantic City dump,
New Jersey
Rounded sand grains, silt,
cinders, slag, paper fibers,
glass wool
Figure 6 Sequence of soil profiles of unpaved roads from Osborne’s car
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ASSESSMENT
1
Consider what indicators might place soil near the
following:
a.
b.
c.
d.
e.
In forensic science analyses, a sample
designated K is the known and originates from a
verifiable source. It is also termed exemplar. The
questioned or unknown (sample), designated Q,
has been collected from a known location, but it
is of unknown origin, initially.
a highway
a home
a commercial building
the ocean
a garden or farm
f.
g.
h.
i.
j.
a river
a gas station
a railroad track
a forest
a volcano
2
Why is sand not as useful as soil as evidence?
3
A burglar entered a house by jimmying open a back
window above a flower garden. Muddy footprints were
found in the house, on the windowsill, and in the garden
below the window. Police apprehended a suspect with
muddy shoes. How would you investigate the crime scene
and any evidence? Define the exemplars and the
questioned material.
4
Glass and sand are composed predominantly of
. How could one tell them apart?
5
Would a body decay faster if buried in the A and upper B
horizon, or in the lower B and upper C horizon?
6
Taxonomy is the science of classification. A hierarchical
organization system arranges items into groups with
common properties for use in making comparisons,
establishing relationships, and managing and locating
data. For example, the Henry-FBI system is used to classify
fingerprints; chemistry has many classification systems,
the periodic table being the most fundamental; Linnaeus
worked out an extensive system of classification for plants
and animals. What other systems can you think of? Is there
such a classification system for soils? If so, describe it.
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7
Here is a “back-of-an-envelope calculation”: How many
grains of 40-mesh sand are there in one cubic foot of dry
beach sand, assuming a 25 percent pore volume? How
much would one cubic foot weigh? Would one cubic foot
of beach sand 40 to 100 mesh weigh more, the same, or
less? Why?
Additional Projects
1. What does a forensic environmental scientist do? Is this an important field
of forensics? What is its future? Prepare a report with examples of cases,
real or hypothetical. See, for example, A. Dallas Wait and Linda L. Clark’s
article, “Opportunities in Environmental Forensic Chemistry Analysis,” in
Environmental Testing & Analysis, p. 31, July/August 1999. There is actually
a scientific journal published entitled Environmental Forensics. See
www.aehs.com/journals.htm
2. Write a short crime scenario using sand as evidence. What tests could
be performed for comparative analysis? See Jane Justus Frazier’s article,
“Sand Studies,” in The Science Teacher, May 1996, p. 14.
3. Sometimes the tools or clothing of a person suspected of breaking into
a safe will contain traces of safe insulation. What materials are used for
such insulation? How could they be characterized and differentiated?
Sand grains, transmitted light
Sand grains, reflected light
Sand grains, crossed polarizers
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References
Books and Articles
Loynachan, T. E., K. W. Brown, T. H. Cooper, and M. H.
Milford. “Sustaining Our Soils and Society,” American
Geological Institute. General information on soils. This
pamphlet can be purchased through this site or downloaded directly from www.agiweb.org/pubs/pubdetail.
html?item=603601al
Lynn, W. C., and M. J. Pearson. “The Color of Soil,”
The Science Teacher, May 2000, p. 20.
McPhee, J. “The Gravel Page,” The New Yorker,
January 29, 1996, pp. 46–90. Cases and detailed geological descriptions. This material is also included in
McPhee’s book Irons in the Fire, New York: Farrar, Straus
and Giroux, 1997.
Meloan, C. E., R. E. James, and J. R. Saferstein.
Criminalistics, An Introduction to Forensic Science, Lab
Manual (6th ed.). Upper Saddle River, NJ: Prentice-Hall,
1998.
Miller, L. S., and A. M. Brown. Criminal Evidence
Laboratory Manual; An Introduction to the Crime
Laboratory (2nd ed.). Cincinnati, OH: Anderson
Publishing Company, 1990.
Saferstein, R. Criminalistics: An Introduction to Forensic
Science (7th ed.). Upper Saddle River, NJ: Prentice-Hall,
2001.
Thorwald, J. Crime and Science. New York: Harcourt,
Brace & World, 1966. Detailed cases, with a riveting
account of Popp’s use of soil layers on a shoe to solve a
1908 murder, pp. 235–252.
Van Burgh, D., E. N. Lyons, and M. Boyington. “Teach with
Topographic Maps,” NSTA, Stock No. PBO38X8; 1994. This
pamphlet is available from National Science Teachers
Association, Arlington VA.
Websites
soils.ag.uidaho.edu/soilorders; soil taxonomy information
www.itc.nl/~rossiter/Docs/FM5-410/FM5-410_Ch4.pdf;
good technical definition of soil, how it is formed, and
test methods
www.geoforensics.com/geoforensics/art-1101a.html;
good overview of what a forensic geologist does
web.umr.edu/~rogersda/forensic_geology; case histories, including “How geologists unraveled the mystery of
Japanese vengeance bombs in World War II”
Murray, R.“Devil in the Details, The Science of Forensic
Geology,” Geotimes, February 2000, p. 14.
Murray, R. C., and J. C. F. Tedrow. Forensic Geology. Upper
Saddle River, NJ: Prentice-Hall, 1998.
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