1. Chapter 12 Soil Examination By the end of this chapter you will be able to:
Identify the different minerals in sand
Analyze sand found in different Hawaiian beaches
Recognize various soil types
Discuss soil horizons
Explain the chemistry of soils
Describe the collection and examination of soil evidence
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Forensic Science: Fundamentals & Investigations, Chapter 12

2. Introduction Factors affecting soil and sand
Temperature
Rainfall
Chemicals and minerals in the soil
Soil and sand physical and chemical characteristics vary by location
Soil and sand analyses help link:
Suspects to crime scenes
Locating burial sites
Forensic Science: Fundamentals & Investigations, Chapter 12

3. History of Forensic Soil Examination
Dr. Hans Gross—
Criminal Investigation (1893)
One of the first to recognize the importance of physical evidence like soil
Georg Popp
First to use soil evidence to solve a crime
Linked soil samples found on a suspect with samples found at the crime scene (coal on handkerchief) .
Forensic Science: Fundamentals & Investigations, Chapter 12

4. Sand & Soil Analyze for mineral content. Gross Examination
Use microscopic examination.

5. Sand—Weathering
Breaking down rock into sand with wind and water forces
Old sands are more around.
Forensic Science: Fundamentals & Investigations, Chapter 12

6. Mineral Composition of Sand
Quartz
Sand may contain minerals:
Quartz
feldspars
micas
iron compounds
Sand can contain organic materials
Coral
Seashells
Mica
Forensic Science: Fundamentals & Investigations, Chapter 12

7. Composition of Hawaiian Sand
Unlike the sand on a typical continental beach, the sands of Hawaii's beaches contain very little quartz. This is because there is almost no quartz present in the dark basaltic lavas of the Hawaiian volcanoes. 
See the following slides for different minerals found in the sand.
Forensic Science: Fundamentals & Investigations, Chapter 12

8. Biogenic Sand Sea Shells & Coral
Forensic Science: Fundamentals & Investigations, Chapter 12

9. Magnetite
iron bearing mineral (a form of iron oxide) that is magnetic.
opaque, very small and very black and are attracted by a magnet.
Forensic Science: Fundamentals & Investigations, Chapter 12

10. Olivine A yellow-green mineral, translucent.
Forensic Science: Fundamentals & Investigations, Chapter 12

11. Basalt Fragments Small pieces of lava rocks Dark gray to black and
are opaque
Forensic Science: Fundamentals & Investigations, Chapter 12

12. Soil Composition Soil is top layer of Earth’s crust It is composed of
Minerals
Decaying organisms
Water
Air
All in varying amounts
Forensic Science: Fundamentals & Investigations, Chapter 12

13. Soil Texture/Types The 3 main grain sizes in soil are Sand (L)
Silt (M) –sediments in riverbeds
Clay (S)
Loam – all three sand, silt, and clay combined. (best for agriculture)
Peat – decaying organic material
Chalk – alkaline soil with mineral (poor for agriculture)
Forensic Science: Fundamentals & Investigations, Chapter 12

14. Soil Profiles Humus, the O horizon, is made of decaying organic matter
Topsoil, the A horizon, is a mixture of humus and minerals
Sand and silt makes up the E horizon\
Subsoil, the B horizon, is made of clay and minerals
Broken rock, the C horizon, has very little humus present
Solid rock makes up the R horizon
Forensic Science: Fundamentals & Investigations, Chapter 12

15. Chemistry of the Soil
The pH scale measures the acidity or basicity of a solution
Forensic Science: Fundamentals & Investigations, Chapter 12

16. Chemistry of the Soil Acidic or basic (alkaline)—the pH scale
What affects the pH level?
Materials that make up a soil
Rainfall
Pollution
Fertilizer
The pH value of a soil sample helps scientists match it to other samples
Forensic Science: Fundamentals & Investigations, Chapter 12

17. Soil Collection —Chain of Custody
A chain of custody log is essential
Bag, identify, seal, and sign
Each subsequent user opens bag on a “new” side
Return contents to original bag evidence bag, seal it in another bag, and sign the evidence log
Forensic Science: Fundamentals & Investigations, Chapter 12

18. Analysis
Obtain some soil samples from your teacher and try to match sample with crime scene.