Soil

Question 1

What is Forensic Geology?

Answer 1

• application of the geological information and techniques to problems that may come before a court of law

Question 2

What is Forensic Soil Science? (also forensic pedology)

Answer 2

• application of information relating to the properties of soils in matters that may come before a court of law

Question 3

Trace evidence is governed by what principle?

Answer 3

Locard Exchange Principle

Question 4

What other evidence uses the sediments and soils as matrices?

Answer 4

• human remains

- non-soil trace evidence (hair, fibers, ignitable liquid residues, explosive residues)

Question 5

What is the Locard Exchange Principle?

Answer 5

• every touch leaves a trace
• holds that the perpetrator of a crime will bring something into the crime scene and leave with something from it, and that both can be used as forensic evidence
• there is a triangle between victim, perpetrator, and crime scene

Question 6

What are the limitations to the Locard Exchange Principle

Answer 6

• not all trace evidence is transferred
• not all transferred trace evidence is retained
• not all transferred trace evidence is recovered
• trace evidence may be transferred without direct contact

Question 7

What are some methods that is used at the CS to collect trace evidence?

Answer 7

• hand picking
• taping
• adhesive lifters
• vacuuming

Question 8

What are some precautions that investigators must remember when collecting evidence at the CS?

Answer 8

• must take care not to leave their own trace evidence at the scene
• items of evidence must be handled and packaged to minimize redistribution of trace evidence and to prevent cross-contamination

Question 9

What are some methods used in the lab when collecting trace evidence?

Answer 9

• hand picking
• scraping
• taping
• adhesive lifters
• vacuuming

Question 10

What are some precautions that technicians must remember when collecting evidence in the lab?

Answer 10

• only one item of evidence should be examined at a time
• a special clean room should be used for examinations
• work surfaces should be thoroughly cleaned after the examination of each item of evidence

Question 11

What are some types of geological and soil materials that may appear as Forensic Evidence?

Answer 11

• rocks
• sediments
• soils
• dusts and particulates
• minerals
• glasses and other amorphous materials
• fossils
• anthropogenic materials

Question 12

What are the three main types of rocks?

Answer 12

• igneous
• metamorphic
• sedimentary

Question 13

Igneous Rocks

Answer 13

• formed by crystallization from molten magma
  
  • below Earth’s surface (intrusive or plutonic)
  • at the surface (extrusive or volcanic)

Question 14

Metamorphic Rocks

Answer 14

• formed from a pre-existing rock or sediment
  
  • there are changes in mineralogy, chem & structure
• these are subjected to high temps, pressure &/or sheering

Question 15

What are the types of metamorphism

Answer 15

• burial
• contact
• shock

Question 16

What are the three classifications of main Sedimentary Rock types?

Answer 16

• siliciclastic rocks
• carbonate rocks
• chemical precipitates and residues

Question 17

Sediments

Answer 17

• loose mixtures of particles, which have been deposited by air, water or ice
  classified on the basis of the amount of gravel, sand and mud they contain
• (___) that contain no gravel are classified on the basis of the amount of sand, silt and clay they contain

Question 18

What are the two types of Sediments

Answer 18

• detrital (allochthonous)

- chemical (autochthonous)

Question 19

What is the grain-size classification for sand, silt, and clay?

Answer 19

sand: 2m > d > 0.0625mm
silt: 0.0625mm > d > 0.0039mm
clay: 0.0039mm > d