Geology

Question 1

What are some examples of samples for forensic geology?

Answer 1

• rocks
• sediments
• soils
• dusts
• minerals
• fossiles
• concrete
• bricks

Question 2

What are sediments, soils and dusts made from?

Answer 2

mixtureso of organic and inorganic particles

Question 3

What are some examples of inorganic fractions?

Answer 3

• rock fragments
• mineral grains
• amorphours matter

Question 4

what are some examples of organic fractions?

Answer 4

made from biological processes
* shells
* forams
* phytoliths
* diatoms
* CHO based products (coal)

Question 5

Where are rocks encountered in forensics?

Answer 5

• weights to sink bodies
• in bags containing illicit substances/firearms
• as concealment material in smuggling cases
• projectiles

Question 6

What are the three main classifications of rocks?

Answer 6

1. igneous
2. metamorphic
3. sedimentary

Question 7

What is diatomaceous earth made from?

Answer 7

• diatoms
• clay minerals
• iron oxide

Question 8

What are the four forms of sediments in size order from largest to smallest?

Answer 8

1. gravel
2. sand
3. silt
4. clay

Question 9

Where is gravel encountered in casework?

Answer 9

• tyre treads
• shoe soles
• drowning victims mouth/respiratory tract/clothing
• associated adhesive tapes

Question 10

Where is sand encountered in casework?

Answer 10

• beaches
• sand dunes
• construction sites
• found on/in footwear, clothing, vehicles, bodies, washing machine filters, U-bends of sinks and toilets

Question 11

Where is mud encountered in casework?

Answer 11

• on skin
• under fingernails
• on clothing/footwear
• in/on vehicles
• from coastal/river floodplains
• fields
• woodlands

Question 12

What makes up soil?

Answer 12

• non-living: inorganic material, salt crystals, decaying plant/animal matter, shells, insect exoskeletons, fossils, bones, teeth
• living: bacteria, algae, fungi, plant roots, invertebrates, small mammals
• unusal: cement, plaster, metallic fragments, glass, paint flakes, paper, fibres, plastic fragemtns

Question 13

How is dust used in casework?

Answer 13

• chemcial composition can vary a lot - indicative of geographical area
• can be transported thousands of miles
• natural, industrial, household, street, water sources

Question 14

What are the uses for vermiculite mineral?

Answer 14

• insulating material in fire resistant safes
• chimneys
• brake-lining
• floor screed, concrete
• fire-proof walls

Question 15

What is anthropogenic and what are some examples?

Answer 15

man made
* concrete
* bricks
* glazed ceramics
* plastic fragments
* fibres
* paint flakes
* glass fragments
* metal fragments

Question 16

What are some recovery considerations for soil?

Answer 16

• package in a paper bag or
• freeze in a tamper evidence bag to reduce yeast or fungal growth

Question 17

What is the analytical workflow for soil?

Answer 17

1. gross examination, recovery and collection
2. preliminary evaluation of physical characteristics
3. polarised light microscope
4. microspectrophotometry - colour determination
5. measurement of pH and electrical conductivity
6. IR - organic content
7. Raman - inorganic and carbon content
8. SEM-EDX - SE mode for topology and BSE for homogeneity
9. XRD - crystal structure and polymorphs
10. AAS, XRF, ICP-AES - elemental composition
11. isotopic analysis
12. MVA = HCA and PCA

Question 18

What are the physical characteristics of soil?

Answer 18

• weight
• volume
• colour
• texture
• for individual particles: dimensions, surface area, perimeter, shape

Question 19

What mainly makes up mud?

Answer 19

silt and clay

Question 20

What makes something mud?

Answer 20

any sediment that has a sticky character when wet

Question 21

What determines soil type formation?

Answer 21

• climate
• parent material
• age
• bio activity
• topography