Unit 5 Flashcards
What features in a crush-rock sample that may indicate it was salted with river gold?
-no signs of host rock
-shape indicative of move water (smooth, flat or rounded, spherical)
-purity (high for river gold)
Name some ways to differentiate a diamond from a cubic zirconia.
Diamond tester, thermal conductivity tester, x-ray diffraction, refractometer, heat test, scratch test, density test, visual test (UV, color, florescence).
Or look for laser markings and serial number.
Why is the testing of white paint on paintings significant in forensic analysis?
the record of varying materials used to create pigments throughout history
Name some different materials used to create white pigments throughout history.
Chalk, lead, zinc, titanium
How can an explosion be identified based on short and long wave seismic energy?
Explosions have lower energies at long wavelengths and higher energies at short wavelengths. There ratios are usually above 1.0
What material do caves form in?
Limestone
How can an earthquake be identified based on short and long wave seismic energy?
Earthquakes have higher energies at long wavelengths and shorter energies at short wavelengths. There ratios are usually below 1.0
Describe Quaternary alluvium.
Poorly sorted geological deposit formed during the Quaternary period.
What is an isotope?
Element with the same number of protons but different numbers of neutrons resulting in different atomic weights.
How are isotopes detected?
Through isotopic analysis using a mass spectrometer
What is the Rb-Sr decay system?
A geochemical tracer
1/4 isotopes for Strontium, (87Sr) is produced through radioactive decay of rubidium isotope (87Rb). Anything that originally contained Rb will have increasing levels of 87Sr.
How does the Rb-Sr decay system help us understand the movements of past individuals through time?
Sr can substitute for calcium during the formation of bone, dentine, and enamel
Different Sr values are found in different geologic areas.
Varying Sr levels can be found in a persons remains based on when and where the Sr was stored (close to water vs inland, Sr value from dentine, enamel or bone)
When is enamel formed?
the first 4-12 years of life and doesn’t change after that
When is bone formed?
throughout an persons life
What does different Sr levels in a person enamel vs bone indicate?
They moved at some point in their life
How are “local” Sr isotope ratios obtained?
Comparing Sr levels in local proxies (e.g. local animals)
How could you assess human mobility from a tooth sample?
By extracting a purified Sr sample and comparing it to a living and deceased proxy animal from the area. If its different, the sample if from a different area.
What 4 steps are important in investigating a potential contamination?
- Information gathering
- Testing, sampling, analysis
- Hazard/risk analysis and mitigation
- Findings and recommendations
How is potential contamination of ground water and wetlands assessed?
-the analysis of molecular containment trace elements both regularly and ongoing through monitoring wells, ground and surface samples
How would you test potential contamination of a water supply?
routine monitoring of river water (up and down stream), the water supply plant, the supply plant intake system, and monitoring wells
