Jambo !

1. Jambo! • Do Now: • Take out HW and Thank you notes • Agenda: • Notes quiz • Intro to Soil • HW: • Soil Handout online

2. What Is Soil? • Mixture of organic and inorganic material • May range from 100% inorganic (sand) to nearly 100% organic (peat) • Inorganic part is minerals • Organic part is decayed plant and animal material and is sometimes called humus

3. Soil • primarily made of: • weathered rock • air • H2O • bacteria • Humus • soil formation process is what makes soils unique • influenced by temperature, rainfall, chemicals and minerals present

5. Forensic Significance of Soil • Soil is class evidence - cannot be individualized to a particular location • Soils can be easily transported • Soils within a few meters horizontally or vertically differ

6. Soil Composition • Three main grain sizes • Sand largest • Silt • Clay  smallest • Three sub categories of soil • Loam  sand, silt, clay • Peat  more than 20% decaying material • Chalk  Alkaline, solid but soft rock

7. Soil Type Comparison

8. Horizons in a Soil Sample

9. Horizons • O Horizon • Humus- decaying organic material • A Horizon • “top soil” soil is dark in color • mixture of Humus and mineral particles • This is where seeds sprout and plant roots grow • E Horizon • Light in color Made of sand and silt • H2O drips through this layer and carries away most of the minerals and clay originally present

10. Horizons cont’d • B Horizon • “subsoil” • contains clay and mineral deposits that have leached from layers above • C Horizon • layer is made up of partially broken rock • no humus or plant roots • R or D Horizon • soild rock

11. Chemistry of Soil • Nutrients: NPK • Nitrogen • promotes chlorophyll production • needs a pH >5.5 to be dissolved in H2O and contained within the soil • Phosphorus • necessary for root development and increases flowering ability and size • needs a pH between 6.0-7.0 • Potassium • guards against disease and aids in draught protection and cold tolerance

12. pH Review • NPK dissolves more easily in slightly acidic or alkaline environment • Rainfall, pollution, acid rain, and fertilizer can all affect pH

13. Results of nutrient Deficiencies

14. Sand • Formed by Weathering • action of wind and water on rocks • collisions break rock into smaller and smaller pieces • grains are usually • 0.05mm to 2mm in diameter • Shape is rounded or angular • Crystal- if sand only contains one type of mineral • Fragment- if the grain consists of 2 or more minerals

17. Sand • Rounding • can take millions of years to complete • Immature or Young • contains a large portion of clay • grains have a high % of fragments • Found in bottom of bays, lagoons, swamps or river plains • Mature or Old • No clay and fewer fragmented edges • Found in beaches and desert dunes • lots of H2O and weathering

18. Sand Composition

19. Continental • contains quartz, micas, feldspar, hornblede, magnetite • Feldspar • if present then the sand probably came from a temperate, polar climate, or a high latitude • in warm, tropical climates it weathers away quickly • Quartz • high % means that the sand is very old • weathers very slowly

20. Mineral Components of Sand

21. Volcanic • usually dark in color because of black basalt or green olivine • From mid-ocean volcanoes, hot-spot volcanoes (Hawaii) • sometimes contains volcanic cinders or other volcanic debris • very young and has little to no quartz

22. Jambo • Do Now: • Take out your HW and compare what you found with your lab bench. Describe the soil around your houses. What kinds of plants are growing around your house? What do you think forensic scientists would find unique about the soil around your house? How do you think they could determine that soil came from your house and not a neighbor’s house? • Agenda: Soil Activity • HW: Read Coors Case and Answer Q’s Due 11/8

23. Soil Observation Activity • Visually examine the soil on each plate and take notes about each sample. Write down which samples you believe came from the same location. Explain your conclusions

24. Skeletal • made from marine organisms: • microogranisms • shells • corals • younger type of sand • Coral is found only in tropical regions • Large amounts of CaCO3 creates bubbles with the addition of acid

25. Precipitate • contains dissolved minerals • when H2O evaporates minerals come out of solution and form crystals • CaCO3 can precipitate out of sea water forming a coat of hard particles that resemble an onion • eventually form small, round particles oolites

26. Soil Collection • collect all samples as soon as possible • collect at surface baseline and samples that appear different or out of place from the rest of the environment • collect at least 4 tbsp of material from several locations at the scene. (Plastic Vials) • sketch the crime scene and note where the samples were obtained • be careful not to remove soil stuck to shoes, clothing, or tools found at the crime scene.Package these items separately in appropriate containers (Paper Bags) • carefully remove soil from vehicles and package the soil samples separately • Document all samples by taking photographs, drawing sketches, and labeling the evidence collection containers • Collect additional soil samples from the four compass point (N,S,E,W) within a few feet of the crime scene. Collect another set 20-25 feet from the crime scene

27. Soil Examination • compare characteristics of the soil samples from suspect or crime scene to those from a known location • layers of soil or mud from shoes or wheels can show that a suspect was present at a series of locations • compare size, shape, color by looking macroscopically • soil type, amount of organic material, particle size • Can be identified and compared by • density • moisture content • chemical testing for mineral content • X-ray Diffraction

29. To identify the minerals in rock and soil samples, the Curiosity will lean heavily on X-ray diffraction technology • X-ray diffraction is the most reliable way to identify minerals, but this is the first time it will be used on a mission to Mars. • When samples are collected, an X-ray beam will be focused at it, and the sample will scatter the X-rays in different directions

30. each mineral has a trademark diffraction pattern, allowing scientists to identify what mineral they're looking at • NASA’s Curiosity rover has completed the first-ever detailed X-ray analysis of Martian sand, determining that it contains minerals similar to volcanic soil found at places like the Mauna Kea shield volcano in Hawaii