1. BILL MCFARLAND
MENTOR: SCOTT BRAME
CLEMSON EEES GEOLOGY RESEARCH
FOREST MAPPING
Geochemical Analysis of Sloped
Site between Outcrops of
Amphibolite and Mica Schist

2. Site
Information
Clemson
Experimental Forest
Outcrops are scarce
Heavily forested
Moderate Slope
Bottom of slope:
Amphibolite
- Soil pH≈7.5
Top of Slope: Mica
Schist
- Soil pH≈ 5.5

3. Objectives
 Characterize soil transitions between amphibolite
and mica schist outcrops with no outcrops in
between
 Analyze borehole samples using hand methods and
X- Ray Diffraction (XRD)
 Assess whether geochemical and XRD analysis are
reliable indicators of lithology for mapping

4. Core Sample Collection
 AMS Soil Core Sampler Kit with Hammer
Attachment
 Collected cores on linear transect
 Challenges
 Compaction
 Parent material
http://www.forestry-suppliers.com/product_pages/Products.asp?mi=31181

5. pH Analysis
 pH was determined using colorimetric technique
 pH of borehole samples were taken
 Technique
 3-5 inches deep
 Surface effects
 reagents
 Challenges
 Colorimeter chart not precise
 Removing organic/ surface
material
http://pecosales.com/product_pages/view_catalog_page.asp?id=3068

6. X-Ray Powder Diffraction
 Technique used to study atomic spacing and crystal
structures
 Bragg’s law
 nλ= 2dsinθ
 Sensitivity
 Software measurements
 Sample preparation
 Preparation
 Grind
 Sieve to powder- 53 micros
 Properly prepare slides
http://education.mrsec.wisc.edu/nanolab/F_center/index.html

7. Bragg’s Law
 William Lawrence & William Henry Bragg
 Nobel Prize in Physics
 nλ= 2dsinθ
 d=d-spacing
 λ= wavelength of beam
 n= integer
 θ= incident angle
 Each mineral has own unique signature
 d-spacing allows identification
 Reference patterns
 XRD & PDXL basis
 PDXL based on Bragg’s Law with knowledge of crystal structure

8. XRD & PDXL Usage
 Initial XRD settings
 θ=5-90°
 y-axis= d-spacing intensity
 x-axis= 2θ
• PDXL Settings
• Settings management
• Composition identification
• Element filtering
• d-spacing intensities
• Analytical justification

9. Sampling Arrangement
Am
MS
1
2
3
4
5
6
7

10. Transition Zone
 Transition Zone
 Boreholes 3-4
 Color Characterization
 Sudden change in soil color
 pH Analysis
 Substantial change in pH
 Hand Sample Comparison
 Weathering and minerals
 XRD & PDXL Analysis
 Strontium and hydroxamic acid

11. Manual Soil Analysis
 Munsell color system characterization
 Color identification
 Hue: lightness
 Chroma: color purity

12. pH Analysis
 Amphibolite: pH≈7.5
 Fe2+ ions
 Mica Schist: pH≈5.5
 Aluminum silicate
 Garnetiferous
 Ionic influences
 Microorganisms
 Weathering

13. BM3_1-2 Bm4_3-4
Transition Zone: Hand Sample Comparison
Amphibolite
Quartz
Mica schist Muscovite
Quartz

14. BM3: 1-2 ft. BM4: 3-4 ft.
XRD Results for BM4

15. Strontium Hydroxamic Acid
 Alkaline Earth Metal
 Extreme Reactivity with
oxygen and water
 Intermediate to acidic pH
 Strontium binds to soil
particles by cation
exchange
 Organic compound
dissolved from strontium
 Known for chelation
ability
 Fe3+, Mg2+, Al3+
PDXL Analysis of BM4

16. BM5: 0-1 ft Bm6: 0-1 ft
XRD Results from BM5

17. Conclusions
 Transition zone identified between borehole sites 3-4
from hand sample and XRD analysis
 Analysis of XRD signatures that is not a reliable
method of outcrop transition because of inability to
collect unweathered soil samples
 At this site, the best method of lithology changes was
from hand sample analysis

18. Special Thanks
 Clemson University EEES Geology Research
 Prof. Scott Brame
 Victoria Sellers

19. Questions?