1. Native elements, sulfides, oxides, & hydroxides JD Price

2. GoldAu SilverAg DiamondC GraphiteC SulfurS Images from mineral.galleries.com Native Elements

3. Gold deposits

4. Cyanide Leaching NaCN combines with Au or Ag to form a liquid. Gold can be removed from the gangue. 4Au + 8NaCN + O 2 +2H 2 0 = 4Na[Au(CN) 2 ] +4NaOH This is employed at a number of scales.

5. SphaleriteZnS ChalcopyriteCuFeS 2 BorniteCu 5 FeS 4 TetrahedriteCu 12 Sb 4 S 13 Octahedral coordination Pyrrhotite Fe 1-x S 2 GalenaPbS NiccoliteNiAs Image from mineral.galleries.com Copyright © 2002 - James A. Burbank, Jr. Tetrahedral Sulfides

6. Image from Klein and Hurlbut, 1993 Tetrahedral Sulfides

7. Molybdenite MoS 2 ArsenopyriteFeAsS MarcasiteFeS 2 PyriteFeS 2 StibniteSb 2 S 3 OrpimentAs 2 S 3 RealgarAsS CinnabarHgS CovelliteCuS ChalcociteCu 2 S Image from mineral.galleries.com www.wilenskyminerals.com Other Sulfides

8. Pyrite Arsenopyrite Marcasite Image from Klein and Hurlbut, 1993

9. Marcasite habit

10. Covelite CuS Image from Klein and Hurlbut, 1993

11. WHOI Seafloor Hydrothermal “Black Smoker” Deposits Grow as fast as 30 centimeters per day. Begins with a ring of anhydrite around a jet of 350°C fluid, which exits the seafloor at velocities of between 1 and 5 meters per second

12. WHOI

13. MVT Migration of hydrothermal fluid and its interactions with limestone form large sulfide deposits

14. Tri-state (KS-OK-MO) 200 foot tall tailings (chat) piles from Zn-Pb mines. Mining concentrates, relocates, and makes accessible materials to the surface environment Time Ground water Cd 93 µg/L Pb 130 µg/L Zn 240,000 µg/L (Parkhurst, 1987).

15. Disseminated Sulfide Igneous rocks may host small amounts of sulfide minerals. At Bingham canyon, these are economic.

16. Oxides are typically either Tetrahedral Octahedral Mixed (Tetra- and Octahedral) Simple packing of O with cations in interstices - packing! These are clear representations of the ionic crystal structures we talked about in the first few weeks of the class. Oxides

17. Few significant Tetrahedral Oxides ZnO, BeO Octahedral oxides more common MgO, Al 2 O 3, Fe 2 O 3, FeTiO 3, TiO 2 Coordination in oxides

18. Corundum group CorundumAl 2 O 3 HematiteFe 2 O 3 IlmeniteFeTiO 4 Rutile type RutileTiO 2 CassiteriteSnO 2 PyrolusiteMnO 2 PericlaseMgO Columbite(Fe,Mn)Nb 2 O 6 Tantalite(Fe,Mn)Ta 2 O 6 PerovskiteCaTiO 3 Image from mineral.galleries.com Octahedral Oxides

19. Corundum group

20. Spinel Group SpinelMgAl 2 O 4 MagnetiteFe 3 O 4 ChromiteFeCr 2 O 4 UlvospinelFe 2 TiO 4 FrankliniteZnFe 2 O 4 CupriteCu 2 O Image from mineral.galleries.com www.mineralminers.com Mixed Coord. Oxides

21. XY 2 O 4 X octahedral Y tetrahedral Chromite FeCr 2 O 4 Spinel MgAlAlO 4 Magnetite FeFe 2 O 4 Mixed Oxides

22. TiO 2 - FeO - Fe 2 O 3

23. Iron oxides differ because of the valency of the transition element, Fe. The result of oxidation 2 FeFe 2 O 4 + 0.5 O 2 = 3 Fe 2 O 3 With increasing depth, there is less oxygen available. Fe becomes more reduced. Oxygen and oxides

24. Yet another thermodynamic parameter f fugacity Chemical potential µ (not really new) µ = U+PV-TS (that’s G) for an individual component f = exp  µ = exp [µ T,P - µ ss ] Fugacity as a measure of how much the chemical potential of the component in the gas deviates from the chemical potential of the standard state due to changes in P and/or the mole fraction of the component. Just like a partial pressure (just not so ideal).

25. Oxygen and oxides MH - 2Fe 3 O 4 +O = 3Fe 2 O 3 WM - 3FeO + O = Fe 3 O 4 IW - Feº + O = FeO NNO - Niº + O = NiO

26. Maun and Osborne Now with f O 2

27. Meet BIF (Banded Iron Formation) Rock is 2.5 billion years old (found world wide from 3 - 1.8 Ga) Dark: Hematite (Fe 2 O 3 ) Red: Quartz (with iron) Yellow: Crocidolite (blue asbestosform) The accumulation of iron as seafloor sediments is thought to result from early photosynthesis on the ocean surface under N 2 – CO 2 rich conditions. A lack of atmospheric O 2 permits Fe ions in surface seawater – these bond with O 2 produced by photosynthesis.

28. Prolonged runs at high temperature produce a solid state reaction between MgO and Al 2 O 3, forming a layer of spinel This study Evaluated spinel growth rate as function of t, T, and P Constrained the thermodynamic stability of spinel at elevated P Constructed Al-Mg coupled diffusion model

29. Boundary compositions EMPA traverses of spinel Stoich. spinel Al enriched 1400 o C 4 GPa 89 hr 30  m 600 o C 3.2 GPa 16 hr 66  m 1978 o C 2.5 GPa 0.4 hr 115  m

31. GoethiteFeO(OH) Bauxite Monhydrate Diaspore AlO(OH) BoehmiteAlO(OH) Trihydrate GibbsiteAl(OH) 3 Image from mineral.galleries.com Hydroxides