GEOL6550 Clay Mineralogy - Final exam – Spring 2006

Use any resource (i.e., open book) and work independently.  Due under my door (room 329) Friday, May 5^th at 5 PM.

1.  The figure below contains diffractograms of an oriented <2µm mount. Identify the phase(s) present. Discuss the basis for your interpretation.

 

°2Θ Cu Radiation

 Top pattern -  Ethylene Glycol and Ca-saturated:        Bottom pattern - Heated 100 °C 
 

2. Recalculate the chemical analysis below into a structural formula for a 2:1 phyllosilicate. What mineral group is represented by the chemical analysis below?

                                Oxide     Wt. %

                                SiO₂       53.45

                                Al₂O₃       2.49

                                TiO₂         0.05

                                Fe₂O₃     15.85

                                FeO          3.55

                                MnO         0.01

                                MgO         6.44

                                CaO          0.07

                                Na₂O        0.04

                                K₂O        10.33

                                H₂O⁺        8.04

3. Read the attached article. (a) What was the objective(s) of the study? (b)What methods were employed? (c) What were the significant results? (d) What were the major conclusions of the study? (e) Critically comment on the interpretations of the authors. (f) What would you have done differently or what study would you propose to do next?

4. Construct a reciprocal lattice for anatase assuming an orientation of the b* perpendicular to the page. Please note scale and label first 3 orders of +/- hkl.