Elementary Geochemistry

Geochemistry Final Exam Deadline: October 19, 2011 Briefly answer the following questions: 1.     Derive the formula for calculating age, given the half-life of and amount of parent and daughter isotopes. 2.    Chemically, mineralogically and texturally, distinguish a gneiss formed from the metamorphism of shale from a gneiss formed from a quartz-diorite parent rock. 3.     Explain why underground water in contact with limestone is alkaline. 4.     List the chief products of chemical weathering of a) basalt b) dolomite. 5.     Why are clays a primary hydrothermal alteration material? Bonus: 1. Draw a snail. 2. Best love team sa ageos, why?

Phase Diagrams The figure above shows the phases of water at different pressures and temperatures. Clearly shown is that at constant pressure of 1atm, and with increasing pressure, water will melt (solid to liquid) at 0 ° C and will evaporate at 100 ° C. 1 atm is then the vapor pressure of water at 100 ° C, or the pressure that water will evaporate at the given temperature. The curve connecting the triple point and critical point is called the vapor-pressure curve. Liquid water and water vapor may coexist at any point in this curve. This curve also shows that the vapor pressure of water increases as temperature increases. The triple point is where all three phases (solid, liquid and gas) are exhibited by water. The critical point is the pressure and temperature combination where liquid water and water vapor may not be distinguished as separate phases. The above illustration is a Phase Diagram of a One-Component System , the sole component being water. In this particular di...