Plan of the Course
      •  The Geochemical Toolbox
          o Thermodynamics
          o Kinetics
          o Aquatic systems
          o Trace elements & magmatic systems
          o Isotopes
              • Radiogenic
              • Stable
      •  The Big Picture: Cosmochemistry
          o Formation of the elements
          o Formation of the Earth and the Solar System
      •  Chemistry of the Earth
                               Other Info
   Text: White: Geochemistry, Wiley-Blackwell,  •   Grading: 40% Problem 
   ISBN 978-0-470-65668-6                           Sets (6 to 8),20% 
                                                    Prelim, 40% Final 
                                                    Exam
                                                •   http
                                                    ://www.geo.cornell.ed
                                                    u/geology/classes/geo
                                                    455/EAS455.
                                                    html
                                                •   Office: 4112 Snee
                                                •   Office Hours: no 
                                                    formal office hours – 
                                                    drop by anytime.
                     Thermodynamics
      •   Thermodynamics is the study of energy & its 
          transformations.
           o Chemical changes involve energy; by “following the energy”, we can 
              predict the ‘equilibrium’ state of a system and therefore the outcome of 
              reactions.
                • For example, we can predict the minerals that will crystallize from a 
                  cooling magma.
                • We can predict that as the concentration of atmospheric CO  
                                                                                 2
                  increases, so does that of the ocean and the calcium carbonate shells 
                  of oysters and skeletons of corals will become more soluble.
                    o (This at first seems counter-intuitive, and has to do with a 
                       decrease in ocean pH).
      •   Thermodynamics uses a macroscopic approach.
           o We can use it without knowledge of atoms or molecules.
           o We will occasionally consider the microscopic viewpoint using statistical 
              mechanics when our understanding can be enhanced by doing so.
             Thermodynamics and 
                                   Kinetics
      •  The equilibrium state of a system is independent of 
         any previous state. So, for example, if we do a partial 
         melting experiment with rock, it should not matter if 
         we start with a solid and partially melt it or with a melt 
         and partially crystallize it, or whether we partially 
         dissolve calcium carbonate or partially precipitate it.
      •  Kinetics is the study of rates and mechanisms of 
         reaction. Kinetics concerns itself with the pathway to 
         equilibrium; thermodynamics does not. Very often, 
         equilibrium in the Earth is not achieved, or achieved 
         only very slowly, which naturally limits the usefulness 
         of thermodynamics. 
                  ‘The System’
     Four Kinds of Systems     • A thermodynamic 
                                 system is the part of 
                                 the universe we are 
                                 considering. 
                                 Everything else is 
                                 referred to as the 
                                 surroundings. 
                                  o We are free to define the 
                                    ‘system’ anyway we chose. 
                                    However, how we define it 
                                    may determine whether we 
                                    can successfully apply 
                                    thermodynamics.