GEO 195 Introduction to Geochemistry

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Transcript GEO 195 Introduction to Geochemistry

GEO 135
Introduction to Geochemistry
Greg Druschel
321 Delehanty Hall
[email protected]
Course Goals
At the end of this course…
• You will be able to utilize thermodynamic to determine if
individual reactions are feasible/important under any
given condition
• You will be able to design a sampling protocol, analyze
key chemical components, apply thermodynamic or
kinetic models, and test hypotheses concerning the
mobility of elements in any setting
• You will be able to appreciate both the dynamics and
complexity of geochemistry yet utilize what you know to
ascertain processes important in the stability, movement,
and reactivity of elements in the earth
What is Geochemistry??
• Victor Goldschmidt defined the study of
geochemistry as: “the laws governing the
distribution of the chemical elements and
their isotopes throughout the earth”
• What does that mean?
• We are interested in understanding the
different ways in which elements move 
whether in the core, mantle, crust, oceans,
sediments, air, space, or other planets…
Light  photochemical rxns, phototrophic organisms??
O2 diffusion
FeS2 + 3.5 O2 + H2O  Fe2+ + 2 SO42- + 2 H+
Bacteria/ archea  Fe oxidizers, S oxidizers
Fe2+ + O2 + H+  Fe3+OOH + 2 H+
H+ + SO42- < -- > HSO4CH2O + FeOOH  Fe2+ + CO2
CH2O + SO42-  HS- + CO2
Field Geochemistry
• Scale – Where and when do you take a sample??
Field Notebook
• Need to record all observations,
measurements, and sampling
• Get something weatherproof (Write-in-the
rain notebooks work great)