The characteristic structure of a sterane molecule, a biomarker. Living organisms possess exclusively one type of sterol, but during diagenesis and catagenesis, steranes are gradually transformed, until an equilibrium is reached. Thus, the ratio of transformed steranes to untransformed steranes can be used to estimate the maturity of sedimentary rock and the thermal history of a sedimentary basin. (Image by Prof. Roger Summons.)
12.491 is a seminar focusing on problems of current interest in geology and geochemistry. For Fall 2005, the topic is organic geochemistry. Lectures and readings cover recent research in the development and properties of organic matter.