ABSTRACT
Organic geochemistry is the study of the organic chemistry of the geosphere. It is an inter-disciplinary subject encompassing many of the traditional sub-divisions of the physical sciences, for example biochemistry, organic chemistry and sedimentary geology, although a working knowledge of many other subjects (e.g. microbiology, physical chemistry and aquatic chemistry) is also helpful. Organic matter, that is reduced carbon, occurs in many guises in the geosphere and it is convenient to distinguish between fractions (e.g. lipid, asphaltene and kerogen) which are typically operationally defined by their solubility, or otherwise, in a particular solvent system and, consequently, are analysed using different techniques. These gross fractions are usually further sub-divided, as exemplified by the lipids.
