Preface 1 Carbon, the Earth and life: 11 Carbon and the basic requirements of life12 Chemical elements, simple compounds and their origins13 The origin of life14 Evolution of life and the atmosphere15 Major contributors to sedimentary organic matter 2 Chemical composition of biogenic matter: 21 Structure of natural products22 Carbohydrates23 Amino acids and proteins24 Lipids25 Lignins, tannins and related compounds26 Nucleotides and nucleic acids27 Geochemical implicatiions of compositional variation 3 Production, preservation and degradation of organic matter: 31 How and why organic-rich deposits form32 Controls on primary production33 Preservation and degradation of organic matter34 Depositional environments associated with accumulation of organic matter 4 Long-term fate of organic matter in the geosphere: 41 Diagenesis42 Humic material43 Coal44 Kerogen45 Catagenesis and metagenesis46 Temporal and geographical distribution of fossil organic carbon 5 Chemical stratigraphy 51 Biologically mediated transformations52 Examples of source indicators in recent sediments53 Diagenesis at the molecular level54 Source and environment indicators in ancient sediments and oil55 Thermal maturity and molecular transformations56 Palaeotemperature and age measurement57 Maturity of ancient sedimentary organic matter58 Isotopic palaeontology 6 The carbon cycle and climate 61 Global carbon cycle62 Changes in carbon reservoirs over geological time63 Palaeoclimatic variations64 Isotopic excursions at period boundaries65 Human influence on the carbon cycle 7 Anthropogenic carbon and the environment 71 Introduction72 Halocarbons73 Hydrocarbon pollution in aquatic environments74 Endocrine disrupting chemicals75 Environmental behaviour of selected xenobiotic compounds76 Factors affecting the rate of anthropogenic components Appendix 1: SI units usedAppendix 2: SI unit prefixesAppendix 3: Geological timescaleReferencesIndex

An introduction to organic geochemistry

Carbon and nitrogen isotopes in hydrocarbon research and exploration

Genetic and post-genetic molecular and isotopic fractionations in natural gases

Carbon isotopic and molecular constraints on the formation and the expulsion of thermogenic hydrocarbon gases

The natural distribution of carbon isotopes between hydrocarbon gas components is used for (1) determining a gas's maturity, (2) correlating a reservoired gas to its source, (3) correlating one reservoired gas with another, and (4) recognizing gas mixtures. Calculated separations of carbon isotopes between the normal alkane components of a natural gas have been related to source rock maturity by use of a single, continuous diagram, independent of source type. Actual data from a wide variety of geologic settings and geologic ages confirm this relationship and demonstrate its applicability to the source rock Levels of Organic Metamorphism ranging from 8 to 13, covering the entire range of oil and wet-gas generation. At greater maturities, the wet-gas components are found to undergo thermal degradation, losing their usefulness for correlation. Three examples showing indigenous gas (west Texas), non-indigenous gas (Gippsland basin, Australia), and gas mixtures from multiple sources (southeastern Alberta) illustrate exploration applications.

E. M. Galimov

Papers

Carbon isotopes in oil-gas geology