The second edition of The Biomarker Guide is a fully updated and expanded version of this essential reference. Now in two volumes, it provides a comprehensive account of the role that biomarker technology plays both in petroleum exploration and in understanding Earth history and processes. Biomarkers and Isotopes in the Environment and Human History details the origins of biomarkers and introduces basic chemical principles relevant to their study. It discusses analytical techniques, and applications of biomarkers to environmental and archaeological problems. The Biomarker Guide is an invaluable resource for geologists, petroleum geochemists, biogeochemists, environmental scientists and archaeologists.

The Biomarker Guide

Analyses of the natural variation in stable isotopes of components of ecological systems have provided new insights into how these systems function across paleoecological to modern timescales and across a wide range of spatial scales. Isotope abundances of the molecules in biological materials and geochemical profiles are viewed as recorders that can be used to reconstruct ecological processes or to trace ecological activities. Here, we review key short-, medium- and long-term recording capacities of stable isotopes that are currently being applied to ecological questions. The melding of advances in genetics, biochemical profiling and spatial analysis with those in isotope analyses and modeling sophistication opens the door to an exciting future in ecological research.

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Stable isotopes as one of nature's ecological recorders

Geochemical evolution of organic-rich shales with increasing maturity: A STXM and TEM study of the Posidonia Shale (Lower Toarcian, northern Germany)

The Puguang gas field is the largest gas field found in marine carbonates in China. Marine carbonate reservoirs in this field were buried to a depth of about 7000 m (22,966 ft) and experienced maximum temperature up to 220C before uplift to the present-day depth of 5000–5500 m (16,404–18,045 ft), with present-day thermal maturity between 2.0 and 3.0% equivalent vitrinite reflectance (Ro). Sulfur-rich pyrobitumens with reflectance up to 3.5% are widespread in the reservoirs and resulted from thermal cracking of crude oils most likely generated from Upper Permian source rocks and thermochemical sulfate reduction (TSR). Natural gases in the Puguang gas field have wide variations in nonhydrocarbon gas contents, with H2S contents between 5.1 and 58.3% and CO2 contents between 7.9 and 18.0%. The hydrocarbon gases originated mainly from thermal cracking of accumulated oil but were altered by TSR. Thermochemical sulfate reduction in the study area exerted different effects on the isotope compositions of different hydrocarbon gas components at different TSR stages. The differential increase of 13C values for different gas components reflects transformation from a heavy-hydrocarbon-gas–dominated TSR stage to a methane-dominated TSR stage. This caused a decrease of 13Cmethane13Cethane values and a corresponding conversion from reversed to normal isotope distributions. Thermochemical sulfate reduction in the study area appears to have been limited by sulfate concentrations in the reservoirs. A successive, three-stage TSR series, namely, liquid-hydrocarbon–involved TSR, heavy-hydrocarbon-gas–dominated TSR, and methane-dominated TSR, occurred in reservoirs with sufficient sulfate concentration. Methane can be the dominant organic reactant for TSR, but only at elevated temperature and after most C2+ hydrocarbons are exhausted.

Evidence for multiple stages of oil cracking and thermochemical sulfate reduction in the Puguang gas field, Sichuan Basin, China

Changes in the D/H ratio of sedimentary organic matter (SOM) during thermal maturation have been difficult to interpret because the effects of hydrogen exchange and kinetic fractionations are confounded in natural samples. Recent analytical developments have significantly improved our understanding of the responsible mechanisms. In this paper, we review experimental and field data that document a progressive increase in the D/H ratio of most organic hydrogen at the bulk and molecular levels, and suggest that the transfer of hydrogen from water to organic matter is the most important mechanism leading to those changes. SOM and water in natural petroleum systems approach a pseudoequilibrium D/H fractionation of about −80 to −110‰. D/H ratios of organic hydrogen can preserve quantitative information about paleoclimate throughout diagenesis, and some qualitative information through catagenesis.

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Hydrogen Isotopic (D/H) Composition of Organic Matter During Diagenesis and Thermal Maturation

Chemical and carbon isotopic fractionations of gaseous hydrocarbons during abiogenic oxidation

The effects of calcite and montmorillonite on oil cracking in confined pyrolysis experiments

Pyrolysis experiments on kerogen (Estonian Kukersite) were conducted in a confined system (gold capsules) in the presence and absence of water and various minerals, i.e., kaolinite, montmorillonite, calcite, and dolomite, respectively, at a fixed pressure of 50 MPa and in the temperature range 240–400 °C. For the four experiments in the presence of minerals and a large amount of deionized water (OC/mineral/water 1:24:7–10), the ratios of isobutane/n-butane and isopentane/n-pentane generally increase with temperature and mineral acidity. As to the two experiments for kerogen alone and kerogen plus a small amount of water (OC/water 1:1.5), these two ratios are relatively high at low temperature (280–320 °C) and substantially low at high temperature (320–400 °C) in comparison with the experiments in the presence of minerals and a large amount of deionized water. The ratios of ethene/ethane and propene/propane generally decrease with increasing temperature. At the same temperature, these two ratios increase w...

Changchun Pan

Papers

Chemical and carbon isotopic fractionations of gaseous hydrocarbons during abiogenic oxidation

The effects of calcite and montmorillonite on oil cracking in confined pyrolysis experiments

Kerogen Pyrolysis in the Presence and Absence of Water and Minerals. 1. Gas Components

Kerogen pyrolysis in the presence and absence of water and minerals: Amounts and compositions of bitumen and liquid hydrocarbons

Molecular correlation of free oil and inclusion oil of reservoir rocks in the Junggar Basin, China