Carbon and Oxygen Isotope Fractionation in the Skeletal Carbonate of Reef-Building Corals
Weber JN and Woodhead PM. 1970. Carbon and Oxygen Isotope Fractionation in the Skeletal Carbonate of Reef-Building Corals. Chemical Geology. 6(1):93-117
Important to the geochemistry of carbonate sediments and carbonate rocks is a detailed understanding of the isotopic composition of the various sediment contributors. The coelenterates are of particular interest in this respect as the stable isotope ratios of their skeletons are controlled by both vital and inorganic environmental factors. To determine the relative importance of these factors, 475 specimens referred to 50 genera were selected to represent the coral population of Heron Island on the Great Barrier Reef of Australia. With a few exceptions, the samples were taken from two depth environments: (1) surface, defined as 0-4.6 m; and (2) 18 m. The observed range of o^13C is 13% (max. +2.6%0 ; min. -10.0% with respect to PDB standard CO2 ); that of o^18O is 4% (max. -1.2%0; min. - 5.4%0). A model incorporating both biological and environmental factors has been developed to account for isotope ratio variations in coelenterate carbonate. A depth effect predicted by the model provides an opportunity to test its validity in that a number of critical relationships must be observed. The analytical data are consistent with the model. At a specific reef locality, the most important factors causing isotope ratio variations in the skeletal carbonate of corals are zooxanthellar activity and temperature.
- Type
- Journal Article
- Authors
- Weber, Jon; Woodhead, Peter
- Units
- SFCN
- Keywords
- Coelenterate Carbonate, Coral Population, Geochemistry, Inorganic Environmental Factors, Zooxanthellar