Strontium-isotope stratigraphy: applications in basin modelling and reservoir correlation
The 87Sr/86Sr isotope ratio is homogeneous in sea water at any one time, but has fluctuated during geological time along the path which can be reconstructed by the Sr-isotopic analysis of marine precipitates (e.g. carbonate or phosphate fossils) of known age. The resultant ‘seawater curve’ can be used as a relative dating tool by analysing carbonate/phosphate fossils from a marine sediment, locating its position on the curve and reading off the corresponding age. Such ages are independent of biofacies or faunal provincialism. The hypothetical chronological resolution, which depends upon analytical reproducibility and the gradient of the seawater curve during the period of interest, lies between 0.4 and 1.0 Ma for much of the Cenozoic and Mesozoic. However, the practical resolution is limited in sediments of certain ages by uncertainties in the definition of the seawater curve; this may be improved with further work.
KeywordsSequence Boundary Marine Carbonate Strontium Isotope Hydrocarbon Exploration Cenozoic Sediment
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