--> ABSTRACT: Sr Isotopic Chronostratigraphy: Past, Present, and Future Applications, by Richard W. Hurst; #91003 (1990).

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ABSTRACT: Sr Isotopic Chronostratigraphy: Past, Present, and Future Applications

Richard W. Hurst

The development of strontium isotopic chronostratigraphy has been an iterative process involving geoscientists in many disciplines. Significant improvements in both Sr isotopic analyses and biochronology have refined the seawater Sr evolution curve (SSEC) to the point where high-resolution stratigraphy is possible; in addition, SSEC inflection points reflect variations in the marine Sr budget and can be correlated to specific paleo-oceanographic and climatic events. This paper will address some applications of Sr isotope chronostratigraphy to stratigraphic, diagenetic, and petroleum production problems via specific examples.

Calcareous marine sediments can be dated to various degrees of chronologic accuracy by this method. Accuracy depends upon (1) our knowledge of the SSEC during the time interval in question, (2) our ability to separate or extract an authigenic phase which retains the Sr isotopic signature of the seawater from which it precipitated, and (3) the extent of postdiagenetic exchange reactions. Analyses of carbonates from the Monterey Formation (Missippian), Morrison Formation (Jurassic), Atoka Formation (Carboniferous), and Shady Dolomite (Cambrian) will be presented. Applications of Sr isotopes to basin evolution and diagenetic exchange reactions will also be discussed.

Future research directions not only include the next iteration to further refine the SSEC but also the application of the technique to solve problems encountered by the petroleum industry. Examples include formation water plus or minus petroleum source rock correlations, reservoir continuity studies, and casing leak detection. Strontium isotopic chronostratigraphy will continue to evolve into a tool with applications in many geoscientific disciplines.

AAPG Search and Discovery Article #91003©1990 AAPG Annual Convention, San Francisco, California, June 3-6, 1990