Isotopic composition of strontium in sea water throughout Phanerozoic time

Z. E. Peterman; C. E. Hedge; H. A. Tourtelot

doi:10.1016/0016-7037(70)90154-7

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Isotopic composition of strontium in sea water throughout Phanerozoic time

Z. E. Peterman·C. E. Hedge·H. A. Tourtelot

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Abstract

Isotopic analyses of strontium in primary fossil carbonate reveal significant variations in Sr 87 Sr 86 "> Sr87Sr86 of sea water during the Phanerozoic. The strontium isotopic composition may have been uniform from the Ordovician through the Mississippian, with an average Sr 87 Sr 86 "> Sr87Sr86 of 0.7078. A subsequent decrease in this value into the Mesozoic is interrupted by two provisionally documented positive pulses in Sr 87 Sr 86 "> Sr87Sr86 —one in the Early Pennsylvanian and one in the Early Triassic. The lowest observed value (0.7068) occurred in Late Jurassic time, and this was followed by a gradual increase to 0.7075 in the Late Cretaceous and a more rapid increase through the Tertiary to 0.7090 for modern sea water. These variations are thought to be the result of a complex interplay of periods of intense volcanism and epeirogenic movements of the continents on a worldwide scale.

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Z. E. Peterman, C. E. Hedge, H. A. Tourtelot. 1970. Isotopic composition of strontium in sea water throughout Phanerozoic time. https://doi.org/10.1016/0016-7037(70)90154-7

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