عنوان مقاله [English]
Changes of Strontium isotopic ratios (87Sr/86Sr) of oceanic waters are not detectable, since they occur over millions of years. Strontium exists in calcareous shell of marine organisms. 87Sr/86Sr ratio of oceanic waters at different geologic times can be estimated by calcuting this value in calcareous shells of living organisms. Similar to conventional techniques, age correlation can be based on 87Sr/86Sr changes. By applying this study method, geologists, paleontologists and oceanographists have been able to clarify many ambiguities. In this study, the strontium isotopic ratios of 158 samples from Well Gurpi#1 located in East of Dezful, Iran (from upper Cretaceous to lower Jurassic period) were measured and a 87Sr/86Sr profile was created and then compared to the global profile. Comparing 87Sr/86Sr values of upper Cretaceous to lower Jurassic sediments to those of evolutionary ones from Phanerozoic seas revealed a good agreement.