Strontium Isotope Stratigraphy of the Aalenian/Bajocian Auxiliary Stratotype Point at Bearreraig, Isle of Skye, NW Scotland

摘要

The ~(87)Sr/~(86)Sr value of the Aalenian/Bajocian boundary is 0.707 288 ±0.000 014 (2 s.e.), based on analysis of belemnites from the Auxiliary Stratotype Point (ASP) at Bearreraig, Isle of Skye. The previous value for this boundary, based on a statistical analysis of data for belemnites from the Inferior Oolite in Dorset, UK, is 0.707 287 ±0.000 020 (95% C.I.). During the Aalenian, the ~(87)Sr/~(86)Sr of marine strontium changed by 0.000 017; correlation and dating of Aalenian strata using strontium isotope stratigraphy is of little value, given the present practical limit of measurement of about ±0.000 004 on multiple repeat analysis and the present uncertainty of ±0.000 020 on the Aalenian Sr isotope calibration curve. correlation within the Aalenian will be possible when the uncertainty on the Sr isotope calibration curve for the Aalenian approaches the uncertainty of ±0.000 003 currently attained for the best-defined parts of the Neogene isotope calibration curve.