Re-Os isotopic dating procedures for organic-rich samples

Abstract

The rhenium-osmium (Re-Os) geochronometer is newly developed technology and has been regarded as a promising radiometric tool for the direct dating of the deposition of source rock, hydrocarbon generation, migration and consequent alteration (e.g., thermal cracking, thermochemical sulphate reduction), and oil-source correlation. However, the complex nature of Re-Os systems in organi-rich samples, including their relatively low elemental contents, multiple origins and occurrences, ambiguous homogenization mechanisms of 187Os/188Os and our limited understanding of the closed system of Re-Os systematics etc., often result in the relatively large uncertainties of obtained isochrones. In this paper, to improve their data quality and yield ideal Re-Os isochrons, the existing Re-Os isotopic analysis method was improved by the terms of sample selection and screening, chemical pretreatment, total analytical blank control and international reference material monitoring. Results showed that a comprehensive guide to researching working in Re-Os geochronology for petroleum system analysis can be available.

Keywords

• re-os dating
• sample selection
• chemical pretreatment
• total analytical blank control
• reference material
• petroleum system