Research Progress on Re-Os Isotopes Application in Dating and Paleoenvironmental Interpretation during the Neoproterozoic to Early Cambrian Periods

Abstract

The Neoproterozoic to Early Cambrian period is a very important era in the history of earth evolution. Research on stratigraphic framework, paleo-oceanography, palaro-atmospheric, and paleoclimatology are focuses of international geosciences. As a new stratigraphic dating method, Re-Os isotopic dating was developed rapidly in the last decades. It has dual advantages of dating and tracing the paleoenvironment for the organic-rich black shale deposited at the important timing turning points during Neoproterozoic to Early Cambrian. Taking the Neoproterozoic to Early Cambrian strata as an example, the application of the Re-Os isotopic dating method in chronostratigraphy is described in this paper and the reliability of the Re-Os dating method by comparison with numerous precise zircon U-Pb ages is confirmed. This method has played an important role in the research of the building order in the Doushantuo Formation and the sedimentary time of the Liuchapo Formation. Combining previous Sr isotope curves with the initial 187Os/188Os ratios of Neoproterozoic to Early Cambrian strata, the role of Os isotopes in the interpretation of the paleoenvironment and tracing the source of Ni-Mo-V polymetallic layers is discussed. Sr isotope analysis is difficult to conduct on black shales, while initial 187Os/188Os can complement this defect. Therefore, the mutual combination of these two methods can contribute to the exploration of the paleoenvironment during Neoproterozoic to Early Cambrian. Finally, with the development of Re-Os isotope analysis technology and establishment of more experiment processes, it will produce a significant effect on the study of future chronostratigraphy, especially on the age-determination of the older strata.

Keywords

• black shale
• re-os isotope
• initial 187os/188os value
• early cambrian
• late neoproterozoic
• south china