The Coupled Re-Os and Pt-Os Systematics: A Theoretical Consideration

The ^190Pt-^186Os system should be a unique tracer for mantle processes be-cause both Pt and Os are concentrated in the mantle.The ^190Pt-^186Os system will also be a good supplement to the ^187Re-^187Os system for dating and tracing mantle pro-cesses because the ^190Pt-^186Os system is not so easily contaminated by crustal materials as the ^187Re-^187Os system.In turn,the application of the ^187Re-^187Os system to Pt-enriched materials uncontaminated by crustal materials will indirectly refine the half life of ^190Pt.The ^190Pt is refined.In the coupled ^187Re-^187Os and ^190Pt-^186Os sys-tematics,an ^186Os*/^190Pt-^187Os*/^187Re Concordia diagram similar to the ^206Pb*/^238U-^208Pb*/^232Th Concordia can be constructed.In such a Concordia diagram,a date will be obtained so long as the ^190Pt-^186Os system remains closed even if the ^187Re-^187Os sys -tem is contaminated by crustal materials.In addition ,for the coupled ^190Pt-^186Os and ^187Re-^187Os systematics,the mantle processes and the interactions between the mantle and the crust will be described by two ratios:^186Os/^188Os and ^187Os/^188Os .The coupled ^187Re-^187Os and ^190Pt-^186Os systematics will be a powerful tool in the investigation of the geodynamic history of the Earth because the ^187Re-^187Os system is sensitive to the interactions between the mantle and the crust,while the ^190Pt-^186Os system is a good tracer for mantle processes.

The 190Pt-l86Os system should be a unique tracer for mantle processes because both Pt and Os are concentrated in the mantle. The 190Pt-186Os system will also be a good supplement to the 187Re-187Os system for dating and tracing mantle processes because the 190Pt-186Os system is not so easily contaminated by crustal materials as the 187Re-187Os system. In turn, the application of the 187Re-187Os system to Pt-enriched materials uncontaminated by crustal materials will indirectly refine the half life of 190Pt. The 190Pt-186Os system will be a promising tracer and chronometer when the decay constant of 190Pt is refined. In the coupled 187Re-187Os and 190Pt-186Os sys-tematics, an 186Os*/190Pt-187Os*/187Re concordia diagram similar to the 206pb*/238U-208Pb*/232 Th concordia can be constructed. In such a concordia diagram, a date will be obtained so long as the 190Pt-186Os system remains closed even if the l87Re-187Os system is contaminated by crustal materials. In addition, for the coupled 190Pt-186Os and 187Re-187Os systematics, the mantle processes and the interactions between the mantle and the crust will be described by two ratios 186Os/188Os and 187Os/188Os. The coupled 187Re-187Os and 190Pt-186Os systematics will be a powerful tool in the investigation of the geodynamic history of the Earth because the 187Re-187Os system is sensitive to the interactions between the mantle and the crust, while the 190Pt-186Os system is a good tracer for mantle processes.