11:00 〜 13:00
[SGC36-P01] Recycling age of oceanic crust: constraint from FOZO and HIMU OIB
キーワード：海洋地殻のリサイクル年代、FOZO、HIMU
One of distinctive features of the Earth is presence of mantle convection and plate tectonics. These processes inevitably follow recycling of crustal material into deep mantle. The recycled crustal materials are inferred to be resurfacing by mantle plume from Earth’s deep interior because geochemical signature of crustal materials could be discerned in isotopic composition of OIB. This material cycling could be manifest mantle convection, and thus constraining time scale of the crustal recycling (recycling age) is essential to understand the geodynamic system of the Earth.
There are mainly two approaches to estimate recycling ages. One is models using mixing lines between DMM and mantle end components that represent different parts of the Earth’s interior with different histories or processes. The other is models using the pseudo-isochron of MORB and OIB on 206Pb/204Pb vs. 207Pb/204Pb diagram, such as mean/statistical box models and numerical simulations of mantle convection. These models were successfully determined recycling ages from 0.3 to 2.4 Ga. However, they only determined mean recycling age and did not constrain deviation of the recycling ages. As the recycling process is continuous, recycling ages should have variation which may provide constraint on the mantle convection. In this study, we will estimate recycling age of oceanic crust for different hotspots using OIB with FOZO and HIMU isotopic signature by combining Nd-Sm and U-Pb systems.
There are mainly two approaches to estimate recycling ages. One is models using mixing lines between DMM and mantle end components that represent different parts of the Earth’s interior with different histories or processes. The other is models using the pseudo-isochron of MORB and OIB on 206Pb/204Pb vs. 207Pb/204Pb diagram, such as mean/statistical box models and numerical simulations of mantle convection. These models were successfully determined recycling ages from 0.3 to 2.4 Ga. However, they only determined mean recycling age and did not constrain deviation of the recycling ages. As the recycling process is continuous, recycling ages should have variation which may provide constraint on the mantle convection. In this study, we will estimate recycling age of oceanic crust for different hotspots using OIB with FOZO and HIMU isotopic signature by combining Nd-Sm and U-Pb systems.