Subduction Factory: Its Role in the Evolution of the Solid Earth Y Subduction Factory: Its Role in the Evolution of the Solid Earth Y.Tatsumi (IFREE, JAMSTEC) ・Outline of subduction factory ・General characteristics of magmatism and basalt genesis ・Andesite genesis and continental crust formation ・Fate of waste materials and mantle evolution

The Subduction Factory Raw materials Oceanic material Mantle material Products Magma/Volcanoes Volatiles Continental crust Residues Chemically modified slab Delaminated lower crust

General Characteristics of Arc Magmatism ・Dual volcanic chains ・Inverse correlation between arc width and subduction angle ・High-T mantle wedge and hot fingers ・Selective enrichment of LIL elements

Volcano Distribution in NE Japan Arc

Distance from Volcanic Front vs. Number of Volcanoes

General Characteristics of Arc Magmatism ・Inverse correlation between arc width and subduction angle ・Dual volcanic chains ・High-T mantle wedge and hot fingers ・Selective enrichment of LIL elements

Subduction Angle vs. Arc Width

Constant Depth to Slab Surface タイトルお願いします。

Hydrous Phases Stability: Basalt

Migration of Fluids タイトルお願いします

Hydrous Phases Stability: Peridotite

Formation of Hydrous Curtains

General Characteristics of Arc Magmatism ・Dual volcanic chains ・Inverse correlation between arc width and subduction angle ・High-T mantle wedge and hot fingers ・Selective enrichment of LIL elements

Generation of Arc Basalt Magmas Tatsumi et al. (1983)

Seismic Tomography Image beneath NE Japan Zhao et al. (1992) タイトルお願いします

Numerical Simulation Experiments Furukawa (1993) タイトルお願いします

Heterogeneous Volcano Distribution in NE Japan Arc

Heterogeneous Distribution of High-T Mantle Wedge タイトルお願いします

Heterogeneous Distribution of High-T Mantle Wedge タイトルお願いします

Hot Fingers in the Mantle Wedge タイトルお願いします

General Characteristics of Arc Magmatism ・Dual volcanic chains ・Inverse correlation between arc width and subduction angle ・High-T mantle wedge and hot fingers ・Selective enrichment of LIL elements

Trace Element Characteristics Subduction zone basalt 配置、順序等はてきとうですのでご指示お願いします。

Element Transport during Dehydration Starting Materials Plate-forming hydrous materials such as sediments/amphibolites Being set in a perforated platinum capsule High-P/T Dehydration Experiments Decomposition of starting materials Releasing H2O that dissolves elements Leaving anhydrous residue Chemistry: starting materials vs. residue 配置、順序等はてきとうですのでご指示お願いします。

Element Transport via. Dehydration

Inferred Arc Magma Compositions

Origin of Andesites and Continental Crusts ・Calc-alkalic vs. tholeitic andeistes ・Bulk continental crust: 　andesitic, not basaltic compositions

Arc Magmas vs. Continental Crust TH CA 黄色の部分が最前面なら問題ないのですが、背面におくるため画像の処理をしていますのでちょっと図が粗くなってしまいます。

Characteristics of Calc-Alkalic Andesites Rather straight differentiation trend Disequilibrium phenocryst assemblages (e.g., ol+qz) Presence of reversely-zoned phenocryst Bimodal distribution of phenocryst-core compositions Origin of End-member Magmas Basalt magma:mantle-derived Felsic magma:external or internal origin? A Plausible Mechanism: --mixing of basaltic and felsic magmas

Crustal Origin for Felsic Magmas

Andesitic Continental Crust Formation Ancient MORB Ridge Alteration Element Transport Slub Fluid Ancient Altered MORB Ancient Magma Source Ancient Original Mantle Wedge (Primitive Mantle) ancient Primary Basalt Initial Arc Crust Remolten Felsic Magma Continental crust Mixing Primary Basalt Magma Source Original Mantle Wedge (N-MORB Source) Element Transport Slub Fluid Altered MORB Fresh MORB Ridge Alteration

Inferred Andesites produced by Magma mixing

Delamination Process Required Initial Arc Crust Dacite Restite Anatexis/Mixing Basalt Mixing Delamination Andesite Restite Basaltic Comp.

Fate of Waste Materials ・Oceanic crust (dehydrated and fresh) ・Sediments ・Delaminated anti-continental crust

Isotopic characteristics of Oceanic Magmas

Chemical Modification of Altered Oceanic Crust Element Transport via. Dehydration

Isotopic Evolution of Sinking Crusts

Chemical Modification of Subducting Sediments Element Transport via. Dehydration

Isotopic Evolution of Sinking Sediments

Isotopic Evolution of Delaminated Arc Crust

Material Recycling in the Earth Interior

The Subduction Factory Raw materials Oceanic material Mantle material Products Volcanoes Volatiles Continental crust Residues Chemically modified slab Delaminated lower crust

I F R E E Institute for Frontier Research on Earth Evolution