Title: Subduction Factory: Its Role in the Evolution of the Solid Earth Y.Tatsumi (IFREE, JAMSTEC)
1Subduction FactoryIts Role in the Evolution of
the Solid EarthY.Tatsumi (IFREE, JAMSTEC)
2The Subduction Factory
3General Characteristicsof Arc Magmatism
4Volcano Distribution in NE Japan Arc
5Distance from Volcanic Front vs. Number of
Volcanoes
6General Characteristics of Arc Magmatism
7Subduction Angle vs. Arc Width
8Constant Depth to Slab Surface
9Hydrous Phases StabilityBasalt
10Migration of Fluids
11Hydrous Phases StabilityPeridotite
12Formation of Hydrous Curtains
13General Characteristics of Arc Magmatism
14Generation of Arc Basalt Magmas
15Seismic Tomography Imagebeneath NE Japan
16Numerical Simulation Experiments
17Heterogeneous Volcano Distributionin NE Japan Arc
18Heterogeneous Distribution of High-T Mantle Wedge
19Heterogeneous Distributionof High-T Mantle Wedge
20Hot Fingers in the Mantle Wedge
21General Characteristicsof Arc Magmatism
22Trace Element Characteristics
23Element 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
24Element Transport via. Dehydration
25Inferred Arc Magma Compositions
26Origin of Andesites and Continental Crusts
27Arc Magmas vs. Continental Crust
TH CA
28Characteristics of Calc-Alkalic Andesites
- Rather straight differentiation trend
- Disequilibrium phenocryst assemblages (e.g.,
olqz) - Presence of reversely-zoned phenocryst
- Bimodal distribution of phenocryst-core
compositions
- Origin of End-member Magmas
- Basalt magmamantle-derived
- Felsic magmaexternal or internal origin?
A Plausible Mechanism --mixing of basaltic and
felsic magmas
29Crustal Origin for Felsic Magmas
30Andesitic Continental Crust Formation
31Inferred Andesitesproduced by Magma mixing
32Delamination Process Required
33Fate of Waste Materials
Oceanic crust (dehydrated and fresh)
Sediments
Delaminated anti-continental crust
34Isotopic characteristicsof Oceanic Magmas
35Chemical Modificationof Altered Oceanic Crust
36Isotopic Evolution of Sinking Crusts
37Chemical Modificationof Subducting Sediments
38Isotopic Evolution of Sinking Sediments
39Isotopic Evolutionof Delaminated Arc Crust
40Material Recycling in the Earth Interior
41The Subduction Factory
42I F R E E Institute for Frontier Research on
Earth Evolution