Subduction Factory: Its Role in the Evolution of the Solid Earth Y.Tatsumi (IFREE, JAMSTEC) - PowerPoint PPT Presentation

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Subduction Factory: Its Role in the Evolution of the Solid Earth Y.Tatsumi (IFREE, JAMSTEC)

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... Peridotite Formation of Hydrous Curtains General Characteristics of Arc Magmatism Generation of Arc Basalt Magmas Seismic Tomography Image beneath NE Japan ... – PowerPoint PPT presentation

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Title: Subduction Factory: Its Role in the Evolution of the Solid Earth Y.Tatsumi (IFREE, JAMSTEC)


1
Subduction FactoryIts Role in the Evolution of
the Solid EarthY.Tatsumi (IFREE, JAMSTEC)
2
The Subduction Factory
3
General Characteristicsof Arc Magmatism
4
Volcano Distribution in NE Japan Arc
5
Distance from Volcanic Front vs. Number of
Volcanoes
6
General Characteristics of Arc Magmatism
7
Subduction Angle vs. Arc Width
8
Constant Depth to Slab Surface
9
Hydrous Phases StabilityBasalt
10
Migration of Fluids
11
Hydrous Phases StabilityPeridotite
12
Formation of Hydrous Curtains
13
General Characteristics of Arc Magmatism
14
Generation of Arc Basalt Magmas
15
Seismic Tomography Imagebeneath NE Japan
16
Numerical Simulation Experiments
17
Heterogeneous Volcano Distributionin NE Japan Arc
18
Heterogeneous Distribution of High-T Mantle Wedge
19
Heterogeneous Distributionof High-T Mantle Wedge
20
Hot Fingers in the Mantle Wedge
21
General Characteristicsof Arc Magmatism
22
Trace Element Characteristics
23
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

24
Element Transport via. Dehydration
25
Inferred Arc Magma Compositions
26
Origin of Andesites and Continental Crusts
27
Arc Magmas vs. Continental Crust
TH CA
28
Characteristics 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
29
Crustal Origin for Felsic Magmas
30
Andesitic Continental Crust Formation
31
Inferred Andesitesproduced by Magma mixing
32
Delamination Process Required
33
Fate of Waste Materials
Oceanic crust (dehydrated and fresh)
Sediments
Delaminated anti-continental crust
34
Isotopic characteristicsof Oceanic Magmas
35
Chemical Modificationof Altered Oceanic Crust
36
Isotopic Evolution of Sinking Crusts
37
Chemical Modificationof Subducting Sediments
38
Isotopic Evolution of Sinking Sediments
39
Isotopic Evolutionof Delaminated Arc Crust
40
Material Recycling in the Earth Interior
41
The Subduction Factory
42
I F R E E Institute for Frontier Research on
Earth Evolution
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