Presentation is loading. Please wait.

Presentation is loading. Please wait.

Subduction Factory: Its Role in the Evolution of the Solid Earth Y.Tatsumi (IFREE, JAMSTEC) ・ Outline of subduction factory ・ General characteristics of.

Similar presentations


Presentation on theme: "Subduction Factory: Its Role in the Evolution of the Solid Earth Y.Tatsumi (IFREE, JAMSTEC) ・ Outline of subduction factory ・ General characteristics of."— Presentation transcript:

1 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

2 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi The Subduction Factory Raw materials ■ Oceanic material ■ Mantle material Products ■ Magma/Volcanoes ■ Volatiles ■ Continental crust Residues ■ Chemically modified slab ■ Delaminated lower crust

3 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi 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

4 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Volcano Distribution in NE Japan Arc

5 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Distance from Volcanic Front vs. Number of Volcanoes

6 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi 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

7 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Subduction Angle vs. Arc Width

8 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Constant Depth to Slab Surface

9 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Hydrous Phases Stability: Basalt

10 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Migration of Fluids

11 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Hydrous Phases Stability: Peridotite

12 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Formation of Hydrous Curtains

13 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi ・ Dual volcanic chains ・ Inverse correlation between arc width and subduction angle ・ High-T mantle wedge and hot fingers ・ Selective enrichment of LIL elements General Characteristics of Arc Magmatism

14 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Generation of Arc Basalt Magmas Tatsumi et al. (1983)

15 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Seismic Tomography Image beneath NE Japan Zhao et al. (1992)

16 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Numerical Simulation Experiments Furukawa (1993)

17 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Heterogeneous Volcano Distribution in NE Japan Arc

18 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Heterogeneous Distribution of High-T Mantle Wedge

19 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Heterogeneous Distribution of High-T Mantle Wedge

20 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Hot Fingers in the Mantle Wedge

21 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi 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

22 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Trace Element Characteristics Subduction zone basalt

23 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi 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 H 2 O that dissolves elements ■ Leaving anhydrous residue ■ Chemistry: starting materials vs. residue Element Transport during Dehydration

24 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Element Transport via. Dehydration

25 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Inferred Arc Magma Compositions

26 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Origin of Andesites and Continental Crusts ・ Calc-alkalic vs. tholeitic andeistes ・ Bulk continental crust: andesitic, not basaltic compositions

27 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Arc Magmas vs. Continental Crust TH CA

28 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi 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 A Plausible Mechanism: --mixing of basaltic and felsic magmas Origin of End-member Magmas Basalt magma:mantle-derived Felsic magma:external or internal origin?

29 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Crustal Origin for Felsic Magmas

30 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Ancient MORB Ridge Alteration ElementTransport Slub Fluid Ancient Altered MORB Ancient Magma Source Ancient Original Mantle Wedge (Primitive Mantle) ancient Primary Basalt Initial Arc Crust Remolten Felsic Magma Continent al crust Mixing Andesitic Continental Crust Formation Primary Basalt Magma Source Original Mantle Wedge (N-MORB Source) ElementTransport Slub Fluid Altered MORB Fresh MORB Ridge Alteration

31 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Inferred Andesites produced by Magma mixing

32 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Delamination Andesite Restite Basaltic Comp. Delamination Initial Arc Crust Dacite Restite Anatexis/Mixing Basalt Mixing Delamination Process Required

33 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Fate of Waste Materials ・ Oceanic crust (dehydrated and fresh) ・ Sediments ・ Delaminated anti-continental crust

34 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Isotopic characteristics of Oceanic Magmas

35 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Chemical Modification of Altered Oceanic Crust Element Transport via. Dehydration

36 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Isotopic Evolution of Sinking Crusts

37 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Chemical Modification of Subducting Sediments Element Transport via. Dehydration

38 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Isotopic Evolution of Sinking Sediments

39 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Isotopic Evolution of Delaminated Arc Crust

40 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi Material Recycling in the Earth Interior

41 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi The Subduction Factory Raw materials ■ Oceanic material ■ Mantle material Products ■ Volcanoes ■ Volatiles ■ Continental crust Residues ■ Chemically modified slab ■ Delaminated lower crust

42 Institute for Frontier Research on Earth Evolution Yoshiyuki Tatsumi I F R E E Institute for Frontier Research on Earth Evolution


Download ppt "Subduction Factory: Its Role in the Evolution of the Solid Earth Y.Tatsumi (IFREE, JAMSTEC) ・ Outline of subduction factory ・ General characteristics of."

Similar presentations


Ads by Google