1. S. Sobolev, GFZ Potsdam “Geodynamic modeling and integrative interpretation” group in the GFZ Potsdam S. Sobolev, GFZ Potsdam

2. Surface topography at t=16 Myr (105 km strike-slip motion) Boundary weak zone 3D model of the Dead Sea evolution -13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 0 1 Depth, km S. Sobolev, GFZ Potsdam

3. Factors controlling subduction orogeny in Central Andes Stephan Sobolev and Andrey Babeyko GFZ Potsdam Outline Geological time scale model (Myr) of interaction of the subducting and overriding plates time zoom Human time scale model (yr)

4. S. Sobolev, GFZ Potsdam Brasilian shield thick (50-70 км) hot and felsic crust Subandean thin-skin deformation zone 3 cm/yr Andean Orogeny The high-mountain belt has been formed only during the last 30 Myr and only in the central part of the South America plate margin. Nazca plate 5 cm/yr

5. S. Sobolev, GFZ Potsdam Pattern of Central Andean Deformation (21°S) Elger, Oncken & Glodny, in prep.

6. S. Sobolev, GFZ Potsdam Which processes are responsible for the tectonic shortening in Cenozoic Transfer function Pardo-Casas and Molnar (1987) Silver et al. (1998) Lamb and Davis (2003) Oncken, personal communication

7. S. Sobolev, GFZ Potsdam Key questions Why only in Cenozoic and why only in the Central Andes? How important are plate kinematics and plates coupling in the Andean orogeny? Model testable predictions?

8. S. Sobolev, GFZ Potsdam Momentum conservation equation: Mass conservation equation and constitutive laws: visco-elastic body Mohr-Coulomb failure criterion non-associated shear flow potential Energy conservation equation including shear heating term: 2-D Thermomechanical Modelling Implimentation: Finite element, LAgrangian, Particle Explicit, code LAPEX-2D,2.5D,3D

9. S. Sobolev, GFZ Potsdam Large-scale model setup fertile peridotite depleted peridotite felsic upper crust V2V2 Dynamic subduction channel with special rheology depleted peridotite gabbro V 1 Pz sediments h1h1 z  h2h2

10. S. Sobolev, GFZ Potsdam V 1 V2V2 Friction angle 10° (  = 0.17) Effect of interplate friction S. Sobolev, GFZ Potsdam

11. Large-scale model Evolution of the lithospheric structure in the best fit model Friction angle 3° (  = 0.05) S. Sobolev, GFZ Potsdam

12. Large-scale model Evolution of the lithospheric structure in the best fit model Evolution of the density distribution in the best fit model S. Sobolev, GFZ Potsdam

13. Large-scale model Evolution of the lithospheric structure in the best fit model Evolution of the temperature distribution in the best fit model S. Sobolev, GFZ Potsdam

14. Cumulative strain distribution in the best fit model S. Sobolev, GFZ Potsdam

15. Topography in the best fit model S. Sobolev, GFZ Potsdam

16. Tectonic shortening in the best fit model High converg. rate Active delamination Subandian thrusting South America acceleration

17. S. Sobolev, GFZ Potsdam Effect of the overriding velocity 101520253035 Time, Myr 0 100 200 300 400 S h o r t e n i n g, k m fr=0.05, V=2-3 cm/yr (best fit model) fr=0.05, V=1 cm/yr

18. S. Sobolev, GFZ Potsdam Effect of friction 101520253035 Time, Myr 0 100 200 300 400 S h o r t e n i n g, k m fr=0.05, V=2-3 cm/yr (best fit model) fr=0.005, V=2-3 cm/yr

19. S. Sobolev, GFZ Potsdam Brasilian shield Nazca plate 5 cm/yr 3 cm/yr High overriding rate fr=0.03-0.05 Friction and trench fill Model prediction

20. S. Sobolev, GFZ Potsdam locking at high friction z  h1h1 h2h2 locking at low friction Change of the friction coefficient by 5-10 times should result in the change of the locking depth by 15-25 km Friction and locking depth Model prediction

21. S. Sobolev, GFZ Potsdam Brasilian shield Nazca plate 3 cm/yr shallow locking deep locking no sediments in the trench - high friction a lot of sediments in the trench - low friction Model prediction 5 cm/yr

22. S. Sobolev, GFZ Potsdam Klotz et al., 2003

23. S. Sobolev, GFZ Potsdam Brasilian shield Nazca plate 3 cm/yr 33 km deep locking 50 km deep locking 5 cm/yr

24. S. Sobolev, GFZ Potsdam Brasilian shield Cenozoic Central Andean orogeny was likely controlled by both: plate kinematics (high speed of the overriding of South America) and climate (high friction in the subduction channel in the arid Central Andes). 3 cm/yr High overriding rate fr=0.03-0.05 Conclusions 1 Nazca plate 5 cm/yr

25. S. Sobolev, GFZ Potsdam Human time scale: GPS data

26. S. Sobolev, GFZ Potsdam

28. Zooming in Time Mln. yearsyears Friction coefficient (fr) =0.03fr=0.03+-0.0015

29. S. Sobolev, GFZ Potsdam Friction down 0.0525 0.0475 S. Sobolev, GFZ Potsdam

30. Friction up 0.0475 0.0525 S. Sobolev, GFZ Potsdam

32. Friction down 0.0525 0.0475 S. Sobolev, GFZ Potsdam

33. (0.005)

34. S. Sobolev, GFZ Potsdam (0.003) (0.010)

35. S. Sobolev, GFZ Potsdam Conclusions 2 The same thermo-mechanical model can explain both geological-scale and human- scale deformations in the Central Andes