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GEO-4840 TECTONICS-S05

GEO-4840 TECTONICS-S05. PART 1: LECTURES [ Wed 12-14 (16) ] 19/1 - 09/3. PART 2: STUDENT PROJECTS [ Presentations ] 13/4. PART 3: FIELD TEACHING [ Corsica ] end April. PART 4: FIELD REPORTS [ Hand in ] 11/5. PART 5: EVALUATION [PROJECTS, REPORTS & EXAM] 14/6.

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GEO-4840 TECTONICS-S05

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  1. GEO-4840 TECTONICS-S05 PART 1: LECTURES [Wed 12-14 (16)] 19/1 - 09/3 PART 2: STUDENT PROJECTS [Presentations] 13/4 PART 3: FIELD TEACHING [Corsica] end April PART 4: FIELD REPORTS [Hand in] 11/5 PART 5: EVALUATION [PROJECTS, REPORTS & EXAM] 14/6

  2. GEO-4840 TECTONICS-S05 LECTURES: Introduction and course content; Anatomy and tectonic processes in mountain belts. Main themes: 1) Material balance and properties Uplift and subsidence. Topography, crustal and lithospheric thicknesses/structure 2) Wilson cycle tectonics, Ocean-continent transition, Oceanic complexes, exotic terranes. Ophiolite obduction, (Oman, Caledonian and Appalachian). Andean margins, Incipient continental collision, Australia - Banda Arc collision.  Continental collision

  3. LECTURES (continued): 3) Examples of Continental collision zones: The Himalayan-Tibetan region The Caledonides, with emphasis on Scandinavia Mediterranean  4) From collision to extension, Dynamics of orogenic wedges, Exhumation, Renewed rifting.

  4. Student projects (written and oral presentation): All projects are related to the field-course/work/excursions. The student seminar day will be Wed. 13. April The Herzynian basement of Corsica () The main tectonic units of the Alps and their correlation with Alpine Corsica. () The structural geology of Alpine Corsica, an overview () The high-pressure metamorphism of Alpine Corsica () 5) Exhumation of high-pressure rocks in the transect from Corsica to the Apennines in Italy () The Alpine ophiolitic rocks of Corsica () Formation of Pseudotachylytes () Formation of Olistostromes ()

  5. MOUNTAIN CHAINS ARE THE MOST IMPRESSIVE VISIBLE TOPOGRAPHIC FEATURES ON THE EARTH´S SURFACE

  6. The anatomy of mountain belts: The product of complex interactions of thrusting and extension accompanied by pro- and retrograde metamorphic reactions and erosional denudation

  7. MOUNTAIN BELTS, OLD (at least from Mid Proterozoic) and YOUNG, • HAVE VERY SIMILAR INTERNAL STRUCTURES: • FORELAND • CONTINENTAL BASEMENT-CORED NAPPES • SUTURE WITH OCEANIC AND EXOTIC TERRANES • HINTERLAND / PLATEAU REGIONS • FORELAND

  8. Various stages of orogenic maturity along strike Andean margins Foreland flexure Suture(s) Common internal structure of orogenic belts (in space and time) Hinterland orogenic plateau Foreland basin

  9. Schematic view of stages in a classical Wilson cycle 5) Remnant stage Continental collision, suture zones, deform- ation and metamorphism, mountain building Extensional collapse, faulting and collapse basins 4) Terminal stage Near closure of ocean, mature arcs and back-arc, accreationary wedges, HP-LT metamorphic complexes (Mediterranean See area) 3) Vaning stage: Intra-oceanic subduction and island arcs transition to Andean margins. (SE Asia and Western Passific) 2) Mature stage Passive margins with large shelf-areas (Atlantic Ocean) 1) Embryonic to Young stage. Rifts to small ocean basin with sea-floor spreading. (East African rift and Red Sea)

  10. Exact estimates of material present in the orogen Le Pichon et al., 1993

  11. ESTIMATES OF MISSING CONTINENTAL MATERIAL Topography and erosional levels are taken into consideration: Dewey et al. (1986) ca 1,2 x 104 km2 Le Pichon et al (1993) Linear shortening between 1850 - 2600 km Surface loss during the past 45 myr from 57 to 62 x 105 km2 Rate of surface loss: ≈ 1,1 x 10 km2 x 10-6yr Arial deficit in sections ≈ 33 - 52 x 105 km2 (max) 18 - 30 x 105 km2 (min) (Depends on estimates of original surface elevation) WHAT IS THE EXPLANATIONS FOR THE DEFICIT? erosion India Tarim Present continental crust

  12. LATERAL TRANSPORT OF MATERIAL

  13. The lateral extrusion model For SE Asia Tapponnier et al., 1982, 1986

  14. Fournier Jolivet et al.

  15. 2) VERTICAL TRANSPORT OF MATERIAL (SUBDUCTION / EDUCTION)

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