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GEO-4840 TECTONICS-s06

GEO-4840 TECTONICS-s06. PART 1: Lectures [ Mondays 8-12 ] 23/1 - 06/3. PART 2: Student projects [ Essay and presentation ] Weeks 16-17. PART 3: Field teaching [ Western Norway ] Weeks 18-19. PART 4: Field reports [ Hand in ] Friday 2/6.

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GEO-4840 TECTONICS-s06

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  1. GEO-4840 TECTONICS-s06 PART 1: Lectures [Mondays 8-12] 23/1 - 06/3 PART 2: Student projects [Essay and presentation] Weeks 16-17 PART 3: Field teaching [Western Norway] Weeks 18-19 PART 4: Field reports [Hand in] Friday 2/6 PART 5: Evaluation [projects, reports, examination] 14/6

  2. GEO-4840 TECTONICS-s06 LECTURES: Introduction and course content; Tectonic processes and anatomy of 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. Reading list:

  5. Reading list forts:

  6. Student projects (written with oral presentation): All projects are related to the field-course/work/excursions. The student seminar day will be Mon 24. and Wed 26. April Extensional detachments in Norway () Main tectonic units in the Scandinavian Caledonides () Main tectonic units in east Greenland Caledonides () Ophiolites in the Scandinavian Caledonides () 5) Lower Palaeozoic rocks in the foreland Scandinavia () PT-time history of eclogites in Western Gneiss Complex() Melanges and Olistostromes () Ultramafic rocks in the Western Gneiss Complex () The mineralogy of Ultra-high-pressure rocks () PT-time history of eclogites in the Caledonian nappes

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

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

  9. 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

  10. 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

  11. 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)

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

  13. 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

  14. LATERAL TRANSPORT OF MATERIAL

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

  16. Fournier Jolivet et al.

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

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