GEO-4840 TECTONICS-s06

PART 1: Lectures [Mondays 8-12] 23/1 - 06/3PART 1: Lectures [Mondays 8-12] 23/1 - 06/3

PART 2: Student projects [Essay and presentation] Weeks 16-17PART 2: Student projects [Essay and presentation] Weeks 16-17

PART 3: Field teaching [Western Norway] Weeks 18-19PART 3: Field teaching [Western Norway] Weeks 18-19

PART 4: Field reports [Hand in] Friday 2/6PART 4: Field reports [Hand in] Friday 2/6

PART 5: Evaluation [projects, reports, examination] 14/6PART 5: Evaluation [projects, reports, examination] 14/6

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

GEO-4840 TECTONICS-s06

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.

EXAMINATION RELEVANT MATERIAL FOR GEO4840 TECTONICS, 2006: Paper copies in bold

1) ALL HANDOUT S AND LECTURES 2) STUDENT CONTRIBUTIONS AND THE FIELDCOURSE 3) THIS READING LIST

1) Andersen T.B., (1998) Extensional tectonics in the Caledonides of southern Norway, An overview. Tectonophysics, 285,333-351. (available as PDF) 2) Andersen T.B., Jamtveit, B., Dewey, J.F. and Swensson, E. (1991): Subduction and eduction of continental crust; major mechanisms during continent-continent collision and orogenic extensional collapse. Terra Nova 3, 303-310 (available as PDF) 3) Austrheim H. (1998): Influence of Fluid and Deformation on Metamorphism of the Deep Crust and Consequences for the Geodynamics of Collision Zones. In. Hacker & Liou (eds) When Continents collide: Geodynamics and Geochemistry of Ultrahigh-Pressure Rocks, 297-323. 4) Burbank, D.W. (2002). Rates of erosion and their implications for exhumation. Min. Mag. Vol. 66 (1), 25–52 (available as PDF) 5) Carswell, D. A., Brueckner, H. K. Cuthbert, S. J. Metha, K. and O’Brien, P. J. 2003 The timing of stabilisation and the exhumation rate for ultra-high pressure rocks in the Western Gneiss Region of Norway. J. metamorphic Geol. 21, 601–612 (available as PDF) 6) Chemenda A.I., Mattauer, M. & Bokun, A.N. (1996): Continental subduction and a mechanism for exhumation of high-pressure rocks: new modelling and field data from Oman. EPSL, 143, 173-182 (available as PDF) 7) Dewey J.F. (1988): Extensional collapse of orogens, Tectonics, 7, 1123-1139. 8) Dewey J.F., Shackelton, R.M., Chengfa C. and Yiuin S. (1988): The tectonic evolution of the Tibetan Plateau, Philos. Trans. Royal Soc. London, ser. A, 327, 379-413. 9) Fossen, H. & Dunlap, J.W. 1998: 40Ar/39Ar dates and implications for the structural development of southern Norway. Jl. Struct. Geol., 20, 765-781. (available as PDF) 10) Hacker, B.R., Andersen, T.B., Root, D.B., Mattinson, J.M., & Wooden, J.L. Exhumation of high-pressure rocks beneath the Solund Basin, Norway. Jl Metamorphic petrology, 613-629 (available as PDF) 11) Hacker, B.R., Mosenfelder, J.L., and Gnos, E., Rapid emplacement of the Oman ophiolite: Thermal and geochronologic constraints. Tectonics, v.15, pp. 1230-1247. 12) Hodges K.V., Parrish R. & Searle M.: Tectonic evolution of the Central Annapurna Range, Nepalese Himalayas. Tectonics 15, 1264-1291 13) Hartz, E.H. ; Andresen, A. , Hodges, K.V., Martin, M.W. 2001 Syncontractional extension and exhumation of deep crustal rocks in the east Greenland Caledonides Tectonics Vol. 20 , No. 1 , p. 58 (2000TC900020) (available as PDF) 14) Jolivet, L. , Faccenna, C., Goffe, B., Burov, E. and Agard, P. (2003) Subduction tectonics and exhymation of high-pressure metamorphic rocks in the Mediterranean orotens. Am. J. Sci. Vol. 303, 353–409, (available as PDF) 15)Krabbendam, M & Dewey J.F. (1998) Exhumation of UHP rocks by transtension in the Western Gneiss Region, Scandinavian Caledonides. Geol. Soc. Spec. Publ. 135, 159-181.

Reading list:

15)Krabbendam, M & Dewey J.F. (1998) Exhumation of UHP rocks by transtension in the Western Gneiss Region, Scandinavian Caledonides. Geol. Soc. Spec. Publ. 135, 159-181. 16) Le Pichon, X., Fournier, M. & Jolivet, L. (1992): Kinematics, topography, shortening and extrusion in the India-Eurasia collision. Tectonics 11, 1085-1098 17) Osmundsen, P.T. & Andersen, T.B.: The Middle Devonian Basins of western Norway: Sedimentary response to large-scale transtensional tectonics. Tectonophysics, 332, 51-68 (available as PDF) 18) Platt J.P. (1993): Exhumation of high-pressure rocks: a review of consepts and processes. Terra Nova , 5, 119-133 19) Platt J.P. & England (1994): Convective removal of lithosphere beneath mountain belts: Thermal and mechanical consequences. Am. Jl. Sci., 293, 307-336. 20) Torsvik T. H., (1998) Palaeozoic palaeogeography: A North Atlantic viewpoint. GFF, 120, 109-118. 21) Wernicke B. (1992): Cenozoic extensional tectonics of the U.S. Cordillera.In Burchfield B.C., Lipman P.W. and Zorback M.L. (eds) Geology of NorthAmerica, Vol G-3, The Cordilleran Orogen: Conterminous U.S. The Geological Society of America.

Reading list forts:

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

1) Extensional detachments in Norway ()2) Main tectonic units in the Scandinavian Caledonides ()

3) 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()

1) Melanges and Olistostromes ()3) Ultramafic rocks in the Western Gneiss Complex ()4) The mineralogy of Ultra-high-pressure rocks () 5) PT-time history of eclogites in the Caledonian nappes

MOUNTAIN CHAINS ARE THE MOST IMPRESSIVEVISIBLE TOPOGRAPHIC FEATURES ON THE

EARTH´S SURFACE

MOUNTAIN CHAINS ARE THE MOST IMPRESSIVEVISIBLE TOPOGRAPHIC FEATURES ON THE

EARTH´S SURFACE

The anatomy of mountain belts:The product of complex interactions of thrusting and extensionaccompanied by pro- and retrograde metamorphic reactions anderosional denudation

The anatomy of mountain belts:The product of complex interactions of thrusting and extensionaccompanied by pro- and retrograde metamorphic reactions anderosional denudation

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

Variousstages of orogenic maturityalong strike

Andean margins

Forelandflexure

Forelandbasin

Suture(s)

Hinterland orogenic plateau

Commoninternalstructureof orogenicbelts (inspace and time)

5) Remnant stageContinental collision, suture zones, deform-ation and metamorphism, mountain buildingExtensional collapse, faulting and collapsebasins4) Terminal stageNear closure of ocean, mature arcs andback-arc, accreationary wedges, HP-LTmetamorphic complexes(Mediterranean See area)

3) Vaning stage: Intra-oceanic subductionand island arcs transition to Andean margins. (SE Asia and Western Passific)

2) Mature stage Passive margins with largeshelf-areas (Atlantic Ocean)

1) Embryonic to Young stage.Rifts to small ocean basin with sea-floor spreading. (East African rift and Red Sea)

Schematic view of stages in a classical Wilson cycle

Le Pichon et al., 1993

Exact estimates of material present in the orogen

ESTIMATES OF MISSING CONTINENTAL MATERIALTopography 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 kmSurface loss during the past 45 myr from 57 to 62 x 105 km2

Rate of surface loss: ≈ 1,1 x 10 km2 x 10-6yrArial 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?

India Tarim

erosion

Present continentalcrust

1) LATERAL TRANSPORT OF MATERIAL

Tapponnier et al., 1982, 1986

The lateral extrusion modelFor SE Asia

FournierJolivet et al.

2) VERTICAL TRANSPORT OF MATERIAL(SUBDUCTION / EDUCTION)