Jean-Philippe Avouac photoJean-Philippe Avouac Professor of Geology:Director of the Tectonics Observatory:CaltechCaltech logo

GE277 : Himalayan Tectonics Seminar

Professor Jean-Philippe Avouac

We will have 5 Seminars to be held on Fridays, 11-12:00

Students are required to have read ‘Mountain building, erosion and the seismic cycle in the Nepal Himalaya’ [Avouac, 2003] before the second seminar as well as 'Evolution of the Himalaya' [Le Fort, 1996]. For those of you who may wish a broadened picture of the geological history of the collision zone I recommend ‘Geological Evolution of the Himalayan-Tibetan Orogen’ by Yin and Harrison (Ann Rev Planet Sci, 2000).

I will give the first seminar, this Friday (1/29). The following seminars will consist of presentations by students of key papers addressing a variety of Himalayan topics, followed by an open discussion. Students enrolled to get credited for their participation in GE277 are required to pick one of the papers listed below and prepare a 10 minute presentation. Other seminar participants are most welcome to give a presentation if they wish.  Each presentation should be focused on the topic of the seminar, rather than being a full account of the paper.

Students can drop by my office if they need clarification ahead of their presentation (check with Heather for schedule).

Friday 1/30 :  Introduction to Himalayan tectonics and seismicity by Jean-Philippe Avouac.

Friday  2/13:  I will finish the introduction tour. Aron Meltzner will discuss the seismicity budget based on Seeber and Armbruster [1981] and Biham and Ambraseys [2004]. We will discuss the proportion of deformation that is taken up by recurring large earthquakes, and the faults capable of producing recurring large earthquakes.

Friday 2/20:  Presentation of Bilham et al. [1997] by Sarah Minson. Presentation of Cattin and Avouac [2000] by Carl Tape.  We will discuss some aspects of the mechanics of the seismic cycle: what controls the geometry of the Locked Fault Zone? Can we relate interseismic deformation (as measured from GPS) to co-seismic deformation? To what extent the various phases of the seismic cycle contribute to mountain building in the long term?

Friday 2/27:  Presentation of  Lave and Avouac [2001] by Kathy Brantley.  Presentation of the MCT zone by Elisabeth Nadin, based on Pecher [1989] and Hubbard [1996]. Evidence for recent reactivation of the MCT by Nick Van Buer, based on Wobus [2003].   Overview of the structural evolution of the Himalaya by Nadine McQuarrie (based on papers by Schelling, DeCelles, Robinson, and others).  We will review the geological evidence for an inverted metamorphic gradient across the Himalaya and introduce various possible mechanisms, and discuss the various arguments that can be proposed to explain the location of the steep front of the high range 100 km north of the MFT (recent activity of the MCT). We might also discuss whether the kinematics of deformation and metamorphic organization of the range is compatible with the prediction of 'critical wedge' models.

Friday 3/5:  Adam Borgonzone will discuss the timing of the collision and the kinematics of the Indian plate since the collision.  Kyle Bradley will next discuss the effect of the Tibet uplift on climate change. Richard Wildman will discuss chemical erosion in the Himalaya and its effect on CO2 cycle based on Galy and France Lanord [1998]. 

Thursday 3/11:  Joint seminar with An Yin's ESS 298 class at UCLA.  This seminar will include a free pizza dinner. Transportation will be arranged from Caltech. We will be leaving Caltech around 4:45 pm, and the seminar is from 6-9 pm.  We will have a presentation by Ravi Kanda of coupling between erosion, thermal structure and deformation based on Royden [1993] and Avouac and Burov [1996].  Presentation of the MCT zone by Elisabeth Nadin, base on Pecher [1989] and Hubbard [1996]. Students from UCLA will present DeCelles et al, [1998a, 1998b] and White, et al, [2002].

Papers for 3/11:

DeCelles, P.G., Gehrels, G.E., Quade, J., Ojha, T.P., 1998a. Eocene Early Miocene foreland basin development and the history of Himalayan thrusting, western and central Nepal. Tectonics 17, 741-765. 

DeCelles, P.G., Gehrels, G.E., Quade, J., Ojha, T.P., Kapp, P.A., and Upreti, B.N., and 1998b. Neogene foreland basin deposits, erosional unroofing, and the kinematic history of the Himalayan fold-thrust belt, western Nepal. Geological Society of America Bulletin 110, 2-21.

White, N.M., Pringle, M., Garzanti, E., Bickle, M., Najman, Y., Chapman, H., Friend, P., 2002, Constraints on the exhumation and erosion of the High Himalayan Slab, NW India, from foreland basin deposits, Earth and Planetary Science Letters, 195, 29-44.)

Friday 3/12:  Marin Clark will give an overview of the various mechanisms that could have led to some coupling between climate and tectonics, and discuss the relation between Asian monsoon and the India Asia collision (based in particular on Molnar et al, [1993], Raymo et al, [1989], An et al, [2001], Ramstein et al., [1999]).  Gweltaz Maheo will discuss magmatism in the Himalaya and its relation to the tectonic evolution of the range. We might also come back to any subject that you would like to address during this last seminar.

**Please see REFERENCE section below for available PDF files**

1. Structure of the range.

- {Schelling, 1991}  (discussion of a balanced cross section across the whole range)

- {Hauck, 1998}  (putting together structural and geophysical observations across the Himalaya)

- {Lemmonier, 1999} (discussion of the electrical conductivity structure obtained from a Magnetotelluric experiment)

- {Lavé, 2001} (discussion of fluvial incision across the whole range and the link with the geometry of thrust faults at depth)

2. The Main Central Thrust fault and regional metamorphism. What is the MCT?

- {Le Fort, 1996}* (structure of the range and summary of metamorphic history)

- {Pêcher, 1989} (geological expression of MCT)

- {Bollinger, submitted to GRL} (geological expression, geochronology)

3. Interpretation of the ‘inverse’ thermal gradient.

- {Le Fort, 1996}* (presentation of the ‘ironing model’)

-{England, 1993} (simple model of heat advection and diffusion

- {Royden, 1993}  (effect of erosion on thermal structure)

- {Hubbard, 1996} (post metamorphic shearing)

- {Bollinger, submitted to GRL}  (reconciling observation with thermokinematic modeling)

4.  What controls the large scale morphology of the Himalaya, in particular the fact that the steep front of the high range lies 100km north of the MFT?

- {Seeber, 1983}* (discussion based on geomorphology and seismicity)

- {Bilham, 1997;Bilham, 1997}* (discussion based on geodetic measurements)

- {Lavé, 2001} (discussion based on rates of fluvial incision)

- {Wobus, 2003} (discussion based on geochronology and geomorphology)

- {Harrison, 1997} (discussion based on geochronology)

5. Himalayan seismicity. Do large Himalayan earthquakes necessarily break the MHT-MFT? What mechanism triggesr background seismicity? Is deformation along the MHT nececesarily seismic?..

- {Seeber, 1981}* (activation of blind decollements below the Gangetic plain)

- {Cattin, 2000} (a model of the seismic cycle)

- {Bilham, in press},  Current Science, in press* (comparison of seismic moment released by large historical EQ).

6. Timing of the collision

- {Rowley, 1996}(summary of stratigraphic evidence)

-{DeSigoyer, 2000}., (geochrono)

- {Patriat, 1984} (plate tectonics reconstruction, paleomag)

7. Forces driving the collision, the transition from subduction to collision, effect of topography on the force balance

- {Coblentz, 1998} (modeling the stress distribution in the Australia-India plates)

- {Ranalli, 2001} (evolution of buoyancy forces during subduction of continental lithosphere)

- {Molnar, 1988}(discussion of the evolution of potential energy during mountain growth and boundary forces)

8- Coupling between Climate and Mountain Building

- {Ruddiman, 1991}, Scientific American

- {Molnar, 1993}, (reviews of Geophysics, 1993)

- {Pinter, 1997}* (How erosion builds Mountains)

- {Harris, 1995} , (link between Himalayan erosion and seawater 87Sr/86Sr)

- {Avouac, 1996} (numerical investigation of coupling between lithospheric deformation and erosion)

- {Ramstein, 1997}., (discussion of the mechanisme that caused intensification of the monsoon during the Cenozoic)

- {Kerrick, 1999} (Effect of Himalayan  metamorphisme and weathering on CO2 cycle)

 There is a file with printed versions of all these papers and some additional ones available with Heather.

References

Avouac, J.P., and E.B. Burov, Erosion as a driving mechanism of intracontinental mountain growth, Journal of Geophysical Research-Solid Earth, 101 (B8), 17747-17769, 1996.

Bilham, R., and N. Ambraseys, Apparent Himalayan slip deficit from the summation of seismic moments for Himalayan earthquakes, 1500-2000, Current Science, in press.

Bilham, R., K. Larson, J. Freymueller, F. Jouanne, P. LeFort, P. Leturmy, J.L. Mugnier, J.F. Gamond, J.P. Glot, J. Martinod, N.L. Chaudury, G.R. Chitrakar, U.P. Gautam, B.P. Koirala, M.R. Pandey, R. Ranabhat, S.N. Sapkota, P.L. Shrestha, M.C. Thakuri, U.R. Timilsina, D.R. Tiwari, G. Vidal, C. Vigny, A. Galy, and B. deVoogd, GPS measurements of present-day convergence across the Nepal Himalaya, Nature, 386 (6620), 61-64, 1997.

Bollinger, L., P. Henry, and J.P. Avouac, Mountain building in the Himalaya: Thermal and kinematic model from 20 Ma to present, Geoph. Res. Lett., submitted to GRL.

Cattin, R., and J.-P. Avouac, Modeling of mountain building and the seismic cycle in the Himalaya of Nepal, J. Geophys. Res., 105, 13389--13407, 2000.

Coblentz, D.D., S. Zhou, R.R. Hillis, R.M. Richardson, and M. Sandiford, Topography, boundary forces, and the Indo-Australian intraplate stress field, J. Geophys. Res., 103, 919--931, 1998.

DeSigoyer, J., V. Chavagnac, J. Blichert-Toft, I.M. Villa, B. Luais, S. Guillot, M. Cosca, and G. Mascle, Dating the Indian continental subduction and collisional thickening in the northwest Hiamalaya: multichronology of the Tso Morari eclogites, Geology, 28 (6), 487--490, 2000.

England, P., and P. Molnar, The interpretation of inverted metamorphic isograds using simple physical calculations, Tectonics, 12, 145--157, 1993.

Harris, N., Significance of weathering of Himalayan metasedimentary rocks and leucogranites for the Sr isotope evolution of seawater during the early Miocene, Geology, 23, 795--798, 1995.

Harrison, T.M., F.J. Ryerson, P. Le Fort, A. Yin, O.M. Lovera, and E.J. Catlos, A late Miocene-Pliocene origin for the central himalayan inverted metamorphism, E. P. S. L., 146, E1--E8, 1997.

Hauck, M.L., K.D. Nelson, L.D. Brown, W. Zhao, and A.R. Ross, Crustal structure of the himalayan orogen at 90deg east longitude from project INDEPTH deep reflection profiles, Tectonics, 17, 481--500, 1998.

Hubbard, M.S., Ductile shear as a cause of inverted metamorphism: Example from the Nepal Himalaya, The Journal of Geology, 104, 493-499, 1996.

Kerrick, D.M., and K. Caldeira, Was the Himalayan orogen a climatically significant coupled source and sink for amostpheric CO2 during the Cenozoic?, Earth Planet. Sci. Lett., 173, 195--203, 1999.

Lavé, J., and J.P. Avouac, Fluvial incision and tectonic uplift across the Himalayas of Central Nepal, Journal of Geophysical Research, 106, 26,561--26,592, 2001.

Le Fort, P., The Himalayan evolution, in The tectonics of Asia, edited by A. Yin, and Harrison, T.M., pp. 95-109, Cambridge University Press, New York, 1996.

Lemmonier, C., G. Marquis, F. Perrier, J.P. Avouac, G. Chitrakar, B. Kafle, S. Sapkota, U. Gautam, and D. Tiwari, Electrical structure of the Himlaya of central Nepal: high conductivity around the mid-crustal ramp along the MHT, Geophys. Res. Lett., 26, 3261-3264, 1999.

Molnar, P., P. England, and J. Martinod, Mantle Dynamics, Uplift of the Tibetan Plateau, and the Indian Monsoon, Reviews of Geophysics, 31 (4), 357-396, 1993.

Molnar, P., and H. Lyon-Caen, Some simple physical aspects of the support, structure, and evolution of mountain belts, in: Processes in continental lithospheric deformation, Geol. Soc. Am. Spec., Rap., 218, 179-207, 1988.

Patriat, P., and J. Achache, India-Eurasia collision chronology has implications for crustal shortening and driving mechanism of plates, Nature, 311, 615-621, 1984.

Pêcher, A., The metamorphism in Central Himalaya, Journal of Metamorphic Geology, 7, 31-41, 1989.

Pinter, N., and M.T. Brandon, How erosion builds mountains, Scientific American, 276 (4), 74-79, 1997.

Ramstein, G., F. Fluteau, J. Besse, and S. Joussaume, Effect of orogeny, plate motion and land sea distribution on Eurasian climate change over the past 30 million years, Nature, 386 (6627), 788-795, 1997.

Ranalli, G., R. Pellegrini, and S. D'Offizi, Time dependence of negative buoyancy and the subduction of continental lithosphere (vol 30, pg 539, 2000), Journal of Geodynamics, 31 (4), 445-445, 2001.

Rowley, D.B., Age of initiation of collision between India and Asia: a review of stratigraphic data, E.P.S.L., 145, 1--13, 1996.

Royden, L.H., The steady state thermal structure of eroding orogenic belts and accretionary prisms, Journal of Geophysical Research, 98, 4487--4507, 1993.

Ruddiman, W.F., and J.E. Kutzbach, Plateau Uplift and Climatic-Change, Scientific American, 264 (3), 66-&, 1991.

Schelling, D., and K. Arita, Thrust Tectonics, Crustal Shortening, and the Structure of the Far-Eastern Nepal Himalaya, Tectonics, 10 (5), 851-862, 1991.

Seeber, L., and J.G. Armbruster, Great detachment earthquakes along the Himalayan arc and long-term forecasting, in Earthquake prediction-An international review, edited by D.E. Simpson, and Richards, P.G., pp. 259-277, Maurice Ewing Series 4, The American Geophysical Union, 1981.

Seeber, L., and V. Gornitz, River profiles along the Himalayan arc as indicators of active tectonics, Tectonophysics, 92, 335--367, 1983.

Wobus, C.W., K.V. Hodges, and K.X. Whipple, Has focused denudation sustained active thrusting at the Himalayan topographic front?, Geology, 31 (10), 861-864, 20

Yin, A. and T.M. Harrison, Geologic evolution of the Himalayan-Tibetan orogen, Annual Review of Earth and Planetary Sciences, 28, 211-280, 2000.

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