Structural Geology

TECTONICS

The Mechanics of the Earth

Revealed by the Geology

-

Frédéric Flerit

Our aim

we study the DEFORMATION of the Earth

before After

and we study the E V O L U T I O N

of the deformation

before After how long ? rates

Our Objects

1) The Earth

Gravity + Rotation => Ellipsoid

2) The Mantle

Convection => Plate Motion

3) The Lithosphere

Intra-plate deformation => Orogenic belts

India

Eurasia

Events !

4) The Crust

Deformation produced by similar events…

4) The Rocks

RocksRocks 1 m1 m

Crust Crust 10 km10 km

Lithosphere Lithosphere 100 km100 km

MantleMantle 1000 km 1000 km

EarthEarth 40.000 km40.000 km

The Deformation Processes several objects and scales

After one Earthquake…

After thousand earthquakes…

Holocene scarp, west side of Mankhan Valley

The Deformation Processes at several

Time and Space scales

The geology for reference

The geological-time scale

Earthquakes 1 s

Two successive Earthquakes (Inter-seismic) 100-1kyr

Landscape evolution 10 kyr

Geology 1-1k Ma

And Several TIME scales

Method and Tools

1 ) We Observe the structures(geology geomorphology)

Satellites

Airplanes

Field : morphology

Field : rocks

Mosaic of Landsat

1) And structures at depth(geophysics)

Tomography Seimic profiles

1) We observe active deformation

GPSGeodesy SismologyRadar

2) We MapTopography

Geology

Mathematics : Geometry

Structures

2) And we Measure

Holocene offsets of river beds

3) We use analogs and simple physics

ElasticElastic

PlasticPlastic

ViscousViscous

- 10k yrs

(3) To Explain

the observations

Physics :

Block motion

Present

(3)

At several scales

Carte tectonique Himalaya-Tibet

Modele pour la deformation du Tibet

1

2

Method

1) Observe < Earth Sciences

2) Measure < Mathematics

3) Explain < Physics

The Math. recquired to attend the Course (I II) :

- Geometry 3D (dot and scalar product)

- Matrixes, Tensors, vectors

- Projections,

- Motion and combinaison of motion (translation rotation)

- Integration, derivation

- Trigonometry

Published papers on the Ailao Shan - Red River Fault zone and SE Asia:Harrison, T. M., Chen Wenji, P. H. Leloup, F. J. Ryerson, and P. Tapponnier, An early Miocene transition in deformation regime within the Red River fault zone, Yunnan, and its significance for Indo-Asian tectonics, J. Geophys. Res., 97, 7159-7182, 1992.Harrison T.M., P.H. Leloup, F.J. Ryerson, P. Tapponnier, R. Lacassin, and Chen Wenji, Diachronous initiation of Transtension along the Ailao Shan-Red River Shear zone, Yunnan and Vietnam, in The Tectonics of Asia, edited by An Yin, and T.M. Harrison, World and regional geology series, 208-226, Cambridge University Press, 1996.Lacassin, R., P. H. Leloup, and P. Tapponnier, Bounds on strain in large Tertiary shear zones of SE Asia from boudinage restoration, J. Struct. Geol., 15, 677-692, 1993.Lacassin, R., U. Schärer, P. H. Leloup, N. Arnaud, P. Tapponnier, Liu Xiaohan, and Zhang Lian-Sheng, Tertiary deformation and metamorphism SE of Tibet: The folded Tiger-leap décollement of NW Yunnan, China, Tectonics, 15, 605-622, 1996.Lacassin R., H. Maluski, P.H. Leloup, P. Tapponnier, C. Hinthong, K. Siribhakdi, S. Chuaviroj, and A. Charoenravat, Tertiary diachronic extrusion and deformation of western Indochina: structural and 40Ar/39Ar evidence from NW Thailand, J. Geophys. Res., 102, 10013-10037, 1997.Lacassin, R., A. Replumaz, and P. H. Leloup, Hairpin river loop and slip sense inversion on SE-Asian strike-slip faults, Geology, 26, 703-706, 1998.Leloup, P. H., Cinématique des déformations "himalayennes" dans la zone de cisaillement crustale de l'Ailao Shan - Fleuve Rouge, Doctorat thesis , 148 pp., Université Paris 6, Paris, February 1991.Leloup, P. H., T. M. Harrison, F. J. Ryerson, Chen Wenji, L. Qi, P. Tapponnier, and R. Lacassin, Structural, petrological and thermal evolution of a Tertiary ductile strike-slip shear zone, Diancang Shan, Yunnan, J. Geophys. Res., 98, 6715-6743, 1993.Leloup, P. H., and J. R. Kienast, High Temperature deformation in a major Tertiary ductile continental strike-slip fault: evidence of shear heating at lithospheric scale?, Earth Planet. Sci. Lett., 118, 213-234, 1993.Leloup, P. H., R. Lacassin, P. Tapponnier, Zhong Dalai, Liu Xiaohan, Zhang Lianshang, Ji Shaocheng, and Phan Trong Trinh, The Ailao Shan-Red River shear zone (Yunnan, China), Tertiary transform boundary of Indochina, Tectonophysics, 251, 3-84, 1995.Leloup, P.H., Y. Ricard, J. Battaglia, and R. Lacassin, Shear heating in continental strike-slip shear zones: numerical modeling and case studies, Geophys. J. Int., 136, 19-40, 1999.Leloup P.H., Arnaud N., Lacassin R., Kienast J.R., Harrison T.M., Phan Trong Trinh, Replumaz A., Tapponnier P, New constraints on the structure, thermochronology and timing of the Ailao Shan - Red River shear zone, SE Asia, J. Geophys. Res, 106, 6657-6671, 2001.Replumaz, A., Lacassin, R., Tapponnier, P., Leloup, P.H., Large river offests and Plio-Quaternary dextral slip-rate on the Red-River fault (Yunnan, China), J. Geophys. Res., 106, 819-836, 2001.Roger F., P.H. Leloup, M. Jolivet, R. Lacassin, Phan Trong Trinh, M. Brunel, D. Seward, Unravelling a long and complex thermal history by multi-system geochronology: example of the SongChay metamorphic dome, North Vietnam., Tectonophysics, 321, 449-466, 2000.Schärer, U., P. Tapponnier, R. Lacassin, P. H. Leloup, Zhong Dalai, and Ji Shaocheng, Intraplate tectonics in Asia: a precise age for large-scale Miocene movement along the Ailao Shan-Red River shear zone, China, Earth Planet. Sci. Lett., 97, 65-77, 1990.Schärer, U., Zhang Lian-Sheng, and P. Tapponnier, Duration of strike-slip movements in large shear zones: The REd River belt, China, Earth Planet. Sci. Lett., 126, 379-397, 1994.Tapponnier, P., R. Lacassin, P. H. Leloup, U. Schärer, Zhong Dalai, Liu Xiaohan, Ji Shaocheng, Zhang Lianshang, and Zhong Jiayou, The Ailao Shan/red River metamorphic belt: Tertiary left-lateral shear between Indochina and South China, Nature, 343, 431-437, 1990.Zhang L., and U. Schärer, Inherited Pb components in magmatic titanite and their consequence for the interpretation of U-Pb ages, Earth Planet. Sci. Lett., 138, 57-65, 1996.

Several sources to retrieve the Earthquake information

TECTONICS

Bathymetry-Topography

Geomorphology (river bed, moraines…)

Seismic (reflexion, refraction)

Observe the Surfaces of the Earth

Measure its Evolution

Geodesy (GPS, Leveling, triangulation…)

Seismology (tomography, focal mechanism, magnitude and locations)

Geology