Major tectonic systems Dispersion of the Gondwana continents

Major tectonic systems § Dispersion of the Gondwana continents § Closing of Tethys Ocean § Pacific System: rimmed by subduction zones • East Pacific Rise moving towards the Americas • Western Pacific island arcs

Major tectonic systems operating during the past 200 My I. Fragmentation of the Gondwana super-continent § Creation of new Oceans • Atlantic • Indian • circum-Antarctic • formation of passive margins § Closing of Tethys Ocean: • complex Mediterranean – Middle East interactions • major continental collisions in central Asia • Australian-SE Asian collisions

# 18 42. 7 Ma Middle Eocene Drake Passage Indian Pacific connection

#13 35. 5 Ma Early Oligocene Drake Passage Indian Pacific connection

#6, 20. 5 Ma Early Miocene Drake Passage Indian Pacific connection

Drake Passage Indian Pacific connection

Formation of Circum-Antarctic Current >> isolation of Antarctica >> formation of ice sheet circum-Antarctic Current

Formation of North Atlantic Deep water (thermo-haline convection system)

Formation of continental passive margins continental shelf

continental passive margins Sedimentation on subsiding continental shelf thinned continental crust oceanic crust

Major tectonic systems operating during the past 200 My I. Fragmentation of the Gondwana super-continent § Creation of new Oceans • Atlantic • Indian • circum-Antarctic • formation of passive margins § Closing of Tethys Ocean: • complex Mediterranean – Middle East interactions • major continental collisions in central Asia • Australian-SE Asian collisions

Complex intra-continental Mediterranean-central Asian “plate boundary” Earthquake depth 0 -33 km 33 -70 70 -300 300 -700 Indonesian (Sunda. Banda) island arc

Topography for previous slide: note complex topography of Mediterraneancentral Asian “plate boundary”.

India moving northwards

Himalayan evolution

Indention of India into Asia The named dashed and dotted lines represent boundaries between terranes successively accreted to Asia. The accretion increases in age to the north: Indus Tsangbo, 40 Ma Banggong, 160 Ma Jinsha, 200 Ma Kunlun, 255 Ma Tienshan, late Paleozoic The indentation has moved these sutures northwards The dotted areas show the regions of shearing that accomodated the northward indentation of India

Tibetan plateau models

Region of the. Tibetan Plateau Ignore white rectangle. The blue line shows the approximate location of the section shown in the third slide after this one.

A recently published geological cross section See the section line (blue line) on the map shown in the third preceding slide. From Yin, A. and T. M. Harrison, 2000, Geologic Evolution of the Himalayan-Tibetan Orogen, Ann. Rev. Earth Planet. Sci. , v. 28, 211 -280.

Central Asian active tectonics

Major tectonic systems operating during the past 200 My II. Pacific System § East Pacific Rise (EPR) moving towards the Americas and away from Asia § Hot spot tracks §Rimmed by subduction zones • Western Pacific • Subducting old oceanic lithosphere • Formation of back-arc basins and island arcs • Eastern Pacific • Subducting young oceanic lithosphere • Andean type mountain building • Collision and accretion of exotic terranes • Collision of EPR with North America

East c Rise Pacifi

Major tectonic systems operating during the past 200 My II. Pacific System § East Pacific Rise (EPR) moving towards the Americas and away from Asia § Hot spot tracks §Rimmed by subduction zones • Western Pacific • Subducting old oceanic lithosphere • Formation of back-arc basins and island arcs • Eastern Pacific • Subducting young oceanic lithosphere • Andean type mountain building • Collision and accretion of exotic terranes • Collision of EPR with North America

Northwestern Pacific Subduction zones: seismicity Ryukyu island arc Kurile. Kamchatka island arc Aleutian Island arc N. Honshu subduction zone Izu-Bonin. Marianas island arc Earthquake depth 0 -33 km 33 -70 70 -300 300 -700

Northwestern Pacific Subduction zones: bathymetry

New Britain Island arc Southwestern Pacific Subduction zones: seismicity Vanuatu island arc Tonga island arc Kermadec island arc New Zealand Earthquake depth 0 -33 km 33 -70 70 -300 300 -700

Southwestern Pacific Subduction zones: bathymetry

Major tectonic systems operating during the past 200 My II. Pacific System § East Pacific Rise (EPR) moving towards the Americas and away from Asia § Hot spot tracks §Rimmed by subduction zones • Western Pacific • Subducting old oceanic lithosphere • Formation of back-arc basins and island arcs • Eastern Pacific • Subducting young oceanic lithosphere • Andean type mountain building • Collision and accretion of exotic terranes • Collision of EPR with North America