Download reading and synthesizing

Patrice Rey
Room: 407
[email protected]
Tel: 12060
•Lecturers are guides, they open doors and show paths to knowledge...
…but it’s up to you to do the journey.
•Consider lectures and practical classes for what they really are:
introductions to knowledge.
•1 hour of lecture should be followed by 2 hours of work involving
reading and synthesizing information gathered from textbooks and
other resources. Use the web and make the library your second home!
•Become an independent learner.
•Do not work alone.
•There is no bad students, only bad learning habits.
•Most importantly: Get organized, work steadily, and have fun!
Lecture 1:
Lithosphere, asthenosphere, and Archimedes (287212 BC)
Aims: A brief reminder about
he earth and lithospheric plates
Structural geology deals with deformation of
earth materials: From minerals to tectonic plates
• ~15 plates travel at
the surface of the
earth @ a speed of a
few cm/y
• Plates travel at
various speed and in
various direction
...=>
• …seismicity and
deformation at plates
boundaries
Plate boundaries features
• Topography
Plate boundaries
features
•
Seismicity
Plate boundaries features
• Volcanism
Australian plate
Plate tectonics and things that happen @ plate boundaries
Divergent plate boundaries
Convergent plate boundaries
Transform fault, and strike slip fault boundaries
Transform fault, and strike slip fault boundaries
Earth’s structure
Continental lithosphere: Some physical characteristics
Temperature
Radiogenic upper crust
Radiogenic elements
U, Th, K
Continental lithosphere: Some physical characteristics
Density
Density lithosphere ?
(zc/zl)*rc+(zlm/zl)*rlm
Isostasy and surface
topography
Isostasy and surface topography
Isostasy: A surface exists
at a certain depth where
the pressure, from the
column of earth material
above, is the same across
and underneath the
surface.
Continental lithosphere: Some physical characteristics
Strength
•Strong upper crust
•Weak upper crust
•Strong upper mantle
•Weak lower lithospheric mantle
•Very weak asthenosphere
Lecture 1 at a glance
~15 plates move at the surface of the earth.
Plate boundaries: locus of seismicity +/- magmatic activities, and high topography.
Divergent, convergent, and transform plate boundaries.
Lithospheric plates: oceanic lithosphere only, or both oceanic and continental
lithosphere, they float on the asthenosphere.
•Thickness
Continental lithosphere: 180 +/- 100 km thick; Oceanic lithosphere: 0-100 km
Continental crust: 35+/-10 km;
Oceanic crust: 5-7 km
•Temperature
Temperature at continental Moho: 500+/-150ºC
Temperature at base of lithosphere: 1300 +/-100ºC
•Density
Density continental crust: 2800 +/-100 kg.m-3
Density lithospheric mantle: 3350 +/-100 kg.m-3
Density asthenosphere: 3300 +/-100 kg.m-3
•Strength of continental lithosphere
Strong upper crust, weak lower crust, strong upper mantle, weak lower lithospheric mantle,
very weak asthenosphere.