Download GEOL107 – GENERAL GEOLOGY – LABORATORY OUTLINE

GEOL107 – GENERAL GEOLOGY – LABORATORY OUTLINE
PLATE TECTONICS LAB
Material covered in Chapter 2 in Ludman & Marshak Laboratory Manual for
Introductory Geology
I. Definition of lithosphere and asthenosphere and relative and absolute plate motion
II. Definition of divergent, convergent, and transform plate boundaries
Work Exercise 2.1 in the Lab Manual
III. Divergent plate boundaries, sea-floor spreading and mid-ocean ridges
Work Exercise 2.4 (a)-(c) in the Lab Manual
Work Exercise 2.5 in the Lab Manual
Work Exercise 2.6 (a)-(c) in the Lab Manual
Work Exercise 2.7 (b)-(d) in the Lab Manual
IV. Convergent plate boundaries, subduction zones and volcanoes
Work Exercise 2.11 in the Lab Manual
V. Transform plate boundaries and the San Andreas Fault
Work Exercise 2.12 in the Lab Manual
VI. Hot Spots and Absolute Plate Motion
Work Exercise 2.8 in the Lab Manual
Work Exercise 2.9 in the Lab Manual
By the completion of this lab you should be able to:
1) Given magnetic anomalies, calculate the rate of spreading between two plates
2) Understand the age-versus-depth relationship for oceanic lithosphere
3) Be able to make a sketch of a subduction zone showing the subducted lithosphere,
and associated volcanic arc, trench, and earthquakes
4) Given the ages of a volcanic island chain, determine the direction and rate of
absolute plate motion
Definition of lithosphere - zone of strength at the outer surface of the earth; near its
surface, the lithosphere will respond to stress by brittle failure (it breaks);
approximately 100 km thick beneath the continents; grows in thickness from nearly 0
km at a mid-ocean to 100 km thick beneath the oceans; in the oceans the lithosphere
thickens with increasing age
Definition of asthenosphere - zone of low strength lying directly beneath the lithosphere
and extending to depths of 700km beneath the earth's surface; the asthenosphere will
respond to stress by plastic failure (it will flow); the asthenosphere contains
approximately 1-2% liquid melt
The outer surface of the earth can be broken up into a series of lithospheric plates.
These plates are in motion in two ways - 1) relative to each other and 2) with
respect to the deep interior of the earth
Definition of relative plate motion - the direction and rate of motion between lithospheric
plates
Definition of absolute plate motion - the direction and rate of motion between a
lithospheric plate and the deep interior of the earth
Definition of a divergent plate boundary - boundary between two lithospheric plates that
are moving away from one another in relative motion
Definition of a convergent plate boundary - boundary between two lithospheric plates
that are moving toward one another in relative motion
oceanic-continental convergent plate boundary - convergent boundary where
oceanic lithospheric is moving towards continental lithosphere
oceanic-oceanic convergent plate boundary - convergent boundary where oceanic
lithosphere is moving towards oceanic lithosphere
continental-continental convergent plate boundary - convergent boundary where
continental lithosphere is moving towards continental lithosphere
Definition of a transform plate boundary - boundary between two lithospheric plates that
are sliding past one another
Definition of a hot spot - source of heat and magma that lies deep within the earth's
interior, perhaps as deep as the base of the earth's mantle
The direction and rate of movement of volcanoes produced by hot spots can be used to
determine the absolute motion of a lithospheric plate.