Tectonics and The Provinces of the Oceans. I. Theory of Plate Tectonics. A. The theory states that the earth’s crust is broken into 7 rigid pieces called PLATES . B. The plates are moving in different directions and at different speeds.
A. The theory states that the earth’s crust is broken into 7 rigid pieces called PLATES.
B. The plates are moving in different directions and at different speeds.
C. The movement of the plates results in a geological FAULT
(Sea-floor spreading resulted in the formation of theMid-Oceanic Ridge)
A. Radiometric Dating
1) In the basaltic rocks magnetic patterns are retained (like a tape recording) on either side of the ridge.
2) These magnetic patterns can be dated to the time-scale of geomagnetic reversals, which occur at irregular intervals of every 300,000 to 500,000 years
1. The existence of the ever-changing
mid-oceanic ridge proves that
tectonic plates move.
2. When the sea-floor spreads
apart the magma from
beneath rises up through the
gap in the crust.
3. The result is the formation
of an underwater volcanic mountain.
A. Sea-floor divided into
1. Deep-Sea Floor
2. Continental Margins
B. Continental Margins -
1. Boundary between continental and oceanic crusts.
1. Shelf – slightly slopping surface
3. Shelf break – edge of the shelf separating the shelf from the slope.
4. Continental slope – steep descent from continent to the ocean bottom.
5. Continental rise – transitional region that gently slopes onto the ocean floor.
inactive margin having flat coastal plains, wide shelves, and gradual continental slopes.